RB25Det Nissan Terrano

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Paulballz
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Re: RB25Det Nissan Terrano

Postby Paulballz » Tue Oct 30, 2012 11:20 am

DEATH_INC wrote:
Paulballz wrote:Ok have tryed that before will do again though run straight to batt earth

Sorry, I may have to take that back...does the megasquirt have 1 or 2 earth wires? Most ecu's have a main earth and a sensor earth.


Just one earth... This is where i had so much drama doing wiring as the megasquirt diagram i got was for a car that already had loom wired up i.e sensors already grounds ect...i did not have any of that so made loom from scratch...That spot on the engine orignally had 6 ground wires coming from it for original ecu. (3x per bolt)

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Tue Oct 30, 2012 11:24 am

Paulballz wrote:
DEATH_INC wrote:
Paulballz wrote:Ok have tryed that before will do again though run straight to batt earth

Sorry, I may have to take that back...does the megasquirt have 1 or 2 earth wires? Most ecu's have a main earth and a sensor earth.


Just one earth... This is where i had so much drama doing wiring as the megasquirt diagram i got was for a car that already had loom wired up i.e sensors already grounds ect...i did not have any of that so made loom from scratch...That spot on the engine orignally had 6 ground wires coming from it for original ecu. (3x per bolt)

Woops edited too late...is yours a V3?
Have a look at this:
http://www.diyautotune.com/images/mshar ... wiring.png

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Tue Oct 30, 2012 11:27 am

Paulballz wrote:
DEATH_INC wrote:
Paulballz wrote:Ok have tryed that before will do again though run straight to batt earth

Sorry, I may have to take that back...does the megasquirt have 1 or 2 earth wires? Most ecu's have a main earth and a sensor earth.


Just one earth...

I doubt that's right. It should have at least 2.

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Re: RB25Det Nissan Terrano

Postby Paulballz » Tue Oct 30, 2012 11:34 am

Nope mine is v2.2

This diagram here http://www.megamanual.com/v22manual/mwire.htm

Only difference is the drawing i have has
* Pin 24 = CAS
* Pin 25 = COIL 1/6
* Pin 27 = COIL 2/5
* PIN 29 = COIL 3/4
* PIN 31 = VCT
* PIN 32/33 goes to INJECTOR 1-2-3
* PIN 34/35 goes to INJECTOR 4-5-6
* PIN 30/31/37 control relay negative

Now it already came with 1 metre long loom, this loom had all the wires labeled and the ecu plug already done. Even though the diagram shows all those wires it must be done inside the ecu as mine only has 1 BLACK wire label GROUND. Rest are White wires (sensors ect) and couple of red wires (12v)
Last edited by Paulballz on Tue Oct 30, 2012 12:26 pm, edited 1 time in total.

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Tue Oct 30, 2012 11:47 am

Paulballz wrote:Nope mine is v2.2

This diagram here http://www.megamanual.com/v22manual/mwire.htm

Only difference is the drawing i have has
* Pin 24 = CAS
* Pin 25 = COIL 1/6
* Pin 27 = COIL 2/5
* PIN 29 = COIL 3/4
* PIN 31 = VCT
* PIN 32/33 goes to INJECTOR 1-2-3
* PIN 34/35 goes to INJECTOR 4-5-6
* PIN 20/31/37 control relay negative

Now it already came with 1 metre long loom, this loom had all the wires labeled and the ecu plug already done. Even though the diagram shows all those wires it must be done inside the ecu as mine only has 1 BLACK wire label GROUND. Rest are White wires (sensors ect) and couple of red wires (12v)


This note is at the bottom...

"Try to ground the MegaSquirt® EFI controller as close as possible to the battery ground, sensor grounds, and other grounds on the engine. Often grounding the MegaSquirt® EFI controller to the engine block (or intake manifold), with additional heavy gauge ground wires from the block to the frame and to the battery, is sufficient. If necessary, run additional wires to any other part of the vehicle that may be marginally grounded.

