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Robert, Technician
Category: Car
Satisfied Customers: 13362
Experience:  6 years experience with car repair.
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1993 GMC Safari Van: vortec..problems starting..starts right..shut

Customer Question

I have a 1993 GMC Safari Van with a 4.3 Vortec High Performance engine. I have been having some problems starting it when it is warm. If I leave it for 2 days, it starts right up, but then as long as it is warm whether it is shut off for 5 minutes or 24 hours, it has to wind over a lot to get it running. Now the past few days it has been idling rough at startup ( idling high and then low for about 5 minutes) and then after about 15 minutes, it starts to cut out when coming to a stop. I put a new oxygen sensor on it 2 years ago and a new fuel pump, filter, and fuel pressure regulator this past summer. Can someone please tell me what the problem might be?
Submitted: 9 years ago.
Category: Car
Expert:  Robert replied 9 years ago.

Hi There!

Thanks for Choosing Just Answer.

I would look at a couple components. A plugged PCV valve or hose may cause rough idle, stalling or slow idle speed, oil leaks, oil in the air cleaner or sludge in the engine. A leaking PCV valve or hose could cause rough idle, stalling or high idle speed.

With the engine running, remove the PCV from the valve cover and place your thumb over the end of the valve. Check if vacuum is present at the valve. If vacuum is not present, check for plugged hoses, blockage of the manifold port at the throttle body/carburetor unit or a faulty PCV valve. Replace as necessary. With the engine not running, remove the PCV valve from the vehicle. Shake the valve and listen for the rattle of the check valve needle. If no rattle is heard the valve is defective and must be replaced.

I would also give the throttle body a good cleaning.While throttle-body cleaning is good preventative maintenance, it should also help engine drivability. In fact, if you've noticed a rough idle, stumbling initial acceleration or even stalling - all when the engine is fully warmed up - a dirty throttle body could be the culprit. Once you look inside a throttle body, you will probably be surprised at the dirt, gum and varnish that have accumulated there over time. I would look at these first to see if it is causing the issues.

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Customer: replied 9 years ago.
I checked the PVC va;ve recently and it is fine. This is a CMFI engine and when I replaced the fuel pressure regulator, I had to remove the intake manifold to replace it and it wasn't very dirty there. I cleaned it just the same. I replaced the pump and regulator because someone told me they were the problem. I also went to the dealer and purchased fuel injection cleaner for it to see if the injectors were dirty. This din't solve it either.
Expert:  Robert replied 9 years ago.


Do you have a Volt meter? I would think it is possible one of your sensors could be causing the issue. I can give you the directions on checking some sensors. I would check the MAF sensor first from the symptoms you are describing.


Customer: replied 9 years ago.
I have a volt meter
Expert:  Robert replied 9 years ago.


I just thought of something on why it will not start warm. It may be two issues, the warm start and the idling.First, get the starter checked. It sounds like when the starter becomes hot it has a spot in the wiring that goes "open," causing a break in the electrical contact. When the starter cools, the open spot will make contact again and the starter works as if nothing were wrong. This is something worth checking out. Instead of going through each sensor I am going to send you a link for vehicle troubleshooting guide on your vehicle. The reason I am sending you this link is because it could be a number of issues on the idling and this will tell you how to test all the sensors. I would focus on the MAF first. If you would like me to re-post your question I can but I feel this link will help you out a great deal.

Thank You! Please hit ACCEPT for my efforts Positive feedback and BONUS welcomed!!

Customer: replied 9 years ago.
I went to the site and will try some of the things there. Thank you for your help