Hey, this is my first visit to this forum. I bought a 1996 4.3L Vortech C1500 this past year. It has about 140,000 miles on it right now and just recently i have been running into a hard start (some times No-Start) when cold (sitting over night on a cold day).

I have checked the plugs, spark at the wires, fuel pressure (holds about 62 psi steady). The crank sensor was replaced, the injector has been cleaned (disconnecting the fuel line and running the
pressurized solvent throught the injector). I pulled the IAC motor and cleaned the carbon from it (wasnt too gunked up anyway).

Using the Haynes manual i checked the Cam Sensor (not a complete check as i could only check for voltage with a DVOM).

I checked the resistance of the coolant sensor against the resistance vs. temperature chart in the Haynes manual and it seems good.

No trouble codes have been set.

To top it off, when i spray starter fluid into the throttle body, it starts up without and issue, and will restart without a problem after that. This leads me to beleive that the problem is related to fuel.

Any ideas on what could be my problem? At this point i am open to any and all suggestions.

Thanks a lot in advance!

 

Welcome to the forum
Excellent descriptions of what you have done to troubleshoot the issue, as many of those would have been the things you would have heard listed to check.
I tend to agree with you on the fuel delivery since it firing up with stater fluid... I know you said the injectors have been cleaned, how long ago where they done? it might be worth trying a couple of bottles of injector cleaner threw the tank, the reason I say that is because I had a similar issue and every time I ran the cleaner the hard starting would go away for a few weeks.
I ended up replaced my injectors and that did solve the hard start problem
mine was on a 97 5.7.

 

cleaner wise, use Seafoam. STRONG medicine.
CHeck your coolant temp sensor. One that tells ECM coolant temp, not one that turns fan on. Those are told to be real pain in too-too on cold starts problems.

http://autorepair.about.com/cs/troub...042603a_04.htm

from here:
http://autorepair.about.com/cs/faqs/l/aa042603a_1.htm

 

thanks for the responses guys!

in2pro:
I just cleaned the injectors 2 weeks ago. I used the pressurized service, where the injectors run on straight solvent. Of course it doesnt hurt to throw in a couple bottles of Techron again.

ukrkoz:
I did check the ECT, but i am going to check it again against the info in the pages you sent. I might even just replace it since the cost is only $13 from Advanced.

I'll let you all know how i make out

 

A quick thing you can try is to cycle the keyswitch from OFF to ON (not to START) a few times and see if it starts normally afterward when cold. If so, then for some reason, the fuel pressure isn't getting primed very well. But, you said the fuel pressure primes ok with a cold engine before the engine is started? If so, then the only other thing I can think of is that you may have a lean cold start issue. Have you checked for vacuum leaks? I use t-body cleaner and spray around areas where leaks can occur and if the engine surges or dies, then that would indicate a leak. Then make sure the EGR closes ok. After that, you'll probably need to get a scanner that can read the PCM data stream and see if things are reading normally. Let us know what you find out if you get it fixed.

 

This isn't fuel-related, and as long as you have a strong spark and plenty of cranking power, I could be barking up the wrong tree. However, corroded battery cables are a largely ignored problem with older trucks. They imitate all sorts of grounding problems, rob your battery of critical amperage at start-up, and destroy your alternator and starter in the long run. Good news is they're cheap, and easy to replace.