I took my car to a GM Shop to figure out why my car royally puked on me and they told me it was my Computer (ECM). They said the year of computer has had a history of ECMs going bad. They said they would need to put in a GM aftermarket ECM that is more reliable. They qouted me $220 w/o the stock chip.

Now, what I was wondering is if anyone else makes aftermarket ECMs that would be a significant difference in price to the one the shop told me?

Thanks in advance for any help.

 

Go to a wrecking yard - you generally can pick them up for the price of a core charge. Do some searches on other vehicles that used the 1227165 ECM (your ECM). The late 80s 2.5 Inline 4 TBI pickups used the same ECM.

 

I hope you didn't laugh too hard. $220, Like Glenn said Juckyard time. $50 should cover it.

?? ya, but the signifigant difference is not the direction you want.
For 2-4 grand you can get a nice fulll function aftermarket one.

 

YOU CAN GET A USED ECM FROM THIRD GEN RESOURCE, ONE OF OUR SPONSORS FOR $50.00

 

For a good used ECM $50.00 is a decent price. NAPA sells GM remanufactured ECMs (original GM ECMs) for about $110. I replaced my dealer installed ECM which failed after 1 year of use with an exact match from NAPA for almost half the dealer price. Well, not quite an exact match, the NAPA unit has been going fine for 4 years now.

If you still have have an original 1227165 ECM then there is a very good chance that the ECM could be bad. That ECM version did have a history of problems. GM has service bulletins out for several PROM & relay problems specific to 86 model F-bodies and Vettes.

Before beginning diagnosis, all 1986 models should be updated to the appropriate service PROM listed in bulletins: 86-657-106 and 86-650-109.

Mass Air Flow (MAF) power and burnoff relay part numbers should be checked to assure that they agree with those listed in bulletin 87-650-119 and 87-657-113.

Go by a reputable GM dealer and ask them to print out the above service bulletins. They can.

If your ECM set a code 33 then the car went into limp-home mode and ran like crap. If Code 33 is intermittent it will be necessary to change the MAF power relay. The MAF power relay new P/N is 10067925.

If you get a new ECM from NAPA they will know the new GM ECM part number that you need.
-Good Luck.

 

I got a remanufactured aftermarket ECM for $75. When I took the old ECM out, I found out that it was already an after market ECM and not the stock one. That explains why the hypertec chip was in it. The original ECM probably went bad and had to replace it so the previous owner thought he should buy an aftermarket "performance" chip since he had to buy a new one.

Unfortanatly I thought the ECM I recieved had a chip in it already, but I was mistaken. I replaced the ECM and put the hypertec chip back in, in hopes that it would start so I could get it off the GM mechanics lot. (its been there for almost 3 weeks now) But it wouldn't run. It turns over and fires for a second or 2 but thats it.

I am guessing the hypertec chip is F****d up. I read in one other post that all these chips really do is advance the timing some. I am kind of thinking that it actually throwing the timing way off. I also replaced the manifold intake temp. sensor. I took the plenum off to get at it better and holy Sh*t! The ENTIRE inside of the plenum and runners were covered with a thick layer of black carbon!

Am I not right in thinking that the manifold should be completely clean? Could incorect timing cause this? Or is this an indiction of a bad vavle?

Thanks for any additional info,
-xmind2006

 

Check the fuel pump.

 

fuel pump is fine, I am pretty sure it is just that stupid Hypertec chip. I will know for sure this weekend when I get the replacement chip.

 

Make sure the memcal is properly seated and in the right direction (some of those after-market don't have the proper "key" to stop you from inserting backwards).

Generally if an eprom/memcal is bad, you get a code 51. Sounds like something else IMO.

 

The black stuff in the plenum and runners is a natural effect of the EGR rerouting combustion gasses back to the intake. A thick black layer is not normal unless you have a LOT of miles or some other problem.

The cause could be due to several things. Improper EGR functioning/cycling which could be caused by a bad EGR sensor switch, or a bad EGR valve, or ECM failure in its circuit affecting the EGR (unlikely but possible). If the engine is way off time, or running way rich, or there is oil getting past the rings, any one of these could contribute to the EGR recycled gasses carboning up the intake.

I'd consider a compression or leak down test to see if the carbon is due to mechanical problems. Pull the plugs and make sure all cylinders are firing correctly. Double check the base timing. The ECM starts from there. It doesn't set base timing. An fuel injector test may find a leaking fuel injector or injectors. -Good Luck

 

I can't help you w/your problem-but my 89 350 has a Hypertech in it too--I'm also having problems w/it, and I've heard alot of problems from other guys who are running the same brand chip. Seems like Hypertech needs to work out alot more bugs!

 

Well, a lot of interesting things.

Closer inspection of the Hypertec chip shows that there is no mem cal in there!! Is this possible or did the dealership take the mem cal chip out of the casing?

Well the replacement prom and mem cal didn't come in the week that I was back in WI (where my Camaro is; I'm in MI). So all my dad and I did was replace the ecm but kept the hypertec chip. It would turn over and fire for about 2 secs max and that was all it would do.

SInce then the replacement GM prom chip came in so my dad pugged it in (from what he observed, the memcal chip was already included with the casing). He tried starting the car, but would only fire and run for about 4-5 secs before it would just quit.

I have not a dollar left to my name that can go towards my car unfortantly, but would really like to know what is going on.

I am correct in thinking the mem cal and Prom chip fits in the same slot with a case?

Thanks for any help in my very depressing situation (to me anyway) since summer is really winding down.

-xmind2006