1990 928 GT with chronic 4 cylinder mode issue

malcolm;5976 wrote: Didnt know what you did Brad and wouldn't presume anyway.

Stan, I do have a harness off a '87.....let me know.

I have an '85 harness that might have the right connector. I started the shrink wrapping yesterday, so will finish that up and see where I am afterwards.

I am wondering how different the harness is from year to year. If someone had a real good harness, I would consider the task of swapping it in

Thank you for the offer, I will keep it in mind.

First, thanks to those who have made suggestions so far

Today I finished putting shrink tubing on the MAF wires that had broken coating. I then wrapped that section with electrical tape as a replacement for the cracked boot, and to further hold the shrink tubing in place.

I started the car and it idled well, even when I put the A/C on. I drove it 1/2 mile or so, with no issues. I then drove @60 miles round trip tonight without the limp mode symptom occurring at all. Perhaps I will jinx myself, but I would rather have it happen again and know, then have false optimism.

I do have (at least) two problems to address *if* the limp mode problem is gone. Sometimes my gauge cluster warning will flash “anti lock brake disabled” and “locking differential disabled”, this has often been after a bump in the road. My volt meter also will drop to 0 for long periods of time. Prior to taking the car in for service, the volt meter symptoms existed, but not the other symptoms. When tested in the past the battery was getting charged when the volt meter was 0. I am guess this might be a ground issue, maybe in the pod… I am interested in hearing other's thoughts.

good job Stan.....hopefully you have the 4 cyl issue fixed.

The loosing signals on the pod is perhaps one issue a 3 or more. I'd start by looking at the ignition switck then pull the pod and inspect the wiring and circuits.

When was the PSD serviced?

Has any of the ABS relays been replaced? Does the ABS work?

malcolm;5983 wrote: good job Stan.....hopefully you have the 4 cyl issue fixed.

I am hoping and am concerned that I am overly optimistic

malcolm;5983 wrote: The loosing signals on the pod is perhaps one issue a 3 or more. I'd start by looking at the ignition switck then pull the pod and inspect the wiring and circuits.

I have a replacement pod in hand to address the splits in this one, so it gives me another reason to take this task on.

malcolm;5983 wrote: When was the PSD serviced?

In the 2010 service.
The PSD light comes on often enough when accelerating in corners with slipage that I am confident it was working.

malcolm;5983 wrote: Has any of the ABS relays been replaced? Does the ABS work?

I have not replaced any relays.
I believe I have had the ABS kick in when on wet roads.

Since these problems are not present at startup, except for the volt meter issue intermittently, I can verify PSD and ABS before proceeding.

Thank you again for your thoughts.

Good news on the MAF connector. This can absolutely be the cause of the issue and for some reason I thought we'd been through that. Hope it fixed the issue.

On the PSD/ABS, check the barrel connectors at each wheel for condition, a broken ground wire can cause this. If those are all good, get under your seat and check the inertia switch, these can get unplugged, or inside they need to be cleaned. Don't think about buying a new one, they are expensive. Search on R-list for inertia switch in both the 928 and the 964 sections.

It also could be a crappy relay, that has a loose component when hitting a bump.

Hi Stan, I have a different idea.
Since you are having more then 1 gauge problem, try this.
Well driving, put your right hand under the pod and feel for the wires where they go into the pod.

Move them around, push them tight, and see if this changes the volt gauge issue.
I know that I have a bad contact on 1 of my connectors as well as when I squeeze the right side of the cluster, my problem goes away.

I’m not saying anything but this is a quick check that will help locate loose wires if there are any in that area.

I need to pull mine apart and tighten the pin grip as mine looses connection as the dash and wires warm up.

Brad:)