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This is interesting, summit racing shows they have 2 of the 38352 kits in stock yet have to special order the basic 38350 kits
I put a moment of thought into that when I seen that on the summit site a couple weeks ago. They had 3-4 of each kit that had the 4L60E and 4L80 transmission controller.
I wonder if they have stock on those kits because people ordered them, waited months and then cancelled the order resulting in Summit being stuck with them when they finally showed up??
Yes that is interesting, curious as to why it is so hard to have stock on the basic kit when that's how the kits start off... want to order one and then throw a big single turbo on my l98 but I would love to see or hear some feedback first.
I feel bad for you guys, I ordered mine two days ago when I saw the sale at Summit and it's already here!
It's going to be a bit before I install it but I'll keep you guys in the loop when I do. I really liked the sub harness with fuses and a relay for the fuel pump, I'm installing it into a gmt400 that needs all of those things so on paper this solves a lot of problems I have. Still need another relay for the electric fan I think, but that might be all.
You bring up some fair and valid points. In retrospect I was too enthusiastic and should have stated "minimal splicing into harness". I think if you splice into the necessitated harness wires within the loom you could reverse the splices at a later date without visible detection if that matters to you. I agree that the age of the factory harness represents a challenge in using each cars original factory harness as the backbone of a true plug & play install; however, it would make for an easy install. A few sub harnesses would need to be included for the WBO2's.
The system including the new harness should install relatively easily with the amount of additional time for aesthetics chosen by the individual end user. My plan is to install the system for functionality at first to get it up and running, after everything is dialed in I'm going to take the time to run the harness as OEM as possible while performing several other engine bay detailing functions such as spark plug wire looming, removing the AIR system, removing the MAF and factory air cleaner assy, etc.
Just as an FYI, Jegs shows the base kit as shipping immediately. I don't know if Jeg's offers the same shipping deals to Canada that Summit does.
Thanks for your well thought out reply to my previous post - will be good to get a couple of these systems into cars and get feedback on everyone's experience is with it.
Back in the day, there were a few companies that created piggy back harnesses for the Accel DFI and FAST EFI boxes that allowed them to be plugged directly into the factory 3rd gen harness. Unfortunately those guys are long gone. The header connector that allows a piggy back harness are still available. If someone were savvy with electrical connections and soldering, one could create the same type of harness for the FI Tech.
Here's my old White Racing piggy back harness for my Accel DFI 6 that's I've used since the late 80's
Last edited by FAST LiFE; 11-26-2022 at 10:27 PM.
Reason: info
Back in the day, there were a few companies that created piggy back harnesses for the Accel DFI and FAST EFI boxes that allowed them to be plugged directly into the factory 3rd gen harness. Unfortunately those guys are long gone. The header connector that allows a piggy back harness are still available. If someone were savvy with electrical connections and soldering, one could create the same type of harness for the FI Tech.
Here's my old White Racing piggy back harness for my Accel DFI 6 that's I've used since the late 80's
funny, I had one of those old boxes. worked great tuned in dos. looked a bit different but was plug and play. I think I sold it to someone in Hawaii on here years and years ago.
but yes, today's stuff should be pretty easy to be plug and play. at this point all the imports have plug and play stand alones like ecm masters and stuff. such a shame they don't support domestic stuff besides ls
This is very interesting. I will be following. I hope this works out good for you guys. I would like to keep the canister purge though. I guess you will have to install a vented gas cap. I wonder how this compares to EBL P4 FLASH?
This is very interesting. I will be following. I hope this works out good for you guys. I would like to keep the canister purge though. I guess you will have to install a vented gas cap. I wonder how this compares to EBL P4 FLASH?
I'm going with a remote rollover vent valve unless somebody has a better idea:
This is very interesting. I will be following. I hope this works out good for you guys. I would like to keep the canister purge though. I guess you will have to install a vented gas cap. I wonder how this compares to EBL P4 FLASH?
