Tiburwolf

I will try to be as clear as I can. I have a 93 6spd with 38k. I replaced opti-plugs-wires-waterpump about 1500 miles ago and it took care of the miss I was having.


The other day going to work, I had cruise control on, and heard a pop...I am not sure if it was a back fire or something else....here is what the car did:
SES and ASR lights came on.
Speedo read 0
SYS Flashed
Digital readouts were not working either. (I don't believe they were...can't remember now)
Analog gauges on right Froze where they were.
Car ran with a bit of a miss here or there.
AC blew hot.


I was able to limp it home.


I waited a few hours and went out to start it. It started as normal, no lights, revved fine, AC blew cold. I did not go for a drive because I didn't want to get stuck. after about 10 minutes of running the lights came back on and the behavior started again.


I tried again after a few hours. Same behavior.


My first impression when it happened was that it was ECM related. I've searched and found some folks with this issue and it seems to be ECM or CCM related. My tach seemed to work during all this.


So, being the brave soul I went to pull the ECM and noticed one of the bolts was missing. My first guess was that the ECM had already once been replaced. Upon opening the cover underneath I found in actuality that they had put a HyperChip in. All I have read on them is to avoid them. Well, too late. The previous owner already put that in.


So, I reinstalled just the normal chip, and reinserted the computer making sure connections are good.


I start it up and vroom. Good revving and all things work. Within 3-5 minutes the following:
SES and ASR come on.
SYS flashes
The analog gauges seem to still work.
AC blew hot again.
Tack seemed to start having issues...just turning the key caused it to bounce.
Car died.


Restarted and didn't restart. So, the behavior is similar, but different in that different things seem to be wrong and now it dies and has a hard time staying running.


Things I know I need to check:
I have NOT pulled codes yet, so I have to do this.
Check the ground wire underneath by oil filter?
Get battery tested.


I believe it is the ECM, but any guidance is greatly appreciated. I have had the car for a year and a half and have not been able to drive it a whole lot. I love the thing. Makes me smile every time I drive it.


I have tried to research this and have not found something exactly like it, especially since a HC Chip was in it already.


Thanks.
Jeff

JimLentz

Jeff,

I recently purchased a '92 6 speed and had very similar problems. It was very random. For me what seemed really odd was I purchased it around 240 miles away and when I drove it home it drove great and got very good fuel economy. The next week I started driving it to work and had most of the same issues you have had, plus the security light going on. Here is the thread I had going about the issue. What my issue was is that the ECM had an intermittent issue with cold solder joints on the printed circuit board, apparently a fairly common issue. I sent the ECM to SIA Electronics and they tested the ECM and re-soldered all of the PCB connections. I have been driving it without issue for a couple of weeks and believe this issue is fixed. You should pull the codes, but I bet they are very similar to mine. Most of the issues I saw were relating to the CCM losing communication with the ECM. Replacement ECMs are hard to find.

Jim

Tiburwolf

Thanks Jim. I will check that thread. I have found, but have not ordered yet, ECMs at Autozone. They say they are in stock. One is a Blue Streak and one an A1 Cardone Reman. I am looking at the Cardone because I've read others have had good luck with them. Will check your link and keep you posted.


Plan to check codes tonight if I have time. If not, it'll be a weekend chore.


Jeff

JimLentz

Jeff,

If you go the AutoZone route I would purchase the Cardone, as I have never heard of Blue Streak. Let me know if you go that route and how it works out for you. I purchased a spare ECM cheap, but most of the latches for the connector are broken and don't know if it has other issues, so the Autozone route might work for me for that ECM. The MEMCAL for the 6 speeds (BAFL) for 92-93 are hard to find/expensive. Pulling the codes doesn't take long with a jumper wire, just make sure you use the correct pins.

kael

I think you really should check for codes first. This may help point to ECM if code 12 isn't shown (assuming similar to '87 ECM).

Tiburwolf

That is definitely on the plate. My money trees haven't been watered in awhile, so my desire for a correct diagnosis is definitely on the table.



Thanks.
I don't want this to sit like my MR2 has been...

JimLentz

Info on getting the codes. I am betting you get an H.41.

Tiburwolf

Pulled codesMod 1 - C41 and H41. As you mentioned Jim.
Mod 4 - Err
Mod 9 - H72

JimLentz

Your ECM is losing communication with the CCM. It could be the serial communication line to the ECM, but sounds more like a cold solder joint like I had. I sent mine into SIA Electronics in Tilden, IL and it has not acted up since. One of the things they do is resolder all of the solder joints and they also give a lifetime warranty.

ddahlgren

The solder job sounds likely as what happened to my dishwasher LOL. It is a high end Bosch unit but the control board has issues with cold joints. Out of warrantee and dealer said a new board 240 plus labor. Found out on the net about the particular bad ones and had it working in an hour.

If there are any electrolytic caps in the ECM they are always suspect and easy to spot if bad will either be leaking or swollen. Fixed my LG flat screen TV for 16 bucks rather than 285 for new power supply and labor. Found this on the net as well.

Nobody fixes anything anymore just swap one Chinese part for another with an equally short lifespan. When just out of HS I worked for a service station and rebuilt starters turned brake drums and stuff like that all the time and takes less time than waiting for the parts truck store to get there. The upside is you knew it was right and not have to change it again when the replacement fails.

I can easily believe bad solder joints and/or bad caps if that style is used.

1993C4LT1

When it starts acting up

Use a multimeter
Put key in the ON position.
Disconnect theTPS, MAP, and coolant sensor on the water pump. Do it one sensor at a time.
The ECM should be giving you 5 volts to all those sensors.
If the number is way higher, it could be the ECM grounds. Lower, most likely a bad ECM.
Make sure you have a good battery when performing this test.

JimLentz

Good idea about the grounds. I have heard the one on the engine block is a common issue.

Tiburwolf

So, sorry it has taken so long to post an update. I sent the ECM out through Autozone to Cardone. $170. Put it in and have been driving it now for a few weeks. Seems that was my issue.


I did not put the Hypertech chip back in. So when I started driving, I thought I forgot how to shift. That is until I realized the 1-4 shift was now activated. Makes me want the hypertech chip just for that. Now I know why people hated it. UGH. I guess I just have to press the gas harder!


Thanks everyone for the top notch advice. I feel much better going through a refurb for my own ECM than picking up a used, unknown unit.

Richard Raichert

If you don't want to mess with the chip you can buy the plug in cags plug that goes into the trans to eliminate the annoying 1-4 shift pretty easily and cheaply. The light on the dash will still come on showing the 1-4 but you can ignore it. Handy in slow stop and go traffic and no grind!