s4bill

89 928 s4

The car was sitting for some time. This is the thread.

https://rennlist.com/forums/928-foru...me-help-2.html

I had to replace the fuel pump and purge the fuel via a jumper wire on the fuel felay socket.

I pulled the plugs, put a small amount of MMO in the cylinders, retourqued the plugs. Removed the acorn nut on the fuel rail when I cranked over the engine to confirm that gas was pumping with the relay re-inserted and alll seemed great. I cranked the engine enough for the oil pressure gauge to go the first or second line.

I started the car and the car ran rough, made a little noise at first but it ran. I had planned on pulling the car out of the garage so I could hose it down and slowly drive it around the town so I was moving stuff that had accumulated around the car. I imagine the car had run for some time. I would think long enough to get to operating tempature.

All of sudden it start behaving like it was starving for fuel. Spit and sputtering. My immediate thought was oh it must have run out of the little bit of fuel that I put in the tank. I didnt want to fill it up until I saw that everything was ok. So I immediately shut it off and pull another gallon or two of gas that I had left in the gas can and attempted to restart it. The range says 75 miles. I realizd that is maybe an 1/8 tank? Anyway I attempted to restart it and it cranks, starts and immediately dies. So I disconnected the ground, pulled the fuel relay. Re-inserted the jumper wire and turned the fuel pump on and it is running. So I pulled the acorn nut again on the fuel rail and hit the on switch let it run for a second or two and there was gas collected int he container. So it appears that the fuel pump is delivering fuel.

Here is the interesting part. I am not sure if this indicates anything or is expected behavior. I got irritated so I turned the fuel pump off and turned the key and it started and ran a tiny bit longer. It starved and stalled versus stalling immediately. It didnt run long but a half second or second (or two) vs nothing.

I am just wondering why it started an ran after sitting but now it wont.

I thought maybe it was related to the temperature of the engine.

I went out this morning, turned on the fuel pump(with the jumper wire) and it started and it ran. It ran rough. The tach needle seemed to bounce a little maybe even on the low side. I let it run a few seconds 5 or so and then decided to shut it off. I tried to restart it and back to the situation from last night.

There are a lot of threads on this but I wanted to see if there was anything specific about my situation that anyone could determine.

Thanks to everyone who has helped me do the diagnostic on the fuel pump and get it this far.

davek9

I think the 89 has the CAT protect Relay mounted just outside/next to the EZK, see if one of the LEDs are lit

Courtshark

When mine sat for a while, the culprit was the MAF that was causing it to run rough. Swapped out the MAF, and runs like a top again (after having replaced the spark plugs, adding 2 cans of Sea Foam, doing an oil change, cleaning the distributor rotor and connections, and investigating the coils for "fireflies", none of which changed anything). Check your MAF connection first, too. There was nothing outwardly wrong with my MAF, and it was a JDS/928sRUS rebuild from about 3 years ago. Replaced it with one I had on the bench, and all was well. Good luck.

dcrasta

Bouncing tach makes me thing electrical. Maybe a loose or bad engine ground. Also check the igniter pack on the front bumper support. I would disconnect and reconnect all of those things. (Disconnect the battery first.).

Also idling sometimes can foul plugs (especially if the TempII sensor is bad) as the enrichment takes longer to turn off if you are not driving. Probably just needs a good drive but after you confirm your electrical stuff is up to par. Last (sorry this was off the top of the head) change the plugs, confirm the plug wires are all connected well .

jej3

+1 on MAF.... I let mine sit for like 8 weeks and the MAF and the LH turned out to be bad.

My whole saga is documented here.... https://rennlist.com/forums/928-foru...-no-start.html

s4bill

"I think the 89 has the CAT protect Relay mounted just outside/next to the EZK, see if one of the LEDs are lit "

I see a plastic box next the the EZK. I assume that is what you are referring. If so, I dont see any lights.

This is the irritating part. I found this relay or believe I found it and noticed no lights. So I decided to turn the key to ON to see if that is needed for the light. No light so I decide that I would try to start it to see if that would generate a light. I turn the key and the car starts and runs. The tach goes to the line just below 1K and then settles down below that line. So I just patiently wait for it to stall. It doesnt. I let it run until it reaches about 170 or just past 170 degrees and turn it off. I am convinced that I will have a problem restarting it. I restart the car at least times and it runs. Its not as smooth as I think it should be but it is running.

I leave the car sit for a couple hours. I thought I would take it for a ride when I took a break from work. I go back outside to start it and it has the problem again. Start then immediately stall. If I leave the gas pump off. Start, run briefly and studder and stall. I pressed the pedal to the floor turned the key and it briefly started and it studdered and I got the bright idea of pumping the pedal and that did nothing more than stalll the car.

"Maybe a loose or bad engine ground. Also check the igniter pack on the front bumper support. I would disconnect and reconnect all of those things. (Disconnect the battery first.)."

The tach was not bouncing when I ran. I am saying that it jumped when it started or dipped when it was stalling. It doesnt move around a little bit. Where is the engine ground and there are a few thins on the bumper support. Is it on the driver or passenger side?

Does it sound like my engine is flooded?

I am going to check the wires ot the MAF


So I am back to the problem.

Bilal928S4

Check the main ground. Other people have had the problem of it corroding under the platic sheathing and causing these problems. Also the car really needs a fully charged battery to start. Might be worth while to put a temporary ground from the battery to the body in parrallel to the original. Then it seems you just need to drive the car to get all the new fuel flowing and clearing out the system.

s4bill

"Bilal928S4 Check the main ground. Other people have had the problem of it corroding under the platic sheathing and causing these problems. Also the car really needs a fully charged battery to start. Might be worth while to put a temporary ground from the battery to the body in parrallel to the original. Then it seems you just need to drive the car to get all the new fuel flowing and clearing out the system. "

Are refering the ground in the rear hatch from the battery? I have had it off and on several times and seems clean and fine. If not, where is it located?

Bilal928S4

Yes, however there have been instances that the corrosion is inside the sheathing at the transition point and not visible outside. Might be worthwhile to just get a generic piece of grounding cable and just connect both the points in parrallel to rule out a bad battery ground.

C4Scott

I had some of the same symptoms you had and here is what it turned out to be for me.

Check the fuel pressure regulator and the two fuel dampeners for leaking first. Pull the vacuum hose off each one and smell for gas as they will leak into the vacuum system.

When one or more leaks, you can get the symptoms you describe. Also black sooty exhaust for the few moments after it starts.

s4bill

"Check the fuel pressure regulator and the two fuel dampeners for leaking first. Pull the vacuum hose off each one and smell for gas as they will leak into the vacuum system.
"

Where are these located?

928Myles

The regulator and dampers are all cylindrical metal valves with 2 or 3 fuel fittings and one vacuum fitting on each. One sits in front of the engine just to the right of the oil filler neck (as you look at it). The other two sit at the rear of the engine block below the air filter housing.

Myles

SteveG

Number 6. There is also one under the air box, drivers side IIRC. They have a vacuum line coming off the diaphram.

s4bill

I will try to smell the vacuum lines but I cant say that I will be able to tell as my garage already smells like gas and my sinus are not great.

Is there anothe way to check to see if they are leaking?

Mrmerlin

if there is gas in the vacuum lines you will smell it