Engine misfire - fuel starvation??
Discussion
Evening folks,
Just had my first real problem with the car when driving home tonight. Seems like either ignition (or lack of) or fuel starvation. The engine would run reasonably well but not as good as usual at about 3-4k but any attempt to rev beyond that would result in the engine almost cutting out. Also the engine would cut out instantly if I lifted & dipped the clutch. I had to stop for a couple of sets of traffic lights but couldn't keep the engine running and re-starting was a problem too.
I've done a quick search of the forum for any possible causes (search function not working correctly so had to manually go back through previous posts)and the first I came across was CTO3's problem
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
This sounds similar but happened under very specific and different circumstances. At present my fuel tank is 3/4 full.
The strange thing is I just went outside just now and it started first time and would rev as freely as normal.
As always any assistance would be greatly appreciated.
Graeme
Just had my first real problem with the car when driving home tonight. Seems like either ignition (or lack of) or fuel starvation. The engine would run reasonably well but not as good as usual at about 3-4k but any attempt to rev beyond that would result in the engine almost cutting out. Also the engine would cut out instantly if I lifted & dipped the clutch. I had to stop for a couple of sets of traffic lights but couldn't keep the engine running and re-starting was a problem too.
I've done a quick search of the forum for any possible causes (search function not working correctly so had to manually go back through previous posts)and the first I came across was CTO3's problem
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
This sounds similar but happened under very specific and different circumstances. At present my fuel tank is 3/4 full.
The strange thing is I just went outside just now and it started first time and would rev as freely as normal.
As always any assistance would be greatly appreciated.
Graeme
Thanks guys,
It's a 3.0l
Checked all the vacuum pipes. All are secure and correctly positioned. Started again this morning without any problem and idled happily enough. Engine would rev freely when sitting in neutral so went for a quick run. When I put my foot down at lowish revs (2-3k) the engine would momentarily struggle and then would pick up as normal but would feel as if it were still under-powered or missing which seems like the problem Nicksy described.
Any tips or things to watch out for when removing the fuel filter? At the moment I'v got over half a tank of fuel so was wondering what is the best way to isolate the upstream side of the fuel filter so as not to dump the petrol in the tank.
Secondly, anything to watch for when removing the plugs. I take it the inlet manifold has to come off to get to plugs 1, 2 & 3? I've been told that the plugs can be a pain to slacken off in all these Duratec engines so again any advice or words of wisdom would be much appreciated.
The bugger of it is that the weather is superb today!
Cheers,
Graeme
It's a 3.0l
Checked all the vacuum pipes. All are secure and correctly positioned. Started again this morning without any problem and idled happily enough. Engine would rev freely when sitting in neutral so went for a quick run. When I put my foot down at lowish revs (2-3k) the engine would momentarily struggle and then would pick up as normal but would feel as if it were still under-powered or missing which seems like the problem Nicksy described.
Any tips or things to watch out for when removing the fuel filter? At the moment I'v got over half a tank of fuel so was wondering what is the best way to isolate the upstream side of the fuel filter so as not to dump the petrol in the tank.
Secondly, anything to watch for when removing the plugs. I take it the inlet manifold has to come off to get to plugs 1, 2 & 3? I've been told that the plugs can be a pain to slacken off in all these Duratec engines so again any advice or words of wisdom would be much appreciated.
The bugger of it is that the weather is superb today!
Cheers,
Graeme
Edited by Naso Grande on Saturday 21st March 12:58
Dude, just start with the plugs as I think that is what the problem is, I wouldn't bother withe the fuel lines yet. The plugs are available from most auto factors I think that I put the top spec NGK ones on for less than £40. The plugs can get a little tight but not realy a problem , just ensure you gap the new ones to between 35 and 38 thou of an inch or you will have the same problem. You don't have to take the manifold of completly, just loosen the bolts and that should give you enough room.
Nicksy
Nicksy
Nicksy said:
Dude, just start with the plugs as I think that is what the problem is, I wouldn't bother withe the fuel lines yet. The plugs are available from most auto factors I think that I put the top spec NGK ones on for less than £40. The plugs can get a little tight but not realy a problem , just ensure you gap the new ones to between 35 and 38 thou of an inch or you will have the same problem. You don't have to take the manifold of completly, just loosen the bolts and that should give you enough room.
