Flashable ECU in auto 2g problem

[agarc023]

I just ordered an ECU from Jeff at Dsmchips. I put it in the car and went for a drive but there was a problem. The car is an automatic, but it seemed that it was stuck in drive the whole time. What I mean is that it took a while to get to speed. Moving the shifter into 2, 1, or throwing on the overdrive made no difference, it would just not shift.

Anybody know what could be wrong?

 

[the_mork]

Swap your original ecu back in and see if that fixes it. I suspect you may have upset the tcu ground, pulled too much on the wiring harness, or pulled a plug from the tcu. There really isn't much interaction between the tcu and the ecu.

 

[knochgoon24]

The only time the TCU and the ECU communicate (as far as I know) is for a "torque kickdown" signal that drops timing between shifts to reduce slipping while shifting.

 

[agarc023]

I have the original ecu in it now and it drives fine. I was talking to Jeff and he is a bit confused as well. Is there anything else I can check?

 

[the_mork]

It does more than send a timing pull signal, but not by a whole lot. There has never been an issue using a manual ecu in an automatic car to the extent that both Knockgoon and I are using evo8 ecus in automatics with no issue and the evo8 never came with an automatic.

I STILL expect this to be coincidence. At one point I was having transmission issues and it would go into limp mode any time that I went in reverse but if I started the car and only went forward it was fine.

 

[agarc023]

So is there anything that can be done about this? Jeff offered me a refund if I couldn't get it figured out, but I really wanted to use this for my tuning solution.

Another thing that happens when using the new ecu is that when its on a cold start and I put into gear (reverse for example), the whole car jerks horribly, but I think that may be because of an increased idle rpm

 

[Ceddy]

Make sure the Park/Neutral switch is working properly.

The 98/99 ecus do some weird things when it thinks the car isn't in drive. (Can cause knock, bogging, jerking, etc.)

-> Another option is to just ground the ecu pin 91(Park/Neutral Switch), this is how the 5-Speeds are set up. (I would try this first)



Also make sure you didn't pull any wires when swapping ecus, I pulled the TPS wire slightly out of the ecu plug once when swapping ecus.
It would make intermittent contact everytime I hit a bump or launched the car, took me a week to figure out what was going on.

Log everything with EvoScan and see if any reading is out of range or looks weird.

To my knowledge TCUs 95-99 are all the same, so shouldn't make a difference what year DSM ecu is connected. (There are a few guys with Evo8 ecus in DSM Autos)

 

[the_mork]

Even grounding pin 91 wouldn't be an ideal fix if the P/N switch is bad. I have mine bypassed temporarily in a very hacked way and I must say that it sucks, no cruise control, weird shifting, inconsistent behaviors, etc.

I'll be making it less rigged later today by adding a switch to manually operate the park circuit, and this will also be a temporary solution but I don't have a garage right now or a new switch to try out. All the other gear circuits work.

 

[agarc023]

Just an update for you guys. Jeff just contacted me and told me that he would be sending another ecu for me to try out. On the last one I had him ground a pin in the ecu to get rid of a p1500 code that came after swapping in a saturn alternator. He is not doing that for this other ecu.

I will try to get a log and check the wires soon. I am a bit busy right now with a test at school.

 

[agarc023]

Okay so another update. The problem was resolved. To my embarrassment, I ended up pulling the damn TCU and throwing on the new ECU there. The car was running on the stock ECU and without a TCU. In my noobish hastiness I only saw the TCU sitting there so I assumed that was the one that needed to come out.

Thank you to everybody that replied and I thank Jeff for having such awesome customer service.

Problem solved

 

[jeffo]

I'm just glad that I thought of it last night. I was beginning to panic that there might be a compatibility issue.