If I go out to start my 95blazer after it has been sitting for a while it is very hard to start. It will turn over and over and sometimes will not start. If I go out and let the fuel pump cycle before actually turning it over it starts. I put a guage on the schrader valve and the pump is putting out 61 lbs if I let it cycle, and it runs at approx 54/55 lbs.Anyone have any suggestions or has had this problem? thanx for the help.wnk.

 

Sounds like you have a slow leak somewhere in the system that is allowing the pressure to bleed down over time. There are a bunch of possibilities, but you have to determine how bad the leak is. Have you done a leak down test? Hook up your pressure gauge and watch the pressure over time. With the gauge hooked up, prime the system, then turn everything off. Watch the pressure on the gauge and write down the reading at the beginning, 1 minute, 5 minutes, 10 minutes, 30 minutes, 45 minutes, and ever 15 minutes after that until it goes below 10psi (if you make it that long).

Also, crack the throttle body open, if you have a leak in the FPR or fuel lines internal to the plenum, then you should smell raw fuel in the intake with the engine off. If you wanted, you could pull off the upper plenum cover (you'd need a new gasket) and inspect for leaks while you are doing the pressure leak down test.

Good luck and let us know!

 

I did leave the guage on for a while and watched it.(id did this test approx a week ago when i borrowed the guage)It did very slowly leak down, it took approx 2 minutes to get down to 50 lbs from its original 61 lbs. My biggest question is why doesn't the fuel pump build up enough pressure while cranking to start the motor, it will start right up if you just turn the key to the run position and let it cycle. After reading some of the posts in the archives, I find there is problems with the ignition switch. Could this be the problem in that the fuel pump is not activated in the crank position. Does anyone know where the fuel pump relay is located in my 95 so that I can check to see if it is putting power to the fuel pump in the crank position. thanx again.

 

The problem most often is that when you immediately go to start the vehicle, the fuel pump hasn't had enough time to prime and you are drawing the fuel pressure down while trying to start it (injector opening to attempt to supply fuel). This can be compounded by weak or stuck open poppet nozzles in your CPI injection spider. If the poppet nozzles are stuck open or weak, then they would just allow that fuel to drip down into the intake runner instead of allowing the fuel system to build pressure. The poppet nozzles in a properly working CPI spider should not open until there is 48+psi (typically) acting on them. They are a mechanical nozzle requiring fuel pressure to compress a spring, opening the nozzle. When the main electronic fuel injector opens, the fuel pressure rises in the spider and the poppet nozzles open, delivering the fuel.

There are often a conglomeration of small seemingly inconsequential problems that, taken together cause a much larger issue. Above is my take on what is going on with your truck. If allowing the fuel system to prime allows you go get it going and there are no other ill affects, I would stick with that. If you wanted to repair the problem, you will probably find that the CPI spider is at fault (combination FPR leak and weak/stuck poppet nozzle(s)). But like I said, if you have a workaround... It's up to you if you which way you would like to go. Before you replace anything, remove your upper plenum and verify where the leak is coming from. A 10psi drop in 2 minutes is a fairly decent leak and venture a guess that its the FPR.

 

Swartllk: I will take the intake top off and see what is going on probably this weekend. I do need to fix the problem because other than only starting issues now that I can compensate for by letting the fuel pump cycle,down the road this thing is going to crap out on me somewhere. I don't want to put a fuel pump in it because the guage is telling me the pump is acting fine. I don't mind spending the money to fix it but I don't want to put something in that is not the problem. I will get the guage back and test the pressure holding ability again also. Can you give me some idea what is normal on the system holding pressure. Also, if it is something leaking in the intake area will I see the leaking or is it possible that the spider assembly is bad and I won't see the leak. thanx. again wnk.

 

By no means am I just telling you to go out and replace everything. That is why I recommended pulling off the upper intake plenum and inspecting the fuel lines, FPR and such while the system is under pressure. You can pull out the poppet nozzles from their respective places and see if any of them are weeping as well. If they are, then that would indicate that the electronic injector is also leaking. I is quite possible that you only need to replace your FPR. You can save a bunch of money that way, but the only way to know what needs replacing is to get in there.

The pressure should rise up to around 60psi and stay there. Any pressure drop is caused by a leak somewhere. Possibilities are external line leak, leaky check valve in the pump, leaking internal fuel lines (typically referred to as the 'nut kit'), leaking FPR, or leaking electronic injector. The first two are unlikely. Weak poppet nozzles should show up as poor performance due to poor spray pattern, but the symptoms usually come on gradually so as not to alert the operator.

 

I had this exact same problem a few summers ago with my 95 CPI, it would restart ok if it had just been running, but if I let it sit for about 10 minutes it didnt want to start. It would crank for about 30 seconds before starting, even with letting the fuel pump prime, which I do at every start. The culprit was a leaking electronic fuel injector.

 

I am having the exact same problem as described in this thread. Not trying to hi-jack, I just don't want to start a completely new thread. One single question - if she still starts after cranking for a few seconds and runs fine after that..should i invest in repair work, or just leave her be?

 

I had the same problem and mine was the Fuel Pressure Regulator. They list anywhere from 40-80 bucks i bought mine off ebay for 35 bucks.I replaced it and starts quick everytime. Easy to install. now i just can't get those dam fuel line to stop leaking. Word of advice, disconnect the fuel lines at back of the motor instead of bending them to take intake off. I made that mistake.