The engine starts up fine when cold but when it's hot sometimes I have to feather the gas pedal a little to get it started. I checked the fuel pressure in accordance w/ my factory manual and everything is w/in spec. The throttlebody is clean and the spark plugs look fine. Need recommendations on what to check next.

#1 - Try something - key in, turn to ON, and leave it there for 4 or 5 seconds before attempting to start. If that cures it, then you have a fuel pressure problem, probably a regulator.
#2 - Auxiliary Air Valve
#3 - 5'th injector leaking


hth

Thanks for the reply.:) I've checked the fuel press when the engine is hot and the press is good. Also checked the regulator using the FSM and it checks out. I'm running a later style intake and t-body so there's no AAV. I assume the 5th injector is the cold start injector? Pulled it out and shorted the pump connector and no leak. Resistance check is good too. The AFM, cold start injector switch and coolant temp switch all check out as well. The thing is that it doesn't do it all the time but it's starting to bug me. :mad: :D Any other suggestions?

Have you tried jumpering the fuel pump test connector (I assume so since thats the factory manual test procedure) and leaving it jumpered while you try starting the engine? If it starts right up, then one option is just to leave the test jumper in place, mine has been jumpered for the last two years. Some day I'll try to figure out the real problem.

4CrawlR, did you have problems starting it all the time, or was it intermittent? One thing I've been thinking about is my coil/igniter might be getting too hot. I relocated it to make room for an air compressor and it's sitting somewhat close to the header. Would this cause any probs?

Did you check the mass air flow meter? I would check that next. It's a common part to fail.

Yup, I checked the AFM.:)

Originally posted by Arnold
4CrawlR, did you have problems starting it all the time, or was it intermittent? One thing I've been thinking about is my coil/igniter might be getting too hot. I relocated it to make room for an air compressor and it's sitting somewhat close to the header. Would this cause any probs?

Mine was somewhat intermittent. Its easy to check if the fuel pump jumper works, just install it and if it helps, great, if not, keep looking. In my case there is an obvious lack of fuel pressure (I have a gauge) when the engine is cranking but not starting. Feathering the throttle seems to help get enough air through the AFM to trip the fuel pump contacts, since I see the fuel pressure will suddenly come up and the engine fires.

I have tested the AFM and the fuel pump contacts do seem to be OK, and I think I may have a very slight air leak somewhere in my fuel system that lets the residual pressure bleed off. Until I get motivated to find and fix that, the test jumper is working just fine.

I have the same problem as well. I've had a code 71 for a while - and I think it's my EGR vacuume modulator. Since all this started around the same time I'm going to see if it goes away after the EGR part swap.

Mine is also very intermittent, and only occurs after it has run at least once that same day.

I found this page while searching, http://www.babcox.com/editorial/ic/ic110028.htm
It has some pretty good info. According to the page, there's a check valve on the fuel pump to maintain pressure in the system after shutting down, allowing for easier hot starts. Mine seems to be working though 'cuz my fuel pressure never goes below 27 psi after shutting the engine down. I'll just keep the fuel pump jumpered for now and see if my prob goes away.

You mentioned vacuum leaks, While checking for leaks always remember to check your vacuum brake booster... if it is leaking it will draw a lot of air into the engine.

I would try the fuel pump jumper. also try replacing your fuel filter.

How much residual fuel pressure does your engine hold when you shut it off? most engines will hold pressure after you shut them down. if the pressure bleeds off quickly this is a sign of a bad pressure regulator.

"You mentioned vacuum leaks, While checking for leaks always remember to check your vacuum brake booster... if it is leaking it will draw a lot of air into the engine."

I checked for vacuum leaks using carb cleaner and didn't find any. Checked all the vacuum hoses including the booster using my vacuum pump and everything seemed fine. The intake piping between the AFM and t-body looked OK too.

"I would try the fuel pump jumper. also try replacing your fuel filter. "

I got the pump jumpered now and checking to see if the prob persists. If that doesn't work I'll replace the filter.

"How much residual fuel pressure does your engine hold when you shut it off? most engines will hold pressure after you shut them down. if the pressure bleeds off quickly this is a sign of a bad pressure regulator."

The pressure reads >27 psi when the engine is shut off so I'm pretty sure the reg is OK. Pulled the vacuum hose off the reg while the engine is running and the press increased which indicates that it's fine.

I just wanna remind you to post back later once you get it figured out with an explanation, to many engine posts on here go open ended, then everyone tells you to search later and there isnt anything but 50 posts with 10,000 suggestions!

Not saying your guilty, just trying to get folks to work on this...

I sure will.:) It hasn't given me any probs yet w/ the pump jumpered so time will tell.:D