Chip Swap Problems

[MELOVEGN]

I have an older Dynotech Chip that i got with my car
i have recently tried to swap them (not sure what is in the car now) and when i did the swap I:
1 unplug the ecm wire near the battery
2 unplug ecm with old chip and replace with new ecm with new chip
3 reconnect ecm wire near battery
4 start car

am i missing something here???

now when i start the car i get a flashing check engine light and the car idles at 2k rpm and then i shut it off just because i didnt know what to do or why it happened so i figured i would come to the guys who would know

A friend of mine said something about the car/chip having to learn eachother???
HELP!!!!!

 

[blackbuick87]

Why did you change ECMS?

Any time the ECM loses power it will runs like crap for a minute or two while it takes in readings from the various sensors and "learns" about your car. It will run its best after about 1/2 hour of driving.
You should not get any codes during a normal chip swap, but I dont know about ECM swaps, I would think no codes should come up there either.

 

[MELOVEGN]

Sounds Good to me
Thanks i will try it tonight
Thanks
More opinions or ideas alwys wlecomed

 

[gofstbuick]

When the engine is first started, the SES light should not flash while the engine is running. The learn process will not flash the SES light. Are you sure the prom is seated properly in the new ECM? Remove the PROM from the ECM and check the pins (maybe a bent pin) also, you may check to see if codes are stored in the ECM (prior to removing the PROM).

 

[Scott231]

Bzzzt. Flashing SES light means either the PROM is not fully seated or you have zapped the PROM and ruined it (i.e. wither way the ECM is not seeing a valid chip as being inserted in the computer.

Steps 1, 2a and 3, were all unnecessary...but it makes people feel good. Please tell me you really didn't remove the whole ECM to change chips.

 

[MELOVEGN]

yes i swapped the whole ecm just because i had them i didnt purchase them special

and i will check and see if the chip is seated properly and if not then its probably done for huh?

thanks guys

 

[gofstbuick]

Originally posted by MELOVEGN
yes i swapped the whole ecm just because i had them i didnt purchase them special

and i will check and see if the chip is seated properly and if not then its probably done for huh?

thanks guys

It doesn't necessarily mean the chip is done for, it may just mean the chip is not fully seated, or seated properly. Please check for bent pins and or seating problems before condemning your prom or ecm. I would remove the prom, straighten any bent pins (if necessary) and properly reseat the prom into the ECM, and see if that works. Please be sure to wear a ground strap, gound mat or physically touch a metal portion of your vehicle prior to removing and re-installing the prom (to prevent static discharge to the prom or ECM). I hope everything is okay, and was just a prom seating problem.

 

[gofstbuick]

MELOVEGN
So what did you find? Please tell us what happened.

 

[Sinful6]

After I unplug my orange wire to change chips, my car runs like crap for a couple minutes (may even stall). My question is, is it really necessary to unplug the orange wire when changing chips, and what happens if you change without unplugging.

 

[gofstbuick]

My understanding is that when you disconnect the org/blk wire, it resets the ECM to factory parameters. This allows your ECM to learn the new PROM. I don't think it is necessary to disconnect prior to installing a new PROM, but just disconnect for a minimum of 10 seconds and then reconnect prior to starting the engine with a new PROM in the ECM.

 

[MELOVEGN]

Originally posted by gofstbuick
MELOVEGN
So what did you find? Please tell us what happened.

Well i put in the ecm and chip that had given me the flashing check engine light and high idle rpm(2k) etc. i let it idle for 5 mins approx and then took her for a ride (about 10-15 minutes) the flashing check engine light never went away and neither did the high rpm's at idle (2k)

so i have decided to wait untill i finish my fuel system and a few other mods and get a chip burnt for me

Thanks EVERYONE for your help!!!!

 

[Night Train]

Make sure you don't have a volt booster plugged into the TPS. I had one that worked well until I unplugged it and re-plugged it. After doing that, I had a problem similar to yours. Unplugged the Volt Booster and simply plugged in the TPS and the problem went away.

