SalzundPfeffer

So my ’84 N/A started acting up last week. The car was having stumbling issues when I would get on the gas the first time after I started the engine. I don’t know if it was stumbling or not. It felt like the car was running out of gas. I had to gas it pretty good to get the revs back up so I could get going. It only did this right after startup and then would be just fine. Turning the car over after it had been sitting wasn’t an issue either.

However, I went to start it Saturday morning, and nothing. Would just sit there and crank. I had to crank it a good 5 minutes before it finally caught. Again, it felt like a no gas situation. I had to give it some gas to finally get the revs up so it wouldn’t stall.

I am thinking it could be my fuel pressure regulator. Maybe the fuel rail is vaporizing at shutdown and I am left with a vapor lock in the engine. I put some HEET in to see if it is moisture related, but still have had the same results. I know I have sufficient gas in the tank too.

Just wanted some opinions.

*On a side note, I wanted to also mention that my alternator light has been coming on in the morning. Has just started with the cold weather. However, after I bring the RPM’s up, the light goes out. I don’t think it’s related, but wanted to throw it out there. The light thing has been going for about a month now, and I haven’t had any running issues until this past week. Another thing I will have to fix when I get time.

bbourdon

Check to see if the fuel rail is leaking. Put your key in the ignition and turn it to the first position to prime your fuel pump. Pop the hood and put your ear to the fuel rail. Do you hear leaking? If yes, from where?

If it is coming from around the injectors, it's time to replace the o-rings, spacers, and caps on them.

If the leak is coming from the FPR or FPD, replace as required.

If the leek looks like a vegetable, you are in the grocery store.

DarylJ

Does that work on an early? It doesn't on a late.

bbourdon

It worked on my 85.5

mtccl

Alternator is on the way out. Happened to me last year with same indications. One day the light will come on and stay on and the alternator will be dead. Get a replacement now.

Fuel issue is probably the fuel pump. That is where I would start. But, it could also be spark if you are having electrical issues. You may not be getting a good spark due to your alternator going bad.

Start by replacing the alternator and see if that helps. Then Fuel pump and more diagnostics.

StoogeMoe

It's not supposed to work. The DME only turns on the fuel pump when it thinks the engine is rotating.

StoogeMoe

Oh, and back to the original question, I would check your engine temperature sensor. It may not think it's cold and not be giving the appropriate mixture.

DarylJ

That was my understanding on how things were supposed to work as well as my experience with my 85.5. If this is wrong, I'd like to know, as I've got something wrong or have missed something somewhere along the line.

SalzundPfeffer

Are you suppose to be able to hear the pump running when you have the key in the first ignition position? I tried and couldn't hear anything in the pump area, so I didn't think anything was happening. Is there a way to jumper the fuel pump at the relay board?

Also, does anyone know of any auto parts stores who rent fuel pressure gauges?

bbourdon

When you turn the key to the first position, you should hear the pump priming the system. I found a leak around the #3 injector.

Just buy one from pep-boys. They are cheap.

SalzundPfeffer

Does the pump only operate momentarily to prime the system. Or does it stay on to continuously prime the system?

SalzundPfeffer

Resurrecting this thread...

Just got the car out from hibernation this weekend. Right before the first snow, I replaced the fuel filter and resealed the orings to try to fix the stumbling issue. All indications were that the problem was fixed when winter hit.

The "shakedown" this weekend looked good too, no issues. However, stumbling issue started up again this afternoon on the way home from work. It got so bad I had to pull it into an Oreilly. I remember clarks garage mentioning stumbling issues could be spark plug related.

I pulled the plugs at Oreilly...Those suckers were done. PO said they were replaced "recently." Corroded, gap up to 0.060" on some. Replaced with new. The car ran great all the way home. I believe this was what was causing the issue. It may also explain my alternator light if the plugs were pulling excessive load. Just wanted to update to hopefully help someone else down the road.

-bp

peanut

remove the DME and link pins 30 & 87b you should hear the fuel rushing through the rail. Alternatively remove the bleed nut on the rail ( watch out for the ball bearing) and see if you have fuel there. Put a rag under or it will go everywhere.
Place a bit of garden hose on the threaded boss where you removed the bleed nut and place it into a 2lt plastic bottle and re-connect the jumper wire and you should see fuel gushing into the bottle at approx 900mlts every 30 seconds .



My guess would be the injectors are sticking due to fuel residues and maybe lack of use recently ? you can remove the injector power connectors and run a 12v cable from the battery.

Touch the neg onto one injector pin and brush the 12v+ wire across the other pin. You should hear a distinct click as the injector piston bounces . Don't keep the 12v+ cable on the injector at any time. It must be a very quick touch to get an arc . Repeat 10-12 times each injector to free them up.

Fuel pressure guages cost about 15$ on ebay or you could probably use a tyre pressure guage they are the same guage. Must be able to reach min of 4 Bar pressure .

oops should have read the last post. Still the advice might be helpful to someone searching the forum for similar problem