Fuel starvation?
Discussion
Anything upto to 3 quarters throttle is fine, but after this I seem to get some kind of fuel starvation problem. The car will suddenly 'pull up' and jump along. I think it happens in all gears (havent tried reverse at full throttle yet 
).
Lifting off to below 3 quarter throttle seems to bring it back in line. Drives impeccably and ticks over fine otherwise. The first time it happend was a bit frightening as I was in the opposite lane overtaking
I had been running it on standard U/L for about a month because our local shell had shut for a refit. However, the problem didnt arise until after 2-3 weeks of being back on Optimax so I dont think all that standard octaine stuff would have caused any detrimental effects. Plus I often put the odd tank of U/L in anyway when optimax isnt available.
I'm going to stick a decent fuel system cleaner in it and see if that makes any difference.
Any other ideas?
). Lifting off to below 3 quarter throttle seems to bring it back in line. Drives impeccably and ticks over fine otherwise. The first time it happend was a bit frightening as I was in the opposite lane overtaking
I had been running it on standard U/L for about a month because our local shell had shut for a refit. However, the problem didnt arise until after 2-3 weeks of being back on Optimax so I dont think all that standard octaine stuff would have caused any detrimental effects. Plus I often put the odd tank of U/L in anyway when optimax isnt available.
I'm going to stick a decent fuel system cleaner in it and see if that makes any difference.
Any other ideas?
See what happens after cleaning.
My 3-guess's are:
that you may have a fuel pump getting tired or:
the fuel filter is getting blocked or:
finally, the fuel regulator is about to expire.
The only way is either substitution of know "S" parts or, put a pressure guage on the fuel line after the regulator.
Trev McM
My 3-guess's are:
that you may have a fuel pump getting tired or:
the fuel filter is getting blocked or:
finally, the fuel regulator is about to expire.
The only way is either substitution of know "S" parts or, put a pressure guage on the fuel line after the regulator.
Trev McM
less likely to be cam wear if it's not drinking oil. another question: does it misfire at all or does it spit back and/or pop and bang any more than usual?
could be fuel feed problems but i would check the timing anyway as even if that isn't the problem, it'll be worth checking anyway.
give it a good blast through with a fuel line cleaner and then look to fuel filter/pump.
if you check the timing anyway, the car will undoubtedly be a wee bit off so that'll just sweeten it up.
could be fuel feed problems but i would check the timing anyway as even if that isn't the problem, it'll be worth checking anyway.
give it a good blast through with a fuel line cleaner and then look to fuel filter/pump.
if you check the timing anyway, the car will undoubtedly be a wee bit off so that'll just sweeten it up.
As above - could well be the fuel filter or pressure regulator - two of the fiddliest P.I.T.A jobs I've done on a car. One prob you may have is checking the fuel pressure - the 500's have a tapping for a pressure gauge after the regulator, whereas my precat doesn't, from what I remember, as the later cars have a different fuel rail arrangement I think.
Will the fuel rail have a pressure test connection? I can borrow a gauge from a mate but not too sure I want to mess around making my own connections if theres no specific test port.
Edited to say that yes, it does seem to pop and bang on over run a lot more than it used to. But its been doin this since its last service before christmas. I did post a topic a few months ago about loss of top end power which seemed to solve itself in the end. Seems like this is all related and that problem never did solve itself but was a precussor to whats happening now.
A trip to peninsula me thinks....
>> Edited by jam1et on Monday 26th April 15:39
Edited to say that yes, it does seem to pop and bang on over run a lot more than it used to. But its been doin this since its last service before christmas. I did post a topic a few months ago about loss of top end power which seemed to solve itself in the end. Seems like this is all related and that problem never did solve itself but was a precussor to whats happening now.
A trip to peninsula me thinks....
>> Edited by jam1et on Monday 26th April 15:39
Tuscan thunder sounds like he's spot-on - could be over-fuelling/timing if its popping and banging, or the cams on it's way out. Could even be plug leads or ignition amp, although that would be revs-related rather than throttle opening. If it's coincided with 'crap petrol' (cue Peter Kay...) could just be the filter - that's the cheapest bit to change, but then again, after an hour under the wheelarch with a filter and waxoyled jubilee clips, you'll take it to a garage I guarantee it
well, it could well be just the timing is out. obv. that's linked to cams but could just need the timing put back to spot-on. could be as simple as that. (fingers crossed it is!)
it just sounds like it's overfuelling for the spark. as stated before check plugs, look for cracks, check plug gaps, clean plugs, try a new set of HT leads. checking them with a multimeter rarely works as they can break down under load and a multimeter works at low voltage. see if you can get a shot of leads, maybe from a dealer, just to try them.
i must say, i don't know much about this engine really, more just engines in general. could be distributor or rotor arm? (if it has them? excuse the ignorance) it just sounds like too much fuel or not enough spark.
let's hope it's not cams!
it just sounds like it's overfuelling for the spark. as stated before check plugs, look for cracks, check plug gaps, clean plugs, try a new set of HT leads. checking them with a multimeter rarely works as they can break down under load and a multimeter works at low voltage. see if you can get a shot of leads, maybe from a dealer, just to try them.
i must say, i don't know much about this engine really, more just engines in general. could be distributor or rotor arm? (if it has them? excuse the ignorance) it just sounds like too much fuel or not enough spark.
let's hope it's not cams!
All I did was loosen a clip and let the petrol p*ss out on the floor into a bucket (with a stone cold engine obviously!!!). Very little came out, not like the tank was draining out or anything - just what was in the hoses. One thing I would recommend is to clean the area round the filter really carefully, 'cos no matter how hard you try, you'll get some cr*p down the fuel lines. Afterwards, I kind of bled the system through to the fuel rail by taking the hose off at the pressure regulator, rigging up a container, and flicking the ignition on and off to prime the pump a few times.
If you don't know what you're doing, don't even think about messing with high pressure fuel systems. A garage would charge peanuts to change a fuel filter. One tiny leak can spray petrol further than the nearest spark or hot bit. But then again, I was clueless before I started, and didn't have any probl....whhhooooommmmpfffff
Edited to add, now I've read what I've typed, forget it - go to a garage or read the bible before you start! Don't want any well-done-to-crispy Griffs on my conscience!
>> Edited by andy43 on Monday 26th April 18:29
If you don't know what you're doing, don't even think about messing with high pressure fuel systems. A garage would charge peanuts to change a fuel filter. One tiny leak can spray petrol further than the nearest spark or hot bit. But then again, I was clueless before I started, and didn't have any probl....whhhooooommmmpfffff
Edited to add, now I've read what I've typed, forget it - go to a garage or read the bible before you start! Don't want any well-done-to-crispy Griffs on my conscience!
>> Edited by andy43 on Monday 26th April 18:29
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