 

[Night Train]

Another thought. Have you changed your O2 sensor lately? Might also cause the high idle condition if it is no good. Only use a GM purple wire O2 for the best results.

 

[MELOVEGN]

no volt booster and also i have not changed my o2 lately but it works fine as long as i dont use this other chip thanx

 

[FJM568]

If the SES light is flashing, the computer will never learn in...You are running in backup mode off of the Calpak...or did Scott stutter?!?!?

Remove the chip from the ecm that makes the SES light flash and put ONLY the chip into the other ecm that doesn't cause the SES light to flash...That way, you are checking to see if it is actually a bad chip or a bad ecm...

 

[Scott231]

Originally posted by Sinful6
After I unplug my orange wire to change chips, my car runs like crap for a couple minutes (may even stall). My question is, is it really necessary to unplug the orange wire when changing chips, and what happens if you change without unplugging.

When you unplug the Orange wire, the fueling adjustment parameters in memory are all reset to the neutral number 128. This means the car will not add or delete fuel to achieve stoichiometric air-fuel ratio of 14.7:1, until it has seen the O2 sensor read rich or lean for a set amount of time then the short term and long term fueling parameters get reset to whatever is needed to achieve the commanded AFR at the RPM vs. MAF breakpoints (i.e. the "Learn" feature is ON).

If your car runs like crap, it is because it is not receiving the additional fuel (or less as the case may be) that is necessary for the motor to run at stoichio.

To specifically answer your question, NO, it is not necessary to unplug the Orange wire. If you change chips without unplugging, then the BLM and INT do not get changed from their prior values with the other chip until the car is driven around through all the rpm v. MAF breakpoints and the fueling parameters are "re-learned."

 

[Scott231]

Originally posted by gofstbuick
<snip>just disconnect for a minimum of 10 seconds and then reconnect prior to starting the engine with a new PROM in the ECM.

That is an old wive's tale. Once the Orange wire is disconnected, the fueling parameters in memory change to 128 at the "speed of light." If you turn on a lightbulb...how long does it take for it to go dark?

 

[Scott231]

Originally posted by MELOVEGN
Well i put in the ecm and chip that had given me the flashing check engine light and high idle rpm(2k) etc. i let it idle for 5 mins approx and then took her for a ride (about 10-15 minutes) the flashing check engine light never went away and neither did the high rpm's at idle (2k)

Of course not. The ECM does not see a valid PROM. Until a valid PROM is in the ECM, the SES will continue to flash. Chips do not go 'bad' and suddenly get 'good' again (however, a poorly seated chip that becomes properly seated on its own [very unlikely] can also cause this).

Assuming you have the chip fully seated, then the PROM is not passing the Checksum routine. It is not passing cuz either a single data point has changed or the whole chip is wiped out (from static electricity). The high idle will also stick around until a valid PROM is inserted in the ECM.

 

[69GS400s]

Right now, it is undetermined as to wether the New ECM or the New Chip is causing the problem.

I would think this needs to be determined before anything else is done, including other changes that you mentioned.

Making modifications ontop of an existing problem only makes matters worse.....

 

[Scott231]

Originally posted by FJM568
If the SES light is flashing, the computer will never learn in...You are running in backup mode off of the Calpak...or did Scott stutter?

That is correct. If the EPROM is bad, then the ECM ignores all inputs from the sensors. But, in order to run the motor, the ECM needs values from the input sensors. Since that is not possible with a bad EPROM, the ECM uses default values from the Calpack chip (the little one right next to the ERPOM.

Remove the chip from the ecm that makes the SES light flash and put ONLY the chip into the other ecm that doesn't cause the SES light to flash...That way, you are checking to see if it is actually a bad chip or a bad ecm...

Good point. If the SES flashing goes away with an ECM swap, the first ECM is bad. If the SES continues to flash, it is a bad EPROM.