Fuel injector open circuit

[kezcapt]

Hello all,

My 2005 996tt s has developed a problem that I may or may not have caused. I ran the car on a 600 mile trip and the car ran well. I got home and the next day ran a wire through the passenger side grommet in the engine bay. I started the car and now I get a P0201 and rough idle which is a fuel injector 1 open circuit. First, where is the DME located? I was under the Bose amp in the compartment where the harness is located. I wonder if I disturbed something. Also, while trying to fish the wire through the grommet i may have pierced a wire. I was using a piece of fishing leader wire that is very sharp. I stupidly did not disconnect the battery so I wonder if I shorted the circuit that way. It looks like the only wiring in the vicinity of this grommet (behind right rear lens) seems to be related to SAI pump which works well. So maybe all of my concern is for nothing but here is what I have:

P0201, P0301 (related to the first when running above Idle)

I Changed coils to upgraded 997 coils

changed plugs to new Beru Fr6

Exact same OBD read outs after service

I have the basic checklist for P0201 and it is as follows:

P0201 Fuel Injector, Cylinder 1 – Open Circuit

Possible fault cause

♦ Fuel injector (coil) open circuit

♦ Open circuit in wiring

♦ DME control module

Maybe I am just being paranoid. Does anyone have a suggestion about how to proceed? I do not have a DME circuit diagram. Thanks in advance

[Loren]

The DME is behind a carpet panel behind the rear seats. There is nothing serviceable in the DME. If it needs to be replaced (unlikely IMHO) then you would need a PST oe PIWIS tester to transfer the IPAS codes.

Have you checked the fuel injector electrical plug - and then follow the wiring back to the harness looking for damage If it is good shape then replace the fuel injector.

If this is the only fault code(s) you have then the problem is in the injector or circuit at the injector

[kezcapt]

Thanks Loren, I knew I could count on you. I agree your approach is the next logical step. Is there a way to access the injector and associated harness without dropping the engine? I will do a search next. Thanks again!

[Loren]

Just (carefully) move what you need to to see the wiring.

[kezcapt]

Hey Loren,

I got everything exposed and the job, while not easy, was not particularly hard. My question is that you have seen a great deal of failures over the years. Do you think that I should replace all three injectors or just the offending one. if the failure rat id high then I might as well replace all 3. If it is rare then I will take my chances. the going has been tedious but using original parts has helped a lot. Thank you for your help. Of course the filter will be changed.

Cheers,

Rob

[Loren]

I would say rare - I would replace only the one with the fault code.

[kezcapt]

Thank you again. Not an easy job but well worth the effort. Your prompt replies help a lot. It actually worked out for the best as the Bailey Dv's arrive Wednesday and the 30k service was due any way. I am a little distressed that the injector failed so quickly but the Kressieg exhaust keeps my right foot busy. Lastly, what is your opinion on the 5 bar pressure regulator upgrade? I am so into the rush of straight pipe acceleration I wonder about fuel delivery. Nevertheless it is a pleasure dealing with a rational, deliberate adviser. Many thanks.

Rob

[wvicary]

Why not measure the the injector to see if it's open circuit instead of replacing it or are you sure it's the problem?

[kezcapt]

As I lack a manual, I would be interested in techniques for measuring the injector. Frankly, a swap is out of the question as the work to assemble the mess is well worth the money to replace the injector. Your input is always appreciated. Thanks.

Why not measure the the injector to see if it's open circuit instead of replacing it or are you sure it's the problem?

[kezcapt]

well I replaced the injector and installed the Bailey DV's so I am back to a wiring problem. I tested the #1 fuel injector (driver's side at the back) and it had 12v with the key on. I am guessing it is either shorted or the DME is unhappy. I have a durametric coming in a couple of days. Anyone have a DME pinout so I can trace the wire? just knowing the color combo would be useful. Thanks