Starts and then dies.

[LITTLERED]

Hi, Looking for a little advice, 1991 Ranger 2.9 starts but wont idle, dies right away. I can get it to run a little bit by pumping the throttle, and with starter fluid into the throttle body. Fuel pressure seems low. I replaced the fuel pump, and there is a new fuel filter. I'm getting about 10psi at schrader valve unless I cycle the ignition a few times, then it builds to 40. It was running rough, and lacked power. I ran some injector cleaner through it and it seems like that may have contributed to the problem. I have checked the IAC and cleaned it, it seems to be working, but I can get the truck to run with a rough idle when I removed it. I checked the TPS with multi meter and it seems to be working correctly. Ive looked at all the vacuum lines and everything seems to be in place. I actually replaced the IAC valve and it didn't seem to help, but now I'm wondering if the new one was defective, because it will run with no IAC installed. It doesn't seem to have a MAF, looks like MAP which I don't have a way of testing, or now wondering if it could be the PCM.

Also, no fuel in the vacuum line on the fuel pressure regulator, but I'm thinking this might be the next part to throw at it. Is there any ways of testing fuel pressure regulator other than there being gas in the vac. line?

 

[LITTLERED]

An update, I seem to have good fuel pressure. I got the Chiltons and it seems to be in specs. It does hold fuel pressure for quite a while after shutting it down.
I can get it to run if I pump the accelerator pedal while starting it, and it will run roughly after it warms up.
Fuel pressure regulator seems to be working, fuel pressure goes up after removing vacuum line.
I’m thinking it either clogged injectors or a sensor.
Has anyone had similar issues with a sensor?

 

[Brain75]

is that a carb or a efi system.... carb fuel pressure can be very low (like 6 psi), I can't name a FI that is less than 40.... (Ford spec'd 40# for some years and 60# later) and I thought after 1990 all V6 rangers were FI.

 

[LITTLERED]

It is EFI, it was priming to about 10psi, but would go to 40psi when I cranked it over. I replaced the fuel pump and filter thinking that was the problem but its still having the same issue. It does prime to 35psi and holds that pressure for a long time.

 

[SenorNoob]

How long does it take to prime to 35? If more than one cycle of the key, then something is wrong. 3 seconds or less and you should be ok.

 

[Cees Klumper]

You can check the ECU for codes. Injectors is possible, but so is incorrect ignition timing, fouled plugs, vacuum leaks, low compression/worn out engine, sensor problem, ECU faulty, wiring problem ... best be methodical in diagnosing, and I would start by checking for fault codes.

 

[gaz]

@LITTLERED
If you are losing any fuel.peessure after engine shutdown, YOU HAVE A problem.

First item I would procure is a spanky new gas cap, if your's is of unknown life.

Next, a set of new injector "O" rings/hats and "O" rings for your fuel.pressure regulator are not even +$20. If that doesn't correct your fuel pressure bleed off, then I would look at the fuel pressure regulator (FPR).

 

[Bgunner]

10psi after 1 prime says something is wrong. Check valve, pump, pressure regulator would be my guesses.

For clarity I am no expert on the 2.9's but if memory servers there is 2 fuel pumps, 1 low pressure and 1 high pressure on the 2.9's.

@rusty ol ranger maybe you could give some help since you have a good amount of knowledge with these engines and how they are set up.

 

[SenorNoob]

I thought the 2 pump thing changed with the body style in 89?

 

[rusty ol ranger]

91 will be one fuel pump in the tank.

Youre getting 10psi now....or 35psi now? 35psi is good...10psi is not.

First thing i would do is pull codes.

Yes FPR's can fail without fuel in the vacuum line (my bronco did), but they fail rich....meaning its just going to be dumping fuel.

However...since it runs without the IAC attached (weird) seems like it possibly is getting way to much fuel and its getting enough air to run by opening up 2 gapeing holes by removing the IAC.

Pull the plugs, see if they are wet with fuel. That will point to rather its flooding or running out.

All 2.9's (except 92 california models) were MAP, you can test a MAP but im not sure on the procedure.

Check out these things and report back. It could possibly be the ECM but i would at minimum pull codes before you buy one.