raychappell

Hey guys,
I am working on a 1985 Iroc that I have owned for about 11 years now. When I bought my car The original drive train was long gone. They had installed a very strong running 305 and carb setup, along with a T5 tranny and a 10 bolt disc brake rear. As I said, it ran surprisingly well, but they did a real hack job on the wiring and such. Since my car originally came with a TPI, I wanted to add it back to the car, but leave in the T5 and disc brake rear. The rest of the car was still pretty much intact. I bought a TPI setup off of ebay about 10 years ago that was complete with nice wiring and ECM/PROM. I have moved since then, and I cannot locate my ECM...I'm sure it is packed up here somewhere, but it is hiding pretty well. Fast forward to now. I have decided to go ahead and fix this car right, so I am beginning by adding the 1987 TPI and new wiring harness back to the car. I have a few questions since this is the first third gen I will restore. Keep in mind I know very little about fuel injection. Here is my dilemma: Can I run the 1987 engine with TPI installed with my original 1985 ECM and PROM, and since it came originally with an automatic tranny, will that pose a problem? I know ideally I would get an ECM and PROM from a 1987 car with a T5, but I don't know if it really will make a difference. I know the MAF sensor was different in 1985. I have one that I got out of a boney yard, but have no idea what year it was from. I also know the the 85 year model was a different ECM than the later models and cannot be programmed (so I have been told). Can anyone offer some advise on what my options are? I am working on a limited budget so I prefer to avoid costly purchases that are not necessary, or making costly mistakes. Thanks much to anyone who might be able to help.

bigal55

iTrader: (1)

If you are going to use the TPI setup, use the complete package. Your wiring is hacked so you might as well use the whole wiring harness that you got with the TPI and ECM. The connections are different from 85 (one year ECM with external MAF controller) and presumably the later (165 ECM - MAF) so if you have the complete engine harness from the later TPI, use it. The earlier ECM can be tuned but is a one year only system and there is not much support for it. You could go back to stock 85 ECM and find a wiring harness to make the car original but if original is not your goal then the 165 ECM or maybe even a 730 (MAP) ECM or EBL would be a better choice (listed as good to best in that order). Any of those three would use the TPI harness you got off E-bay, the 730 and EBL needing a few wire relocations at the ECM connectors. Just as a side note, there is a difference between auto and manual trans types in the PROM calibrations so, will it run? Yeah but will it be right? No. You just want to put the car back to TPI using the existing 305 and T5, then the stuff you got off E-bay should work fine. If there are extensive modifications (read "tuning") in the future then either E-bay ECM (MAF) or 730 ECM (MAP) would be good but harder to tune than the EBL system. The EBL system would be a higher initial cost but once all the hardware for tuning the 165/730 ECM is added in, it's pretty much a wash. Don't want to confuse you but thought I would give you the extra info so you can think this through and not have a "I wish I would have known that before I got started" moment. Replace the harness and the TPI parts and think about what ECM you want to use. If you can find it, use the 165 that you got with the harness as you can always convert to 730 or EBL fairly easily in the future. Do you have a MAF sensor? The cost of a new or even good working used MAF sensor may push you to using the 730 or even the EBL system. HTH!

red rock

iTrader: (2)

Here is just some general info; http://www.sethirdgen.org/tpi1.htm, http://www.chevythunder.com/, Good luck with the resto.

raychappell

Thanks for the info guys. I pulled out thr ECM that was already in my car today, and it was the 1226870 ECM (a replacement from a salvage yard LOL). Anyway, I have decided to buy a 1987 Firebird ECM (1227165) that has the factory PROM and had a T5 in it...Will the 1987 Camaro TPI Harness that I have (automatic transmission) hook up to the T5 without any modifications? I have read on here just to leave it unhooked, but I have also been told by a guy who burns the chips that it needs to be hooked up to prevent high idle and stalling out at stop lights, ect. Any advice about that issue? Is there any difference in the wiring harnesses, or are they the same? Thanks again!
Ray

MoJoe

iTrader: (5)

Since the car was originally manual, I will assume your backup lights work, therefore those wires are intact and in place. The 87 manual TPI harness had the wires in the underhood harness, but this does not apply to your 85.

Speedo - is cable driven off the trans, so nothing to do here.

TCC - the auto TPI harness probably has the TCC (torque converter control) plug on it, which you will not need since you have a T5. You can leave the wires in place, clip them, remove them, or re-purpose as needed. I would de-pin the wires from the ECM plug (use a tool to push those wire's pins from the plug.)

