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Hi there!
I'm in the procces of fighting p1128+1130 along with -20% LongTerm fuel trims and VERY loooong startup times.
Replaced the AOS yestearday but, opened the old one - membrane looked to be in perfect shape Even tough there was some oil presence in the intake ducts, so I keep hope that old AOS was somehow bad.
Have not restarted the car yet as I have to put all the hardware back. Maybe while still there, I will check my fuel pressure.
2001 uses DME 5.2 so P1128 and P1130 indicate both banks are too lean when close to full load. I would check the MAF (voltage reading using Durametric/OBDII scanner/multimeter) and the fuel pressure. If you have an external fuel filter under the car, it's also a good idea to replace that.
Checking voltage would be a good idea., but...I already tried clearing all codes, disconnecting the MAF and driving like this for my daily commute. At first, the car started "easily", but after a lengthy drive, startups were the same like before, loooong, and in the end P1128 came back. So I kind of dicarded the MAF possibility for now.
Will try to do a fuel pressure test. Any specs, write ups on that besides that I need angular Shrader fitting?
Definitely check the fuel pressure then. Specs are here:
Stationary engine 3.8 +/- 0.2 bar
Engine idling 3.3 +/- 0.2 bar
Quantity supplied must be at least 850 cc/30 s,
Little update,
Got new AOS in place, and cleaned MAF which seemed perfectly clean in first place.
Drove for the weekend, around 100km in two days - CEL has not come up yet, even though Long Term Fuel trims are again at -20% and -19% so I suppose it's mater of days for it to come up.
Startups are somewhat improved but barely, probably due to new starter I put in, which cranks faster, but on hot engine, I still have to crank for 5 seconds and more.
I took MAF reading in lbs per minute. I got 1lb/min at idle, and 2.9lb/min at 3000rpm no load.
Anybody can confirm these readings as normal?
Your problem is either the idle air motor or the fuel vapour purgd solenoid/valve near the throttle body. If this valve is stuck open, it will make starting the engine take 5-10 second. I had this problem and after I cleaned the valve out the engine started like it should. Remove the valve and then active it with a 9V battery. If you can blow through it with your mouth when the voltage is and isn't applied to the valve then it's either gummed up or siezed. You can try leaning it out with some brake cleaner and cycling the valve with the 9V. At some point it should start clicking and when the click start to sound like metal on metal, the valve is clean.
The MAF should read ~4.2g/s for your car at idle, fully warmed up and no load. That's ~0.55lb/min. Your MAF reading is twice of that so that explains the -20% fuel trim to cut fuel.
BTW, I take that you reset the DME after the AOS change (so fuel trims were reset too)?
Is your intake stock? Is your rpm at idle close to 680 at no load when the MAF read 1 lb/min? I checked the spec for a 3.4, at idle it's 15kg/hr which is ~4.2g/s, which is 0.55lb/min.
Cheap MAF from ebay is most likely no good. The other way to check is if you unplug the MAF, reset the DME and see if your fuel trims come back to normal. If it does, it's highly likely your MAF.
My intake is stock.
I already rode around with MAF unplugged, got PSM, ABS, CEL lights right on. And by the end of the day, same p1128 came back, so I kind of discarded the bad MAF idea and plugged it back. I think the trims went to around -20 too, but can't be sure on that.
My idle is more of 800-900, but have to double check on that too.
10-08-2015, 12:18 PM
p1128 1130 related - SOLVED
Even tough there was some oil presence in the intake ducts, so I keep hope that old AOS was somehow bad.
