Possible ECU or Grounding Problem?

[1996Eclipse420a]

I can be driving my car, and randomly it loses power for like half a second, but instantly regains it. I've tried data logging it, but when the "jerk" happens, it shuts off the data logger. The radio and the other electronics don't shut off though, so I don't think the ECU is the problem for me.... I'm about to start a build and will have pistons, and rods in the next couple of days... so hopefully I can find out what the issue is during that time. I kind of think I have a bad ground wire somewhere, or a wire is grounding out somewhere it shouldn't be... It doesn't happen in a sequence, completely random. It's driving me crazy.

 

[ohTONYoh]

Same just happened to me. Turned out that both my battery terminal latches were cracked and not getting all around connection and would start losing power at random. Check your connections and grounds.

 

[bullettdsm]

Turned out that both my battery terminal latches were cracked and not getting all around connection and would start losing power at random. Check your connections and grounds.

^^This. Best place to start. And don't just look at them and say they look fine. pop them off and clean them up.

MB

 

[BK85]

I had the same problem for 6mo or more. It would shut off and right back on and flash the check engine light but leave no codes. I changed cables, cam and crankshaft sensors also the plugs for all with no change. Than finally on day it cut out and never came back on. Motor would crank but no fire or fuel. I changed out the ECU and it started right up. Just for a test I put the old ECU back in and no start.

So all along it was the ECU cutting out.

BK85

 

[chevaholix]

Bk85 exact thing happend to me. it started out jus cutting out once in a blue moon then more and more often itd happen. changed cam and crank sensors plugs wires redid all the grounds, it was my ecu. mine was a 95 aswell esi but same thing.

 

[turboglenn]

i ran into this recently on a ford van i worked on, it wuld only start with an OBD-II connector plugged in because the connector looped pins in the OBD connector 4 and 5 (chassis and ECU ground) so i had to trace the wiring and found many poor grounds whihc i put some new wires in the engine bay and from chassis to trans, then to be extra safe i traced the ECU grounding inside and added one there with a diode so that theere was no chance of a backflow of any sorts (i'm not electronics whiz and it might not have been needed but i wanted to keep the chassis and ecu grounds isolated for cases where a scanner or code reader might not connect them) btu anywaym after the first grounds i added it started up and ran better than it had in a year he said (said it would miss and cut out all the time with a check engine light that only showeed random multip[le misfires)

so hook an OBD scanner to it and see if anything cvhqanges or connect the two middle pins on the wide side of the obd II connector and see if it clears up, they are just grounds and the 5th pin is the most direct ECU ground from the harness and easiest to test

 

[1996Eclipse420a]

sorry about the late reply. okay, I'm going to explain it a little better.

The car starts up fine. Once I start driving it can, have that "Jerk while accelerating, or coasting, but not at IDLE. It's kind it sputters 2 or 3 times before it starts accelerating..

It happens at random times. I've tested the ASD relay, put new battery terminals on it, new plug wires, plugs, and a coil. Nothing that I did there helped it at all.

I'm not sure if it's the ecu or not though. I hooked up a OBD2 scanner, and data logged everything... When it "jerked" it didn't cut the OBD2 scanner off. If I'm right, would the OBD2 scanner reset or shut off if the ECU was dying?

The last thing I know to try is testing fuel pressure, to see if the filter is clogged.

One thing is for sure though, it does it once I put the car under load, not at idle. It has baffled me.

Oh and the TPS is fine I think. I'm going to double check and make sure the sensor doesn't have any dead spots, and I'm also going to clean the map. Hopefully I'll figure something out.

 

[Josh97eclipse]

Same happened to me. I forget what it was because i replaced the batt terminals and some other sensor and it ran like a top.

 

[LeeSD1]

I had this problem with 2 different ECU's both did the exact same thing. It was definitely the ECU's after changing it out with a known good one from a friends 420a It never did it.

 

[Black420RS]

sorry about the late reply. okay, I'm going to explain it a little better.

The car starts up fine. Once I start driving it can, have that "Jerk while accelerating, or coasting, but not at IDLE. It's kind it sputters 2 or 3 times before it starts accelerating..

It happens at random times. I've tested the ASD relay, put new battery terminals on it, new plug wires, plugs, and a coil. Nothing that I did there helped it at all.

I'm not sure if it's the ecu or not though. I hooked up a OBD2 scanner, and data logged everything... When it "jerked" it didn't cut the OBD2 scanner off. If I'm right, would the OBD2 scanner reset or shut off if the ECU was dying?

The last thing I know to try is testing fuel pressure, to see if the filter is clogged.

One thing is for sure though, it does it once I put the car under load, not at idle. It has baffled me.

Oh and the TPS is fine I think. I'm going to double check and make sure the sensor doesn't have any dead spots, and I'm also going to clean the map. Hopefully I'll figure something out.

I had that same problem

just replaced the fuel pump and everything is normal now

when your car die again, push with one pencil the passenger side of the fuel rail and if it doesn't pour a small amount of fuel, there you go (replace fuel pump and fuel filter)

hope it helps

(sorry about my English, sometimes is not so good)

 

[1996Eclipse420a]

alright guys, I think I have gotten the issue fixed. Crossing my fingers though. I hit a deer last December before replacing the bumper and painting the whole car. When I hit the deer the car died, would not start to save my life, and finally about 10 mins later, it started.

Well I started thinking, and figured it could have knocked something loose, and cause a bad connection. (it particularly did it under load, and when I hit bumps in the road)

So, I put it on a lift this morning, checked out the crank sensor just to make sure it didn't come unplugged or anything. It felt like it was secured good, but just to be safe, I gave the plug a pretty good squeeze. Backed it out of the garage, went and gave the car hell down straightaways and it ran great. Parked it for awhile, drove to college for a cruise, and it still ran great!

Hopefully, it will continue to work (knock on wood) Anyhow, I have a few more days to drive it, then she's being put up for a turbo build. It needs it too... I can rev it up to about 4-5k RPM and when I let off the gas she starts smoking. (blue smoke.) My guess is the pistons, ringlands are bad. It eats a quart of oil in about 300-400 miles

! anyway, thanks for the help, and I'll let you guys know if it starts the crap again.