Fitech 38350 tpi Installed
Thread Starter
Intermediate
Joined: Jun 2023
Posts: 37
Likes: 11
From: Tampa, FL
Thank you, I just did it myself. It was decent out of the box as self learning, but needed some adjustments after the break in. I plan on a gear and pro charger later this year. If that happens I'll take it in for Dyno tuning.
Drifting
Joined: Apr 2011
Posts: 1,925
Likes: 441
From: Albuquerque NM
Man that looks good! Slick install of the ECU and fuses in the glove compartment.
Yeah man make a thread! Would be awesome to know the details on the build, heads, cam, displacement, install process etc
Did you go single or dual wideband O2?
Yeah man make a thread! Would be awesome to know the details on the build, heads, cam, displacement, install process etc
Did you go single or dual wideband O2?
Thread Starter
Intermediate
Joined: Jun 2023
Posts: 37
Likes: 11
From: Tampa, FL
Instructor
Joined: Mar 2003
Posts: 182
Likes: 3
From: Phoenix AZ
what did you do with the mess of wiring coming from the factory ecm? 95% of that wiring would be duplicates of what the fitech harness plugs into.
Thread Starter
Intermediate
Joined: Jun 2023
Posts: 37
Likes: 11
From: Tampa, FL
1st Gear
Joined: May 2024
Posts: 1
Likes: 0
Just installed the Fitech Tpi and figured I'd make a post when I was researching about it I couldn't find much info on the install except a few threads on this forum.
Currently I am using the Fitech unit and factory ECM on a 90 with a zf6 with all gauges working. I ended up putting the fitech Ecm and fuse block in the glove box. Removed the plastic connector on the firewall, modified the plastic housing and fed the wiring from under the passenger side dash through the firewall. The glue on the wires to the plastic housing took a wile to clean up, but WD40 made it clean up a bit faster. Once the factory wires and Fitech wires were through the plastic housing, I used RTV on the perimeter of the housing and packed the hole with the wires with 3M weather strips.
If you have a large cap HEI distributor you will need to buy a small cap with a remote coil. 2 Ground wires attach to the block, 2 positive wires go to the battery or power block behind the battery. ( I had to add 1ft of 12 gauge wire to the positives to make the distance)
if you have a manual trans then you don't need to use the VSS wire on the Fitech. That way the speedo reads off the factory ECM.
Key on wire I connected to the ignition wire for the coil. The tach I just connected to the coil, instead of using the tach output wire on the Fitech. AC wire on the Fitech I spliced with the AC clutch wire on the factory ECM. The fans 1 and 2 wires were hooked up to pin 85 on both relays. Knock sensor pugged into the fitech unit using their harness and plug. I think I used the LS1 pigtail that came in the box. Although I'm not sure how long the wire will last since the knock sensor, plug and wire are pretty close to the 2155 super comp headers. Worst case if it burns up, I can turn off the knock sensor on the Fitech.
The water temp gauge will need to be run independent of the Fitech unit. Basically Fitech will need a dedicated CTS sensor, the gauge will need a separate one. I have a first performance manifold that came with additional ports so I was able to just add another CTS sensor and plug the factory plug in. If using the stock manifold, I did see posts about people using a Tee on the manifold port then connecting both sensors. I didn't use the brake wire since it applies for torque converters.
Positive wire for the fuel pump I traced from the rear of the car to the passenger side under the dash. Made the connection there and capped the factory wire.
Initial setup on the Fitech was pretty easy, enter the cam specs, engine displacement, initial timing fan temps and transmission settings.
That's about it off the top of my head. Now I just have to clean up the old wiring that isn't used and put the passenger side kick panel back together.
Anyway, I hope the info helps anyone curious about the standalone Ecm.
Currently I am using the Fitech unit and factory ECM on a 90 with a zf6 with all gauges working. I ended up putting the fitech Ecm and fuse block in the glove box. Removed the plastic connector on the firewall, modified the plastic housing and fed the wiring from under the passenger side dash through the firewall. The glue on the wires to the plastic housing took a wile to clean up, but WD40 made it clean up a bit faster. Once the factory wires and Fitech wires were through the plastic housing, I used RTV on the perimeter of the housing and packed the hole with the wires with 3M weather strips.
If you have a large cap HEI distributor you will need to buy a small cap with a remote coil. 2 Ground wires attach to the block, 2 positive wires go to the battery or power block behind the battery. ( I had to add 1ft of 12 gauge wire to the positives to make the distance)
if you have a manual trans then you don't need to use the VSS wire on the Fitech. That way the speedo reads off the factory ECM.
