Wierd electrical problems. Hammer doesn't work.
Posted: Sat Oct 17, 2009 8:29 pm
1991 Escudo, 16valve, EFI.
It's got a strange misfire in it, it seems to be temperature related. I've replaced plugs, rotor, cap and fuel filter.
Initially it was described to me as losing power, so i did the fuel filter then took it for a drive. I'd already replaced the plugs when i fixed the cracked head on it.
On a dead cold engine you'll get about 45 seconds of running before it starts to miss on acceleration, then miss when you try and hold a steady throttle. If you keep holding that throttle level, the revs just cough and die down to idle. Let your foot off the gas, the revs rise slightly, and then it ticks over at idle like nothing's wrong.
It doesn't seem to be affecting any one cylinder, more it's like the sort of misfire you get when your cap's completely buggered.
It runs fine on fast idle, but as soon as you try and rev it, loaded or not, it just splutters.
When you try and start it after it's been sitting for a few minutes, it runs fine for about 30 seconds then gets progressively worse over the course of 20 seconds or so.
I swapped the leads for a half decent set off my corolla. Although they're far from good condition or the right ones, they worked ok on the corolla...i think i can rule them out too.
I guessed at the leads, perhaps the stems were expanding and causing the spark to track. I'm at a bit of a loss as to why it's affected by the heat though - it gets progressively worse the longer the car runs for.
I've got a sneaking suspicion it's the throttle position sensor, it made no difference to the running when i unplugged it. Qualified mechanic i may be, but electrical problems do my head in.
So, i've tried throwing the two usual fixes at it - hammers and money. Neither worked.
Has anyone got any ideas before i admit defeat and take it to a sparkie?
Cheers
It's got a strange misfire in it, it seems to be temperature related. I've replaced plugs, rotor, cap and fuel filter.
Initially it was described to me as losing power, so i did the fuel filter then took it for a drive. I'd already replaced the plugs when i fixed the cracked head on it.
On a dead cold engine you'll get about 45 seconds of running before it starts to miss on acceleration, then miss when you try and hold a steady throttle. If you keep holding that throttle level, the revs just cough and die down to idle. Let your foot off the gas, the revs rise slightly, and then it ticks over at idle like nothing's wrong.
It doesn't seem to be affecting any one cylinder, more it's like the sort of misfire you get when your cap's completely buggered.
It runs fine on fast idle, but as soon as you try and rev it, loaded or not, it just splutters.
When you try and start it after it's been sitting for a few minutes, it runs fine for about 30 seconds then gets progressively worse over the course of 20 seconds or so.
I swapped the leads for a half decent set off my corolla. Although they're far from good condition or the right ones, they worked ok on the corolla...i think i can rule them out too.
I guessed at the leads, perhaps the stems were expanding and causing the spark to track. I'm at a bit of a loss as to why it's affected by the heat though - it gets progressively worse the longer the car runs for.
I've got a sneaking suspicion it's the throttle position sensor, it made no difference to the running when i unplugged it. Qualified mechanic i may be, but electrical problems do my head in.
So, i've tried throwing the two usual fixes at it - hammers and money. Neither worked.
Has anyone got any ideas before i admit defeat and take it to a sparkie?
Cheers