The MegaSquirt® EFI controller only draws a few hundred milliAmps (from its 12V supply). However it sinks much much more than this by grounding the injectors, coil (if used), Fast idle valve, etc. So the total amount sunk can easily be several Amps to a dozen or more, and ALL of that has to pass through the ground pins. So you will want a multiple ground wires at the DB37 (one pin is rated at a max of 5 Amps). Even if the MegaSquirt® EFI controller works, too small/few ground wires might create a bias in the ground level (where the voltage at the MegaSquirt® EFI controller's 'ground' is higher than at the battery), which can create all sort of mysterious problems. So grounds are very, very important, and should be made as good as you can make them. These means:

use the recommended number and size of wires,
ensure that any connectors are well crimped/soldered, and
attach all the grounds to a single, clean (no paint, oil/grease, etc) point on the engine."

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Tue Oct 30, 2012 12:15 pm

Paulballz wrote:* PIN 20/31/37 control relay negative

Why does 20 go there? (air temp sensor)
And what does 31 do on yours?

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Re: RB25Det Nissan Terrano

Postby Paulballz » Tue Oct 30, 2012 12:25 pm

DEATH_INC wrote:
Paulballz wrote:* PIN 20/31/37 control relay negative

Why does 20 go there? (air temp sensor)
And what does 31 do on yours?


Sorry that was a mistype it is 30/31/37.

Pin 31 controls the ACC valve (fast idle) This works a can hear it click in and engine idles higher while cold.

I am going to go through and redo alot of my earth wiring and get a new heavy duty earth lead from batt to engine / body

Although after reading that still do not understand why i only have 1 earth cable coming from ECU in the loom...This cable is not a heavy gauge cable either but i have soldered it to a 25amp cable to earth

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Tue Oct 30, 2012 1:30 pm

Paulballz wrote:Although after reading that still do not understand why i only have 1 earth cable coming from ECU in the loom...This cable is not a heavy gauge cable either but i have soldered it to a 25amp cable to earth

Mmmm, I'd try to take a peak at what is coming from the plug, see if they've joined 'em all together after they come out of the ecu....

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Re: RB25Det Nissan Terrano

Postby Gardengnome » Tue Oct 30, 2012 2:28 pm

Just a thought with regard to the over fueling.

The injectors, are they closing completely? mechanically or electrically?

Are they sticking open or due to having a residual signal getting sent keeping them open. Your common earth might be a cause. Most trouble shooting stories with regard to EFI I have read or heard of has resulted in seperating the earths or going staright to the battery being a solution. especially for the ECU earth.

If they are holding open the engine might be sucking through the injector allowing it to run with the pump off and then over fuelling when the pump is turned on, flooding and fouling the plugs.
The duty cycle will be what the megasquirt is asking the injectors to do. What they are actually doing could be different.

If the megasquirt has an injector test could you hand hold them and test into a bucket?
Or at least test with pressure to them for mechanical leaking.

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Re: RB25Det Nissan Terrano

Postby philux » Tue Oct 30, 2012 2:41 pm

Paulballz wrote:well my fluke brand multimeter test showed
Ohms symbol selected
Black on NEG battery terminal
Red On Bolthead of Earth clamps then tryed earth wires

Key on =13.2
Key off = 1.2
Battery (Positive) disconected = 0.2

Guessing is this not good at all?


Interesting that it changes depending on the key position, I would of thought earth would be the same the whole time, unless its running through something else via earth? Try run the ecu earth straight to the battery and a 6mm wire from the earth bolts to the battery, then there should be no variation from the key position.

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Re: RB25Det Nissan Terrano

Postby Paulballz » Tue Oct 30, 2012 8:24 pm

Ok will awnser questions then prove im not insane!

Yup Gardengnome i have cranked engine with injectors out fuel pump on and they shut and close completely. They Open on ground signal from MS so shouldnt be opened by stray currents?

Philux, agree hoping someone could tell me what this meant.

Todays progress, contacted mega tuner he told me to unplug everything but the coils/injectors/cas and TPS /Map vacuum... Everything else including alternator unpluged.