Key on wire I connected to the ignition wire for the coil. The tach I just connected to the coil, instead of using the tach output wire on the Fitech. AC wire on the Fitech I spliced with the AC clutch wire on the factory ECM. The fans 1 and 2 wires were hooked up to pin 85 on both relays. Knock sensor pugged into the fitech unit using their harness and plug. I think I used the LS1 pigtail that came in the box. Although I'm not sure how long the wire will last since the knock sensor, plug and wire are pretty close to the 2155 super comp headers. Worst case if it burns up, I can turn off the knock sensor on the Fitech.
The water temp gauge will need to be run independent of the Fitech unit. Basically Fitech will need a dedicated CTS sensor, the gauge will need a separate one. I have a first performance manifold that came with additional ports so I was able to just add another CTS sensor and plug the factory plug in. If using the stock manifold, I did see posts about people using a Tee on the manifold port then connecting both sensors. I didn't use the brake wire since it applies for torque converters.
Positive wire for the fuel pump I traced from the rear of the car to the passenger side under the dash. Made the connection there and capped the factory wire.
Initial setup on the Fitech was pretty easy, enter the cam specs, engine displacement, initial timing fan temps and transmission settings.
That's about it off the top of my head. Now I just have to clean up the old wiring that isn't used and put the passenger side kick panel back together.
Anyway, I hope the info helps anyone curious about the standalone Ecm.
Trying to finish the fitech 38350 installation. So, the Fitech cable labeled 'VSS' goes to the transmission, right? Then how does the factory speedometer gets its signal? Any additional wiring needed?
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Thread Starter
Intermediate
Joined: Jun 2023
Posts: 37
Likes: 11
From: Tampa, FL
Yes, vss goes to the transmission. One of the fitech output wires is for the Speedo. Depending on the year C4 you have would depend on where to connect the wire. FSM would probably be needed. If you have a manual transmission you don't need to connect the VSS and leave the factory in place.
Intermediate
Joined: Oct 2017
Posts: 46
Likes: 15
chumbini
Junior Member
Joined: Nov 2020
Posts: 5
Likes: 1
Re: FiTech 38350 ECUI have gotten nothing but conflicting info from fitech. I can’t get my car to idle correctly and they tell me I have a vacuum leak. I did the smoke test and don’t have a leak. The idle control doesn’t respond to input on the control panel. The only thing that affects my rpm is playing with the throttle body opening screw. I’ve replaced my tps iac, ignition module,etc. it starts to run ok then I drive it and have to keep my fingers crossed. No consistent issues, always a new one. Had my computer back to them, they say it’s perfect. I say different. I have a zf6 trans in my c4 corvette and the speedometer wouldn’t work. The setting says t56 or other. I put in on t56 ,which is what I do not have, and all of a sudden it works. They are inconsistent with their answers. It’s so bad that I even know the technicians name. I haven’t driven the car lately because I can’t stand the unreliability of the system . But they won’t refund my money so I can buy a Holley system or something else.
Junior Member
Joined: Nov 2020
Posts: 5
Likes: 1
Re: FiTech 38350 ECUI have gotten nothing but conflicting info from fitech. I can’t get my car to idle correctly and they tell me I have a vacuum leak. I did the smoke test and don’t have a leak. The idle control doesn’t respond to input on the control panel. The only thing that affects my rpm is playing with the throttle body opening screw. I’ve replaced my tps iac, ignition module,etc. it starts to run ok then I drive it and have to keep my fingers crossed. No consistent issues, always a new one. Had my computer back to them, they say it’s perfect. I say different. I have a zf6 trans in my c4 corvette and the speedometer wouldn’t work. The setting says t56 or other. I put in on t56 ,which is what I do not have, and all of a sudden it works. They are inconsistent with their answers. It’s so bad that I even know the technicians name. I haven’t driven the car lately because I can’t stand the unreliability of the system . But they won’t refund my money so I can buy a Holley system or something else.
Intermediate
Joined: Oct 2017
Posts: 46
Likes: 15
chumbini
Junior Member
Joined: Nov 2020
Posts: 5
Likes: 1
Re: FiTech 38350 ECUI have gotten nothing but conflicting info from fitech. I can’t get my car to idle correctly and they tell me I have a vacuum leak. I did the smoke test and don’t have a leak. The idle control doesn’t respond to input on the control panel. The only thing that affects my rpm is playing with the throttle body opening screw. I’ve replaced my tps iac, ignition module,etc. it starts to run ok then I drive it and have to keep my fingers crossed. No consistent issues, always a new one. Had my computer back to them, they say it’s perfect. I say different. I have a zf6 trans in my c4 corvette and the speedometer wouldn’t work. The setting says t56 or other. I put in on t56 ,which is what I do not have, and all of a sudden it works. They are inconsistent with their answers. It’s so bad that I even know the technicians name. I haven’t driven the car lately because I can’t stand the unreliability of the system . But they won’t refund my money so I can buy a Holley system or something else.
