SE Engine Stutter Under Acceleration?
Discussion
The saga continues.
I have fitted a new IAC valve which seems to have cured all my idling problems and I seem to be achieving more boost. The problem is when the engine is fully warmed up after say 7 miles or so when trying to accelerate reasonably quickly the car will initially accellerate quite hard then stutter and cough hitting a complete flat spot. I have not worked out whether this only occurs when the fuel gauge is reading a quarter full, this may be the case. (The car has stood more or less since 1998). Can anyone tell me where the fuel filter is and whether there is a non lotus replacement item.
Any response would be welcomed.
Regards Mike (UK)
I have fitted a new IAC valve which seems to have cured all my idling problems and I seem to be achieving more boost. The problem is when the engine is fully warmed up after say 7 miles or so when trying to accelerate reasonably quickly the car will initially accellerate quite hard then stutter and cough hitting a complete flat spot. I have not worked out whether this only occurs when the fuel gauge is reading a quarter full, this may be the case. (The car has stood more or less since 1998). Can anyone tell me where the fuel filter is and whether there is a non lotus replacement item.
Any response would be welcomed.
Regards Mike (UK)
Thanks.
The plug holes are dry.
I have a feeling it may have something to do with either the fuel filter or the fuel pump.
After the car is warmed up the fuel pump does seem to wine quite loudly behind you at when pulling up at junctions. Do all SE's do this?
Any sugestions?
Has anyone had a fuel pump problem or blocked fuel filter?
Where is the fuel filter?
Does it sit in a bracket on the bulkhead behind the drivers head connected to the inlet manifold fuel rack by a curly black plastic hose?
Any answers would be appreciated.
Regards Mike (UK)
The plug holes are dry.
I have a feeling it may have something to do with either the fuel filter or the fuel pump.
After the car is warmed up the fuel pump does seem to wine quite loudly behind you at when pulling up at junctions. Do all SE's do this?
Any sugestions?
Has anyone had a fuel pump problem or blocked fuel filter?
Where is the fuel filter?
Does it sit in a bracket on the bulkhead behind the drivers head connected to the inlet manifold fuel rack by a curly black plastic hose?
Any answers would be appreciated.
Regards Mike (UK)
I have some more details off the symptoms.
Having driven the car today with plenty of petrol in the tanks. After 10 miles and having stood in traffic for a while the engine was fully warmed up, I on 2 occasions accelerated to overtake as soon as the boost gauge hits approx 0.4-0.5 bar the engine coughs and splutters and will not accelerate any further as soon as the throttle is backed off the engine returns to smooth run and will accelerate up to 0.4-0.5 bar once again then splutters again.
Note when the car is warmed up after a few miles the cars performance is superb smooth and accelerates using full boost.
ANY IDEAS PLEASE?
MIke(UK)
Having driven the car today with plenty of petrol in the tanks. After 10 miles and having stood in traffic for a while the engine was fully warmed up, I on 2 occasions accelerated to overtake as soon as the boost gauge hits approx 0.4-0.5 bar the engine coughs and splutters and will not accelerate any further as soon as the throttle is backed off the engine returns to smooth run and will accelerate up to 0.4-0.5 bar once again then splutters again.
Note when the car is warmed up after a few miles the cars performance is superb smooth and accelerates using full boost.
ANY IDEAS PLEASE?
MIke(UK)
Again, you have made no mention of the year or type of Lotus you have.
If you are not the first owner, definitely change the fuel filter. I changed mine out on my '89 non-SE the day after I got it at six years old and that was after the PO put $4000 of maintenance on it just before. I couldn't believe it was running at all as dirty as it was. For mine a standard NAPA filter for a GM MPFI, NAPA Gold 3481.
And for plugs. every 10,000-15,000 miles. I went 25,000 on my Bosch Platinums, the ones they supposedly made so the sideways sixs wouldn't have to change them till after 80,000 miles. I should have changed them at 10,000. I did the plugs with the filter job and the NGKs were shot too.
