[Blayze]

Since last post…

Capped the vacuum port going to the secondary smog pump, truck started up 3 days in a row below freezing weather.
Until this morning about 15 degrees, turned over forever like usual.

I went back inside grabbed a 470 ohm resistor i had and plugged it into the intake air temperature sensor wire connector.
Truck started right up.

[Blayze]

🙁

Several months have past since my last posting. Since then my truck has been in the dealership getting worked on..
With no prevail..
The service techs could not identify the problem. Went through everything only thing left was the ecm.

ECM was replaced and programmed still having the same problem. I’m wondering if this could be an issue with the programming after hearing about other gm programming issues.

im at a complete lost

[Blayze]

I wouldn’t think so as this vehicle is my daily driver gas constantly gets cycled through it, I’ve been having the problem for several years at cold weather.

I also have “Heet” fuel stabilizer in the tank aswell.

Interesting tho, I had my Check Engine Light Checked again after it came back on. A new code came up, P0300 for random misfire. I hooked a timing light up to each spark plug wire and the flashing of the light matches up with the rpm of the engine. Nothing intermittent.
Was thinking I’d check the resistance of the wires and inspect the dist. cap for corrosion.
Could I be misfiring on start up and the misalignment is not severe enough to effect warm weather start up.

…idfk but I’ll keep on testing..

[Blayze]

I wouldn’t think so as this vehicle is my daily driver gas constantly gets cycled through it, I’ve been having the problem for several years at cold weather.

I also have “Heet” fuel stabilizer in the tank aswell.

Interesting tho, I had my Check Engine Light Checked again after it came back on. A new code came up, P0300 for random misfire. I hooked a timing light up to each spark plug wire and the flashing of the light matches up with the rpm of the engine. Nothing intermittent.
Was thinking I’d check the resistance of the wires and inspect the dist. cap for corrosion.
Could I be misfiring on start up and the misalignment is not severe enough to effect warm weather start up.

…idfk but I’ll keep on testing..

[Blayze]

checked compression recently, 165 psi in all cylinders. So that’s good.

Was questioning the ECM, so I removed it and placed it inside overnight. Reinstalled it with dielectric grease the next day. Still cold temp outside but fired right up on second crank.

I’m wondering… did the ECM get reset from being unplugged and solve my problems? Are there any loose connections or solder spots that may be breaking from shrinking in the cold? Was there moisture in the connectors that I cleaned up?

If it starts tomorrow after sitting in the cold overnight, I’ll have more information.

Has anyone experienced similar problems or know of any regarding the ECM and its failures?

[Blayze]

checked compression recently, 165 psi in all cylinders. So that’s good.

Was questioning the ECM, so I removed it and placed it inside overnight. Reinstalled it with dielectric grease the next day. Still cold temp outside but fired right up on second crank.

I’m wondering… did the ECM get reset from being unplugged and solve my problems? Are there any loose connections or solder spots that may be breaking from shrinking in the cold? Was there moisture in the connectors that I cleaned up?

If it starts tomorrow after sitting in the cold overnight, I’ll have more information.

Has anyone experienced similar problems or know of any regarding the ECM and its failures?

[Blayze]

woops, i posted that last reply in the wrong thread :blush:
ment to go in “Cold Weather Crank No Start” thread I posted

[Blayze]

woops, i posted that last reply in the wrong thread :blush:
ment to go in “Cold Weather Crank No Start” thread I posted

[Blayze]

checked compression recently, 165 psi in all cylinders. So that’s good.

Was questioning the ECM, so I removed it and placed it inside overnight. Reinstalled it with dielectric grease the next day. Still cold temp outside but fired right up on second crank.

I’m wondering… did the ECM get reset from being unplugged and solve my problems? Are there any loose connections or solder spots that may be breaking from shrinking in the cold? Was there moisture in the connectors that I cleaned up?

If it starts tomorrow after sitting in the cold overnight, I’ll have more information.

Has anyone experienced similar problems or know of any regarding the ECM and its failures?

[Blayze]

checked compression recently, 165 psi in all cylinders. So that’s good.

Was questioning the ECM, so I removed it and placed it inside overnight. Reinstalled it with dielectric grease the next day. Still cold temp outside but fired right up on second crank.

I’m wondering… did the ECM get reset from being unplugged and solve my problems? Are there any loose connections or solder spots that may be breaking from shrinking in the cold? Was there moisture in the connectors that I cleaned up?

If it starts tomorrow after sitting in the cold overnight, I’ll have more information.

Has anyone experienced similar problems or know of any regarding the ECM and its failures?

[Blayze]

[quote=”JTF” post=118968]If I remember there was a TSB on crank no start when cold, due to low compression.GM said diagnosis lead to a compression loss due to sticking valves because of low detergent fuel been used at that time period. The fuel deposits would get on the intake valve stems and cause the valves to stick in the valve guides. The fix was clean the induction system using GM Top Engine Cleaner.[/quote]

interesting information.
I thought of running seafoam

I’ll do a compression/leak down test and then give that a try.

[Blayze]

[quote=”JTF” post=118968]If I remember there was a TSB on crank no start when cold, due to low compression.GM said diagnosis lead to a compression loss due to sticking valves because of low detergent fuel been used at that time period. The fuel deposits would get on the intake valve stems and cause the valves to stick in the valve guides. The fix was clean the induction system using GM Top Engine Cleaner.[/quote]

interesting information.
I thought of running seafoam

I’ll do a compression/leak down test and then give that a try.

[Blayze]

Yes spark plugs are brand new OEM, and are all getting strong spark.

Cycling the key was just one of my attempts to test my fuel pressure tester accuracy.

Disabling the injectors was also another attempt of starting if there was a flood.

Have checked all fuses, all look good.

I’m not sure if the check engine light stays on while cranking or not, have to get back to you on that.

I think I will test for compression also next. Maybe a shot of oil in the cylinders could help?

Does not try to fire. Sometimes. On chance, I believe. It will, but for the most part; I’m shit out of luck

This is a reoccurring problem I have been facing for the past few years.. Cold Weather, Wont Start.

[Blayze]

Yes spark plugs are brand new OEM, and are all getting strong spark.

Cycling the key was just one of my attempts to test my fuel pressure tester accuracy.

Disabling the injectors was also another attempt of starting if there was a flood.

Have checked all fuses, all look good.

I’m not sure if the check engine light stays on while cranking or not, have to get back to you on that.

I think I will test for compression also next. Maybe a shot of oil in the cylinders could help?

Does not try to fire. Sometimes. On chance, I believe. It will, but for the most part; I’m shit out of luck

This is a reoccurring problem I have been facing for the past few years.. Cold Weather, Wont Start.

[Blayze]

Any progress is good progress I suppose B)

[quote=”college man” post=118805]Sounds like good progress to me. :)[/quote]

[Author]

Replies