My truck ran yesterday, but not today

Tiny
IMAKEORPHANS
  • 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.

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Thursday, October 13th, 2011 AT 11:15 PM

44 Replies

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

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Friday, October 14th, 2011 AT 12:29 AM
Tiny
IMAKEORPHANS
  • MEMBER

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?

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Saturday, October 15th, 2011 AT 2:43 AM
Tiny
JACOBANDNICKOLAS
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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?

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Saturday, October 15th, 2011 AT 3:00 AM
Tiny
IMAKEORPHANS
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No, the psi stays at 40

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Saturday, October 15th, 2011 AT 3:18 AM
Tiny
JACOBANDNICKOLAS
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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?

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Saturday, October 15th, 2011 AT 3:26 AM
Tiny
IMAKEORPHANS
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For a split second

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Saturday, October 15th, 2011 AT 3:34 AM
Tiny
JACOBANDNICKOLAS
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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.

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Saturday, October 15th, 2011 AT 3:56 AM
Tiny
IMAKEORPHANS
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Here is my first post

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Saturday, October 15th, 2011 AT 4:25 AM
Tiny
IMAKEORPHANS
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Asked on October 13, 2011 1992 GMC Typhoon Engine Problem with 83000 miles

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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.

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Saturday, October 15th, 2011 AT 4:26 AM
Tiny
JACOBANDNICKOLAS
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Thanks, I'll get this to him now.

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Saturday, October 15th, 2011 AT 4:51 AM
Tiny
SATURNTECH9
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High imakeorphans why was the throttle position sensor unplugged?You said you plugged it back in?Reset the codes?Do you have any codes now?

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Monday, October 17th, 2011 AT 3:34 PM
Tiny
SATURNTECH9
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Also have you checked the coolant temp sensor yet?

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Monday, October 17th, 2011 AT 3:50 PM
Tiny
IMAKEORPHANS
  • MEMBER

Hi Saturntech, I didn't mean to unplug the TPS, I really don't know how it happened. Unfortunately, that wasn't the problem lol. I reset the computer, but now I can't get my truck to run long enough to throw any other codes. I just sent my injectorswhen out to be cleaned, but when I get them back, I will definitely check the coolant temperature sensor.

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Monday, October 17th, 2011 AT 5:28 PM
Tiny
SATURNTECH9
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Do you know how to test the coolant temp sensor with a multimeter?

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Monday, October 17th, 2011 AT 7:11 PM
Tiny
IMAKEORPHANS
  • MEMBER

Thank you, yes I do. I have my chilton manual that describes the test.

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Tuesday, October 18th, 2011 AT 1:01 AM
Tiny
SATURNTECH9
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Alright just making sure.

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Tuesday, October 18th, 2011 AT 5:57 AM
Tiny
IMAKEORPHANS
  • MEMBER

The coolant temp sensor has been replaced, along with the MAP sensor. I should have tested them rather then purchase new ones because it costs alot of money. The problem persists and I keep getting a trouble code 33.

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Saturday, November 5th, 2011 AT 10:16 AM
Tiny
SATURNTECH9
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So will the engine run and idle smooth?I posted a wire diagram for your map sensor. ALso do you have a scan tool that displays live engine data like the map sensor reading?

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Saturday, November 5th, 2011 AT 10:06 PM
Tiny
IMAKEORPHANS
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The engine starts but it runs terribly, and with alot of smoke before it will stall out. I have a datamaster cable installed in my truck but I do not have the program in my computer.

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Monday, November 7th, 2011 AT 12:46 AM
Tiny
SATURNTECH9
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We really need to see what voltage the computer is reading on the map sensor that would really help find the problem.

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Monday, November 7th, 2011 AT 1:02 AM

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