Nicksy
Do you happen to have the p/no for the NGK plugs? I can probably get them this weekend but would have to wait until the Ford dealers open on Monday to get the Motorcraft plugs.Nicksy
The car was serviced in June last year and has done about 3k since then.
The car is garaged and has not been driven in the rain in since January.
Just reading through Nicksy's post again. I instructed the garage who did the service to gap the plugs at 40thou which seemed to be correct going by the Wiki but is between 35 & 38 correct for a GTO-3?
The hose from the filter to the pump has a nice radius on it and no kinks so pointing towards the plugs as the most likely sourrce of the problem
Thanks again for everybody's input.
Edited by Naso Grande on Saturday 21st March 14:22
Afternoon folks,
Just changed the plugs for the NGK ITR6F type and gapped at 37thou however the underlying problem is still there. Everything is fine if the engine is not under heavy load however when I give it some beans it slows then surges before slowing again and would probably continue to do so if I didn't back off. Seems now like either the fuel pump can't deliver the flow required or there is a restriction in the fuel filter.
Cheers,
Graeme
Just changed the plugs for the NGK ITR6F type and gapped at 37thou however the underlying problem is still there. Everything is fine if the engine is not under heavy load however when I give it some beans it slows then surges before slowing again and would probably continue to do so if I didn't back off. Seems now like either the fuel pump can't deliver the flow required or there is a restriction in the fuel filter.
Cheers,
Graeme
maybe the fuel filters is clogged
that or contaminated petrol
seems to have happened before
see:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
that or contaminated petrol
seems to have happened before
see:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Thanks fellas,
I'm a bit stumped myself and can't really progress much further without taking it to the guys who do the servicing. The connections to the pump look OK and survived being given a good tug and what little I can see of the cable run back to the relay looks in good condition with no obvious signs of damage. All the relays seem to be well seated and were very tight to pull out of the sockets. from what I could see the wires underneath are all solid as well.
All the old plugs that I removed were in good condition with no carbon build up, oil on the tip, etc and all had 37thou gaps. There did look as though there had been some water lying around plugs 1, 2 & 3 as there was some rust on the exposed part of the plug and the shrouds on those three coil packs were all stained orange. There was no sign of any HT tracking so I don't think this would have been the problem. All the coil packs were cleaned but as I said the problem remains.
I'm just outside Aberdeen and there have been stories recently of some petrol stations around here having fuel contaminated with water however I'd ruled this out as I'd already used about a 1/4 tank before the problem started.
Cheers,
Graeme
I'm a bit stumped myself and can't really progress much further without taking it to the guys who do the servicing. The connections to the pump look OK and survived being given a good tug and what little I can see of the cable run back to the relay looks in good condition with no obvious signs of damage. All the relays seem to be well seated and were very tight to pull out of the sockets. from what I could see the wires underneath are all solid as well.
All the old plugs that I removed were in good condition with no carbon build up, oil on the tip, etc and all had 37thou gaps. There did look as though there had been some water lying around plugs 1, 2 & 3 as there was some rust on the exposed part of the plug and the shrouds on those three coil packs were all stained orange. There was no sign of any HT tracking so I don't think this would have been the problem. All the coil packs were cleaned but as I said the problem remains.
I'm just outside Aberdeen and there have been stories recently of some petrol stations around here having fuel contaminated with water however I'd ruled this out as I'd already used about a 1/4 tank before the problem started.
Cheers,
Graeme
Edited by Naso Grande on Sunday 22 March 20:26
Some random thoughts:
- Hook up a fuel pressure gauge to the fuel rail and watch the pressure as you recreate the problem. That should give you an idea if the problem has to do with the fuel pump or filter. May be an injector problem, but you can usually see this by reading the plugs.
- Drain the fuel tank, and refill with fresh gasoline. While you have the tank empty, it's a good time to clean your fuel filter. I usually disconnect the fuel line from the fuel rail (you'll either need the appropriate disconnect tool, or you can get clever with a strip of metal cut off a beer can...), and put a piece of rubber fuel hose (I think it's 1/2" hose) onto the fuel line fitting. Put the other end of the hose into your fuel jug, and turn on the fuel pump by wiring it to a battery with some jumper leads.
- I usually gap plugs for the Nobles a little tighter, between 30 and 32 thousandths. I've had instances where I would get high-speed misses under load, with high boost, when I used wider gaps (36-39 thousandths).
