Questions and Answers

Tahoe Hard Start Q. Hi. I have a 1998 Chevy Tahoe with 58,000 miles on it. It has a 350 fuel injected Vortec motor. It has the CSFI injection system. Recently I started having a problem when starting this vehicle. Normally, the vehicle would start within a second or two when cranking it. Now, I have a problem where it takes several seconds to start when cranking it.

I have had this vehicle for a year and this problem has come around for about two months now. I took it for a diagnostic where the fuel pressure was checked. The fuel pressure checked out normal. I had it to the shop twice and both times the vehicle would not duplicate the problem when I dropped it off. Since then, I have done much research online to try and find the problem. I know it is not a faulty fuel pump relay because if I turn the key on to run, I hear the fuel pump run for two seconds like it is supposed to.

I know that my problem is a pressure leak in the fuel system. If I turn the key on to run and wait for the pump to stop running and then turn the motor over, it starts every single time in a second or two like it is supposed to. I have recently found that my problem is partially affected by the level of gas in my tank. When I fill the tank to full, I will rarely have this problem. The motor starts up the first time like it is supposed to. Once in a while it won't. As the tank drops to below at least a quarter tank, the problem comes back. This is why I think it is the check valve in the fuel pump. If it was a leaky injector or pressure regulator I don't think it would be affected by the level of gas in the tank. Once the truck starts, it runs perfectly with no problems.

My question to is what do you think of this? I have a subscription to Alldata but nothing addresses my exact concerns with my exact symptoms. If it is a leaky fuel pressure regulator, would the motor run crappy? Also, if it is a leaky fuel injector, wouldn't that also causer a poor running condition? If it is a check valve in the pump itself, how much longer do I have on the pump before it fails completely? Also, if I replace the fuel pump, are there any other parts of the fuel pump assembly that I should change to avoid having to drop the tank again? Please let me know.

Thanks.
Richie

A. You need to re-check the fuel pressure. Should have between 58-64 psi when you turn key to on. After that, watch the gauge for 5 or 10 minutes to see if it bleeds down. If so, you have a leak somewhere. Probably the pressure regulator. This will make your car start like it's flooded, chug chug for a couple of seconds. There is a diagnostic chart in GM service manual for this. If it comes down to the fuel pump, just put the whole module/tank unit in. This will give you everything including fuel level sender unit.

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