Hard hot start
 

Hello All,

I've searched the forums here, and tried a few ideas, and am at a bit of a loss.

2000 5.3L 4wd Tahoe

It's becoming increasingly difficult to start after sitting when hot.

First thing in the morning, it fires right up. If I drive the kids into school, get out of the car for 10 mins, and come back, it doesn't want to start.

Smooth idle and acceleration.

55psi static on fuel pressure test. 48psi running, and no noticeable drop for a half-hour after shutdown.

No noticeable fuel on the vacuum line to the fuel-pressure regulator.

I'm about 2/3 of the way through a tank with 32oz of Techron in it.

Did a fairly thorough cleaning of the throttle body and plate by removing only the air intake. Should I remove the entire throttle body to *really* get this clean?

No codes are being shown.

I've read about the CPS and ECM. Could it be the main ground? Does it go to the driver's side head?

Thanks for any tips!

JC

Fuel filter?

I did the filter maybe 20k ago. I tried to get one at the last parts store I went to, but they didn't have it. They DID have the fuel pressure tester.

I was under the assumption that if the pressure was in spec (55psi is the low end of spec), the filter was OK. Is that not the case?

Thanks!

No since that pressure is at a relatively low flow rate. When the demand goes up, a clogged filter will limit the flow and drop the pressure.

Swapping the fuel and air filter out now.

well, if the fuel filter wasn't it, I'd be surprised.

I could basically blow both ways through the new fuel filter.

Could blow backward into the old filter, but could barely blow through it as normal gas would flow. Tapping the input end on a rag dumped all kinds of nasty black stuff out.

Thanks for the feedback!

It appears that I still have the problem. It's making me crank it two or three times to start it after a 15 minute rest.

Have you guys seen the starter be the problem in situations like this where it's not carburated (no vapor lock) and hard to start when hot?

Thanks!

JC

How old are the spark plugs?

Well the filter was definitely clogged. Now you need to recheck the pressure for fall off again. I ran into this before with a 95 Tahoe. Pressure stayed good until I replaced a clogged filter then because the block was not in the filter anymore ( new filter) pressure would now fall off. Also just because the pressure is good does not mean the filter is not clogged a clogged filter usually cause a reduction in fuel volume not pressure.

It might be worth cleaning the fuel metering body if you had that much build up in the filter, that and give the Techron time to work its magic