I have uploaded videos

First Video
This shows the fuel on/off and pressure to confirm..first video to show im not insane and truck runs with no pump pressure quite well.
http://www.youtube.com/watch?v=mUQtIm9k ... utu.beLast

video to prove im not insane
Revving, running WITHOUT fuel pump "ON"watching Megatune.
http://www.youtube.com/watch?v=soZNvsru ... e=youtu.be

Very frustrating as it runs really well before what i believe it starts to foul the plugs from fuel

Hopefully megatuner or someone can spot something wrong in by the gauges...please note the intercooler was unbolted so was pipe work...just throttle body into plenum.

Excuse the wire birdnest, i redone all the earths and they are running every where at moment until it all confirmed. (there is also a background pump sounding noise some might hear, ignore it the house water pump)

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Re: RB25Det Nissan Terrano

Postby philux » Tue Oct 30, 2012 8:54 pm

Current will always take the easiest path back, for example the current from the injector bank #1 might go back to the battery via another sensor that's earthed giving the ecu a false reading, the earth bolt on the manifold should be at the same potential as the ecu and battery, no matter what the key position is. I would bond/tie the ecu earth, manifold earths all to the battery (-) post. Well that's all I can suggest. As my work mate says, rule out the impossible and it only leaves the improbable :D

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Re: RB25Det Nissan Terrano

Postby Paulballz » Tue Oct 30, 2012 9:02 pm

philux wrote:Current will always take the easiest path back, for example the current from the injector bank #1 might go back to the battery via another sensor that's earthed giving the ecu a false reading, the earth bolt on the manifold should be at the same potential as the ecu and battery, no matter what the key position is. I would bond/tie the ecu earth, manifold earths all to the battery (-) post. Well that's all I can suggest. As my work mate says, rule out the impossible and it only leaves the improbable :D


Cool that is a idea, i will do that when get some time to work on her next... One thing i forgot to mention was that the rb25det coilpacks have a noise supressor that is little plug with two wires one goes to 12v (spliced on coil 12v feed) other ground..i did NOT connect this up in my new loom

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Re: RB25Det Nissan Terrano

Postby meatc » Tue Oct 30, 2012 9:14 pm

I still think there is an earth issue. ECUs switch the earth to fire things so need a nice earth for a ower source and will often have a sensor earth so the ecu knows what the sensors are seeing. If your ecu only has one earth that is shown in a diagram as having to go to the same place as the sensors i would be making sure your ECU is mounted witha ground, not sitting on the seat with no earth.

The fouling sounds to me like its opening the injectors for to long because the ecu cant see how much earth the injectors are getting (if that makes sense) Once the fuel is up to pressure there will be enough for it to run for a very short time with no fuel pump, but only really if the injectors are open wide for ages.

If its not the earths it could well be a mapping problem in the ecu.
Toy - Zuk chassis tub, hilux 4.88 axles and transfer, Nissan CA18DE motor and auto trans, sc12 supercharger, 32 10'5 simex, twin motor 8274 custom freespool. Well the parts are all there in various corners of the shed

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Re: RB25Det Nissan Terrano

Postby philux » Tue Oct 30, 2012 9:26 pm

meatc wrote:I still think there is an earth issue. ECUs switch the earth to fire things so need a nice earth for a ower source and will often have a sensor earth so the ecu knows what the sensors are seeing. If your ecu only has one earth that is shown in a diagram as having to go to the same place as the sensors i would be making sure your ECU is mounted witha ground, not sitting on the seat with no earth.

The fouling sounds to me like its opening the injectors for to long because the ecu cant see how much earth the injectors are getting (if that makes sense) Once the fuel is up to pressure there will be enough for it to run for a very short time with no fuel pump, but only really if the injectors are open wide for ages.

If its not the earths it could well be a mapping problem in the ecu.

Think we are on the same wavelength there, from what I understands oldyella's problem is he had false readings due to his alternator fault (a crook earth can give false readings too) which then caused the ecu to alter the injector timing without realising it had happen, maybe fix the earths, wipe the fuel map etc, and get that one reloaded onto it again.