Junior Member
Joined: Nov 2020
Posts: 5
Likes: 1
Re: FiTech 38350 ECUI have gotten nothing but conflicting info from fitech. I can’t get my car to idle correctly and they tell me I have a vacuum leak. I did the smoke test and don’t have a leak. The idle control doesn’t respond to input on the control panel. The only thing that affects my rpm is playing with the throttle body opening screw. I’ve replaced my tps iac, ignition module,etc. it starts to run ok then I drive it and have to keep my fingers crossed. No consistent issues, always a new one. Had my computer back to them, they say it’s perfect. I say different. I have a zf6 trans in my c4 corvette and the speedometer wouldn’t work. The setting says t56 or other. I put in on t56 ,which is what I do not have, and all of a sudden it works. They are inconsistent with their answers. It’s so bad that I even know the technicians name. I haven’t driven the car lately because I can’t stand the unreliability of the system . But they won’t refund my money so I can buy a Holley system or something else.
Thread Starter
Intermediate
Joined: Jun 2023
Posts: 37
Likes: 11
From: Tampa, FL
chumbini
Junior Member
Joined: Nov 2020
Posts: 5
Likes: 1
Re: FiTech 38350 ECUI have gotten nothing but conflicting info from fitech. I can’t get my car to idle correctly and they tell me I have a vacuum leak. I did the smoke test and don’t have a leak. The idle control doesn’t respond to input on the control panel. The only thing that affects my rpm is playing with the throttle body opening screw. I’ve replaced my tps iac, ignition module,etc. it starts to run ok then I drive it and have to keep my fingers crossed. No consistent issues, always a new one. Had my computer back to them, they say it’s perfect. I say different. I have a zf6 trans in my c4 corvette and the speedometer wouldn’t work. The setting says t56 or other. I put in on t56 ,which is what I do not have, and all of a sudden it works. They are inconsistent with their answers. It’s so bad that I even know the technicians name. I haven’t driven the car lately because I can’t stand the unreliability of the system . But they won’t refund my money so I can buy a Holley system or something else.
Junior Member
Joined: Nov 2020
Posts: 5
Likes: 1
Re: FiTech 38350 ECUI have gotten nothing but conflicting info from fitech. I can’t get my car to idle correctly and they tell me I have a vacuum leak. I did the smoke test and don’t have a leak. The idle control doesn’t respond to input on the control panel. The only thing that affects my rpm is playing with the throttle body opening screw. I’ve replaced my tps iac, ignition module,etc. it starts to run ok then I drive it and have to keep my fingers crossed. No consistent issues, always a new one. Had my computer back to them, they say it’s perfect. I say different. I have a zf6 trans in my c4 corvette and the speedometer wouldn’t work. The setting says t56 or other. I put in on t56 ,which is what I do not have, and all of a sudden it works. They are inconsistent with their answers. It’s so bad that I even know the technicians name. I haven’t driven the car lately because I can’t stand the unreliability of the system . But they won’t refund my money so I can buy a Holley system or something else.
The zf6 being set to t56 on the controller shouldnt matter in performance or operation. I think the controller just reads that as a manual and has something to do with the vss signal output. If you have the factory ecm just plug the factory vss into the Trans and the speedometer will bypass the fitech and operate separately. Only automatics have to run through the fitech ecm. Unless you wanted to completely remove the factory ecm.
Intermediate
Joined: Oct 2017
Posts: 46
Likes: 15
Thanks for the information. I’m going to go through these steps again. I’ve done it twice with the technician on the line. When all else fails, their answer is always “ you must have a vacuum leak somewhere. That’s always their answer. How about a new computer? Or a refund. I’ve even had tech people say to ignore the directions in the manual and “ do it this way”. I’ve completely restored this car and would love to drive it but it’s so unpredictable. At least the factory computer had a limp home mode. Do you think that I should actually add additional grounds? That was suggestion of one of the techs. Hell, I’ll run grounds all over like spaghetti if that would help.
1st Gear
Joined: Sep 2023
Posts: 1
Likes: 0
Distributor question. Dmall cap vs large HEI
You said if you have a large HEI distributor you need to convert to a small cap w separate coil. On the Fitech 8350 description it says "plus the harness plugs into the factory distributor," So, did you have to convert to a small cap?