Easy question fellas....

If wires for the crank position sensor pigtail where not wired correctly (meaning the three wires were mismatched), would this fry the ECU.

Thanks

Tony

bump.

Please help! I'm trying to eliminate any possibilities.

Thanks
Tony

Depends on how they were wired. if you connected the yellow 9v+ supply to the black / green stripe sensor ground, you might have burnt up the 9v+ stepdown in the ECU. Does the Cam angle have power on the yellow wire? (expect 8-9V+)

Okay, sorry I'm doing this but I'm going to try and make this short as possible.

After rebuild, car is fine. After hitting 181 miles, car will start up and run for 15 minutes, shut off, will not start until cooled off('bout half-hour.) Cooled off, car will start again to repeat same cycle. Took car to shop. Shop replaced ECU to only have same problem again. Replace ECU again(warranty.) Second ECU, same deal. Run car for 15 minutes, upon it shutting down they shoot freon on the crank position sensor. Car starts right up. Seems everything points to crank position sensor. To try new cps, different pigtail must be wired. They get new pigtail and "carquest" cps. No start. Find out that wiring diagram with new pigtail is wrong so they try all combinations possible with the 3 wires. No start for any combination. They then follow arrangement on old pigtail. No start. Get different "carquest" cps. No Start. Get "Mopar" cps. No start. They have been stumped since. (ECU has not been replaced since trying different wiring combos on cps.)

They have checked all of the wiring harness, relays, other sensors, dropped oil pan and checked trigger wheel.

In their words, "We aren't getting a pulse from the crank position sensor." "Everything else checks out."

They have sent the car to a second shop on their own bill, second shop is stumped as well. Although my tab for the car is at a fixed amount for the original diagnosis, it's going on 2 months, what are these guys missing?

Sorry, it's a long reply
Thanks
Tony

From what it sounds like the shop is just a bunch of parts changers, and they dont actually diagnose anything. And how does it shut off? does it sputter and die or does it die immeatly? What about when its running does it run rough or good? A possibilty is what Darkone said that the 9v fried out the latest ecu you put in. Also a problem that seems to be coming from the CPS could aslo be casued by other varios things like; ingition coil/module, injectors, wiring harness or ECU. Try hooking up an oscilloscope to the ingition coil and see what happens to the spark voltage when it dies or if its erratic. You should look at the coil oscillations, I belive ther should only be three after the spark line. But an easier way to check it is to check the resistance with an ohm meter. You need to check the primary and secondary resistance. In order to check your primary resistance on the coil attach the black lead on the ohm meter to the battey voltage on the side on the coil (where the three wires go into the coil its the center one) and the red lead to the cylinder 1&4 connection (the connection most towrds the firewall) there should be .5 to 1.5 ohms. Do the same thing for cylinders 2&3 but attach the red lead to the connection twords the front of the car again .5 to 1.5 ohms. To test the seconday resistance attach the ohmmeter across the 1 and 4 towers of the coil and then 2 and 3. readings should be about 8K-9K ohms (8000 to 9000 ohms). And you can test the wires the same way just connect the leads to each end of the plug wires and there should only be 8000 ohms of resistance per foot of wire. And the easiest way is just to swap it out to conferm that this is where the problem is. Now thats only for ingition components you can test the CPS by attaching a volt meter set to AC and spin the engine and look for a voltage from the sensor (this is for hall effect sensors). Good luck

1. The car shuts off immediately, like you turned the key off.

2. When the car was running, it had a lope in the idle because I gotta redo the timing (skipped tooth,) but the engine was strong and very responsive on the road.

3. Coil pack good, all wires on harness have been checked, cps is good.

I'm thinking that all the switching around of the cps's wires did something to the ECU, that would be an easy fix since it's under warranty.

Thank you Quadman for the info, please keep ideas coming.

Thanks in advance
Tony

EDIT--Replacement ECUs were remanufactured, I wonder if it is common for these to be defective.

Originally posted by enhance
I'm thinking that all the switching around of the cps's wires did something to the ECU, that would be an easy fix since it's under warranty.

Yea most likely thats what happened to much voltage into sensative electronics doesnt mix well since the ECU's under warrenty I would send it back and make sure that the CPS is correctly connected.

well tony you know my theory. i think they put the hot wire to the ground and ended up shorting out the cps portion of the ecu. thus requiring a new ecu

Yeah,

From what I understand the cps is now wired correctly due to following the arrangement of the wires on the old pigtail. That is of course after they tried all the different wire combos.

I don't know, they are paying the bill for their error, so who knows when they will realize that they possibly burnt the ECU.

Thanks
Tony