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Re: RB25Det Nissan Terrano

Postby Dirtydog » Tue Oct 30, 2012 9:37 pm

Have you thought about redoing the loom?

it may be easier to start from the start than piddling around chasing ghosts, cause this is starting to sound like alot of problems and headaches.

then you can make sure everything is running as it should along the way.

My brother is putting a vh41 into a nissan 300zx, and hes doing the loom from scratch, because its a bit easier than trying to get a pre done loom to work. at least then you definitly know everything is in the right place.

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Wed Oct 31, 2012 8:35 am

I'm at an absolute loss as to how it can run that long and rev that much with 0 fuel pressure. It makes absolutely no sense at all.
All I can think is the injectors are wide open and it's sucking a shitload of fuel whenever the throttle is closed and it creates a heap of vacuum. But even that doesn't really sound right.
Did you put the ecu earth on a separate bolt/attachment point? This will stop the coils etc from earthing through the ecu. + run a big earth wire to the battery from where the sensor/coil etc earths bolt to the engine to the battery (I think someone else said this already). You need to do everything you can to stop the power feeding back through that ecu earth.

One other little experiment if you could....may not help but does it run if you remove the fuel line so there is no residual pressure in the system? Needless to say, don't turn the pump on :shock:
Where is your fuel gauge pressure taken from?
The noise suppressors from the coils shouldn't be the problem, they may make it run a bit odd at times, but won't do this I don't think....
I can't make out the gauges in your vid....old fella :lol:

meatc wrote:I still think there is an earth issue. ECUs switch the earth to fire things so need a nice earth for a ower source and will often have a sensor earth so the ecu knows what the sensors are seeing. If your ecu only has one earth that is shown in a diagram as having to go to the same place as the sensors i would be making sure your ECU is mounted with a ground, not sitting on the seat with no earth.

The fouling sounds to me like its opening the injectors for to long because the ecu cant see how much earth the injectors are getting (if that makes sense) Once the fuel is up to pressure there will be enough for it to run for a very short time with no fuel pump, but only really if the injectors are open wide for ages.

Good idea running an earth from the ecu body, though it should be done internally, another won't hurt.
As I said earlier, with my bikes system I didn't reconnect the sensor ground wire, and it just ran the injectors wide open and fulled everything with fuel quick smart. I'm thinking this has a similar problem....

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Wed Oct 31, 2012 8:47 am

(edit; Ive edited heaps from my first attempt... :lol: )
I think I've got something...if the gauges on the top right are pulse width and duty cycle?
They both go way to high. Off boost the injector (duty) cycle should only go to around 20% max. Yours is going full. So is the pulse width.

I thought it may be rpm inputs but I've removed that...the rpm looks good.
Map is good.

This proves what we all think about your injectors staying open far too long though.

Something is telling them to do it.
Fit those suppressors. Just in case.
Can you bring the injection/ignition tables/maps up and post a pic?
Check the tps readings, there isn't a lot else that can do it. (is there a check on the ecu for tps readings?)
And air temp...is it disabled?

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Re: RB25Det Nissan Terrano

Postby philux » Wed Oct 31, 2012 9:33 am

You can't see what the fuel mixture is doing can you? If the injectors are open and dumping to much fuel into in it would show that its super rich with the pump on. Switch pump off carrys on running cos it's got to much fuel and slowly leans out until the point of stalling?

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Wed Oct 31, 2012 10:10 am

philux wrote:You can't see what the fuel mixture is doing can you? If the injectors are open and dumping to much fuel into in it would show that its super rich with the pump on. Switch pump off carrys on running cos it's got to much fuel and slowly leans out until the point of stalling?

No, He doesn't have an oxy sensor hooked up. But yes, that's pretty much what it looks like it's doing, except the injectors are open for so long that it seems to be drawing enough fuel to keep going for a good period of time even after the pressure has gone...

