Hey guys,

I am having some strange issues with my truck.. Sometimes it doesn't want to start. Well it does fire up and then immediately dies. It usually does this after its been sitting a while. I usually pop the hood, pull and tug on a couple harnesses/plugs try again.. Still nothing.. then if I keep trying or if I wait a couple of minutes, it just fires up like nothing ever happened..

I ran a KOEO test to pull the codes and got a 511 and a 172.

When it does start up, it sometimes stumbles or hesitates. A couple of times something happened and the Check Engine light went on and the truck would not go anymore.. I had the gas to the floor and it wouldn't go forward at all.. it just popped.. I tried different gears and got the same popping on and off. This lasts for a couple of minutes and then out of the blue the check engine light turns off and it starts going again.. And it runs great, when it does run..

I'm completely baffled by this one, so any help or input would be greatly appreciated.

**FIXED** Check the first post on the second page **FIXED**

I'm having a strange issue like that. My truck once every few months won't start. It will just turn over. It is something eletrical. I doubt this helps, but I figured it couldn't hurt to throw out there.

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20O3 extended cab, 2wd, silver, 3.0, toyo spectrum tires, 10,000k HID's, 8' in bazooka tube, and UWS toolbox

Thanks Southbama..

I forgot to give you guys the details.. Sorry about that..

Its a '94 2.3L Dual plug motor with a manual transmission.
I have a drop in K&N air filter, an old school SuperChip, and deleted cat.
It sounds like its getting spark and fuel because it will fire. I have checked the fuel pump and it does come on with the ignition.
I have reset the computer by disconnecting the battery. Drove it and pulled the codes again. Still getting the 511 code.

I'm not sure what I should check next...

I have tried searching and reading threads on starting issues but couldn't find anything that is the same as what I am experiencing.

511=(O) No power to PCM pin 1 or bad PCM (processor)
I would at least replace the pcm FUSE and RELAY. then check the wiring to the pcm. make sure the pcm is secure etc.......if all that fails you probably have a bad pcm....

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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).

modelageek - Thanks for the info bro.. I'll see if I can find them and replace them tonight.

Is there a way to test if its getting a signal with a multimeter?

wrote this up for another user. figured I wld post for future searches

coolant temp sensor, and coolant temp sender sensor, your truck has both.

They are two separate and distinct sensors.

The CTS coolant temperature sensor send signals to the ECU (computer) telling the engine how hot it is or isn't allowing the computer to send the ignition signals to advance or retard the timing to allow your car to be more efficient. When it goes bad it will and can cause the following conditions:
no start when warm
no start when cold
crappy gas mileage
crappy idleing.

The Coolant Temperature Sender (usually black or brown) lights up the idiot light or the water temp gauge by sending signals to the Coolant temp relay.
Both work on the same principle that resistance to the unit varied with the temp of the water.

So re-capping one sends signals to the computer.
One sends signals to the gauge.

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ASE Certified Mechanic, Builder of Show Destroying Protouring and Classic cars..

terryduanemiller - Thanks for the input sir.. I will replace both sensors tomorrow.


UPDATE: I had to call into work today because its down for the count.. It won't start at all anymore. I replaced the fuel filter today but it's still not starting. It cranks and it fires up for like a half second and then dies right away..

I checked the PCM fuse and relay but they seem to be working fine. I pulled up the wire diagram and tomorrow morning I will check if the yellow wire going to the PCM is getting power..

Thanks again for the input guys.. I'll let you know what the resaults are tomorrow.

Hey guys.. When you turn the key to the on position, the fuel pump comes on, but is it supposed to stop at some point? Or does it just stay on the entire time? With the key just in the on position, not running or cranking..

it should only run for abut 2-3 seconds

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+1. It should run for a few seconds and shutoff

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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).

Dang.. Mine just keeps going and going.. The "whirling" noise from the fuel pump can even be heard from the engine bay.. I was thinking of getting a fuel pressure tester so I can check if its actually getting to 40psi or not.. What would make the pump stay on like that? Could the pump itself be going bad or is it just not reaching the target pressure that tells it to kick off?

Swap out the relay. Is anything else avting up

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Your issues are all related to the p0511 code. Your pcm is acting up.

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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).

Your issues are all related to the p0511 code. Your pcm is acting up.

__________________
2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).

hey guys I tried to read the codes again and its not working anymore... the KOEO test will not start... does this mean my PCM is dead?? should i try removing the Superchip module?

I'd suggest cleaning up both sides of the fuel pump connector... I had a strange problem like that with my 95 this year and it was corrosion on the connector causing an inconsistent connection.