Two weeks ago I had the fuel pump replaced on my 2001 zr2 blazer. About a week later im having issues with it starting after sitting. I have to crank it over 7-8 times before it finally starts up. The weird thing is is it fires every time you crank it over but wont start. Eventually one of the times you crank it over it fires right up lik nothing's wrong. And will run fine for the rest of the day. I replaced the fuel filter thinking maybe it caught something from the pump going out but that didnt help at all. This morning I tried starting it and actually couldnt get it to start. Let it sit for an hour then tried it again and it started right up. In the last year ive changed: distributor (whole dist cause bearing was bad in it), fuel pump, fuel filter, plugs, and wires. Im planning on getting a fuel pressure tester tomorrow since I get paid tomorrow. Ive had a few people suggest things it could be, one said fuel pressure regulator and one said a fuel rail issue. Any help appreciated. Plan on running a fuel leak down test hopefully tomorrow.

 

Anyone?

 

Running fuel leakdown test right now. 55psi on key turn, 60psi after 20 seconds and holding 60 psi after 10mins.

 

i have the same issue and cant seem to figure it out, have you checked for any vacuum leaks? i let the engine run and spray around the air intake and and vacuum hoses (with soapy water) ...if the engine runs rough, when you spray in a certain area you found your issue ( air leaking). thats the cheapest check, and worth doing first.


also any codes? note that you can have a pending code that wont light the check engine light.

 

No codes besides the p0101 ive had forever and no pending ones. Im suspecting a lemon fuel pump out of the box. Its only getting 50psi when you turn the key on. I called my uncle (gm mechanic who installed my pump) and agreed its probably the pump. I cant do the tests from in front of the fuel filter cause I dont have the parts.

Also I feel if it was a vacuum leak that the truck would run poorly. It runs fine once stared, its just getting it started is the issue.

 

Yea I have the same symptoms....starts beautifully after somewhat warm. Did you use a delco/ dephi pump? If not I guarantee it is the new pump.. Also...did you replace the fuel filter? You may have said it already I'm on my phone and can't look at recent posts lol

 

Yep, filter is new. Pump is whatever gm uses. Had a dealership do it.

 

SHOULD be delco/delphi, imo, id bring it back and explain the issue, if they find an answer for you, please share this hard start thing pisses me off and i feel like ive been chasing a ghost with this issue

 

Well like I said in my other post, I called my uncle who is my mechanic and a GM mechanic at th dealership, I told him the numbers I was getting for fuel pressure and he agrees its a bad fuel pump. Ill get it replaced with no cost to me.

 

if you only tested at the shrader valve near the distributor, you are only testing regulated pressure, set by the fuel pressure regulator, so the pump may be fine, without testing at the fuel filter, you cant determine the fuel pumps psi its sending to deem it within spec or failing to push the correct pressure

but like i said, if you find them swapping the pump out does 100% fix this hard start issue, still keep us posted.