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Re: RB25Det Nissan Terrano

Postby Paulballz » Wed Oct 31, 2012 12:34 pm

DEATH_INC wrote:I'm at an absolute loss as to how it can run that long and rev that much with 0 fuel pressure. It makes absolutely no sense at all.
All I can think is the injectors are wide open and it's sucking a shitload of fuel whenever the throttle is closed and it creates a heap of vacuum. But even that doesn't really sound right.
....


This is what i was trying to mention earlier..injector open so stroke drawing fuel in...it is the only way i can see how it can run without fuel pressure...
Yesterday that video was taken with the ECU connected directly to the Battery, Coil, connected to one bolt on earth block, other sensors connected to other bolt on earth block.

Heres the plan, the earth cable running from the battery goes to the block its self (not the plenium). it bolts to battery tray along way and has a smaller gauge (approx 6mm dia.) running back to gaurd also.
I will get a new heavy heavy duty cable to run straight from negative terminal and bolt it directly to lower plenium (not block).

I will also redo every earth from the sensors, coil pack...even though they have a much bigger ground cable running from them already (standard cable was approx 3mm, i have soldered that into a 25amp 4-5mm cable).

The injectors and coil packs are running the original loom still into original plug, then i have the otherside of plug (side that goes to ecu normally) spliced into new loom. Since the injectors only have 7wire plug in total, 1x 12v, 6x grounds that go directly to MS... The coil packs however have 8 wire plug (orignal loom also)... ECU side of plug i have 1x 12v (relay), 1x Ground (ground block on own bolt) and 6x signal which are paired.

I am going to attempt to overkill the earthing problem as much as possible, but am still leaning more towards the fact that i actually have a ECU tuning problem... I pulled the ecu plug apart and took a photo, this shows how the earths have been done, they have a peice of wire in the plug linking them but then leave through one relativly small gauge wire (main ecu ground)... Although i think it should be as the diagram said, the guy that done this does it for a living and is very knowledgeable so i am not going to question him...

Here is some pictures of some of the tables... ANOTHER PROBLEM I AM NOTICING IS THAT IF THE BATTERY IS EVEN THE SLIGHTEST DOWN (NOT 100%) CHARGE THEN THE PULSE DOESNT GO AND THE GAUGE GOES RED WHILE CRANKING OVER.

My working week has started today so please keep your thoughts coming and i will reply as i can, should get a little bit of time possibly thursday night to spend on truck an try ideas...

Also i cant stress enough that all the problems with the megasquirt are due to my lack of knowledge and the views i express here are my own through frustration due to my lack of knowledge no other reason...I do not want to give the megasquirt a bad rep or harm in anyway the people providing this products business...The guy i have dealt with has been amazing from emails at 11:30pm at night to 13emails in one day some days... So please do not let this forum at any stage put you off buying a megasquirt system if you are/have been wanting one.

p.s sorry about poor pic of plug this site makes me downgrade my pics, it has a black wire going side ways that is soldered to the groun pins then goes out in 1 earth wire as stated
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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Wed Oct 31, 2012 2:29 pm

Cool as, just wanted to see that the maps hadn't gone haywire, look pretty good to me.
Fwiw I don't agree with the local megasquirt guy, it may work with the earths like that, but I wouldn't do it that way. There is too much potential for electrical noise like that.

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Re: RB25Det Nissan Terrano

Postby oldyella » Wed Oct 31, 2012 5:19 pm

Hey,

Just regarding the differences in resistance you measured with the key in the on and off position.

A multi-meter calculates resistance by injecting small fixed amount of current through a circuit, and reads the voltage rise between the two probes. R = V/I

Therefore, measurements in Ohms on your multi-meter should only be performed with your key in the off position.

By attempting to measure the resistance with the key in the ON position, current is passing through the circuit due to the computer and sensors etc. This, added to the current which the multi-meter is injecting, causes a much higher voltage between the probes of the multi meter which is interpreted as a much higher resistance circuit.

To measure if your grounds are suitable, check the voltage rise between the computer earth on the engine and the -ve of the battery while the engine is running. I would expect it to be less than 0.5V.

