Last night I just completed installing my new fuel injectors, the same ones as DarkHalo; SLP /Bosch 25lb. Anyway, I put everything back together and prep it for the start, I go to start it and still nothing happens. It turns over but doesn't stay running. But it does sound alot better trying to start before I switched out the bad injectors. The only thing left on my mind, that I haven't replaced on the fuel system is the fuel pump. I hear it turn on when I turn the keys to run, but could it be pumping weak? I really wish I could figure out what the h*** is wrong becuase I'm losing time and money! Please someone help!! Thanks.....

Things Replaced so far:
Fuel Filter
Fuel Injectors
Fuel Pressure Regulator


[Modified by -=Persephone=-, 3:38 PM 2/27/2004]

 

I would connect a fuel pressuge guage to the fuel rail if you have not already done so. See what the fuel pressure is doing, just to be sure it is infact a fuel problem, so you are not wasting time and money for nothing. Also, when you replaced the fuel regulator, did you replace the diaphragm too?

 

1. Does it smell like it's running rich? Do you smell fuel i the exhaust when it stalls? Did you get an adjustable FPR for the new injectors, since they are larger than the stock injectors?

2. What is your fuel pressure when you turn the key to "on" and the pump primes the system? What is the pressure when you try to crank the engine?

3. Have you disconnected the 9th or "cold start" injector from the temperature switch in the front of the manifold?

4. When you put it all back together, did you reset the TPS and IAC?

 

Is the cold start injector in between the runners on the drivers side? How do i reset the tps and iac?

 

did you reinstall the FP fuse?

 

I never took out the fp fuse, the pressure had already escaped from the leaky injectors

 

You need to pick up a FP gauge before doing anything else.

 

When the pump primed the system it would only go up to about 28 psi or so.

 

If the lines were emptied then it should go up to nearly 50psi if you turn the key on 3 seconds, off 10, on 3, off 10, on 3.

 

Definately wasnt going up like it should......not like that. It just seems odd that it would fail at the exact same time as the injectors were being replaced...I guess the real question is, could changing the injectors worsen a weak fuel pump situation, or is there something else he would have missed when installing the injectors.

 

What was the pressure before the injector change? Might be that the pump was to blame all along and you just threw money at the wrong parts.

 

Got out there with the fp gauge on the rail and primed it a few more times, still wouldnt go up much more, after that I held the starter and just let it crank, and the fuel pressure slowly started to go up to around 40 where it was supposed to be, it would try to start and ran rough for a second or two then would die again

 

What was the pressure doing while you cranked it, did it just rise steadily or did the needle bounce? Is the pressure holding when you stop cranking the engine?

 

It was rising steadily as it was cranked, and it was holding fine when I stopped cranking


[Modified by Wheelman, 7:13 PM 2/27/2004]

 

Well that's kinda odd.

I'm no expert on the fuel system on these cars, but it sounds like it might be an electrical problem. Usually if the pump is bad, it won't deliver full pressure at all.

So just to summarize,

Priming pressure is low ~20lbs.
Pressure rises steadily as motor cranks.
Pressure holds after motor dies.


This one has me stumped. :confused:

 

Someone help!

 

[QUOTE]Someone help! [QUOTE]

Looks like it's going to be a process of elimination to find the cause.

Things to check:

1. Are you sure you installed the fuel filter the correct way/flow direction? There should be an arrow or some other indicator as to which way the flow travels. Arrow should point toward the front of the car.

1A Are the injector fuses good (not blown)?

2. Is it possible the fuel lines were installed on the wrong port? I recall someone had a problem a while back that was drivng him crazy and it turned out he'd screwed the return line into the fuel rail FEED PORT and the feed line into the RETURN PORT. I didn't know this was possible; be he said he did. Correcting that mis-installation solved his problem.

3. Pull the fuel pump out of the tank and check that the sock hasn't collasped and that the hoses are fitting tightly. I put hose clamps on mine just to be on the safe side.

4. Since you don't have a fuel pressure gage, I'd unscrew the fuel pressure line from where it screws into the fuel rail, slip a long piece of rubber hose over the end of the metal line and clamp it. Point the hose in a safe direction or in a bucket/gallon bottle, etc. and have someone turn on the ignition key. Fuel should shoot out under a lot of pressure instantly then, after two of three seconds, stop. This is one of those tricks I hesitate to recommend because you'll be dealing with a highly flammable substance, but in a pinch you've gotta do what you've gotta do. I use to have to do this on the race car systems to make sure the pumps were pushing enough fuel and in those cases I'd have to let it pump for 20 (TWENTY) seconds, not just two or three. Just don't burn down the house and garage. BE CAREFUL; Nothing should be nearby that could cause ignition; NO OPEN FLAMES, SMOKING, ELECTRICAL EQUIPMENT INCLUDING DROP LIGHT, HEATER, ETC.

5. Could some foreign material be partially blocking the fuel rail(s) or the fuel flow upstream/downstream of the filter?

6. If all those checks don't discover the cause, you'll need to check the regulator. I left this to last since the plenum needs to come off to be able to remove the regulator. Been a while since I've had mine off, but if I remember correctly, it's the bladder (I guess that's what it's called) first, then the spring, then metal housing and then the ring goes on top of the metal housing. (Someone correct me if I'm wrong on the order).

You didn't forget to install the spring did you? Hole or tear in the rubber?

7. If the vacuum line is left disconnected from the regulator (but plugged), the fuel pressure should be higher. Rule of thumb is 1 psi of fuel pressure increase for every 2" Hg of vacuum the engine pulls.

Keep us posted.

Jake

 

You can apply 12 volts to terminal "G" on the aldl. This will run your pump as long as you like, while you try to figure out the problem.
:cheers: