Mechanics

MY TRUCK RAN YESTERDAY, BUT NOT TODAY

1992 GMC Typhoon • 83,000 miles

My truck ran fine yesterday. It has a fresh tune up, good spark, fuel pressure at 36psi with vacuum hose attatched, and proper timing. I had my truck in storage for 2 years with gas stabilizer and decided to empty the tank and add fresh gas. Now it won't start.

The truck will fire intermittently while trying to start and produces black smoke. The engine is flooding at startup and the spark plugs were a wet black color. I cleaned the spark plugs with acetone and it still runs the same. I noticed that the throttle position sensor was disconnected so I reconnected it and pulled the ecm fuses to clear the code. There was no change. Unfortunately, I cannot get the truck running long enough to set any trouble codes if there is one. Please give me and idea what to check next.
Avatar
Imakeorphans
October 13, 2011.



Hi: I think I already answered this. Is that correct with the fuel pressure issue?

Yes you did, sorry about the double question. You had told me that either the fuel return line was clogged or the fuel pressure regulator was bad. I used an air hose to blow through the fuel return line and heard a thud come from the fuel tank. I did it a couple of times and heard the noises coming from the tank so I think the line is clear. I also repaced the fuel pressure regulator with a OEM unit. The fuel pressure is now 40psi when I turn the key and the problem still exists. I don't know for sure if the return line is completely unblocked. Is there any way to check? Are there any other causes?

Tiny
Imakeorphans
Oct 15, 2011.
I just spent about 30 minutes looking through different manuals. One manual says 9-13psi is spec, another one says 35 to 38 is normal. It should drop by 10 psi when started. Is that heppening?

No, the psi stays at 40

Tiny
Imakeorphans
Oct 15, 2011.
I am so sorry about the two different specs I found. Thank goodness for old shop manuals. As far as the drop when started, does it drop at all?

For a split second

Tiny
Imakeorphans
Oct 15, 2011.
I am going to ask another tech for his opinion. I'm not leaving, but adding another person into our conversation. Can you send me the original post you sent with all the symptoms the car has? Even at 40psi, that is above what my shop manual says is okay. Maybe you are right and there is something blocking the return line. Lets see what he comes up with. His user name is Saturntech with some numbers after his name. He is really good with GM vehicles.

Here is my first post

Tiny
Imakeorphans
Oct 15, 2011.
Asked on October 13, 2011 1992 GMC Typhoon Engine Problem with 83000 miles

Thanks! You've donated $ 5.00 to this question!

Flag for review

DONATE

Your Donation Helps

Online Car Repair Manuals

GMC Question

Truck Ran Yesterday, But Not Today

My truck ran fine yesterday. It has a fresh tune up, good spark, fuel pressure at 36psi with vacuum hose attatched, and proper timing. I had my truck in storage for 2 years with gas stabilizer and decided to empty the tank and add fresh gas. Now it won't start.

The truck will fire intermittently while trying to start and produces black smoke. The engine is flooding at startup and the spark plugs were a wet black color. I cleaned the spark plugs with acetone and it still runs the same. I noticed that the throttle position sensor was disconnected so I reconnected it and pulled the ecm fuses to clear the code. There was no change. Unfortunately, I cannot get the truck running long enough to set any trouble codes if there is one. Please give me and idea what to check next.

Tiny
Imakeorphans
Oct 15, 2011.
Thanks, I'll get this to him now.

Page 1 of 5