Starts and dies,,

[94GMC2500]

I hate to be a pest lately, Anyway my truck starts and runs a couple seconds and dies on a cold start, if 80 degrees is a cold start lol. If I hold gas pedal down some it will take off and then it will idle. Once it runs a little while its fine when restarting. When I get it started it runs and drives fine.

I have bleed fuel filter and lift pump is making pressure. It has done this in the past at times. This time it seemed to start this stuff after I put some fuel system cleaner/lube in the fuel.

I don't remember the name of the stuff, the bottle went out in the garbage. did I do a bad thing adding this stuff to the fuel?


I made a video of how it acts but I don't know if I can post it, its over a minute long.

[DmaxMaverick]

If a fuel additive causes poor starting, your injection pump and/or injectors are worn out. Otherwise, look for an air leak. By the sounds of it, it's probably not very big. Begin by replacing the fuel filler cap, if it isn't relatively fresh. A sticky fuel filler cap vent can allow excessive fuel system vacuum after cooling off.

[94GMC2500]

Thanks for the ideas. I just discovered if I unplug the coolant temp sensor it fires up instantly and idles fine, idles faster though.

Coolant temp sensor was new this morning, I was wondering if the sensor was part of the problem so I got a new one.

[DmaxMaverick]

Disconnecting the temp sender tells the PCM the ECT is -40. The GP's should cycle longer and the idle should increase. If your GP's are AC60G's, you need a mod or override to glow them longer when you're in moderate climate, such as 60F+.

Alternatives:
Install "Quick Heat" type plugs.
Disconnect/reconnect the temp sender for cold starts when it's 80F.

[94GMC2500]

I put Bosch glow plugs in a couple years ago.

It wouldn't surprise me with this truck if injectors and pump are junk. Seems like the fixing never stops with this thing.


I wish I could get a Dmax but don't have the money.

[Yukon6.2]

I put Bosch glow plugs in a couple years ago.

It wouldn't surprise me with this truck if injectors and pump are junk. Seems like the fixing never stops with this thing.


I wish I could get a Dmax but don't have the money.
The repairs on a Duramax cost significantly more,and there is a chance that you would have to pay someone to do some of the work.
If you shop wisely you can probably buy and injection pump and injectors for less than the price of injectors for a Dmax

[94GMC2500]

True, I can at least work on my 6.5 myself, Sometimes I wonder if I know what I am doing though.

[Yukon6.2]

Thats what the Page is for...
Enabling owners to fix their vintage GM's

[arveetek]

Disconnecting the temp sender tells the PCM the ECT is -40. The GP's should cycle longer and the idle should increase.

Alternatives:
Disconnect/reconnect the temp sender for cold starts when it's 80F.

One of my favorite mods I did years ago: I installed a time-delay relay into the circuit of the temp coolant switch so that every time the engine starts, that circuit opens and fools the PCM into thinking the engine is stone cold. This allows for a fast and easy startup. A few moments after the engine is running, the relay closes, completing the circuit, and the engine returns to normal operating parameters. Works great for fast, easy starts.

Casey