- Drive the car a little more (recreate the problem once or twice more), and pull out the plugs again. Keep track of which plugs came out of which cylinder. Read the plugs again to see if there's an ignition related problem.
- Hook up a fuel pressure gauge to the fuel rail and watch the pressure as you recreate the problem. That should give you an idea if the problem has to do with the fuel pump or filter. May be an injector problem, but you can usually see this by reading the plugs.
- Drain the fuel tank, and refill with fresh gasoline. While you have the tank empty, it's a good time to clean your fuel filter. I usually disconnect the fuel line from the fuel rail (you'll either need the appropriate disconnect tool, or you can get clever with a strip of metal cut off a beer can...), and put a piece of rubber fuel hose (I think it's 1/2" hose) onto the fuel line fitting. Put the other end of the hose into your fuel jug, and turn on the fuel pump by wiring it to a battery with some jumper leads.
- I usually gap plugs for the Nobles a little tighter, between 30 and 32 thousandths. I've had instances where I would get high-speed misses under load, with high boost, when I used wider gaps (36-39 thousandths).
- Drive the car a little more (recreate the problem once or twice more), and pull out the plugs again. Keep track of which plugs came out of which cylinder. Read the plugs again to see if there's an ignition related problem.
Does this occur at all engine temps or just when the car is hot (or cold)?
If it's a heat related issue could be:
1. electrical; poor relay connection/fried fuel wiring
2. Catalytic converter collapsed internally - had this on my 3R after only 4K miles. Engine would be fine when cold, but when hot would rev to about 3-4K rpm and then behave as if it had hit the rev limiter. Took the factory about a month to suss this out (having replaced all the injectors ,fuel rail etc etc). Apparently it was the lambda sensor shutting the engine done when exhaust gases were not behaving as they should have been (due to blockage by the collapsed cats).
3. collapsing low pressure fuel hose - had this on the M400! Difference in symptoms here was that you could 'drive through it' ie engine would cut-out for a few millisecs between 4-5K revs under full throttle but then pick up again. From the computer read out it was so sudden that it just had to be electrical. Lead Yellowshed, AdrianW and me on a merry chase for quite a while, until a chance observation lead us to the low pressure fuel hose. Replaced it with high pressure fuel hose -end of problem.
If it's a heat related issue could be:
1. electrical; poor relay connection/fried fuel wiring
2. Catalytic converter collapsed internally - had this on my 3R after only 4K miles. Engine would be fine when cold, but when hot would rev to about 3-4K rpm and then behave as if it had hit the rev limiter. Took the factory about a month to suss this out (having replaced all the injectors ,fuel rail etc etc). Apparently it was the lambda sensor shutting the engine done when exhaust gases were not behaving as they should have been (due to blockage by the collapsed cats).
3. collapsing low pressure fuel hose - had this on the M400! Difference in symptoms here was that you could 'drive through it' ie engine would cut-out for a few millisecs between 4-5K revs under full throttle but then pick up again. From the computer read out it was so sudden that it just had to be electrical. Lead Yellowshed, AdrianW and me on a merry chase for quite a while, until a chance observation lead us to the low pressure fuel hose. Replaced it with high pressure fuel hose -end of problem.
Evening folks,
Looks as though the problem was the fuel filter which was full of rusty crap. I'll try and post up a pick of what came out and how the filter looks.
Cleaned it all out but didn't have a replacement element so the old one went back in. I needed to crack the banjo fitting to prime the pump before the engine would fire and after that went for a quick run. The problem is now all but gone although there is still a slight flat spot at about 3-4k.
I'll replace the filter and try again but if the problem still persists then i'll revisit the plugs.
Thanks again for everyones input & assistance,
Graeme
Looks as though the problem was the fuel filter which was full of rusty crap. I'll try and post up a pick of what came out and how the filter looks.
Cleaned it all out but didn't have a replacement element so the old one went back in. I needed to crack the banjo fitting to prime the pump before the engine would fire and after that went for a quick run. The problem is now all but gone although there is still a slight flat spot at about 3-4k.
I'll replace the filter and try again but if the problem still persists then i'll revisit the plugs.
Thanks again for everyones input & assistance,
Graeme
Edited by Naso Grande on Tuesday 24th March 20:36
Edited by Naso Grande on Sunday 29th March 15:24
Edited by Naso Grande on Sunday 29th March 15:26
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