Hi , I'm new to this site and need some information and am hoping someone can point me in the right direction !!

He'rs my dilemina I am 99% sure my injectors are faulty, starts great in morning 1 st time then depending on how long it setts, it usually cranks till I touch the Pedal a little and starts, I have checked for leaking fuel pressure regulator, no fuel smell or leakage when pull vac line. I have available to use a not sure of year 04/05 Trailblazer 5.3, the fuel rail on this is aluminum which is diff. from Silverado, so could I swap the whole intake/fuel rail assembly to my silverado 5.3 ?? I did notice that I did not locate a fuel press. reg on the rail of Trail blazer 5.3 ?? Thanks in Advance !

 

I highly doubt it's your fuel injectors. The possibility of all 8 of them going bad is slim to none. I'd check your fuel pressure with a gauge and see what it does.

 

I do have to check fuel pressure to make sure , I put a pump in a yr ago , which I know does'nt mean anything , but My son had similiar problem on 8.1 and had like 3-4 injectors leaking and they replaced all 8 at shop and took care of problem, thats why I am leaning towards them leaking down (being Bad) I' run chevron techron injector cleaner through it twice now with like double + strength than it calls for and has'nt really improved the problem. My coolant sensor seems to be reading right on scanner , I will pick up a fuel pressure gauge this weekend and hopefully check the psi out. Any other ideas I might be missing, Cats ?? I think cats are o.k. cause it idles fine runs fine, just has a slight rughness when started warm ,only couple seconds then fine ?? Thanks Again in Advance

 

Tonight I purchased a Fuel Pressure gauge, I put it on before starting truck, It read 0, truck had set3.5 hours since ran. I cycled the key but didn't try to start....just cycled pump to check psi, gage read 50 #, I released it and started truck and had approx 46# idling, I drove home with gauge on and let idle and released pressure again to see pressure idling, still approx 45#. Shut truck off,bled gauge did key on pump run got 52 #. Anything I'm reading on GM SI is saying 55-62 #'s So I guess I should check another and see if this new Pressure gauge is reading true, but either way I'm still bleeding off some place, I guess my next check will be fuel press regulator ? any other Ideas would be appreciated, then next I have to find a way to block my return line to actually check the injectors for bleeding down ? or is there another way to check them?

 

How fast does the pressure bleed down when you shut the truck off?

 

Prime the pump, but don't release the pressure. Leave the gauge on overnight to see if it bleeds off. How do you know the injectors are leaking off if you never wait long enough to see if it is leaking off?

 

Today when I got home I let truck idle while I changed out my broken door handle, from 5* weather last night, anyways when I was done I poped hood and checked f.p. 50#.... so then I pulled vac hose @ f.p.r. and pressure raised to 60# , but this time when I pulled hose off there was some fuel come out hose/reg nipple, so I'm hoping my problem is f/p/reg bad. when I shut it off the press was 54#, waited 3-4 min and was holding, went back out to check it bout 1 1/2- 2 hrs later 0 #. will change out reg Monday after work and let you know

 

Yep, that's the telltale sign of a bad FPR...

 

well I changed f.p.r. this evening started truck fuel pressure 50#,let set half hour dropped 8#, went out 2 1/2 hrs later 0#, will drive tomarrow and see how it restarts when warm and see if I gained any progress

 

It could be the check valve in the fuel bucket also.