Ranger will not run

[Rearanger]

Sounds like a bad MAF, without test procedure/tools it will be hard to determine unless you replace. I'd first make sure there is no intake leak after the MAF then clean the MAF.

 

[Earl43P]

http://www.fordfuelinjection.com/?p=26
http://www.fordfuelinjection.com/?p=27

I'm guessing from reading those two links...
but I suspect the MAF also inputs a frequency signal to the PCM, like MAP did.

Cleaning it may help, but I'd at least do a voltage test on its pins, while still connected, key in Run engine Off. A good digital meter will have a Hz setting. Mine doesn't, but it's an old Fluke dating back to 1983.

http://www.explorerforum.com/forums/showthread.php?t=263750 <This is a good read. Newer model, test might not be valid.

http://www.ford-trucks.com/forums/558851-maf-testing.html

A lot of talk about being able to DRIVE with the MAF disconnected. I think you have more than a bad MAF (something other than the MAF is bad if you can't get above idle with it unplugged). Doing some testing will convince you to look elsewhere if the MAF passes some tests (continuity test, voltage and ground present, signal is present, whether it's volts or Hz on the signal wire).

 

[83-2.8 91-3.0]

Would a bad o2 sensor cause this problem?

 

[Rearanger]

Signals from the O2 sensor do not affect mixture when engine cold and in open loop. I would say no O2 sensor would not cause this.

 

[modelageek]

Signals from the O2 sensor do not affect mixture when engine cold and in open loop. I would say no O2 sensor would not cause this.

I agree with him^^^^^^^^^^.....clean or swap out the MAF......most cars die within a few minutes/miles of disconnecting the MAF...

 

[83-2.8 91-3.0]

I have figured out that the truck is flooding itself out. While its runnning it will start blowing out big puffs of blue smoke, so could the computer be bad causing the fuel and air mixture to be off?

 

[83-2.8 91-3.0]

Could it be the crankshaft position sensor??

 

[Rearanger]

I don't think that determines A/F ratio just spark timing, maybe fuel injector timing. The engine coolant temp sensor causes rich run when cold. I would test it to make sure it's within spec. Have you inspected the plugs to see if this is occurring in all cylinders or just a couple?

 

[83-2.8 91-3.0]

The same thing is happening to all the sparkplugs...

 

[Rearanger]

Engine coolant temp sensor and air temp sensor will affect all cylinders, and leaking fuel pressure regulator and purge valve (evap) will put raw gas into engine.

 

[83-2.8 91-3.0]

I have found out that the throttle position sensor is also bad. It looses its voltage when pressing the throttle. Could this be my whole problem???

 

[Rearanger]

Well youd try and crank it and it fires right up with no problem, but then it starts spitten and sputtering and goes dead, and even when you press the accelerator to try and keep it running it still goes dead.

I have found out that the throttle position sensor is also bad. It looses its voltage when pressing the throttle. Could this be my whole problem???

My understanding of TPS is it tells computer when on WOT, Idle, Accel, Decel and can determine shift points for auto trans. I would guess that it's signal replaces the accelerator pump on a carb'd engine so that when you step on the gas there is a slight more gas pumped into the engine so it won't lag/stall/hesitate. I've had TPS problems in the past on other vehicles and had the engine loose power on acceleration. With throttle closed the ECU knows to use IAC to maintain rpm/idle with signal from TPS.

It should show a steady rise/fall of voltage/ohms when tested but I've tested bad TPSs with no sign of test failure where replacement solved the problem or at least cleared the code.

Did you test for codes if possible on a 91? Do you have a MIL?

Edit: I guess if the TPS is not telling the ECU the throttle position is on "idle" then maybe the IAC id not opening??

 

[83-2.8 91-3.0]

I have taken it and got it put on a computer and the mechanic told me that he could not get anything out of it as far as codes.. I don't think I have a MIL..

 

[Rearanger]

I think if you have sensors and an ECU then you have OBDI and a MIL. The method to retrieve the codes is not going to be as easy as OBDII. Your MIL may have a blown bulb, if it doesn't come on with ignition on run then I'd check the bulb. Do you have an owners manual?

 

[DesrtRanger27]

If you havent tried this yet check the fuel pressure under the hood should be a valve. you should have 35-45 with the key on engine off and 30-40 with the engine running. If its low try and replace the pump again my be defective. Also make sure the filter flow is the correct way.