I don't have hands on experience with either this or ebl, but I believe in theory this should be like the new holley where it's real time tuning itself that adjusts air fuel off the wide band. where ebl I believe will self tune off the narrow and wideband but it's a bit more of a manual process, like your run auto tune while driving or off a log of a drive. check the changes it's going to make, and then hit OK to upload those changes then go drive again. the holley is just constantly doing stuff in the background, based on settings of course and if your wide band goes bad, which they do often you get bad settings haha. upsides and down sides to both.
price and ebl being plug and play into the factory harness seems to be an upside, plus the guy that made it posts here and is still active to answer questions. this other stuff I believe requires it's own harness which it comes with and it seems guys have a hard time buying it, no clue on the tech line status if you need it.
funny, I had one of those old boxes. worked great tuned in dos. looked a bit different but was plug and play. I think I sold it to someone in Hawaii on here years and years ago.
but yes, today's stuff should be pretty easy to be plug and play. at this point all the imports have plug and play stand alones like ecm masters and stuff. such a shame they don't support domestic stuff besides ls
My piggy back harness was by White Racing. The other was by Fast Track Performance. Maybe you had that setup? Yeah I see a lot of custom piggy back harnesses for the import cars. I've tried to reach out and see these companies would be willing to do custom work to do the same for Third Gen's but no one is interested as they are only familiar with the Import schematics. If one were talented enough with electronics, you would just need the header connector and modify FiTech harness to it to create a piggy back interface that would plug directly into the factory harness.
Seems like this thread is getting a bit off topic, someone on this forum has got to have this kit installed and have some feedback for us, I see one question on the summit site has been answered by someone who installed this kit saying they had to make some modifications to have all their gauges working, I thought this would be a very hot topic seeing as it's a plug and play fuel management system and all. Happy new year guys
Seems like this thread is getting a bit off topic, someone on this forum has got to have this kit installed and have some feedback for us, I see one question on the summit site has been answered by someone who installed this kit saying they had to make some modifications to have all their gauges working, I thought this would be a very hot topic seeing as it's a plug and play fuel management system and all. Happy new year guys
The gauges don't run off the ecm; it's plug and play for running TPI style MPFI but not third gen f-bodies specifically. The gauges, charging, a/c, and fan harness is something you're going to have to engineer for yourself. I don't think that situation is any different than what you'd find with other engine management setups. It does have configurable tach and speedo out, a relay setup to drive power to a single fuel pump (and supports pwm control which is pretty cool), independent triggers for two fans (no relays), and supports a/c idle up and fan trigger by listening in on the a/c circuit.
It does not have any support for EGR, AIR, or charcoal canister vent purge so that's something else to consider.
Got my rails / runners / plenum / throttle body all cleaned up and ready to go (disregard the brown fingerprint smudges):
Scored this never used Scoggin-Dickey Vortec TPI lower locally for $350 including ARP bolts:
Just pulled the fuel pump yesterday, I'm thinking about going with a Racetronix pump. They have a nice kit for third gens so I thought I'd test it out here where a dead pump is significantly quicker to fix. I'd like to utilize the PWM control (turbine style pump required, Walbros will die) to see if a guy can reduce on the amperages since I'm guessing a 255lph pump could probably be turned down to 65% for whatever TPI can demand, might make the pump last longer too:
I have watched this thread for a while. I installed the Fitech on a stock 88 Iroc in late November. I had the problem of the car going dead at idle at random times. Did all the basic repair work of new: fuel tank, pump, fuel, plugs, all sensors, plugs, air filters, wires, distributor, cap, rotor, knock sensor and ecu. Not one item helped in any way. I ordered the fitech system. It took a couple of days to install working of and on. The car started and ran on the first try. Programming was simple. It did fix the issue of random cutting off. The only issue I am still trying to work through is a rich idle. Keep in mind I will tinker with this car at random times, about once every 5 or 6 weeks. It has allowed me to drive the car with out worries of not making it home. Over all pleased with it so far.