You need the chip burned for a manual trans. Therefore "high idle" and "stalling out at stop lights" without the AUTO trans hooked up does not apply.

On previous topics:
No the '85 ECM will not work with the '87 system.
Kind of, the auto PROM will mostly work with the manual trans. Except the low RPM timing is WAY advanced... the auto cannot put any real load on the engine below the 1800-2000 stall speed, while the manual trans can... For instance, it will ping like a sunofagun with heavy throttle at low (700-1800) rpm.

raychappell

Okay...I need to clarify my original post. I should have been more clear. My car came originally equipped with a 305 TPI with 4 speed automatic transmission and 10 bolt drum brake rear with 3:42 gears. All of this info is inside the console. They guy I bought the car from told me that he had blown the original engine, and it was a 1987 engine out of another IROC. Said it was a 305 HO. I didn't realize it at the time, but the manual transmission was not offered with TPI in 1985 (Please correct me if I'm wrong). To be honest, whoever did the auto transmission to manual did a great job...It looks like it came that way from the factory. As far as the rear goes, It is an older one, a 10 bolt disc..Not 100% sure it is non original, I guess its possible the disc brakes were added to the car. My guess is that rear came from the same donor car as the engine and tranny though, because the emergency brakes were not hooked up when I bought the car. So....For the most part I am 100% sure that none of my drive train is original. As far as the original wiring harness goes, it was all hacked up. That's why I bought the setup off of a 1987, since I believe the drive train all came from a 1987 as well. I honestly dont remember if the backup lights work or not, but my guess is they dont. These guys literally mounted an electic fuel pump to the frame and plumbed in the fuel lines that fed the carb. It was getting way more fuel than it needed. They literally used an orange drop cord to power the fuel pump. So, my question is: Will my 1987 wiring harness (from an automatic car, best I recall( work okay if I get the 1987 ECM that came off a car with a T5? If so, do I just leave the T5 unhooked?

MoJoe

iTrader: (5)

My original answer changes only for the backup lights... From the factory, there are green and blue wires that run from the fuse panel area to the automatic shifter. Find those wires and run them to the switch screwed into the passenger side of the T5. You can follow the factory scheme, and extend the wires across the passenger side dash, out the passenger side kick panel (you many repurpose any TCC wires to pass-thru the sheet metal) and pick the best route down to the trans.

raychappell

Thanks so much for all of the valuable info. This is a great site. I appreciate all comments in this thread. I think I'm good to go now!

raychappell

Wow...I just found the ECM that came with my TPI wiring harness...The number is 16198259. I am guessing I will need to get this burned for a 5 speed car for it to run properly?

bigal55

iTrader: (1)

It depends on the BCC or PROM number. The 259 is just the updated or service replacement for the 165 ECM. The PROM should have a sticker on it (visible through the window) which will tell you exactly what the ECM was intended for. The ECM (165/259) was used in many vehicles so the actual PROM determined what specific engine and trans combination it was used in. If you are lucky, you might actually have an ECM from a T5 car. The engine harness is what concerns you and as stated above, if you use the complete setup (E-bay TPI purchase), then you should be good to go. The wiring differences between auto and manual are not that big a deal, the big difference is in the PROM. Even if you have a PROM from an auto car, you can burn a manual prom for all the existing hardware you have. This relates to "software" as opposed to hardware (which you got off E=bay) so installing all the parts to make your car TPI, you have. Without knowing EXACTLY what you have, I can only say you are about 90% there. That's parts, not time and labor to swap out the harness and all the sensors. Which, by the way, you will either need to re-connect or possibly purchase. You need to figure out exactly what you have and go from there. HTH!

raychappell

I just checked the PROM code and its ABUN 8517 which shows on 3 ebay listings as being a 1987 Camaro/Firebird 305 Auto.....Does anyone have a recommendation on who I can send my ECM and PROM to and have it burned for T5? Also, would there be any benefit to eliminating the EGR and cold start injector while I'm at it? My car will be virtually stock, with the exception of flowmaster exhaust. I may possibly upgrade to a better cold air intake system in the future as well...Just out of curiosity, since I am having it burned, can they make any subtle changes to help me pick up a few HP, or are my only options for picking up HP adding cam, heads, and headers? I'm not looking for a lot really. I'm not gonna be racing it or anything, just thought I would ask if there are a few tweaks that could be burnt to pick up an additional 15-20 HP, or so. Keep in mind, I am working on a budget so a stock burn will suffice for now if thats what I need to do. I just read that the stock 85 TPI car had 215 HP but the HP went down a bit in 86. I was wondering if that was just programming changes...The main thing I need is a good recommendation for someone reliable to do the burn. Again, thanks to all for the help.

