I have been chasing this issue for about 3 years now.

If the car sits for several hours (typically over night), it has a longer than usual crank but eventually starts fine. (No codes, no other issues, new battery, tightened terminals, etc.)

Year one, I replaced the usual suspects (also bc they needed to be done anyway) spark plugs, wires, cleaned MAF, cleaned throttle body, regular use of techron for injectors, etc. No change. Then the issue went away during the Arizona "winter."

Year two, issue came back during the summer. I replaced the fuel pump and passenger sender (also bc I wanted to eliminate my gas gauge problems) and coolant temp sensor. No change. Then the issue went away during the Arizona "winter."

Year three - this year - no issue for the last 3-4 months, but the weather just recently changed to warmer again (75-80+ degrees) and the issue came back this morning!

I cant think of any other variables then the outside temperature affecting this issue. There are no other variables.

Does anyone know of anything that may be affected by the outside temp to cause a cold start long crank? After 3 years, it can no longer be a coincidence. I know there is an external check valve that may be causing fuel pressure to bleed off over night, but can check valves be effected by outside temp?

Thanks!

 

I would have guessed coolant temp sensor, but sounds like that wasn't it.

Intake air temp sensor, which I think is built into the MAF? Might be worth attempting to unplug the MAF and see how it does, both at cold start and while running.

Can always try doing a few key-on cycles prior to starting, to build up fuel pressure prior to starting. Doesn't seem plausible that a check valve would be more affected by warmer temps but you never know.

 

I can only theorize that warm temperatures are causing something in your fuel delivery system to expand causing fuel pressure to bleed down, perform a second turn on sequence and see if that helps the car to start quicker.

 

i should have mentioned i also replaced MAF with new oem. No change.

ok. I’ll try some key cycles. Thanks for the advice!

 

ill give it a shot and report back. Thank you!!

 

Any chance you have an evap system leak into the intake? Extra fuel fumes and warm air would be a rich condition while cold air will not care as much. It seems like you hit the obvious ones so thinking about other possibilities here. I have seen some of those valves leak over the years with no codes on other vehicles. Just fumes accumulating in the manifold when sitting. Just a thought.

Also, you should get a fuel pressure gauge and that will eliminate any fuel pressure questions.

 

thats a good thought too. How would I test that?

(I’m going to pick up a fuel pressure gauge this weekend)

 

My last failed one was on our Dodge Ram. I have not pulled apart the one on my C5 as I have no issues, but the premise would be to check the valve for leakage. There are several videos you could find. The one below gives a good demo on the premise, but the guy cracks me up because instead of using a mity-vac he sucks and blows on the valve. There is also another one where the guy uses the mity-vac and activates the solenoid on the valve.

https://www.youtube.com/watch?v=oeNqJtwmFw8

https://www.youtube.com/watch?v=nfIsYtiH94M



I am interested to find where you land on this issue.

 

Thank you! I’ll check this out.

 

I haven’t tried the “priming” yet…..but After two days wit terrible start ups then last two days have been perfect.