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theWalkinator · 07-04-2024, 03:00 PM

Looks like I get rid of P11298 and P1130 codes after I replaced vacuum reservoir, however, 10 miles short test drive still got P1126 and P1133 (lower range adaption exceeded limit).

I also replaced fuel filter, man it is dirty, I mean very dirty, the gas came out of old fuel filter is very dirty cloudy and has some black sediment after let it siting for a while so definitely it needs to be replaced. After replaced fuel filter, I re-tested fuel pressure, engine idle 3.3 bar, right on the spec, engine off, it gradually creeps up to 3.5 bar after couple of minutes, and 10 minutes later it still holds on 3.5 bar. I also removed the return line but it does not seem to loose the fuel pressure, I did what you said, block off the return line and pressurize the fuel system, still around 3.5 bar so I think neither the fuel pump nor the injectors are leaking.

I was also able to test the EVAP purge valve (under the driver side intake manifold), my scan tool is capable to turn it on and off, so I hooked my hand vacuum pump on the EVAP hose from the throttle body, it held vacuum, then used my scan tool to command the valve to open, I heard a click and immediately the vacuum dropped to 0 so the EVAP purge valve is good.

I also tested fuel regulator by pulling the vacuum hose off the fuel regulator when engine is idling, no change of fuel pressure and I can feel the vacuum suction from that small vacuum tube.

After replaced the fuel filter, I took a quick 10 mile test drive, P1126 and P1133 came back in pending, so I unplugged MAF sensor and clear the code, took another 10 mile quick test drive, fuel trim seems to be fine and no P1126 and P1133 code, does that point to the MAF sensor?

The MAF sensor I got from Rock Auto is Bosch 98660612502, however, my car is 2001 model but production date is in September 2000, so should the MAF sensor be 99660612400?

I will do another smoke test, but I really don't think it is vacuum leak issue, P1126 and P1133 are lower range code not when the car is idling so if there is any small vacuum leak it would more likely present at idle (P1128 and P1130) but at higher RPM small vacuum leak can be neglected, correct?

So that comes down to either the MAF sensor or the fuel pump, but I am still thinking it is the MAF sensor's fault, I need to correct MAF sensor which might be 9966061240, thought?

07-04-2024, 03:00 PM	#10
theWalkinator Registered User Join Date: Jun 2024 Location: PA Posts: 13	Looks like I get rid of P11298 and P1130 codes after I replaced vacuum reservoir, however, 10 miles short test drive still got P1126 and P1133 (lower range adaption exceeded limit). I also replaced fuel filter, man it is dirty, I mean very dirty, the gas came out of old fuel filter is very dirty cloudy and has some black sediment after let it siting for a while so definitely it needs to be replaced. After replaced fuel filter, I re-tested fuel pressure, engine idle 3.3 bar, right on the spec, engine off, it gradually creeps up to 3.5 bar after couple of minutes, and 10 minutes later it still holds on 3.5 bar. I also removed the return line but it does not seem to loose the fuel pressure, I did what you said, block off the return line and pressurize the fuel system, still around 3.5 bar so I think neither the fuel pump nor the injectors are leaking. I was also able to test the EVAP purge valve (under the driver side intake manifold), my scan tool is capable to turn it on and off, so I hooked my hand vacuum pump on the EVAP hose from the throttle body, it held vacuum, then used my scan tool to command the valve to open, I heard a click and immediately the vacuum dropped to 0 so the EVAP purge valve is good. I also tested fuel regulator by pulling the vacuum hose off the fuel regulator when engine is idling, no change of fuel pressure and I can feel the vacuum suction from that small vacuum tube. After replaced the fuel filter, I took a quick 10 mile test drive, P1126 and P1133 came back in pending, so I unplugged MAF sensor and clear the code, took another 10 mile quick test drive, fuel trim seems to be fine and no P1126 and P1133 code, does that point to the MAF sensor? The MAF sensor I got from Rock Auto is Bosch 98660612502, however, my car is 2001 model but production date is in September 2000, so should the MAF sensor be 99660612400? I will do another smoke test, but I really don't think it is vacuum leak issue, P1126 and P1133 are lower range code not when the car is idling so if there is any small vacuum leak it would more likely present at idle (P1128 and P1130) but at higher RPM small vacuum leak can be neglected, correct? So that comes down to either the MAF sensor or the fuel pump, but I am still thinking it is the MAF sensor's fault, I need to correct MAF sensor which might be 9966061240, thought?