Fuel pressure regulator???

Superboom

Registered User
:confused: Hmmm...where to start.

First off, the car is an '89 SC 5-spd.

Here's my situation. Yesterday I had washed the car, and cleaned and detailed the engine bay. Once all of that was done, I tried to move the car, and it wouldn't start. I let it sit for a while, and sure enough, it started. Everything seemed to be running just fine, and I took it around the block. This morning I started it up, and it was running just fine.

Around noon I made a stop, parked on a slight incline, and shut the car down. When I returned, about 5 min later, it would not start. It would simply turn over, but would not fire. It smelled strongly (more than usual) of gas.

I had a friend pick me up, and returned to the car a few hours later. As I figured, it started right up, without hesitation. I drove it around for about 20 min, and stopped for some food. This time I had parked on a slight decline. When I returned to the car, it did the same thing. It would just turn over, but would not fire.

While driving the car it seemed to be running rich, as the exhaust had a slight gas smell, and it was smoking a little under heavy acceleration. I just put the engine in a few months ago, and the car has been up and running for about 6 weeks now. Within the last 2 months I have replaced the battery, alternator, and water pump. Previously, the car sat for about 2 years while I was working on it.

Does anybody have any idea what could be causing the car not to start? I suspect it's getting too much fuel, but don't know how to regulate that. As far as the fuel system, it has a new fuel filter, 38# injectors, and a 190 lph fuel pump. The ignition system has double platinum spark plugs, magnacore wires, and a stock coil pack.

I am suspecting the fuel pressure regulator, but would that cause it not to start? Also, what could the water have gotten into that may have caused this. I figured that if the water were the source of the problem, it would have evaporated by now. I made sure to get minimal water on the alternator, coil pack, battery, and other electronics.

Any ideas would be greatly appreciated.

Thanks in advance,

A.J. Gray
89 SC 5spd
 
You mentioned that you put in new 38Lb injectors.....if you did not change the calibration on the MAF (or EEC tuner if you have one), then it will be spitting more fuel than what the computer thinks it is putting into the engine. The stock injectors are only 32Lb, so there will probably be alot of extra fuel.

I'm assuming you haven't changed to a larger MAF cause you didn't mention it in the above post.
 
That would be 30

Those would have been 30 lb, injectors stock. And the car should, run, maybe a little rich, but run. I would measure the fuel preasure at the schreader valve with the car running. It should read 39 PSI. However, Scot is right, if you have not updated you MAF to reflect the increase is injector size it will lead to problems.

Dave
 
Sorry about the lack of information. Let me clarify what I have replaced/upgraded.

9" K&N Conical Filter, 76mm MAF w/38# calibration, 3" Intake Tube, 70mm TB, M/P Inlet Plenum, S-model SC, Raised top, I/C Fan, 38# injectors, Magnacore Wires, Shorty Headers, Custom Exhaust w/out cats....I think that's it for the engine.

Now that you mention the MAF, could I have gotten some water or cleaner or something on the MAF wire? If I did, and if it dried on the sending wire, I'm thinking that could possibly contribute to the problem.

Any more ideas are quite helpful.
 
I feel your pain.

I've been dealing with a similar problem for almost two months now. Sometimes she'll fire right up, sometimes I'll wait for two hours. What I did eventually realize is that if I gave her electricity, eventually the yellow "check engine" light would turn on and I would hear what I'm now 99% certain is the fuel pump kick on. Only then will she grace me with her presence and fire up. She tends to be more inclined to give me less hassle when she's cold outside, but not always. I paid $200 to have a relay replaced, then another $200 for a fuel pump and now I'm looking at $300 more for some sort of sending unit? what the helllll?!?!? Anyways, waiting on a part but I'll let you know if it fixes it.
 
This may sound off the wall but...

the crank sensor sets up the sequencing for the injectors. If in your cleaning some dirt got jammed down there, it might cause the prob. Since it only happens after it's "hot", that could be due to expansion, making it look intermittant.

Just be careful checking and cleaning.

Lee
 
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this sounds 100% like a failed fuel pressure regulator to me. I've seen the exact same scenario twice. What you should try is to remove the vac line from the top of the fuel pressur regulator and then start the car. Most likely, gas will shoot out of the top of the FPR. That should NOT happen. A failed baffle in the FPR allows gas to get into the vac line and that causes all sorts of problems like you are describing.
 
