issues (pajero 3.5 dohc)

[steweym8]

Hi guys , the other week my engine wasn't playing the game fault code laid blame on coils, new coils have just been put in - no fault code now but engine idles pretty rough until stalling aprox 20 seconds later. Does any one have any thoughts?
Thanks

[nztimr33]

vacume leak i'd be picking

[churchill]

Check all the parts you've touched when putting the coils and make sure they're reassembled correctly.

Was the engine still running wirh the old coils?

[steweym8]

to my eye / ear it's the same , just no more fault code- I'm thinking coil going out at this time was just a coincidence. Tomorrow im going to pull of the plenum and do Leeds and have a look at the bushes for the 2ndry butterfly valves - have found a few links online that lay the blame on a vacume leak down to this also replacing all ralivent gaskets. Well it's open do any of you guys think it would be worth getting a mechanic to come round to check compression and fuelling pressure?

[evilknieval69]

I had an issue with my Pajero and it wasn't firing one of the coils ( which meant two cyls weren't firing). Ended up being the crank sensor trigger plate had a slight bend causing it to contact the edge of the sensor which caused interference in the crank sensor output. Mine didn't have a fault code, but it could be likely that it could throw a coil fault if something like this happened... Something to think about. Could be worth checking the igniter too

[steweym8]

I had an issue with my Pajero and it wasn't firing one of the coils ( which meant two cyls weren't firing). Ended up being the crank sensor trigger plate had a slight bend causing it to contact the edge of the sensor which caused interference in the crank sensor output. Mine didn't have a fault code, but it could be likely that it could throw a coil fault if something like this happened... Something to think about. Could be worth checking the igniter too

Il do leads, etc tomorrow just for piece of mind but that definitely could be an option- the pin that goes from sprocket on the end of the crank into the pully Broke of so i had it replaced along with the water pump, belt & tensioner bolt etc so these symptoms could in fact be related to that?

[Team Tonka]

The spark plugs are hard to swop in these so get left too long. I've seen plugs turn out to be the problem twice now with this motor.
A small amount of water down the plug holes is a pest too. A tear drop is enough. Runs fine when cold then misses when hot and the water has boiled.
Pull the wiring conn off each coil pack in turn and listen to the change in engine.
Transistor / ignite unit on top of plenum chamber do fail, usually dropping one coil. If the rev counter is only showing about half actual rpm then this is the fault.
Faulty exhaust valve - hold a rag over exhaust and see if it pulls the rag in.
Hydraulic cam belt tensioner failed - allows left hand cam timing to jump back and forth. Have to remove top cam belt cover to check this one.

That will keep you quiet for a while!

Oh, air leaks, with it idling spray suspected areas with brake cleaner or similar. Rise in engine speed indicates air leak. Never ever had a problem with air leaks on 6g74 though.

Cheers Andy.

[steweym8]

The spark plugs are hard to swop in these so get left too long. I've seen plugs turn out to be the problem twice now with this motor.
A small amount of water down the plug holes is a pest too. A tear drop is enough. Runs fine when cold then misses when hot and the water has boiled.
Pull the wiring conn off each coil pack in turn and listen to the change in engine.
Transistor / ignite unit on top of plenum chamber do fail, usually dropping one coil. If the rev counter is only showing about half actual rpm then this is the fault.
Faulty exhaust valve - hold a rag over exhaust and see if it pulls the rag in.
Hydraulic cam belt tensioner failed - allows left hand cam timing to jump back and forth. Have to remove top cam belt cover to check this one.

That will keep you quiet for a while!

Oh, air leaks, with it idling spray suspected areas with brake cleaner or similar. Rise in engine speed indicates air leak. Never ever had a problem with air leaks on 6g74 though.

Cheers Andy.

Awesome cheers for the help, Today got the better of me and I'm away tomorrow so il go through the list on fri and by end of play il be in a position to say "sorted" or at the least ruling possibilities out.

Much appreciated
Michael

[steweym8]

Iv gone through the cheek list and can rule out vacume leak, iv done plugs coils and leads, I think checking the timing/ tensioner and crank/ cam sensor is likely to be beyond me so I might have take the hit and take it into a mechanic.

[steweym8]

So the long short as it now stands, replaced the crank sensor and ran mint for approx 150km now same symptoms as before with cam/ crank fails showing up in dignistics- sensors are fine witch lead me to think that the power transister could be at fault. Insanely expensive to get one from donithorns or repco for a part that may or may not be a fix,wreckers don't have any and ebay will be a 3 week wait. Does any one have one I can borrow to confirm the issue or buy cheap?

Cheers
Michael

[Team Tonka]

I think I have one, based on having only ever replaced one and have cut up 2 doner trucks. I'll have a look in the morning for you. The rev counter takes its signal form here though and when mine played up so did the rev counter. For what its worth mine failed because I had broken the tang off its plug and thought it would be ok, however the loose plug allowed water into the module.

Hopefully when they did the crank sensor they made sure the slotted trigger washer on the crank was good. They are easy to damage when you do the cam belt and chew through the sensor. Would explain why a new sensor would fail so quickly.

[steweym8]

I think I have one, based on having only ever replaced one and have cut up 2 doner trucks. I'll have a look in the morning for you. The rev counter takes its signal form here though and when mine played up so did the rev counter. For what its worth mine failed because I had broken the tang off its plug and thought it would be ok, however the loose plug allowed water into the module.

Hopefully when they did the crank sensor they made sure the slotted trigger washer on the crank was good. They are easy to damage when you do the cam belt and chew through the sensor. Would explain why a new sensor would fail so quickly.

Awesome that would be gold,
Il also hit them up about the possibility of the washer being damaged at my local garage.
Cheers
Michael

[Team Tonka]

I do have a coil transistor power unit. I'm in Loburn just north of Rangiora so you can borrow it to see if that's the problem if you want. You can have it for $50 but I'd rather only sell it if you really need it. PM me for contact details, Cheers Andy.