EGR Delete EEPROM Question (Page 1/2)
Wacko1Jacko12 AUG 06, 09:15 PM
Hi everyone,

When I bought my 88 Fiero I did not realize all the emission components were taken out, this includes the EGR, vacuum canister, and the vacuum lines that go to them (ports plugged off). I am on the fence about if I should reprogram a new chip for an EGR delete. I used TunerPro with an ALDL to USB connector to see if there was any egr fault (and values), but I did not see any with my current chip. So I guess the previous owner actually had someone modify the chip to disable the EGR? Would no alarm indicate this? Also, I looked through the forum and found that my chip belongs to an 86 Fiero, however mine is an 88 3 speed auto Formula 2.8. The chip that is in there currently is: APN0154. I am in the process of working on my coolant system but before that I was getting Code 12 only. I never got a code 32 or any other code.

FYI if you have seen my previous questions: I installed a new IAC sensor and cleaned the IAC passage. Still in the process of fixing coolant pipe that got damaged from a shop.
Patrick AUG 06, 10:21 PM

quote
Originally posted by Wacko1Jacko12:

Would no alarm indicate this? I never got a code 32 or any other code.



Have you actually had this Fiero cruising on the highway yet? It seems that a Code 32 doesn't usually get triggered (from an EGR solenoid problem) until the car has traveled a bit at highway speed.
Wacko1Jacko12 AUG 07, 06:58 PM

quote
Originally posted by Patrick:

Have you actually had this Fiero cruising on the highway yet? It seems that a Code 32 doesn't usually get triggered (from an EGR solenoid problem) until the car has traveled a bit at highway speed.



Yes it has been on the highway several times, however this was a while ago. I should be able to fix my other issues this week or so, then hopefully get it on the highway to see if it triggers the alarm. But if it doesn’t would this indicate that the chip was re-programmed?
Patrick AUG 07, 07:10 PM

quote
Originally posted by Wacko1Jacko12:

The chip that is in there currently is: APN0154.



Someone with a better knowledge of PROM chips than me needs to speak up here... but if you have a PROM with numbers such as those on it, I believe it's a factory PROM and not a modified chip. In other words, the factory PROM chips cannot be altered/re-programmed. It would need to be a re-writable chip... which wouldn't have those numbers on it.

[This message has been edited by Patrick (edited 08-07-2024).]

armos AUG 07, 07:47 PM
APN0154 is a legit Fiero chip, but it belongs to a 1986-87 Federal emissions 2.8L 5spd Manual with 215/60R15 rear tires.

I believe your correct factory chip would be AKYM3437 (Federal) or AKYR3452 (CA).


<screenshot from somebody's web site I saved years ago>

Is your EGR *solenoid* (on the passenger side of the engine) still there?
There's some simple way to trick the wiring that connects to the solenoid so that the ECM thinks the EGR is present and defeats the error code. That might be all that was done.

The factory chip is an erasable EPROM - if somebody pulled the sticker back they could have erased and reprogrammed it.

[This message has been edited by armos (edited 08-07-2024).]

Wacko1Jacko12 AUG 07, 07:57 PM

quote
Originally posted by armos:

APN0154 is a legit Fiero chip, but it belongs to a 1986-87 Federal emissions 2.8L 5spd Manual with 215/60R15 rear tires.

I believe your correct factory chip would be AKYM3437 (Federal) or AKYR3452 (CA).


<screenshot from somebody's web site I saved years ago>

Is your EGR *solenoid* (on the passenger side of the engine) still there?
There's some simple way to trick the wiring that connects to the solenoid so that the ECM thinks the EGR is present and defeats the error code. That might be all that was done.



Thank you for that chart! The EGR solenoid is also removed, the 4-pin connector is left unconnected.

Dennis LaGrua AUG 07, 08:40 PM
It is possible to shut off the EGR solenoid function in the program by unchecking the feature flag but federal emissions laws state that this must be for "off road use" only.

------------------
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Patrick AUG 07, 08:40 PM

quote
Originally posted by armos:

The factory chip is an erasable EPROM - if somebody pulled the sticker back they could have erased and reprogrammed it.



Really? Wow, I thought data on the factory chips was carved in stone. They're often referred to as a PROM (not necessarily EPROM), so I assumed they were not erasable. Learn something new every day!

Good thing I mentioned the following!


quote
Originally posted by Patrick:

Someone with a better knowledge of PROM chips than me needs to speak up here...


armos AUG 08, 05:31 PM

quote
Originally posted by Patrick:
Really? Wow, I thought data on the factory chips was carved in stone. They're often referred to as a PROM (not necessarily EPROM), so I assumed they were not erasable. Learn something new every day!


It's feasible that GM could have used "one time programmable" chips (programmable by customer, but with no way to erase) at some point, but I haven't heard of that being the case. I believe they all have erase windows under the sticker, at least on our cars. They definitely didn't use Mask ROMs (hardwired by the chip manufacturer - those would have significant downsides for GM).

I wouldn't erase the factory chip, but some people might. If somebody wants to mess with reprogramming then I think it makes more sense to get EPROMs from eBay/etc to mess with and leave the factory chip alone.
For these ECMs the EPROM chip type is 2732 (my factory chip even has the "2732"xxx part number printed on the back of the chip itself). The chips I've used on mine are M2732A, but the "A" isn't required, just more common.

---
On my car (nonworking EGR solenoid, but plugged in) with a stock 86 CA automatic chip (AATC), I used to get a code 32 within a few minutes of driving as I first got up to about 35mph or so. But I don't know if it would have been the same with the solenoid entirely missing/unplugged.
I also don't know if your chip being programmed for a Manual might change the conditions for Code 32 any.

When you first turn the key to "Run" (engine not started), does the Check Engine light come on, then go blank for an instant before it turns back on and stays? That little "blink" is normal if the ECM is reading and accepting the chip.
I *think* that you'd get a Code 51 if it's rejecting the chip, but if you aren't getting that little blink at Key On then I would wonder.

[This message has been edited by armos (edited 08-08-2024).]

82-T/A [At Work] AUG 08, 06:51 PM

quote
Originally posted by Patrick:

Really? Wow, I thought data on the factory chips was carved in stone. They're often referred to as a PROM (not necessarily EPROM), so I assumed they were not erasable. Learn something new every day!

Good thing I mentioned the following!




Yeah, you can erase them by blasting the chips with Ultraviolet light. You can either let them sit out in the sun for 30 minutes (with the sticker pulled back), or place them under a UV light for a couple of minutes. You can then plop them into a chip burner and go to town. One of my buddies used to do this all the time with his Citations to make changes / modifications.