GMC Full Size Van Starting Trouble

[pthompson7]

Hey guys,
I have a a full size GMC Van, and it starts periodocally, when it wants to really. We have changes the O2 sensors, checked the fuel filters, pretty much changes everything that comes to mind. Here's another nutty deal, it will crank but not start, but if I jump it it will start. So it seems like it just isn't getting enough spark to the plugs. (I did change the plugs as well) I am at my witts end with this thing. I need some HELP!!!!

Any suggestions??????

[leolkfrm]

if it starts with a jump start checking grounds, I would at least replace the neg battery cable. how oldis the battery? it may not be turning the engine fast enough.

[pthompson7]

Yea, we changed the wires as well. I hooked it up to a diagnostic machine and it is saying P0442- evaporated emmission system leak detected. (small leak) From what I have read it doesnt look like that would stop the vehicle from starting would it??

Could a clogged converter cause this. It runs fine once it get running but it just has trouble getting started.

Any other ideas.

Thanks for your quick reply.

Pete

[Case 7230]

Originally Posted by leolkfrm

if it starts with a jump start checking grounds, I would at least replace the neg battery cable. how oldis the battery? it may not be turning the engine fast enough.

I would agree with that. Have you tried a known good battery?
If the cat was plugged it would run bad.

[gmctrucks]

Have a load test done on the battery and have it checked out GOOD you can even buy a tester for less than $5.00 dollars that will check each cell that's another good way of checking it out as well.
Good luck! GMC

[pthompson7]

Yea, I did have the battery tested before and we even changed it out with a brand new battery, so I feel confident that the battery source is good. From time to time after I run the van for a while I can smell just a hint of radiator fluid, but I have never found any under the van after operation. Any chance I could have bad seals allowing some radiator fluid to leak into the cylinders. Could this also lead to low compression not allowing the van to start unless there is additional juice to push it a little harder???

[leolkfrm]

Originally Posted by pthompson7

Yea, we changed the wires as well. I hooked it up to a diagnostic machine and it is saying P0442- evaporated emmission system leak detected. (small leak) From what I have read it doesnt look like that would stop the vehicle from starting would it??

Could a clogged converter cause this. It runs fine once it get running but it just has trouble getting started.

Any other ideas.

Thanks for your quick reply.

Pete

the leak you have coded may be as simple as a bad seal on the gas cap, you can try reversing the o ring on it, it may fix it.
Just for kicks put a jumper cable on the neg side of the battery in the vehicle, and to a good ground on the vehicle and see it it works!

[pthompson7]

The starter was pulling too many amps at all times. It kept shorting itself out. I know that the code points to a faulty fuel cap, or a vaccuum issue, but would that really stop the van from not starting? I cant see a missing gas cap stopping a van from starting, could it. I think it's a fuel issue. Any ideas where I should start checking the fuel system.

[hotrodpc]

Possibly check the fuel pump pressure. If the pressure is not high enough to push the injectors open it can't get fuel. I hate to recommend this, but just for the purpose of elimination, spray some start fluid into the air intake. If it starts up, then you know it is a fuel problem. It may take a few seconds to draw the fluid into the motor, so it won't just start right up. Just a sugestion to try. Don't get to crazy with the start fluid. Its not good on a motor. What year model is this Van?

[pthompson7]

Ill give that a try. We just baught a pressure tester, and will also try that as well, but I will post back to let you know how it went. Thanks for the ideas.

Also it's a full size step van 96-97.

Pete