tuning

[ryanclem74]

Whats the best way to tune a 1985 gn without converting to a 1987 ecm?

 

[BRAD_PADGETT]

Mostly guesswork. Set the TPS to 4.5 volts at WOT, IAC to around 20, and fuel pressure 43lbs line off. Good luck. Brad

 

[Saladin45]

Well its not that difficult to make the conversion, am I right? Why not just switch over?

 

[TType84]

Well its not that difficult to make the conversion, am I right? Why not just switch over?

easy as pie. just add the wires for the IAT and run the wire into the engine bay.

 

[novaderrik]

i got an 87 ecm for $40, ran the IAC wire and sensor from a Chevy TBI harness i had laying around out to the air intake tube, and need to get a TT chip for it (it runs pretty good on the chip that was in the ecm, but i don't want to boost it with a LeSabre chip in it).
so all told, unless i upgrade to bigger injectors for E85 like i want to, i'll be under $150 in the whole swap.

 

[BRAD_PADGETT]

One option is to get an 87 TT chip which ignores the IAT sensor. One less thing to fool with. Brad

 

[TType84]

One option is to get an 87 TT chip which ignores the IAT sensor. One less thing to fool with. Brad

IAT data can be helpful tho

 

[ryanclem74]

i was under the impression that i would have to convert to a 87 coil and maf. Those were the two big money items i didn't want to buy since i already have a 87 ecm.

 

[Saladin45]

I know I am going to sound like a giant noob asking this. But aren't the coilpacks the same??

 

[1dollardog]

I know I am going to sound like a giant noob asking this. But aren't the coilpacks the same??

Nope. The coilpack and module are different from the hotair cars. I just bought mine for the swap.

 

[O SO LO]

here's a comparison of stock HA coil and 87 coil...original on left and only 3 of the HA wires
match to the 87 coil --requires adapter unless you unpin and move the wires.

View attachment 65185

 

[Saladin45]

Ah ok. I know why I got this confused.

My coilpack is not the original one. I have the 86/87 coilpack.

I forgot completely (It's been so long since I've seen the original) that the originals were big giant compared to the 86/87's.

 

[Jerryl]

Whats the best way to tune a 1985 gn without converting to a 1987 ecm?

If your car has no issues, you should be able to follow the advice from Brad.
Not much else you can do besides another TT Chip and playing with the FP.

There are also a few things to look for such as MAF idle/WOT, O2 WOT, and KR readings. This can be done with an OTC monitor (2000 or 4000), or turbolink through the ALDL. It is slow, but, I have seen cars run 110MPH with the OTC2000.

If you are having problems and/or made changes to the OEM set-up, it get a bit more complex and you will need data to review.

The swap can be done for around $170. (ECM and TT Chip)
Sure, some lucky people can find an ECM for $40, but I have not yet succeeded.

 

[TType84]

If your car has no issues, you should be able to follow the advice from Brad.
Not much else you can do besides another TT Chip and playing with the FP.

There are also a few things to look for such as MAF idle/WOT, O2 WOT, and KR readings. This can be done with an OTC monitor (2000 or 4000), or turbolink through the ALDL. It is slow, but, I have seen cars run 110MPH with the OTC2000.

If you are having problems and/or made changes to the OEM set-up, it get a bit more complex and you will need data to review.

The swap can be done for around $170. (ECM and TT Chip)
Sure, some lucky people can find an ECM for $40, but I have not yet succeeded.

i used to get them all the time in the boneyards for $25 each