Ignition Problem 1993 3.0

[PMoreau]

I have a 1993 Ranger XLT 3.0 2x4 with the manual trans.


When this problem began it would start fine, but die after 3 or 4 minutes, then require a 5 min rest before it would fire again. I checked the fuel pump, it is putting out about 35psi with out fail. Checked spark, found that I am not getting a spark when it isnt starting. Therefore this problem lies in the ignition system.


Here is what I have done so far;

Tested for spark at the coil, not getting any there ( cap and rotor are good ). Was advised to replace the EEC relay in fuse box under the hood, did so and thought that fixed my problem for awhile. But 25 miles later it began cutting out. I left the clutch engaged when it did to use the momentum of the truck to turn the motor and it always came back to life, unlike before.

Now that I knew the problem still lived I decided to pull the harness off the coil, TFI ( ICM up by the radiator ), and distributer to check the connectors. They all looked good but when I put everything back together I was back to square one with it dying very frequently and not restarting for awhile.

Replaced the coil. No luck. Decided that it was either ICM or something in the distributer ( Stator, Crank potions sensor, pick up coil... ). Took the ICM to the parts store and it tested fine, all 7 times we tested it. I decided it must be the Ignition pickup on the side of the distributer so I ordered one. It will come in tomorrow but if that doesn't do it, I don't know where to turn.


I want to get it fixed tomorrow so Im hoping to have a plan in place if it still doesn't run right after the new ignition pickup.

Thanks

 

[adsm08]

It's the ICM. They will frequently pass on the tester when they are actually bad. Those testers just look for high-impedance continuity on the circuits. It doesn't do a true at temp load test.


I highly doubt that the pickup would cause that.

 

[PMoreau]

Not surprised to hear that, I never expected it to pass the test.

Thanks

 

[PMoreau]

Yup, what do ya know, ICM. Runs alot better now.

 

[PMoreau]

No thats still not it. Yeah it runs better, but the original problem is still present. All the plugs/connectors seem to be in good condition. Hitting a bump seems to trigger it. Dosent do it every bump and dose it other times too, but there seems to be a connection between hitting a bump and it cutting out.

 

[PMoreau]

Threw some codes; the most relevant one was PIP circuit failure. Looked up the wiring diagram, the PIP wire goes to the ICM, pickup coil ( inside distributer ), and the EEC ( brain box ). I tested the PIP wire from the pickup coil to the ICM and got 2 ohms. Dosent seems to bad there.

 

[adsm08]

Coming out of the coil should be a green and yellow wire that runs to the ICM. Check the resistance across that wire while wiggling it.

 

[PMoreau]

Ignition coil or pick up coil?

 

[adsm08]

Ignition coil or pick up coil?

Ignition coil.

 

[PMoreau]

Theres a tan wire and two red with green stripe.

 

[PMoreau]

On th edge of a breakthrough. The last pin ( either pin 1 or 6 depending on how you look at it ) ( black wire ) on the ICM is supposed to be a ground according to many pinouts. It is not grounded.

Also I found a two pin round connector up in the area of the ICM and headlight. One pin is a ground and the other has a wire ( either white, tank light pink, or light gray, hard to say, with an orange stripe ) the connects to the first pin in the ICM ( 1 or 6 (?)) with a gray / orange wire ( PIP wire, connects to the Crank shaft position sensor and EEC ) . The resistance from the two pin connector to the ICM connector is in the thousands . Heres the troubling part; the two pin connector dose not seem to have anything to connect to. It seems like if I found something to connect it to my problems would be solved.
I cannot find this connector on any wiring diagram. ( it is not the spout connector ).

 

[Earl43P]

Hope this isn't huge......oh good, fits nicely.

I don't have the 3.0 Engine Controls on this computer. I do have 4.0, which for your purposes, may work.

PM me an e-mail address and I'll send the pages.

 

[PMoreau]

I know its a wiring problem. Start it up, shake the harnesses, it dies, wont restart. Shake em again, starts up. Not got it pinpointed yet, but soon hopefully. I tested all the wing related to ignition before and it seemed fine, but thats kinda the definition of intermittent. Maybe I can catch it when its action up.

 

[Earl43P]

Check the security of the PCM Power Diode in the fusebox under the hood.

Same with the PCM relay itself, remove install it repeatedly to clean up its connections.

We just had a guy find a dirty diode. http://www.therangerstation.com/forums/showthread.php?t=104176

 

[PMoreau]

Pulled the diode and ign fuse repeatedly, and put some dialectical grease on them and the relay. So far it hasnt acted up again, we'll see.