ECU problem? 94 Duster 3.0

Hi all. Been a looooong time but I'm back for a bit. I bought a house so naturally car projects are off to the side. I still have an 86 LeBaron ragtop I toot around in over the summer. But that's about it!

Anyhoo, we have a car at my shop, it's a 94 Plymouth Duster, 3.0 604. It's got 66k on it and is a creampuff. It died on the girl while she was driving. Crank, no start, no spark, no codes, no CEL at all. Another shop replaced the computer with one from rockauto, this did not fix the problem.

According to the tests I've done, it still needs a computer. I have had terrible luck with Chrysler reman computers in the past. It took three of them to get a good one for my 86 ragtop.

What do I do from here? Are there any other things I can do before I throw another computer at it?

Also, anyone selling a 94 3.0 64 computer?...

Thanks in advance.

I think the easiest way to get one is from a junkyard caravan. Even those 2nd gen vans are getting sparse in junkyards down here now. :(

So i guess it sees rpm signal but doesnt turn on the asd?

Disconnect the MAP sensor (electrically). I have had them fail and result in stalling and no start conditions. No codes... After disconnecting the MAP, the engine started and ran poorly.... Shut off the engine and plugged the MAP sensor back in. The engine started and ran well enough to get me to a parts store to get another MAP sensor. Never checked for spark...

The no spark has me thinking of two other things.

1) timing belt or distributor optical sensor failure. Do you see RPM on the scan tool? Does the rotor turn when the engine is cranked? (not just the cam sprocket.) If so sheared pin on the front cam.
2) Check the coil output from the ECU with coil connected and unconnected. I have had the ignition FET fail. With the coil connected you would see nearly no change in the voltage. With the coil disconnected you may see some change in voltage.

Seems odd that two ECU's would be failed in the same way...

It can't be a timing belt issue unfortunately.

The fuel pump doesn't even prime when you key "on".

So does the ECU even power up? I am wondering if there is a blown fusable link...

Quote:

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Originally Posted by c2xejk

So does the ECU even power up? I am wondering if there is a blown fusable link...

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Come on Pete, not enough info!

I just went through cleaning all the relays and grounds when I was getting intermittent power to the ECU. There were other things wrong too but if the fuel pump doesn't prime, your ASD or pump relay or ECU is not happy. I would figure its not the ECU as the problems I have with them are sketchy one thing doesn't work kinda problems, not being completely dead.
I only got into the wiring because I started blowing the ASD feed fusible link. Installed a fuse holder and kept blowing that. I didn't figure out what was drawing too many amps as I just added my coil to the fuel pump hotwire relay and the fuse stopped blowing. Before I took load off that circuit, I had to get myself home once with a wire jammed in the fuse holder. Scary because it was stop and stop and stop and go traffic.

I can't even find time or energy to get my house fixed up so I hate when I have a car problem now.

Thanks for the help, Brent.

I did a little more digging into it to day. I did in fact pop a fuseable link. It was white in color, and appears to feed a red/white wire. I forget what the pinout diagram said that wire did, but it seems to feed a whole bunch of stuff.
I put an inline fuse holder in it, and after doing a bunch of tests, found that it will pop when the key is first turned to "on" (as in, fuel pump primes), when the black connector under the hood is plugged in. I'm not entirely sure what's on this circuit aside from the fuel pump. There's probably 12ish wires that go to it. But what else would be active when the fuel pump initially primes? For kicks, I unplugged the fuel pump and it will still blow.

Fuel pump wiring is looking like the culprit right now. But I can't seem to find a pinout of that connector, even on alldata.

Looking on Alldata, there is a black 8-pin connector that only has 7 terminals in it that is your 1 injector power and 6 injector grounds.

There is also a 10-hole black connector behind the battery that has the fuel pump power feed, the o2 heater, the IAC, the alternator field, and 2 injector grounds.

It appears mostly under Vehicle » Diagrams » Electrical Diagrams » Powertrain Management » System Diagram » Part 3 although the part showing the fuel pump wire and o2 heater is actually in the Part 1 diagram.

:)

Thanks buddy! It is in the 10 pin connector.

I have the cheaper version of alldata, maybe that's why I couldn't find it? Either way, you're the man.

It was the Oxygen sensor. All set.

Cool, that's cheaper.