DFI engine vibrate

[drewtommy]

hello all ,

2009CS pdk w/s exhaust

last week Cel on, send to the dealer to check , the code p0171 system too lean bank 1 ,after diagnosis the dealer said that the fuel pressure maybe different between two bank so they replaced the HPFP and

perform fuel adaptation 1-5 .

Been running for a week now the car still vibrate only when idling , CEL still pop out

they have replaced the all O2 sensor , maf sensor but the problem still occur .

Does anyone had these issuse before,

please help !!

thank in advance

drewtommy

[Loren]

You likely have an intake (or exhaust) leak. Smoke test the engine to be sure.

Have them check the motor mounts too.

[drewtommy]

The dealer have smoke test the engine but seem to be no leak .

i ask a friend of my that used piwis to read the actual value and found out that bank 1 sensor 1 reading is 2v at idle but no response when accelerate only bank 2 value jumping up and down , he said normally both bank should be almost the

same.

the dealer just replaced all the o2 sensor .

could it be the wiring from the DME module or something else .

the fault is p2237 o2 sensor positive current control circuit open bank 1 sensor 1 . after clearing of the fault and let it idle for few minutes the fault appear again and the o2 value is 3v.

Loren do you know which wire to check ??? i know there are 5-6 wire .

please help .

Thank for the reply

really appreciate.

drewtommy

[Loren]

the dealer just replaced all the o2 sensor

wow... this is proof the dealer does not know what they are doing!

If that is the correct fault then there is a bad connection at that sensor or wiring harness damage.

[tkh]

Hi Tommy,

I may have the same problem as you are facing.

Have you found a solution?

Regards

Tan

[drewtommy]

the dealer just replaced all the o2 sensor

wow... this is proof the dealer does not know what they are doing!

If that is the correct fault then there is a bad connection at that sensor or wiring harness damage.

The dealer also try to swap the injector , intake manifold , catalytic converter , oil separator but still after a few run the CEL on .

[Loren]

If you are getting the same fault code then the problem is (still) in the bank1 sensor 1 circuit. The DME is sensing that the circuit is open (disconnected) - so they should be going after that sensor wiring, connector and sensor itself.

Rarely does a fault code not point to the exact cause of a problem -- they need to follow the fault code troubleshooting.

[phillipj]

Wow that is scary that the techs at that dealership in Sigapore are that poorly trained. It's not like Singapore is a sleeply little town...

[tkh]

Mine swapped catalytic, hpfp, lambda, airmass. Checked for air leak.

After reset, it runs fine for 10-20mins then cel comes on and idles rough.

Have u tried changing the dme unit?

[drewtommy]

If you are getting the same fault code then the problem is (still) in the bank1 sensor 1 circuit. The DME is sensing that the circuit is open (disconnected) - so they should be going after that sensor wiring, connector and sensor itself.

Rarely does a fault code not point to the exact cause of a problem -- they need to follow the fault code troubleshooting.

The dealer said they have solved the o2 sensor issue , after few days cel on again but now still the same p0171 system too lean bank 1 without the o2 fault . Checked with an independent workshop o2 sensor working fine .

[Loren]

It is not the sensors that is bad - the sensor merely reports the problem.

You need to be checking for air leaks at the intake - that is likely why you have a "too lean" condition - too much air.

[slicky rick]

Reviving this tread, has the op been able to trace the vibrate and solved this issue? i also had a vibration on my dfi engine. Dealer cleaned fuel injectors and replaced all the gaskets and orings all the way to the intake manifold. This removes the possibility of an intake leak i would think. It was mentioned here that an exhaust leak could also be at fault. My exhaust headers are a bit banged up after hitting a few road hazards. It has a few dents here and there. Mostly on bank 1 which is the one with the lean mix. Could this create the problem. Sometimes the exhaust also sounds like it has a leak but im lead to think its porsche way of immitating the air cooled exhaust sound. I hope some of our friends could chime in. How could you safely detect exhasut leaks?

[slicky rick]

In addition wont an intake leak produce a lean mixture on both banks and not only on one bank? This is why i am leaning more into the exhaust leak possibility, this could create the issue only for one bank. But essentially will an exhaust leak cause a lean mixture? Or in my case could a dented up header cause this lean mixture and idle vibration?