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Hello, I’m located in Europe and I have a Honda Accord CL9 2008, like the Acura TSX in USA with K24a3(without egr and 190bhp) My car has aprox 160.000kn(120.000 miles) and i have an issue with positive short trim fuel and long trim fuel(sometimes p0171). My car has also LPG, and when car runs fine on lpg it’s still want to compensate in stfl and ltfl.
I’ve tried several items:
-sprayed brake cleaner on every hose to find a vacuum leak, no found, if i spray directly into intake immediately the values drop and goes negative
-make a profi valve adjustments
-block vacuum from brake booster and the pipe coming from purge valve
-block front mount engine support that is vacuum actuated
-check air valve that closes when antifreeze gets hooter
-replace fuel filter inside the tankWhat to do next:
-check fuel pressure
-change the gasket between exhaust manifold and down pipe and then it comes lambda sensor, if it’s leaking it can give false readings?! but it’s no dark sports visible, like exhaust smoke
-change first lambdaAny ideeas?
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Inspect your PCV valve and fitting. Also check to make sure the fitting area isn’t cracked. It’s threaded into the valve cover, correct? I can’t remember lol. Definitely check fuel pressure, but you should also ensure that your fuel injectors are actuating. They could also be stuck closed or plugged with crap too.
I’ve changed pcv valve and checked the hose from it to intake manifold. The pcv valve on this engine is plugged in a rubber grommet. I will check fuel pressure if it’s a problem with the pressure regulator or injector problems.
I still thinking if it’s a exaust leak before O2 sensor, engine will sound fine but o2 will see more oxigen, but why no signs of exaust leak.[quote=”raresvintea” post=201383]2500 and 4000 under load, or in parking position?[/quote]
Good question. I’d expect them to be the same, but definitely worthwhile to look at both.
800 rpm LTFT 7.8% and STFT 7.0%
2500 rpm LTFT 7.8 STFT 6.2
4000 rpm LTFT 7.8 STFT 4.7Second run after a grocery store visit
800 rpm LTFT 8.6% and STFT 11%
2500 rpm LTFT 7.8 STFT 7.8
4000 rpm LTFT 7.8 STFT 4.7Both measurements are done with coolant on the operating temp 90C, while parked, in parking position. For 2500 and 4000 rpm i’ve waited for 15-20 sec before take the readings.
If would be a vaccum leak at higher rpm would dissapear at least STFT
if would be a fuel delivery issue on higher rpm should increase
If would be an exaust leak should look like a vaccum leak
Correct me if i’m wrong please to leave behing a good infoHow it’s a aged O2 sensor? The fuel consumption is a little bit high
I agree with your analysis, except I don’t know what exhaust leaks do to the trims.
At this point, I’d suspect MAF sensor or upper O2 sensor. Have you cleaned the MAF sensor?I’ve used Seafoam to look for exhaust leaks. Even the slightest crack could effect fuel trim. Just make sure you’re in a very well ventilated area and don’t smoke out your neighbors lol.
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