Factory gauges are independent but wiring is tied into the same harness so I suppose you isolated the appropriate wiring and remove the factory efi harness to run the fitech? I have completely modified my entire engine bay harness to clean everything up and look seamless so what will I need to do to run this fitech mostly likely completely remove my harness and rewire my gauges etc? Thanks for the input 👍🏼
Ok so I have got the fitech system 39351 installed in my 88 gta.went pretty smooth so I thought lol..I pull the factory ecm an harness left only the headlights brakes wiper harness an an the wire for the factory gauges an starter wires..first problem is the car will not turn over.tested the purple wire at the starter solenoid an have no power.tested the wire from one end to the other end an have continuity no breaks in the wire.also my fuel pump is not priming.my question is could the vats still be messing with everything.I have jumped the neutral safety switch to see f that was the problem also.
Ok so I have got the fitech system 39351 installed in my 88 gta.went pretty smooth so I thought lol..I pull the factory ecm an harness left only the headlights brakes wiper harness an an the wire for the factory gauges an starter wires..first problem is the car will not turn over.tested the purple wire at the starter solenoid an have no power.tested the wire from one end to the other end an have continuity no breaks in the wire.also my fuel pump is not priming.my question is could the vats still be messing with everything.I have jumped the neutral safety switch to see f that was the problem also.
I had the issue on my 1989 IROC when I installed the fitech tpi system it's your vat system, will need to be jumpered out or by passed. at the VAT kick panel relay jump the thick yellow wire and 18 gauge green wire
I’ve had it for a few months and finally got my motor built and running so plan to install in the next couple weeks and will take pics and post. Looks easy enough, just not sure about fan and AC relays as those wires are in the same harness as the rest of the right side harness. I doubt I’ll ever go back to stock so I’ll probably just Siamese the new with the old and get rid of what I don’t need. Need to figure out where to put ECM and fuse box
Keep posting updates on how this works out for each install. I've been running their LS harness and computer on 2 swap cars for a couple of years with no issues. The harness for this one looks like a nearly identical process to install as a LS swap. IE: keep the lights, gauges, wipers, HVAC, and the power wires and replace everything feeding from the engine to the ECM with their harness. I'm thinking about trying this on the remaining TPI powered thirdgen.
FWIW, the lead programmer and cofounder of FiTech has a thirdgen. Some of this stuff was prototyped and tested on his car. It isn't perfect but it gives us options we didn't have before to keep the engine bay looking stock, modifying the engines, and being able to tune them at a good price point. If you're ever at a show like GoodGuys and they are there, if any of them have a laptop with them, they will usually be very happy to look at your tune and adjust if you are having issues. If you're in SoCal, they host dyno days and cruises.
I just put the 38350 on a '90 Vette with 6-speed. I did not want to cut wires yet just in case it does not work out, and I wanted to have my dash working so the ECU is still in place. So I have only connected the power/ground, keyed power, TPS, IAC, IAT, MAP, knock sensor, and tapped into and using stock wiring to fuel pump. Using stock location for FiTech temp and put a CNC machined adapter in upper water hose for temp sender so the stock ECU can control fans. https://jagsthatrun.com/products/tra...d87f05e4&_ss=r (FiTech uses + voltage for fans while stock uses ground to activate fans)
It ran good for a couple days then AFR went to 20.58 and engine went rich trying to correct AFR then went back to normal, did it again before getting home. Cooling off it ran OK then went to 20.58, then it would go to 20.58 when first starting up. Researched the sensor it is a 5-wire wideband LSU 4.2 Lambda AFR Upstream Oxygen sensor https://partshawk.com/walker-product...en-sensor.html . Replaced sensor and it is working again, probably going to order another for passenger exhaust.
Only complaints are the AFR going bad and the water temp sender they sent was shorted out, the gauge on the wiring is kid of small, but it seems to be working good now. Tech support is a bit reluctant to give instructions for a emission era car, probably thank the EPA for them being cautious.
Just installed with a friend (with way more knowledge about wiring). Since previous owners have hacked into the stock harness we couldn't get fan2 to work. Will sort that out. Anyways, apart from a little hesistant to cold start the engine idles fine. Will try to actually drive the thing later today. Wish me luck!!
