ECU/electronic issue...?

[GooeyGus]

So my car died on me tonight at an intersection. I was just idling and it died. CEL is on but I didn't have time to check codes. Luckily I was close to my work so a friend came and pushed me into my work parking lot, so it's safe for the night.

A little background:

My car has felt a bit "funny" for the last few weeks. It's been running fine, but it just didn't seem like it had the 'umph' that it should have during part throttle acceleration. Also my fuel economy has gone down, but no check engine lights.

This all seemed to have have happened right when I put my rebuilt ECU into my car.

fast forward to today: I had an idea. I decided to put the EEPROM chip from my old (dead) ECU into my working ECU. So I pulled the chip from the old board, and slapped it into the socket of my working ECU. Car started right up, I let it idle for about 10 minutes then shut it off. Everything worked great.

Two hours later I wanted to take it for a drive. I drove about 5 blocks and the car felt GREAT. Felt like it was running better than it has been for the last month. Then I came to a stop light and I heard a rapid clicking of a relay (not what you are thinking...) and the CEL came on and the car instantly died.

At first I thought it was the MPI relay, but the MPI was turning on with the key just perfectly, and it was turning off about 10 seconds after the key is pulled, just like it should.

The relay that was clicking was the relay WITHIN the MPI relay that controls the fuel pump. I tested the relay, it is fine.

About 10 minutes after dying, the car actually started back up again and ran for about 3 minutes then died. And then after 20 minutes worked again for about 2 minutes and died.

So I thought to myself "what controls the fuel pump relay?" and the answer that my brain gave me was "cam sensor".

Does this sound like a cam sensor failure to you guys? Has anyone with a dead cam sensor ever experienced the fuel pump relay clicking on and off?

Thanks!! I'm going to pop the other EEPROM back in the car tomorrow, although I think it was just purely coincidence that it died after I swapped it. I'm thinking it's the crank sensor... or something in the ECU (I sure hope not...)

Either way I'll find out tomorrow when I check the codes.

 

[SharonTampons]

I had a similar issue a few days/weeks after getting my EPROM socketed.
The MPI Relay would click, but the issue was intermittent. Sometimes it would shut off while the car was idling and sometimes I would not be able to start the car at all. It eventually evolved into a consistent no-start issue, in which the MPI relay would go berzerk with the key in the ON position.

It turned out to be a bad trace wire on the socket job. The best thing to do is to troubleshoot your ECU in a known-running DSM.

 

[DSMopar]

ECU controls fuel pump IIRC.

You just replaced the ECU, and you're having these issues... shouldn't this be obvious? I think you're in denial for some reason, are you friends with the ppl that rebuilt it?

See if you can borrow an ECU from someone, failing that send yours back and let them know what's happening. Sounds like it's heat related (starts ####ing up after driving, gets better for small time after cooling a little)...

 

[GooeyGus]

Well, it is definitely an ECU issue. It started up this morning and died 30 seconds later. 20 minutes later I started it and it ran for 10 minutes before I turned it off.

BUT, when the car died this morning I was able to read the codes. The ECU was flatlining... Constant voltage rather than pulses like it should be.

So I will be getting a hold of the place I bought the ECU from, and I'll check out the socket job too. Hopefully I find something obviously wrong that can be fixed easily.