Upgrade the ecm!

[Shamusvelez]

Im new to the GN family, ive mentioned this in other posts. I just put a shit ton of cabbage into my new baby girl, a 1985 GN. New motor, pretty much new everything under the hood. Some suspension work, interior etc etc blah blah blah!
All in all its still stock though, no upgrades yet.

I recently aquired an 87 gn ecm in great nick with the stick chip and all. Its my understanding that swapping my stock 85 ecm for the 87 ecm will bring certain benefits. Not entirely clear on all of said benefits, so could use some input on exactly what i will gain.... And also, do i have to do anything to make this swap, like burn a special chip or use my stock chip, or use the 87 chip,or click my heels together three times, or just simply swap the old for the new. Could use some help in the matter. Thank you for any info to help enlighten me. Im learning alot real fast with these cars, just some things having a hard time deciphering in past threads. Its almost upgrade time so, starting with the easiest stuff first.

 

[novaderrik]

get a Turbotweak chip- it will be custom made just for your car.
then the ecm just plugs right in.
i don't know what all the benefits are, but it worked pretty damn sweet in my 84..

 

[Jerryl]

If you plan on keeping the car 100% stock at 7-8 lbs boost, the stock ECM is probably ok.
Just for scantool availability . . . You cannot use scanmaster or PL with the 84-85 ECM. That alone is worth the swap.

The custom chip for the 84-85 is almost impossible, plus it does not have the ability to log temp.
Not sure if TT even does stock chips anymore . . . . and even if you get one, I am not sure if you can Tweak it.

As stated by Novaderrik . . . . 86-87 ECM is truly plug and play. There are no tricks, gimmicks.
Just be sure to get a CUSTOM chip, and let TT know if you have the IAT installed . . . .Which I highly recommend anyone does.

 

[Shamusvelez]

Looking for bigger injectors and an alky kit so, once i get those i was thinking turbo tweak can burn me a chip for the combo. Im probably getting the injectors and chip from them. Do i need to specify that it is an 87 ecm and not the stock ecm? Thanks for the help guys, i thought it was pretty much just plug n play.

 

[Reggie West]

Yes you will. When you order a chip from Turbotweak you have to fill out a table with a lot of info. That is so Eric can burn the chip with the correct parameters in it for your motor.

If you do all of this you may have to consider upgrading the fuel pump in the tank too.

 

[Shamusvelez]

Fuel pumps good, i think i can go up to 60 or 70lbs. Thanks for the help

 

[novaderrik]

Fuel pumps good, i think i can go up to 60 or 70lbs. Thanks for the help

you think you can go that high?
under boost?

 

[fixinboats]

Hey Shamus,

I have an 85 with an 87 ECM.You will need to add a second map sensor because the 85 has a single atmosphere map sensor that will goof up the 87 ECM. They used to have a twin map sensor kit with cable available from Postons, but because they are out of business, you'll have to look elsewhere online. You will also have to use an 87 ignition module, as there was a change there as well. The firing order changes as the 87 was mounted on the rear of the engine and the 85 is up front. you basically reverse the order based on the position. You will also need the 87 MAF sensor as the parameter is different on that as well.

So all told, it is not plug & play, and if you attempt to use it you will end up with nothing but codes. Your best source for a chip is like what was said in the post, Turbo Tweek. They will ask you what turbo, injectors and ECM you have. They can tailor it to the 85 with 87 ECM. Plus if you make any changes, you can send it back for a re flash.

 

[novaderrik]

Hey Shamus,

I have an 85 with an 87 ECM.You will need to add a second map sensor because the 85 has a single atmosphere map sensor that will goof up the 87 ECM. They used to have a twin map sensor kit with cable available from Postons, but because they are out of business, you'll have to look elsewhere online. You will also have to use an 87 ignition module, as there was a change there as well. The firing order changes as the 87 was mounted on the rear of the engine and the 85 is up front. you basically reverse the order based on the position. You will also need the 87 MAF sensor as the parameter is different on that as well.

So all told, it is not plug & play, and if you attempt to use it you will end up with nothing but codes. Your best source for a chip is like what was said in the post, Turbo Tweek. They will ask you what turbo, injectors and ECM you have. They can tailor it to the 85 with 87 ECM. Plus if you make any changes, you can send it back for a re flash.

a stock ecm doesn't even use the MAP sensor- that is just there to make the cool boost gauge on the dash light up...
i plugged an 87 ecm right into my 84 and ran it like that for a year- with the na 3.8 chip that came with it, no less.. it ran good and never threw a code.. but i never let it build boost with that chip..i used the stock 84 ignition setup.
then i got the proper TurboTweak chip and added the IAT sensor, even tho i can't even remember if i told him to activate the IAT sensor on the chip.. oh well, it's there anyways..

 

[Jerryl]

Hey Shamus,

I have an 85 with an 87 ECM.You will need to add a second map sensor because the 85 has a single atmosphere map sensor that will goof up the 87 ECM. They used to have a twin map sensor kit with cable available from Postons, but because they are out of business, you'll have to look elsewhere online. You will also have to use an 87 ignition module, as there was a change there as well. The firing order changes as the 87 was mounted on the rear of the engine and the 85 is up front. you basically reverse the order based on the position. You will also need the 87 MAF sensor as the parameter is different on that as well.