I had a similar problem, but with the insight from a $47 fuel pressure guage and the schrader valve by the right front side of the supercharger I was able to figure out that one of my injectors is stuck opon. However, I was not able to reach the FPG vacuum line until apart, but a very good tip.

Link below (hopefully works) will take you to what I too described as a MEGA rich fuel problem, yet everyone thought was head gaskets.

If the link does not work, it is almost at the bottom of the 3rd page of these technical posts "Billowing Smoke in WA"

Good luck!

http://www.sccoa.com/forums/showthread.php?s=&threadid=27299
 
Well, it wasn't the FPR. I replaced it Wed night, and took it for a drive yesterday. Everything seemed to be running better, and no more gas smell in the exhaust. I drove it to work this morning, and once it was parked, I shut it down, and tried to restart it. It wouldn't start.

I read in a similar post that the Temp sensor can lead to a similar problem, telling the ECU that the car is cold, and therefore running it rich. That could cause this as it only does this once the car is warm, and the problem seems to get worse the longer the car is driven.

If anybody could give me input, or if anybody agree's with me, please let me know.

Thanks again for all of the responses.

A.J.
 
well did you ever actually TEST the fuel pressure?........that's what i'd do first, you can get a gauge for about 40 bucks. As for your question on the temp sensor, yes it COULD be the coolant temperature sensor (not the sender for the gauge). I had a very similar problem in my 90 Bronco and it was the Coolant temp sensor that was the culprit. it would flood and smoke black and run real rich, sometimes i could get it to start by holding the throttle open and cranking it, just like if you had flooded an old carbureted engine (yeah i still remember those). the computer uses information from this sensor to determine how much fuel is needed, and it's a cheep part so you might throw one in just for fun. In my Bronco it was easy to get to and took 5 minutes to change, so figure 3-4 days on an SC..............
 
I did test the FPR AFTER I had bought a new one. BTW it was only $21.99 for a new one at Advanced Auto. I don't have a fuel pressure gauge, so I pulled the vacume line off, and fuel did not spit out of it. As far as changing it, it wasn't the easiest thing in the world, but I've torn the engine apart enough times, that it "only" took about 2 hours start to finish. The way I look at it, at least I have ruled that out, and shouldn't have to worry about it in the future.
 
I agree, that a temp sensor for the ECM could cause the TBird SC to run rich. That is what was originaly thought of on my problem. There are 2 temp sensors as Kevin was saying. The one next to where the thermostat housing is goes to the guage. The other one goes to the computer (ECM) and is right behind the DIS module (the gray thing that says "DIS").

Another thing you may want to check is if anything could be banging against the engine, causing a possible False Knock Sensor to tell the ECM to richen it up. When my balancer broke from the pulley/housing shaft thingy..it was free spinning and banging into the housing, thus had me contemplating this theory.
 
My fix

Well...........my guy replaced my fuel pumps "sending unit" and thus far it seems to have solved my freakish starts.
 
Hmmm...Still having problems.

I replaced the Temp Sensor, along with the Cam Sensor this weekend. Everything seemed to be fine. The car was starting, stopping, and starting again...no problems. Then I went to Subway, and parked on a downslope (I don't know if this has anything to do with it, but I'm mentioning it just in case). After about 15 min I came out, and the thing wouldn't start for me. Same 'ol problem. Is it possible that parking on the slope could have anything to do with it? The thing's been running flawlessly for the last couple of days, and now it's back to it's crap.

If anybody can think of anything else to check, please let me know. Also, it doesn't seem to be running rich anymore, it just wouldn't start. I'm assuming that when I go back to get it this evening, it's going to start right up for me as usual.

Let me do a quick run down as to what's been done...
Previously: 38# injectors, 76mm MAF calibrated to 38# inj, 190lph fuel pump, new fuel filter, new spark plugs, magnacore wires. I think that's all that's involved.
Recently: Fuel pressure regulator, Temp Sensor and Sender, Cam Sensor.

Thanks in advance,
A.J. Gray
 
Have you tried the crank sensor? My '91 did the same thing until I replaced it. Would start right up when cold but once I drove it a little I would have to wait about 30 minutes to restart it. Wouldn't explain the running rich problem but maybe they are unrelated? Just thought I would throw that out there.
Brandon
 
huh.....no....and I'm not sure why I didn't even think of that. I'm going to try that tonight.

Thanks for the tip.

A.J.
 
But even if you don't get any trouble codes doesn't mean your crank sensor is good. Mine never threw any codes. I hope you find something. Brandon
 
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