TPI Computer
Thread Starter
Safety Car
Joined: Dec 2012
Posts: 3,789
Likes: 1,695
From: Summerville SC
TPI Computer
OK, I am working on building my 1986 L98 TPI motor that will go into my '78 C3. I pretty much have figured out what direction I am going with my engine harness set up, which brings me to the ECU and prom. As I understand things, the ecu would be a 7165 w/ MAF sensor set up. DO I buy one set up for an auto trans ( I am putting a 200R4 behind this motor). Most of what I found need a core deposit, and since I have no core do I just go to ebay? Then the prom. This will be an almost stock 350. Little higher comp ration. So I am thinking to get a stock used prom for the '86 then have a local shop burn my specific info ( the 200R4 for example) into it. Thanks in advance for your feedback and steering me in the right direction. This old dog is having trouble learning new tricks. 
Instructor
Joined: Nov 2008
Posts: 112
Likes: 8
I installed an 87 L98 in my 79 and converted to Speed Density to avoid all the plumbing issues associated with the MAF sensor. You with a stock engine might want to at least look in this direction. Just something to think about.
Safety Car
Joined: Oct 2008
Posts: 4,022
Likes: 30
From: Los Angeles CA
OK, I am working on building my 1986 L98 TPI motor that will go into my '78 C3. I pretty much have figured out what direction I am going with my engine harness set up, which brings me to the ECU and prom. As I understand things, the ecu would be a 7165 w/ MAF sensor set up. DO I buy one set up for an auto trans ( I am putting a 200R4 behind this motor). Most of what I found need a core deposit, and since I have no core do I just go to ebay? Then the prom. This will be an almost stock 350. Little higher comp ration. So I am thinking to get a stock used prom for the '86 then have a local shop burn my specific info ( the 200R4 for example) into it. Thanks in advance for your feedback and steering me in the right direction. This old dog is having trouble learning new tricks.
they know better and you and your car will be better for it, just like i had a prob with my 700r4, a 1 year thing for 1982, i was tearing into for no reason after 5 postings, they fixed it in one post.
they had it for 10 years(the 700r4), i got the help i needed, over here I was getting spun
Last edited by slickfx3; Sep 29, 2015 at 08:21 PM.
Instructor
Joined: Aug 2010
Posts: 139
Likes: 10
From: Franklin kentucky
i suggest you go to the c4 forum, they have a tune section as well
they know better and you and your car will be better for it, just like i had a prob with my 700r4, a 1 year thing for 1982, i was tearing into for no reason after 5 postings, they fixed it in one post.
they had it for 10 years(the 700r4), i got the help i needed, over here I was getting spun
they know better and you and your car will be better for it, just like i had a prob with my 700r4, a 1 year thing for 1982, i was tearing into for no reason after 5 postings, they fixed it in one post.
they had it for 10 years(the 700r4), i got the help i needed, over here I was getting spun
Safety Car
Joined: Oct 2008
Posts: 4,022
Likes: 30
From: Los Angeles CA
https://www.corvetteforum.com/forums...-question.html
Melting Slicks
Joined: Nov 2010
Posts: 2,216
Likes: 112
From: Michigan
OK, I am working on building my 1986 L98 TPI motor that will go into my '78 C3. I pretty much have figured out what direction I am going with my engine harness set up, which brings me to the ECU and prom. As I understand things, the ecu would be a 7165 w/ MAF sensor set up. DO I buy one set up for an auto trans ( I am putting a 200R4 behind this motor). Most of what I found need a core deposit, and since I have no core do I just go to ebay? Then the prom. This will be an almost stock 350. Little higher comp ration. So I am thinking to get a stock used prom for the '86 then have a local shop burn my specific info ( the 200R4 for example) into it. Thanks in advance for your feedback and steering me in the right direction. This old dog is having trouble learning new tricks.
Now in my research to maybe convert my 86 C4 tpi car to a carb someday if it keeps pissing me off. I came across this http://www.ebay.com/itm/UNIVERSAL-VACUUM-SWITCH-700R4-700-R4-2004R-200-4R-350C-6-22-GM-TRANSMISSION-/330704737891?_trksid=p2141725.m3641.l6368 So if they can't control the 200r4 with the 165 ecm then I'd just get one of those.
Safety Car
Joined: Oct 2008
Posts: 4,022
Likes: 30
From: Los Angeles CA
Many years ago before I was too into the internet when I converted my 85 TA to the 86+ ecm I just got one local at the auto parts w/o a core, but I also checked local salvage yards first because many vehicles used that ecm.
Now in my research to maybe convert my 86 C4 tpi car to a carb someday if it keeps pissing me off. I came across this Universal Vacuum Switch 700R4 700 R4 2004R 200 4R 350C 6 22" GM Transmission | eBay So if they can't control the 200r4 with the 165 ecm then I'd just get one of those.
Now in my research to maybe convert my 86 C4 tpi car to a carb someday if it keeps pissing me off. I came across this Universal Vacuum Switch 700R4 700 R4 2004R 200 4R 350C 6 22" GM Transmission | eBay So if they can't control the 200r4 with the 165 ecm then I'd just get one of those.
