1998 Volvo S40 1.8 with a Fenix 5.1 ECM. Engine is drowning in fuel, but I've made it run for a few secs by pulling the fuel pump fuse so I know it runs and fires when it should. I've tested fucking everything, and everything checks out good. - It does not fuel properly in limp mode either when I pull the plug for O2/MAP/IAT sensors.- ECT resistance is good (around 2600ohm).- Crank sensor ok- IACV operating normally- Throttle pos sensor OK- It doesn't constantly fire fuel when ign is on, but it does not seem to change how much fuel is being shot into the engine (if I fuck around with the fuel pump fuse enough I can manage to make it start and rev to 4000rpm, it stays there no problem but drowns once it goes below 2000rpm).- Timing is still ok, engine does not have any VVT systems.- No vacuum leaks. Still drowns even when I introduce vacuum leaks.- Air filter is not clogged.- Return line is not clogged. FPR valve was replaced due to small dribble from the old one without any change in behavior.- Exhaust is not clogged.I did send the ECU in to an electronics shop and their verdict was that it was fine. Is this diagnosis wrong? I literally cannot figure out what else could cause this rich running condition. Swapping ECMs is difficult because of the immobilizer, and this ECM does not talk to any of my scan tools. Vol-FCR was able to remove a service light and that is it.Noone has responded to me in any Volvo forum and thus I am hoping some electronics autist will be able to give their response here.
It's possible you got a bad FPR out of the box.
>>29127415Mechanically speaking it is intact. Had it been bad it would've been obvious either from a stuck valve causing overpressure (I've tested fuel line pressure which seems to be consistent at 60-65psi) or a fuel leak into the intake thru the vacuum line. The old FPR only had a very small leak into the intake vacuum line and it should technically have run or at least changed the condition still even if it was ever so slightly richer.I appreciate the input but logically speaking that should not be the case.
have you tried turning it off and on again?