raychappell

Hey guys, I know we are not here to advertise our or anyone elses business, so that is not what I'm fishing for...I have no desire to purchase the equipment to burn my own PROM, so just looking for opinions on who would burn it at a reasonable price, is it best to get the piggyback thing that controls the original PROM, or erase the PROM and reprogram, ect. I found a company in Florida that will set it up under the original GM codes at a reasonable price, but they will not program it for performance. I also called a company in South Carolina, who you probably all know, and they will program it for better performance, turn off the EGR and give it the tune for 1989's that allow me to block the cold start injector, which I would like to do, since I understand they can be troublesome, but that company is significantly more expensive. Then there are the chips being sold on ebay, that claim to be programmed for performance,but I'm not so sure I want to go that route. Ideally, I wish there was a local, or semi local shop around that could offer me some options, but I'm not finding any doing google searches (North Georgia about 40 miles north of Atlanta)...I know much of this has been covered multiple times on different posts as I have been a member of the site for more than 10 years, but each situation is a bit different, so please be nice.
I'm just trying to avoid making costly mistakes or investing my money in pixie dust that will not benefit me enough to outweigh the cost... Any thoughts?

raychappell

Bigal55, I appreciate all of the info so far. I can handle removing the Automatic transmission wiring with no problem. Quick question though. I have read on here and other sites as well, that the 1986-1988 wiring is pretty much interchangeable, but it also says that 1985 was a "stand alone" year....I have verified that the harness I am installing came from a 1987 Camaro, so my question is, after removing the transmission wiring can I plug in the harness to my fuse block at the firewall without making any other changes, or is there repinning I will need to do? This is considering I will be using the 1987 ECM and TPI harness as well as all of the other wiring that is forward of the firewall (it all came with my ebay purchase and is nice and uncut). I know this post is over a month old now, but I am trying to avoid creating a new post. Again, thanks for all of the info thus far.
Ray

bigal55

iTrader: (1)

1985 was an oddball year as the ECM didn't have the MAF electronics incorporated into it, there was a stand alone MAF controller which then signaled the ECM. Starting in 86 through 89, the MAF circuitry was incorporated into the ECM. There was a program change for 89 which eliminated the cold start injector, but that was just programming. 1990 through 92 were speed density system and didn't use a MAF but used a MAP instead. What exactly are the wiring changes needed to go from the 870 engine harness to the 165 engine harness, I do not know. There are ECM pinouts and connector pinouts available at Chevythunder.com. That site is not Thirdgen specific but has a ton of technical info. Also try AustinThirdgen.org, there are a bunch of wiring diagrams that you can cross-reference. Sorry I can't give you a definitive answer, you may want to search for posts on changing from 870 to 165 ECM and see what turns up. GL!

Tuned Performance

iTrader: (92)

C100 for 85 & 87
You can remove the csi wiring if you use a 89 tune. Iirc the purple power wire splices off the starter crank circuit.
You may want to double check the differences of c207 as well.
https://www.thirdgen.org/forums/elec...85-1991-a.html
http://www.austinthirdgen.org/mkport..._1987_C100.gif

D&S 85 IROC

I think that all that is a hassle, I have a 85 IROC and done a 350 (5.7 L-31) swap and T-5 trans. It too has the 3:42 rear with disk brakes. I went with a FAST EZ-EFI setup, quick easy setup. Let the computer learn it's self. All that chip burning re-pinning stuff forget it. Sounds like a pain in the *** to me..

raychappell

Well, as far as the wiring for the ECM, I have the harness that came with it (from an 87)...The only thing I was concerned about was the engine and lighting harness that plugs into the bulkhead. Looking at the bulkhead diagrams only, they appear to be identical based on the diagrams I have looked at. Someone, please correct me if I am wrong. I have a Chevrolet Service Manual for the 85 that has the bulkhead diagram, and when I compared it to the 87 bulkhead diagram that I found on this site (I think...), they were identical.

D&S 85 IROC

I completely removed the harness from the engine, kept the A/C wires, I just separated the harness out