# Code P1127



## godoveryou (Apr 1, 2007)

Any ideas what I need to correct to prevent that code on a 97 ABA/M5 Jetta?
Thanks,
GOY


----------



## RUbbish (May 7, 2007)

*Re: Code P1127 (godoveryou)*

P1127
Long Term Fuel Trim mult.,Bank1 System too Rich


----------



## Fast VW (Sep 24, 2002)

*Re: Code P1127 (RUbbish)*

Per the Bentley Manual:
SAE = P1127
Vag = 17535
Description = Long Term Fuel Mult., Bank1 System too Rich
Things to Check:
1. EVAP Purge Regulator Valve - Stuck Open
2. EVAP Purge Solenoid Vavle - Stuck Open
3. Fuel Injectors - leaking (fuel - not a leaky O-ring)
4. Fuel Pressure Regulator - Pressure too high


----------



## godoveryou (Apr 1, 2007)

*Re: Code P1127 (Fast VW)*

Any idea how to test the Evap purge system? I was thinking about buying new injectors anyways simply because I'm very familiar with how brand new injectors can make an old engine feel crisp and new again.
Thanks,
GOY


----------



## JustTheTip (Jan 22, 2008)

where is your fuel trim?..you probaly have one of two things, a vacuum leak, or a bad MAF..check the fuel trim and post it up


----------



## godoveryou (Apr 1, 2007)

*Re: (ScmK4VduBB)*

How would one go about checking fuel trim? I don't have Vagcom, and there's no open source prom reader/writer for the motronic 5.9 (which I'd be all over if there was one, FYI)... leaves me very few options to guesstimate fuel trim. 
I would think that the MAF was good. Daily engine operation doesn't reflect any problems. Cruise and WOT in open loop operation is A-Okay. Open Loop determined via scangauge.


----------



## JustTheTip (Jan 22, 2008)

your gonna need a scan tool to check fuel trim, but check for vacuum leaks. if you dont find any id put my $ on a MAF


----------



## Fast VW (Sep 24, 2002)

*Re: (ScmK4VduBB)*

This would be much easier to diagnosis with VagCom. Usually a bad MAF will cause a P1128 - fuel trim too lean. But I have seen them cause on rare occasions P1127. Just keep in mind that the fuel trim code is being caused by the pre-cat O2 sensor seeing too much fuel in the exhaust.
If you can get something to look at your long term fuel trim you could diagnosis the entire evap system by removing the evap vacuum line from the TB, cap the barb on the throttle body, and then drive the car and watch the fuel trim. If the fuel trim returns to normal, +10 to -10 you know that something is wrong in the evap system. For a CEL, your LTFT must be at +25, or very close.
With VagCom you could also watch the MAF output. It should rise very smoothly and linearly with increased load. If it spikes (i.e. shows more air than is actually moving through it) it will cause the P1127 code.
VagCom was the best purchase I have made for my car. http://****************.com/smile/emthup.gif


----------



## godoveryou (Apr 1, 2007)

*Re: (Fast VW)*

I'm a little biased against them because they don't give us a way to burn proms despite the fact hey obvious understand the motronic data. That's just me though.


----------

