Starting problems. Long post

[foghorn67]

A good friend of mine told me about a starting problem he is having with his pickup. Mind you it's a late '99, so it's basically a 2000 for all intents and purposes. (For those familiar with what GM did with those pickups then).
It cranks strong. I think the starting system is out of the equation. But it will just crank and not fire up. Stop cranking, wait a sec, try again...and it starts like normal.
He said the fuel filter was clogged. He hasn't replaced since he bought it about 2.5 years ago.
I told him that wasn't the issue, but agreed it needed to replaced for maintenance sakes.

I lent him my car for the day, while me and a buddy gave it a look over.
We started by replacing the fuel filter, and proceeded to plug in my buddies laptop to the OBD II sensor. No codes. We were thinking crank and cam sensors, but there was no codes being thrown at us. Spark plugs looked good with normal wear, and everything except for a small waterpump leak seemed okay.
We threw our hands up and fixed some other things un-related. Replaced the water pump gaskets and the squeaky A/C belt.
Just in time for summer I suppose.
Again, the starting system seems okay. About 12.5 volts at the battery, and it cranked strong all day, even after listening to his decent stereo all day while we worked on it.
Voltmeter reads over 14.5 while driving, so the charging system seems to check out alright.

Any thoughts? TIA.

 

[angry hampster]

Fuel pump. My jeep did this same thing a few years ago. Had to drop the F'n tank to put a new pump in, but it fixed the problem entirely.

I would also consider putting a can of Seafoam in your (his) gas tank next time he refuels. It'll clean out the injectors, lines, etc..

 

[foghorn67]

Aww crap. I do know it's in the tank. Arrgh. If it's the fuel pump, I am going to invent new swear words in assorted languages.

 

[woodie1]

Does it do the 'hard to start' all the time or just when cold? If so it could be a sensor isn't enriching the fuel mixture enough if at all.

 

[LTC8K6]

Fuel pressure gauge...and see what you see...

 

[foghorn67]

Originally posted by: woodie1
Does it do the 'hard to start' all the time or just when cold? If so it could be a sensor isn't enriching the fuel mixture enough if at all.

At random. We were able to reproduce almost at will.

 

[Vette73]

You need to trace it first. When it does it, is it a lack of spark or fuel?

If spark it could be a sensor starting to go out, bad ground, etc...

If fuel could be a oil pressure switch, relay, etc... as the fuel pump will not activate unless there is a signla from the relay and/or oil pressure to tell it to kick on. had 1 car I worked on that the fuel pump relay was bad. It gave the fuel pump the signal to pump until oil pressure kicked in. So had to crank it until oil pressure got high enough to start the fuel pump.

 

[JeffreyLebowski]

This is actually an issue with many GM trucks.
Hit up www.fullsizechevy.com and visit their forums for answers.

 

[bruceb]

Start by checking the Fuel Pressure regulator. If that is bad, the injection system will not hold pressure when it is shut down. Hence, it needs to pressurize itself before it will restart.

 

[foghorn67]

Thanks for the tips guys. It looks like I will start by checking fuel pressure.
JL-I'll start looking at that forum you provided.
thanks!

 

[LTC8K6]

I just remembered that we had a salesman get stuck in our lot a while ago in a Sierra. Same complaints. It wouldn't start every once in a while. We tried to help him out. We checked over everything that we could. Couldn't get it to start at all. Cranked over perfectly and everything we could check seemed okay.

Finally we decided to push it away from the road and more onto our lot to await a tow. When we got done pushing it, he tried to start it again and it fired right up. He had it towed anyway because he was tired of wondering when it would leave him stranded.

 

[Sluggo]

Even if it is the fuel pump, aside from the cost of the part, it's not that bad of a job.

I did mine by myself in about 2.5 hours.