j.kenzie@sbcglobal.net

This is what I found for injector no. 2. All others look OK. The fuel rails came out very easily, so I think the seals were past it too. They're off to WitchHunter.
Thanks for all the advice.
I look forward to swapping my 927 for a 928.
Dave

hacker-pschorr

j.kenzie@sbcglobal.net

What a great bunch of people here!
Well I'm pretty blown away. Hacker predicted a bad injector, he told me how to localize which one, and when I described less of a stumble when I pulled #2 spark plug, he predicted exactly the type of situation reflected in the picture. That's a pretty good path to a diagnosis in my book. It is also not the first time that I have received excellent advice on this forum, and I am very grateful. I will post the flow values from WitchHunter when I get them.
Thanks,
Dave

Speedtoys

Well, he agreed...that it could be a bad injector...

j.kenzie@sbcglobal.net

Yes!! You are and were absolutely right. You were the first to mention a possible bad injector.
Thanks very much, Jeff.
Dave

Speedtoys

I was there once..my issue was 1 injector on one side, flowed 2x more...

Here was mine when I found it.

j.kenzie@sbcglobal.net

Results coming soon. I shipped my injectors last Sunday, and USPS says expected return delivery is tomorrow, Monday or 8 days. That's very quick turnaround. I'm anxious to see the pre- and post-service flows. Also to reinstall and check the running.
Can't wait,
Dave

j.kenzie@sbcglobal.net

Hi again guys,
Well I have somewhat disappointing results. My pre-service injector stats were all quite good, 4% variation. Post-service they were better, down to 1.5% variation. All good spray patterns.
So I reinstalled with all new seals and hoses. I checked for leaks, and all was good. I started up and after coming to a stable idle at 900 RPM (I run a little high for alternator output), I get AFR of 14 on the driver's side exhaust, and 16 on the passenger. It actually sounds a little smoother, but could be imagination. I will go around and look at all the plugs and plug wires this week.
Thanks for your interest. I may just learn to live with this.
Dave

hacker-pschorr

Ok....fuzzy memory here.

I "think" the L-Jet cars have separate grounds for each bank of injector plugs and each bank goes directly to the brain. Where as the LH cars it's one set of wires feeding all eight.

So yea...could be a grounding issue or even an L-Jet brain hickup (or something with a wire or wires in that run of the harness).
I don't think the wires will reach but swapping one bank of injector harness over and see if the problem moves is what I would personally try to do. Never done that before.

I have a couple spare L-jet brains.

j.kenzie@sbcglobal.net

Thanks, Eric. I did clean the passenger side grounds, and I will look for the driver's side also. Interesting idea to swap injector harness halves. Not sure if possible or not, I will look.
I may ask to borrow an L-jet brain, if it comes to that. Thanks again for your generosity.
Thanks all,
Dave

j.kenzie@sbcglobal.net

Well I looked. Both L-jet grounds are on the passenger side valve cover. I did clean them. Since the L-jet brain is on the passenger side, I don't think the PS injector harness will reach to the driver's side. Other way, no problem. I was hearing good injector clicking on all 8 injectors.
Maybe the plugs will tell me something.
Thanks,
Dave

j.kenzie@sbcglobal.net

Trial L-jet brain coming on Friday. I will update then.
Thanks,
Dave

j.kenzie@sbcglobal.net

Plugs were pretty unremarkable. I had them in a piece of cardboard, numbered for pictures, but they all looked about the same. No burning, fouling, and they all gapped fine, so I put them back in. I will wait for the trial L-jet brain.
Thanks,
Dave

medipedicman

Thanks for documenting the method for tracking down your problem and thanks to all the owners who have chimed in with advice. While I do not have the same problem I have found the information in this thread very useful.

Thank you

j.kenzie@sbcglobal.net

Hi again,
Well my trial L-jet brain arrived, and there is No Difference. Shucks. Since I had reconciled myself to accepting a 2-point AFR difference, from one cylinder bank to the other, i reconnected all my supercharger piping. That does change the AFM behavior a bit. The best I can get now is a PS AFR of 14.5, with a DS AFR or 12.5, at idle of 800 RPM (open loop). It does idle very smoothly, and throttle response is good, no load. My temporary double O2 sensor setup is not for driving.
All in all, the numbers are not terrible, so I think I will just leave as is for now, barring any other great suggestions, of which you all have provided many so far.
Many thanks,
Dave