So all told, it is not plug & play, and if you attempt to use it you will end up with nothing but codes. Your best source for a chip is like what was said in the post, Turbo Tweek. They will ask you what turbo, injectors and ECM you have. They can tailor it to the 85 with 87 ECM. Plus if you make any changes, you can send it back for a re flash.

Wow, I was unaware of that.

MAP - What does the MAP sensor do in these cars?
Firing order - Is the cam shaft different between the years to change firing order?
Codes - What codes do you get if you plug and play?

 

[fixinboats]

Sorry for the confusion, but the firing order doesn't change (It's waste spark ignition anyway, each coil fires 2 cylinders one waste) but if you look at the two firing order in the service manual, the coil is in a different position, and the wire position changes. My 85 has the 87 ignition module, which may be the reason this happens. I have a Turbo Tweek chip 93 octane 37# injectors and 14 psi boost.

I'm sorry it does not use MAP (my bad, this is a primitive ECM), but it does use mass air flow and you have to add the temp sensor to the system. The SES light that he mentions are the codes you get. The kit was added to the MAP so the dash gauge doesn't peg all the time.

Check out www.gnttype.org/techarea/ecmsensors/8487ecm.html and look under Technical Information. The homepage has articles there that tell you how to convert the ECM, ignition module and wiring diagrams to compare 85 and 87. Here's a couple of paragraphs:


After much testing, I must suggest that you also get a 86/87 MAF part #25007866. The calibration of the 84/5 MAF is different and gave drivability problems with the 1227148 ECM, when cold weather came upon us in St.Louis. The colder air sensed by the MAT richened up the fuel air ratio, trying to compensate for the denser air, to the point that the car would belch black smoke out of the exhaust. Switching to the 86/7 MAF cured the problem.

Before your car can be driven without the SES light on, the MAT sensor must be put in. I cut a hole in the bottom of the K&N right in front of the MAF sensor to sample the incoming air temperature. Then I took the sensor plug/wire and ran it to the ECM by poking thru the grommet on the speedometer cable. I use wire loom in the engine compartment to dress things up and make things look factory. I ran the wire to the ECM under the dash carefully staying away from the gas and brake pedals. The MAT uses the same sensor ground as the TPS and CTS ,so I spliced into the ground wire at the ECM (D-12 black,no stripe). The other wire from the MAT sensor needs to be plugged into pin #C-11 (tan) at the ECM, this is where the wire from the other car came into play. It should still have the clip on the end that will plug straight into C-11 on the ECM plug.

 

[fixinboats]

Sorry about the missteps, it was a while ago that my son converted the ECM on my 85. (I'm going to guess 2005?) I bought the car from him to keep it in the family. He made a bunch of mods that were obtained from various sources. I do know there is an 87 ECM with a chip from TT. A MAF and air temp sensor was added to the system, which requires wiring. I just wouldn't call that plug and play.

 

[Jerryl]

Sorry about the missteps, it was a while ago that my son converted the ECM on my 85. (I'm going to guess 2005?) I bought the car from him to keep it in the family. He made a bunch of mods that were obtained from various sources. I do know there is an 87 ECM with a chip from TT. A MAF and air temp sensor was added to the system, which requires wiring. I just wouldn't call that plug and play.

You can have TT remove the IAT and it will not throw a code.

 

[fixinboats]

Thanks Jerryl, I already have the TT chip that is using IAT. I think if you want it to run well in all temps, you should use the IAT sensor. That's a great service Eric is doing at Turbo Tweek. I think he will make changes for you as well for up to a year, not charging the full price.

Ya'll have a great day!

 

[Shamusvelez]

You guys rock! Thanx for all the info and help, I will keep you all posted with the outcome when I do it all. I would truly be lost without this forum, I love this place! Thx again gentlemen.

Sent from my iPad using Turbo Buick

 

[beeturbo]

I have a question reguarding the 86/87 Ecm being plug and play alot of my uestions arenow answered but now on the 85 ecm it has the 2 harness connectors plus a 12 volt positive single wire pigtail which is the wire that goes to the ornage wire that goes tothe battery..now the 86 ecm that igot out of an 86 olds 3.8sfi only has the 2 harness plugs no pigtail so what do i need to do about that

 

[novaderrik]

an 86/87 ecm literally plugs right in- swap the small chip out of your stock 85 ecm and put in the proper big chip for the turbo motor- either a stock 86/87 TR chip or a Turbotweak chip- and plug it right in..
there should not be a "pigtail" of any sort.

 

[cwmccray]

an 86/87 ecm literally plugs right in- swap the small chip out of your stock 85 ecm and put in the proper big chip for the turbo motor- either a stock 86/87 TR chip or a Turbotweak chip- and plug it right in..
there should not be a "pigtail" of any sort.

NOVADERRICK..
Not hi jack this thread, but are you still mixing E85 and running TT chip with the 87 computer? Any issues? What is your current fuel pump and what fuel pressure running at?

 

[novaderrik]

the car hasn't been out of the storage unit since September of '11.. but i was running the occasional tank of E50 from time to time and it ran pretty damn good- it would have been more fun if the craptastic trans that's in it would shift at above 1/2 throttle...
i can't remember exactly what the fuel pressure is at, but it was right at whatever the piece of paper that came with the TT chip said, which is good, because it's the stock regulator and i can't adjust it at all. the fuel pump is a Carter stock replacement pump. well, it was the "high output" option that was on clearance at Rockauto for $35 when the stock pump died in '08, and i ran a Racetronix hotwire kit when i did the pump.