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Another stalling while driving

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duckie1098

10+ Year Contributor
38
0
Jun 1, 2012
Austin, Texas
I've been having this issue for the last 2 weeks, I've been looking through multiple forums trying to pin point the cause of my issue.

Issue- While driving the vehicle the car will stall for a split second, normally dropping the rpm's by a 1k then goes back to normal. The CEL does come on and goes off after roughly 5 seconds. This happens no matter what throttle % the car is at or rpm however it won't do it while it's idling. Sometimes it happens repeatedly every 3-5 seconds or takes minutes between to do the stall.

At first you could hear a click behind the radio, so after much research I pulled the ecu and found the board to have corrosion/ leaking at the caps and on the knock board (or at least the ecmlink calls the board this). Instead of replacing the caps I ended up picking up a different ecu (92 gsx mt ecu) that appears to be in excellent condition. Went ahead and had the caps replaced and my dsmlink v3 chip and socket installed.

Installed the new ecu and same thing, car still bucks at random rpms and throttle %. Still throws the CEL for a couple seconds and the car returns to driving normal till it happens again.

Before anyone ask, I tried to datalog the issue and reliezed every time it does this the log stops recording. Link says it's still connected but I lose datalogging capabilities when the car bucks.

Sorry for the long winded post. I don't want to throw money at the issue. I'm thinking about replacing the mpi ( correct term?) relay next to the issue but would this be causing my issue or should I be looking at something else?
 
Sounds very very very similar to your battery disconnecting for a second or the mpi fuse attached to the positive terminal fuse box is going.

First I'd check your battery. Is it secured? Then the terminals are they tight no corrosion, no sign of it arcing on the hood? Check the mpi fuse. I've seen one be broken and allow a current to pass through until it got jolted and disconnected the link inside.

Check your CEL yes it goes off but will be stored. If nothing is stored then most likely it's what I said above. Your losing power and resetting your ECU every time this event happens.
 
It does feel like power is being cut for a split second or the ecu is resetting. The battery is in the trunk and shows no signs of corrosion and terminals are tight (made sure by pulling them off and reconnecting them). MPI fuse, is it located under the hood?

It's not storing any CEL I think it's just the typical ecu coming on.
 
Could check the wiring for the relocation. Sounds like your losing the ground for the ECU. It turns off and then back on when ground is reconnected. I don't think this is to good to be doing to the ECU over and over.
 
Could check the wiring for the relocation. Sounds like your losing the ground for the ECU. It turns off and then back on when ground is reconnected. I don't think this is to good to be doing to the ECU over and over.

I'll looked last week at the positive line, though I'll double check the ground. I don't drive the car every day, it started the issue and I put it in the garage. Did the new ecu and noticed it did it again so back in the garage as I don't want to mess anything else up.
 
Checked the ground wire, and even traced it to ensure there was no frays in the line. It's good and and bolted down tightly.

I went ahead and ordered a new relay (mpi/mfi ?) and will be here on wed.
 
If you see the CEL come on and then off but no code stored. It's from what I've found only to be 1 maybe both of 2 things.

1- Power lose to the ECU
2- Bad ECU

Well 3 if you count the initial start up 5 second light check (normal)

So yea. Its for sure something related to how the ECU receives power or is powered on (ignition switch). If you have access to a manual you can look at the wiring diagram for a good idea of what components to check.
 
If you see the CEL come on and then off but no code stored. It's from what I've found only to be 1 maybe both of 2 things.

1- Power lose to the ECU
2- Bad ECU

Well 3 if you count the initial start up 5 second light check (normal)

So yea. Its for sure something related to how the ECU receives power or is powered on (ignition switch). If you have access to a manual you can look at the wiring diagram for a good idea of what components to check.

Looks like I'll take it in to a shop on wed after the mpi relay switch if it's not fixed. We've gone through the wiring with no only one needing to be fixed. Battery wires are good and all grounds are good. Can't tell me the ecu is bad at this point as it's been tested and is in good working order, we also pulled it yesterday and put it in another car with no issue.

The clicking is still happening from that area, I'll take a drive later and have a friend physically put his hand on the relay and see if it's coming from that.
 
So the story continues...

I've replaced alot of parts on this car with no good out comes. I called around and got some advice to go ahead and send the ecu to ECMtuning and have them look over it. Sent it out and was told the ecu looked and tested good and they could not get it to replicate the issue.

Since last I've replaced MPI with a brand new unit, coil packs, and the ignitor, battery, and grounds (though I'm taking some advice and going to add more).

I've never been able to datalog the issue since it cut the connection, however today I updated firmware and was able to pull one log. Tried a total of 4 times and this is the only one that the ecu didn't cut connection to.

Sorry for the long winded post here :boring:. On this log I've attached the problem was happened at 9.460 secs. The thing I see come up is KeyStart and the battery voltage drops to 12.5. Any input, it was hinted at a few times it may be my ignition switch. What do yall think?


Please don't hammer me, I do have wide band but it's not setup... hell not much is setup yet as this car has only moved 1/4 mile in 3 months.
 

Attachments

  • log.2012.09.20-01.elg
    17.8 KB · Views: 57
my car did something similar and it ended up being the EFI plug (on the intake manifold on my 2g) my switch had come loose and it would barely have power whenever it lost connection and then would get it back after a few seconds
 
my car did something similar and it ended up being the EFI plug (on the intake manifold on my 2g) my switch had come loose and it would barely have power whenever it lost connection and then would get it back after a few seconds

I have no clue what your talking about, switch then EFI plug....

I put up a datalog for those who know how to read through it and see what they can come up with.
 
Its the Electronic Fuel Injection connector thats in the engine bay on the Intake Manifold( at least it is on a 2g) my connector had come loose from rattling around
 
That log looked really weard, check your coolent tempture sensor, maff sensor, and tps sensor, I had a problem where my car would run like shit out of no where and then be ok, it was a faulty tps, found out by tapping it with a screw driver, but I don't think it's that. I think a faulty temp sensor can cause problems with the car dieing. Make Shure every thing is pluged and there is no loose wires or missing wires, even sometimes you can find problems by moving wires while its running. On the log were you touching the gas peddle or just letting it idle?
 
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You check the spark plugs? My old 2nd gen was exhibiting the same symptoms and the spark plugs were the problem...
 
Im having this same issue in my 2g. I have a 6 bolt swap and the past week n a half i get this random stall while driving....usally happens when turning and i get a quicl buck el for a few seconds and all is fine.
 
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