Running problem when accellerating
Discussion
Afternoon all - I have a running problem with my 1990 S2 and would be grateful for some guidance.
I notice some fluffing in power delivery under load when accelerating, can be pronounced or quite light, no problems if idling or revved with the car stationary and I think it might be a fuel delivery issue.
I can see the pump and main fuel line from the tank but I dont know if there is an in line filter or if the filter is located in the bottom of the tank.
Guidance would be gratefully received as I think the filter may be choked and I would like to check before I start moving up the line as it were and checking the pump, injectors etc.
Kind regards
I notice some fluffing in power delivery under load when accelerating, can be pronounced or quite light, no problems if idling or revved with the car stationary and I think it might be a fuel delivery issue.
I can see the pump and main fuel line from the tank but I dont know if there is an in line filter or if the filter is located in the bottom of the tank.
Guidance would be gratefully received as I think the filter may be choked and I would like to check before I start moving up the line as it were and checking the pump, injectors etc.
Kind regards
No, the tank can remain in-situ.
Jack the back end up, and you will see a bowl or well in the middle of the underside of the tank.
There is a blanking disc held in place by a profiled, concentric ring which sits in a housing on the bottom of this bowl/well.
MAKE SURE THE TANK IS EMPTY!!!
If you tap the 'ears' on the profiled ring anti-clockwise, you will release the ring and the blanking disc underneath the ring, along with the neoprene gasket. Obviously, you need to use some sort of non-sparking tools to tap the ears - I used a 20mm copper pipe flattened in the vice as a drift.
With the ring and disc released from the housing you can see inside the bowl. The pre filter is plain to see and pulls off an internal nipple for cleaning. I got quite a bit of sediment out plus a few bits of swarf when I did mine.
Re-assembly is the reverse process. Gasket, blanking disc then retaining ring. It will probably need a tap on the 3 tabs that bear down on the wedge shaped profile of the ring to ensure good pull-up against the gasket. I used my handy copper pipe again!
Tap the ears on the ring until the slope/wedge profile engages with the tabs andknock round to make a tight joint.
Good luck- Nick
Jack the back end up, and you will see a bowl or well in the middle of the underside of the tank.
There is a blanking disc held in place by a profiled, concentric ring which sits in a housing on the bottom of this bowl/well.
MAKE SURE THE TANK IS EMPTY!!!
If you tap the 'ears' on the profiled ring anti-clockwise, you will release the ring and the blanking disc underneath the ring, along with the neoprene gasket. Obviously, you need to use some sort of non-sparking tools to tap the ears - I used a 20mm copper pipe flattened in the vice as a drift.
With the ring and disc released from the housing you can see inside the bowl. The pre filter is plain to see and pulls off an internal nipple for cleaning. I got quite a bit of sediment out plus a few bits of swarf when I did mine.
Re-assembly is the reverse process. Gasket, blanking disc then retaining ring. It will probably need a tap on the 3 tabs that bear down on the wedge shaped profile of the ring to ensure good pull-up against the gasket. I used my handy copper pipe again!
Tap the ears on the ring until the slope/wedge profile engages with the tabs andknock round to make a tight joint.
Good luck- Nick
If both the filters are clean - might also be the fuel regulator. This sits on the fuel injection rail and adjusts the fuel pressure within the rail based on throttle requirements (determined by the vacuum pressure in the inlet manifold). If you floor it, the extra vacuum is supposed to tell the regulator to maintain full pressure in the injection rail (it does this by not allowing any fuel to return to the tank via the fuel return line). On part throttle, the regulator allows some fuel to flow straight back to the tank, reducing the pressure in the rail. Very clever, until it sticks in the fully open (all fuel back to tank) postion as mine did as few weeks back! Engine would turn over fine but obviously not fire as no fuel reaching cylinders. Diagnosed when I stuck my head near the regulator and could hear fuel flowing back down the return line as the engine was cranked. After continuously tapping it with an extender bar, the regulator cleared enough to hold some pressure in the line, allowing the engine to cough into life 1 cylinder at a time. Once all 6 were running, the pressure was enough to allow idling although full-throttle caused it to cough and splutter until I hit the first pot-hole which must have nudged the regulator back into normal service! Needless to say, I'm currently fitting an FSE improved regulator which has the advantage of allowing extra fuel pressure on full throttle (see previous threads for details - there are 2 types of FSE valve).
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