Melting Slicks
Joined: Nov 2010
Posts: 2,216
Likes: 112
From: Michigan
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Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
first post got it right, after weeks of doing everything else, dropping the pan, ordering external pressure switchs, takning out the memcal prom chip, yada yada , good news is i learned a lot about lock up, i and now well informed LOL
https://www.corvetteforum.com/forums...-question.html
https://www.corvetteforum.com/forums...-question.html
This just reminds everyone that even when someone goes as far as talking about the power feed and posting a wiring diagram showing the power feed through a brake switch to not trust them to be bright enough to check for power....
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
OK, I am working on building my 1986 L98 TPI motor that will go into my '78 C3. I pretty much have figured out what direction I am going with my engine harness set up, which brings me to the ECU and prom. As I understand things, the ecu would be a 7165 w/ MAF sensor set up. DO I buy one set up for an auto trans ( I am putting a 200R4 behind this motor). Most of what I found need a core deposit, and since I have no core do I just go to ebay? Then the prom. This will be an almost stock 350. Little higher comp ration. So I am thinking to get a stock used prom for the '86 then have a local shop burn my specific info ( the 200R4 for example) into it. Thanks in advance for your feedback and steering me in the right direction. This old dog is having trouble learning new tricks.
I would not use one of those old MAF sensor systems with the relays. That whole system is a piece of crap. I'd use a newer speed density MAP based system. The '7727 or '7730 speed density systems are popular and would be a better choice. This lets you get rid of the cold start injector and associated parts. This also gets rid of the external knock module and you connect the knock sensor right to the PCM.
You might also consider the DynamicEFI EBL locker for the PCM which gives it more capabilities and makes it flash based instead of burning chips.
As for the transmission, the lockup on the 200-4R and 700-R4 work the same so the PCM can control either one.
Racer
Joined: Mar 2003
Posts: 448
Likes: 21
From: Klein Texas
As I understand things, the ecu would be a 7165 w/ MAF sensor set up.
The 7165 can be used but isn't considered the best choice. There are alternative instruction code that can be run to convert it to speed density (no MAF). The 7730 is a well understood/ faster/ later model speed-density ECM used on TPI engines however the OE proms have gotten expensive. Help can be found at Gearhead EFI forums or PCM Hacking Forums.
You can do a ECM prom conversion to flash memory like EBL Flash or just do an aftermarket solution. I'm using a Microsuirt on my TPI.
Thread Starter
Safety Car
Joined: Dec 2012
Posts: 3,789
Likes: 1,695
From: Summerville SC
To those who answered MY questions, thanks. I was leaning towards the MAF since I understood it to be more forgiving of mixing and matchings various pieces. Also, I figured that since GM started with MAF and then came back to it on other later model vehicles, it would be the beat choice. I'll have to rethink it plus I hadn't heard of the flash option. I posted on the C4 side and someone there also recommended the flash option. Thanks.
Drifting
Joined: Aug 2005
Posts: 1,443
Likes: 65
From: Wauconda IL
I wouldn't be scared of the MAF system- You can get programmable chips for the 7165 ECM through Moates and running a bin from an 89' allows you to get rid of the cold start injector while keeping the MAF.
Either system has it's pros and cons-
Most people shy away from MAF systems due to cost and slightly more complicated wiring but if you already have a MAF set-up that is in good shape, there is no reason not to use it.
The external knock sensor module of the 7165 (in my opinion) is more desirable than the expen$ive and hard to find internal module found on the later SD systems.
Do your homework and choose what is best for YOU.
Either system has it's pros and cons-
Most people shy away from MAF systems due to cost and slightly more complicated wiring but if you already have a MAF set-up that is in good shape, there is no reason not to use it.
The external knock sensor module of the 7165 (in my opinion) is more desirable than the expen$ive and hard to find internal module found on the later SD systems.
Do your homework and choose what is best for YOU.
Thread Starter
Safety Car
Joined: Dec 2012
Posts: 3,789
Likes: 1,695
From: Summerville SC
OK, one other question and then I think I am done, for now!. Once I decide on map of mac, get the approriate ecu, then I need a prom. Do I get a stock one for an '86, even though I have no EGR, maybe a little more cam or compression than stock. I think I could use the stock one, but how do I get rid of the vats,speed sensor, egr codes etc.. I am almost there in my knowledge quest, but not sure how to get things lined up just to get it started. I assumed I would need a custom prom, but how to I just get the motor started without a custom one? Luckily the engine isn't done yet. Just between us, I went to the C4 side, you guys know more about this swap thing than they do.
Race Director
Joined: Apr 2007
Posts: 11,150
Likes: 890
From: South Western Ontario
The Gearhead-EFI site probably has a stock tune you could use to start with.
You will want a speed sensor. There are certain algorithms in most GM ECM's that use speed to trigger or operate right. You also need the speed sensor so the ECM can control the TCC lockup.
You will want a speed sensor. There are certain algorithms in most GM ECM's that use speed to trigger or operate right. You also need the speed sensor so the ECM can control the TCC lockup.
Racer
Joined: Mar 2012
Posts: 476
Likes: 37
From: Lynnwood WA
you need to talk to whoever is going to do the programing before you buy anything. Not all the ECMs and proms are going to work or even be available. The best GM setup I have read of is to go with a newer ECM from an LS so you can run a newer trans. The LS style ECM is much more available and offers you a lot more options and can be programed in the car. One of the aftermarket makers (EZ.2) is advertising a setup that gives you every thing you need for your TPI in one package and is self tuning for the price some will charge just for a tuned ECM. I like my TPI and have no desire to replace it, but I but don't really trust or like being limited by the old GM ECM. Just saying, talk to a programmer first.