But after another six years and only Texaco or Chevron gas ( I work in the industry and did gasoline research) never does it stubble.
If you are not the first owner, definitely change the fuel filter. I changed mine out on my '89 non-SE the day after I got it at six years old and that was after the PO put $4000 of maintenance on it just before. I couldn't believe it was running at all as dirty as it was. For mine a standard NAPA filter for a GM MPFI, NAPA Gold 3481.
And for plugs. every 10,000-15,000 miles. I went 25,000 on my Bosch Platinums, the ones they supposedly made so the sideways sixs wouldn't have to change them till after 80,000 miles. I should have changed them at 10,000. I did the plugs with the filter job and the NGKs were shot too.
But after another six years and only Texaco or Chevron gas ( I work in the industry and did gasoline research) never does it stubble.
Fisrt check the condition of the plugs and the correct type of plug.
If they are fouled or burnt they won't fire right under load. If that happens the unburnt exhaust will screw with the o2 sensor and lean out the mix. alos check fuel pressure to as I have heard the secondary fuel pumps fail depending on the mileage of the car.
Check the fuel pick up screens as they are prone to foul. Check fuel filters. Sorry the economy is not so good and we had to lay off 4 workers so I must cover their work. No computer time as I used too.
Good Luck,
Calvin
If they are fouled or burnt they won't fire right under load. If that happens the unburnt exhaust will screw with the o2 sensor and lean out the mix. alos check fuel pressure to as I have heard the secondary fuel pumps fail depending on the mileage of the car.
Check the fuel pick up screens as they are prone to foul. Check fuel filters. Sorry the economy is not so good and we had to lay off 4 workers so I must cover their work. No computer time as I used too.
Good Luck,
Calvin
The car is a 1990 SE Charge Cooler.
I still dont understand how full performance is achieved untill the car has done 10 miles or so then the stuttering starts.
Where is the fuel filter & fuel pump on this model?
Are They hard to replace?
The fuel pump wines quite loudly behind your head at variable pitches. Is this usual?
Regards Mike (UK)
I still dont understand how full performance is achieved untill the car has done 10 miles or so then the stuttering starts.
Where is the fuel filter & fuel pump on this model?
Are They hard to replace?
The fuel pump wines quite loudly behind your head at variable pitches. Is this usual?
Regards Mike (UK)
For what it's worth, my 1991 SE was doing the same type of thing last season. Have you put it on FreeScan yet? When I did, it was showing a lot of knock retards. I've started out by changing out the plugs and ignition wires. I really won't get to troubleshoot this further until the weather breaks in the Chicagoland area... which will be in the March / April timeframe.
Chris
'91 Midnight Blue
Chris
'91 Midnight Blue
Mike
My GT3 has been stumbling over a flat spot the size of Holland ( I read that line about the Countach a few years ago and have been waiting to use it ever since
). Anyway, it turned out to be a sticking waste gate. At WOT in third I was only getting around 0.25 bar, sometimes it would then come on full boost and other times nothing. I had the waste gate accuator stripped and cleaned and now it works a treat, with full umph all the time.
Adrian
www.adrianmugridge.co.uk
My GT3 has been stumbling over a flat spot the size of Holland ( I read that line about the Countach a few years ago and have been waiting to use it ever since
). Anyway, it turned out to be a sticking waste gate. At WOT in third I was only getting around 0.25 bar, sometimes it would then come on full boost and other times nothing. I had the waste gate accuator stripped and cleaned and now it works a treat, with full umph all the time. Adrian
www.adrianmugridge.co.uk
The fuel pump should not be audible over the sound of the engine running, you can normally only hear it for a couple of seconds when you first turn on the ignition. It is located inside the right side fuel tank, under the ECM.
Cheers,
Sanj
>> Edited by grungex on Sunday 26th January 00:06
Cheers,
Sanj
>> Edited by grungex on Sunday 26th January 00:06
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