hey guys...im new to forum and have been having fitts with my 2000 2dr 2wd. it is hard to start. if the truck sits for a extended period of time it will not start. you have to cycle the ignition on and off a few times with the pump priming and eventually it will start. now if you spray some carb cleaner in the throttle body it will start right up. if in park and you try to rev the engine it starts to stumble around 3400rpm. and of course if your driving it and try to accelerate to pass or go up a hill it falls on its face.

i have already put new plugs and wires, and a new fuel filter on it. and still have the same problem. once the truck is started and runs for a few mins. it will start everytime. but its a lil rough starting but it does start. this is the first problem i have had with this truck in the 3yrs i have owned it. it has 145,000miles on it. i have done a search on here and found nothin related to this issue. now i have seen where people are having weak fuel pumps...i have owned several mustangs and have never had a "weak pump" they either work or they dont. also my fuel level gauge is not working and i hear this is a common issue with these trucks. but i dont think that is related to this as its been doing it since i bought it. i guess my next step is to do a fuel pressure test. now do the fuel press. regulators have issues with these trucks??? or is there one??

thanks in advance for your help guys

 

i say do the fuel pressure test and report back the results youll need 60+psi in order for the blazer to start and once you shut the engine off the pressure shouldnt drop below 55psi. you also said you put new plugs in, what brand did you go with?

 

i used autolites....double platnium. i knew better than to do bosch....had problems with them in the past.

 

Start with the fuel pressure test and move from there. It definitely sounds like there is a problem there somewhere. If you can, hook the gauge up so you can see it while you drive down the road to monitor fuel pressure when you experience the bog.

The details found in the 96+ Fuel System Diagnosis thread should help.

 

thanks foryour help guys.....ive got to wait till monday to take a look at the fuel pressure. i hope it is something easy to fix. got another question......is there a seperate circuit for running the fuel pump during starting??? or a difference in voltage?? reason i ask is...i can spray some carb cleaner in the TB and it cranks fine and idles fine. i didnt know if there is a diff circuit or relay for running the pump during starting....thanks in advance!

 

There is only one circuit for the fuel pump. The voltage running to it should be very close to battery voltage. While cranking, the entire system voltage drops due to the current draw from the starter motor.

 

well i think i have nailed the problem. i did a fuel pressure test a day or so ago.....when running (idiling) it runs anywhere from 50-58ish psi. when you cut the truck off it drops to round 50....if the truck sits(like 6-8hrs) it runs down to no fuel pressure. and when keyed to start it jumps to 53-54psi. so imma say its the fuel pump. what you guys think??

 

I would test the pump pressure directly off the pump if you can or at the fuel filter,(you might have to fabricate a hose with the right fittings ) this will give you pressure from the pump, without the rest of the fuel system coming into play, there is a fuel pressure regulator that could be bad, test the pump output you should have 80 or 90 psi or higher if you only have 60 or less you definetely have a bad pump.

 

Sounds low on the pressure side with just the key on.

The leak down could be caused by a faulty FPR or a bad check valve in the fuel pump assembly. By testing the pressure at the pump output, you would be able to determine if the pump is good or bad as Shannon09 has said.

 

well i dont wanna go change the pump and it be the FPR so......i have looed around up under the hood and can not finr the FPR! am im missing something??? or lookin in the wrong place??? and how much do they usually run?? thanks agian guys. im still able to drive it i just have to use some starting fluid to get her to fire up firts thing in the AM