Regarding the issue of it running without the fuel pump on, its certainly a bit strange, but does it really matter? Normally the fuel pump turns off and the ignition system turns off at the same time. Have you just discovered that injected engines can run while the residual fuel pressure runs down and maybe even suck fuel through, aided by the fact it is running so rich.

The fact that it is running so rich leads me to believe that you have a vacuum block. This was the case when I installed my MSII. Disconnect the vacuum line and blow through to ensure its clear. Could also be a vacuum leak in your manifold or turbo set up.

Cheers,

Pete
Last edited by oldyella on Wed Oct 31, 2012 5:56 pm, edited 1 time in total.

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Re: RB25Det Nissan Terrano

Postby oldyella » Wed Oct 31, 2012 5:54 pm

Also, I noticed you are not using an air temp sensor in your manifold.

How I understand it is, the MSII uses MAP and air temperature to calculate the density of the air. This calculation is performed within an algorithm in the MSII. The density of air is used in the requried fuel calculation

Since your rig is turbo, the air feeding the engine could be quite hot. Even if it could run with no air temp sensor, I think you would end up with a more accurate fuelling system if you incorporated one.

From the megasquirt manual:

Naturally aspirated engines using MegaSquirt® can use the same sensors for coolant and air temperature. These sensors are inexpensive (roughly $18 US) GM units readily available from any parts store (GM part number 12146312, may have been replaced by #15326386). They have a 3/4" hex.

Turbocharged or supercharged engines should use an open-element air temperature sensor for a faster response time

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Re: RB25Det Nissan Terrano

Postby DEATH_INC » Thu Nov 01, 2012 9:54 am

His map is reading what looks correct, and is certainly getting varying vacuum measurements...I doubt it's a blocked hose.
Air temp will be ok for what he's doing (no boost off load) and will probably be ok anyway, the Links didn't use air temp 'till the new series and ran fine without it. Map is still pretty accurate, hotter air is thinner, but map only reads density, doesn't matter if it's hot or cold, and it's still an air/fuel ratio so in theory at least, air temp really doesn't make that much difference. (or something, I know what I mean but sometimes it doesn't look right in writing :lol: )
But you're right, it wouldn't hurt to fit it at some point.

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Re: RB25Det Nissan Terrano

Postby oldyella » Thu Nov 01, 2012 5:04 pm

Yep, what I am thinking is:

The MSII has an input for Coolant temp

There is a separate input for Air temp - Pin 20.

If you are not using the air temp input, what has been done with it? Care needs to be taken to ensure noise is not introduced on this input. Otherwise it could potentially screw up the fuelling calculation in the MSII.

Also from the Megasquirt Manual:

MegaSquirt uses coolant and air temperature sensors to determine the warm-up characteristics of the engine and the density of the intake air. They are essential to proper functioning of a MegaSquirt® controller. Both sensors are Negative Temperature Coefficient (NTC) thermistors. This means that they are resistors whose resistance decreases as their temperature goes up

Also, regarding the vacuum, from what has been posted up so far, I haven't been able to see what level of vacuum is pulled at idle. It should be around 30kPa.

For the engine to stall like it is, the overfulling must be pretty major. Even though the MSII is saying the injector open time is 3.5ms which seem reasonable. A sanity check would be to measure the voltage across an injector while the engine is running. It should be almost zero.

An equivalent test is to measure the voltage between pin 28 and pins 32, 33, 34 & 35. They should all be very low.

If you measure a voltage of 12V, your injectors are continiously open.

Hope you get this sorted, truck is going to be a machine!

