[Da S10 Newb]

Hey guys hope yall are having a good start to your new year. i could use some help with some fuel issues that have persisted since ive owned this truck revolving around rough idleing and not wanting to start up after its been started and shut off. the sure fire way to get it started every time has a little ritual where i have to cycle the key on and off a few times, pop the hood aand release pressure on the fuel line using the test port and then she fires right up. wierd right but it works 100% of the time. ive installed a new fuel pump already.and im thinking its injectors but im just wondering what yall think before i invest $300 on new injectors and taking the top of the motor apart. any help would be appreciated.
also my fuel pump is super noisy like it whines so bad. also the rough idle isnt constant sometimes its worse than others

 

[Usagoal]

Year? Engine? Assuming it's a 4.3 if you are posting in the ZR2 section? Just wanted to be sure.

Start out with a fuel pressure test and leak down. Leak down could help tell you if there is a leaky injector (or poppet style spider...depending on the year) or possibly a bad fuel pressure regulator. Did you change the fuel filter when you changed the fuel pump? Is the check engine light on?

A leaky injector/poppet OR bad fuel pressure regulator may leak extra fuel into the combustion chamber or manifold causing over fueling on your next startup. It may be possible to see fuel leaking from the regulator if you have the throttle body off. Flashlight and mechanics mirror also helps. Don't forget to cycle the key on/off to build some pressure.

 

[Da S10 Newb]

2000 S10 ZR2 4.3L engine code is an L35 i believe. yes fuel filter is new. check engine light is on but thats for coolant temp sensor and thats a new code my problem is an older one i havent been able to crack. im definitely getting the correct fuel pressure now. the wierd part is im having to realease the pressure at the test port then she fires right up. sounds like your onboard for a injector R&R like im thinking tho

 

[Usagoal]

What was the older code? Was pressure around 55-60lbs? Try a leak down test too....it will tell you a lot. I agree the pressure release and immediate start up is strange.

I can only theorize that by releasing the pressure (and partially draining the line) on your next startup the engine may be using the leftover fuel from the alleged leaky part to start. Normally there is a pre determined amount of fuel being delivered in the first few milliseconds upon startup....which you may not have from your ritual of depressurizing the fuel system. If your pressure is low and line partially empty, it would take some time to fill the line to the correct pressure to deliver that required fuel....which in your case you don't need. I say some time because it's probably longer than the few milliseconds mentioned earlier, but I don't know. I never timed a fuel pump and how fast it builds pressure.

Again...this is just a hypothetical situation. I'm curious as to what you find. You really need to do a pressure test AND leak down test to confirm a suspect part.

 

[Da S10 Newb]

didnt have any codes before. my ritual on startup is just older than the current DTC i have and that the fuel system has never thrown a code. yeah so before i changed the fuel pump it was only producing aroung 36psi havent checked since the replacement but i know that it runs significantly longer starts up easier for sure. so ill borrow a pressure tester again and see what i can come up with