At a loss

[catdaddyo]

1988 Ford Ranger 2.9 V6 4X4 5 speed. Died as if out of fuel. Started checking, replaced both fuel pumps, fuel filters, distributer cap, rotor button, plug wires, took ICM to auto parts and had tested, 3 tests all showed ok.
Engine will start, run a couple seconds, then die, continued cranking it sounds as if it is trying to start, but won't. Let sit for several minutes, starts, runs a couple of seconds, dies. Having someone crank while spraying fuel in the intake, it runs perfect, stop spraying fuel, it dies. Is something cutting off the injectors? Since it starts and runs for a couple seconds, it sounds as if injectors are working at first. Also, if you pump accelerator rapidly, it will barely run as long as you keep it up. Somethings crazy here, either the truck or me! Please help.

 

[adsm08]

Check fuel pressure. I know you replaced the pumps, but that doesn't mean there isn't a pressure issue.

 

[catdaddyo]

I forgot to put that on here. Fuel pressure at the shrader valve on the fuel rail is 42 psi with switch on and also while cranking. Thanks.

 

[adsm08]

Are the cats present?

 

[catdaddyo]

Yes.

 

[catdaddyo]

I read where the TPS should read 1 ohm with throttle at idle, and gradually rise to 4 ohms wide open. I tested the TPS with ohm meter and it is reversed. At idle position with throttle butterfly closed it read almost 4 ohms, and wide open it went to 1 ohm. Would this be shutting down the injectors. I think I saw where it would do that if it sensed wide open throttle. Is this info correct? Thanks.

 

[RustedRanger]

The TPS doesn't go by ohms but by volts...I'm thinking 1.0 volt is max. If you already didn't read how to set it in the Tech section.

 

[a31ford]

TFI and/or Hall effect sensor in the distributor ?

TFI's generally go bad in a heat situation, BUT, thee are other failure modes for them as well.

Have you verified spark ?

Greg

 

[catdaddyo]

Yes, it has spark. The engine will run fine if you spray fuel in the intake. I'm thinking something is cutting out the injectors, because it will start, run a few seconds, then die, and not start. If you wait five minutes, it will start and run again for a few seconds. This will happen as many times as you want to try it. I'm suspecting the TPS, but I don't know if a bad TPS will shut off the injectors. I need this info.Thanks.

 

[lchappyjr]

would the inertia switch have anything to do with it?

 

[catdaddyo]

I don't think so, as I checked the pressure at the schrader valve on the fuel rail and it maintains 42 psi while cranking, so it wouldn't have pressure if the inertia switch cut off power to the pumps. The schrader valve is also between the fuel pressure regulator and the injectors, so it shouldn't be at fault. I'm still suspecting the TPS, but I have spent so much already trying parts, that I do not want to shell out $35. to 50. dollars more without knowing what the culprit is. Thanks for your response.

 

[catdaddyo]

I don't think so, as I checked the pressure at the schrader valve on the fuel rail and it maintains 42 psi while cranking, so it wouldn't have pressure if the inertia switch cut off power to the pumps. The schrader valve is also between the fuel pressure regulator and the injectors, so it shouldn't be at fault. I'm still suspecting the TPS, but I have spent so much already trying parts, that I do not want to shell out $35. to 50. dollars more without knowing what the culprit is. Thanks for your response.

I finally found the culprit! The map sensor was bad and shutting off the injectors. I did a google search this morning and found someone who suggested unplugging the map electrical connection and see if it would run. I unplugged it, it started right up and I drove it around some to make sure it would run. It does. Thanks to everyone for you efforts, just note this for future reference.