JHowell37

So let me get this straight. Not only did you hear hooves beating in the street, but you looked out your window and saw horse, and despite that you still said "nope, where's that zebra making all the racket?"

1. Your car runs like ****.
2. Mechanic claims there are error codes for the temp sensor and the knock sensor.
3. You spend $500 or more having your LH rebuilt when it may or may not have needed it.
4. Car doesn't run like **** at this point, it just doesn't run at all.

Did the PO provide receipts as evidence of the work done on the car?

Here's a hint. Now I know f*ck all about diagnostic error codes and whatnot on the '87+ cars. What I do know is that if you're car won't run, and you've got error codes, you should probably look at correcting those error codes in your initial plan of attack.

Fnic99

The PO did include receipts for the intake refresh. In addition, I have receipts for all work performed since 1995 (the car is a 91'). My mechanic also made an effort to contact the shop that did the refresh and discuss the work that had been done.

My mechanic did follow-up on the error codes and could not find any problems with the parts that were installed. He said he tested the maf, o2, temp sensor, wiring and could not find anything wrong. He had every financial incentive to start changing any part that could be involved but didn’t.

Since the car was jump-started frequently by the PO, my mechanic and the previous mechanic thought that it would be a good idea to have the LH tested and eliminate it as a problem source. Many people on this board also thought it was a necessary step. Honestly, I believe it is more cost effective to spend $35 upfront and eliminate the LH as a problem source, than to pay for 4-5 hours of troubleshooting to find out that the end that the LH is the source of the problem.

The decision to rebuild it was my own; partly to eliminate the LH as a source of problem, and partly preventative since I read that they fail frequently.

NickT

Today I went down to meet Frank and his ailing 928 to see if my eyes could see anything new..

The car cranks and has spark based on an inductive timing light so I am assuming the EZK is doing it's job along with the CPS. LH is confirmed good.
The engine does not catch at all. Fuel pump does run when the key is turned.

Using a Mightvac (Frank I left it in your garage) I tested both fuel dampers and regulator to see if there was a failed diaphragm, all 3 held pressure with the mightvav directly on them..

What I found puzzling though is with the MAF sealed off with a HDPPHTD (Home depot plumbing parts high tech device) and the mightvac connected to the vacuum line off the front damper I could not pull any vacuum. Looking at the diagram on 24-126 I should have been able to. Was going to test this on mine but I left my mightvac behind. Now I am wondering if I spend enough time trying to draw a vacuum.

I also smelled gas fumes coming out each time I pumped the handle. Not sure if this was just coming up through the plenum as the diaphragms appeared ok.

So what I am getting at here, is we have air, we have spark, so I am leaning towards an issue in the fuel system. Ideally a fuel pressure gauge would be nice to see what the bleed down is as well.

Can anyone confirm that with the MAF sealed a vacuum should be to be drawn down from the vacuum line off the front damper?

I really want to see this car running for Frank, as I am sure he does as well

NoVector

Only throwing this out there because the OP said the car was jumped often, during your next visit, try throwing your battery in his car, foot to the floor and crank for a good 30-45 seconds. That's what started mine; think my plugs were covered in crap... After all this testing, thinking his probably are too. Good luck!

Fnic99

Thank you Nick for taking the time to help me get my car running again. I sent your Vac to you via FedEx today.

If anyone is able to answer Nick's question, I would gladly appreciate it.

Thanks,

Frank

Landseer

You can have an inductive spark detecter prove spark on every cylinder, even if coil wires are sparking to ground.

There is a reason why the advice is to establish a new baseline. Those who search these 30 year old cars for the one solution, trying to surgically and logically find only the one problem that is causing the issue, end up throwing in the towel.

CE panel clean and re-fuse, ground points, cycle-through all the subsystems.

Mrmerlin

pull the plugs and see if they are fouled OR
install a good battery and crank the engine with the pedal to the floor for 30 seconds,
dont pump the pedal.
If your smelling fuel and there is spark it should run.

On the MAF plugged and not being able to pull a vacuum,
you will need a bigger vacuum source to do this

Fnic99

Landseer, I agree with your philosophy, just lack the expertise. The few hours I spent on the car with Nick definitely helped me. Plus, reading all of the posts on here is helping me understand better how everthing works. I always have the thought in the back of my head that I'm really going to screw something up. I thought I did that with the LH. I'm glad to hear that it is working.

I bought a dremel yesterday and will clean the ground points this weekend (will also change the fuses). New plugs seem like something I can tackle too. The old ones are confirmed bad by my old mechanic. The only reason I held back was the rich condition. I didn't want to foul them again. Would you suggest just changing them now?

Fnic99

Mrmerlin, thanks for your reply (and for all of your replies and informative posts). I tried the cranking with the pedal to the floor but the car still won't start. I believe the battery is fine (according to my mechanic) but don't know for sure. It is fully charged (I leave it on a trickle charger).

Mrmerlin

Glad I can assist you and your welcome.

So go to Autozone and buy 8 Bosch silver tip plugs part # 7900
you will have to ask for this part#,

check the gaps and then fit the plugs,
I use a small dab of antiseize for each plug

Fnic99

Mrmerlin, followed your advice and changed the plugs last night. They were pretty black. I tried starting the car and it fired right up. Thanks for the advice. I drove it around this morning and seemed fine for 15-20 minutes but then the "check engine" light came on. The car still smells rich but no surging idle. I am really glad that the car is drivable again. The grounds seem ok but I will sand them down as soon as I get a moment to myself (wife).

BC

We really have to get a set of rules that if you have a thread with a question and a problem and there is some sort of resolution - that you take 4 minutes and post back as to what happened.

Fnic99

Agreed, the resolution came a long time after and the original thread drifted out of memory. Replaced the ground strap, cleaned grounds, and intake refresh. The light didn't come back. Feel free to pm me if you want more details.