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Re: RB25Det Nissan Terrano

Postby Paulballz » Thu Nov 01, 2012 7:31 pm

Hey guys good to see the ideas are still flowing i greatly appreciate the help...and welcome to the nitemare oldyella

Will look into air temp sensor and try source one

News from tuner he said
a) Starts with: Hahahah in the 10 years he’s been doing this he has never seen that problem with fuel pump and he had a rb in his shop and pulled FP fuse and counted it lasted 5sec and died. (when i screw things i do it good)

b) Serious biz now: First of all its good the engine will run with fuel pump on real low psi (2psi) even though it runs like a dog as he said it gives us a base to work with, so to set highest psi possible without engine completely dying.

c) With pump on start to reduce the Pulse width first of all as it makes huge difference, Required Fuel 6.0 ms / 3.0 ms (guess he meant change it from 6 to 3)..also did anyone notice how in that video the pulse width was spiking the red on gauge when reving???is this normal?

d) Then with that all done start to reduce the entire VE table
Will do this hopefully on weekend and i still need to beef up and fit new earths as you guys recommended.

My concern with this is i do not know enough about tuning and i would be so gutted if i leaned the engine to much and caused engine damage (coming from 2 stroke point of view with my bikes i know how important correct jetting is...)

Extras: i will explain / repeat so don’t miss anything and try give you guys full picture of whats going on... In that video you heard the truck run then miss (plugs start failing) then die(all 6plugs fouled), it doesn’t start once this happens until i clean the plugs, they are thick black when i remove them hence it doesn’t start...Now even though in that video i did not have the intercooler / piping connected it was just the J pipe in atmosphere i have run the engine before with all the piping / hoses connected and it did exactly the same thing so is it safe to say its not a vacuum problem??...

My train of thought keeps leaning towards a ecu setting that is causing all this drama, but in saying that, this tune was on running rb25det...
Last edited by Paulballz on Thu Nov 01, 2012 8:42 pm, edited 1 time in total.

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Paulballz
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Re: RB25Det Nissan Terrano

Postby Paulballz » Thu Nov 01, 2012 7:38 pm

oldyella wrote:Hey,

Just regarding the differences in resistance you measured with the key in the on and off position.

A multi-meter calculates resistance by injecting small fixed amount of current through a circuit, and reads the voltage rise between the two probes. R = V/I

Therefore, measurements in Ohms on your multi-meter should only be performed with your key in the off position.

By attempting to measure the resistance with the key in the ON position, current is passing through the circuit due to the computer and sensors etc. This, added to the current which the multi-meter is injecting, causes a much higher voltage between the probes of the multi meter which is interpreted as a much higher resistance circuit.

To measure if your grounds are suitable, check the voltage rise between the computer earth on the engine and the -ve of the battery while the engine is running. I would expect it to be less than 0.5V.

This sounds great and i nod my head up and down :shock: but i think you have forgotten i have the electrical knowledge of a monkey ("click" light ON, "click" light OFF..hhmmmmm interesting) :D ...simple terms on doing this be awesome thanks Pete

The fact that it is running so rich leads me to believe that you have a vacuum block. This was the case when I installed my MSII. Disconnect the vacuum line and blow through to ensure its clear. Could also be a vacuum leak in your manifold or turbo set up.

Checked this and its all clear

Cheers,

Pete

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oldyella
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Re: RB25Det Nissan Terrano

Postby oldyella » Thu Nov 01, 2012 8:13 pm

I have a theory.

Its possible you have fried the injector switching circuit in the MSII so that the injectors are fully open all the time.

Measure the DC voltage between pin 28 and pins 32, 33, 34 & 35. They should all be very low.

If you have a test board for your MSII, plug it in an look at the "inj" LED's. The should flash breifly for each injector pulse

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Paulballz
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Re: RB25Det Nissan Terrano

Postby Paulballz » Thu Nov 01, 2012 8:38 pm

oldyella wrote:I have a theory.

Its possible you have fried the injector switching circuit in the MSII so that the injectors are fully open all the time.

Measure the DC voltage between pin 28 and pins 32, 33, 34 & 35. They should all be very low.

If you have a test board for your MSII, plug it in an look at the "inj" LED's. The should flash breifly for each injector pulse


hmm, when i have injectors out but plugged in and turn CAS by hand they all open and shut, all the injectors also "click" and megatune shows the pulse gauge go up and down so should be safe to say they are switching on and off...Nope no test board for MS...and will put the measuing DC in the list of jobs for saturday be interesting to see what it is

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