Ok, so, besides having no speedo the car feels really good. Haven't timed 0-60 before/after or anything but it sure feels like it has more power down low. I guess the fitech adjusts timing and afr more agressivly than a stock unaltered ecm? Would be interesting to dyno it.
Also cool to see the true idle rpm. Fitech locks the motor to 750 rpm (or whatever value you choose) with no gear while the stock tach says ~1100. Always felt the tach was showing too high.
Another cool thing is that it starts way better now. I guess the fitech ecm figured out my iac.
More tests tomorrow! Got an hour or two away from the family
Fan 2 issue is solved. Previous owner did a single feed from battery to both relays, and the parallel hook up by the relays (hidden inside a loom) must have been glitchy. So, new separate and fused feeds to both relays and both are working.
The car runs really strong. The fitech provides the tune I needed for my Accel Super Ram, 1.6 rockers and dyno don headers.
The speedo out from fitech doesn't speak to the stock speedo in wire. The fitech handheld shows accurate mph but I need the stock speedo to do its thing in km/h to pass car inspection. Bought a Dakota Digital SGI-100 BT which will arrive next week. I guess the old yellow box from the TBI's could have solved the problem far cheaper but I'm in sweden and 3rd gen stuff simply doesn't exist.
Still hard to crank. I tried priming it, increasing the ICV air, lessening air and fuel, lessening the one or the other but simply got lost. Haven't found the right combination. It needs 3-4 cranks and a slight tap on the gas pedal to wake up . By now I think it's more a fuel than air issue.
I just put the 38350 on a '90 Vette with 6-speed. I did not want to cut wires yet just in case it does not work out, and I wanted to have my dash working so the ECU is still in place. So I have only connected the power/ground, keyed power, TPS, IAC, IAT, MAP, knock sensor, and tapped into and using stock wiring to fuel pump. Using stock location for FiTech temp and put a CNC machined adapter in upper water hose for temp sender so the stock ECU can control fans. https://jagsthatrun.com/products/tra...d87f05e4&_ss=r (FiTech uses + voltage for fans while stock uses ground to activate fans)
It ran good for a couple days then AFR went to 20.58 and engine went rich trying to correct AFR then went back to normal, did it again before getting home. Cooling off it ran OK then went to 20.58, then it would go to 20.58 when first starting up. Researched the sensor it is a 5-wire wideband LSU 4.2 Lambda AFR Upstream Oxygen sensor https://partshawk.com/walker-product...en-sensor.html . Replaced sensor and it is working again, probably going to order another for passenger exhaust.
Only complaints are the AFR going bad and the water temp sender they sent was shorted out, the gauge on the wiring is kid of small, but it seems to be working good now. Tech support is a bit reluctant to give instructions for a emission era car, probably thank the EPA for them being cautious.
I'm installing on a 90 Vette with a 6-speed also. I'd also rather not cut out the factory wiring just in case. Where did you mount the fitech ecm and fuse block?
Set my IAC today. It was ideling with IAC 60 before adjustment and now below 10. Feels quicker off the line now when the throttle blades are providing air from the first millisecond instead of the IAC. Different crank/start sound as well. It revs up to 1300-1500 for a second and then settles at 700. Never did that before.
I'm installing on a 90 Vette with a 6-speed also. I'd also rather not cut out the factory wiring just in case. Where did you mount the fitech ecm and fuse block?
Back in the day there were a couple places that made interface harnesses that would allow Accel DFI 6.0/7.0/Thruster and FAST ECU's to plug directly to the factory harness. Those places are long gone. I've been trying to find someone that would do the same for the FiTech or Holley ECU's but haven't found someone yet. Here's a photo of an interface harness I still have for my Accel 6.0 ECU
Has anyone hooked up their stock 3rd gen speedo to fitechs speedo out? I bought a Dakota digital sg100bt to translate the fitech signal to my dash but still no luck. The vss is working (shows correct mph on the fitech handheld) as does the Dakota's test program on my dash speedo but something isnt working correctly, yet. I measured AC from fitech and it is sending pulses at a rate of about 1 per sec, when it should be 60-70 per sec (4000 ppm)
So just to clarify the factory gauges will still work with the 38350 because they are independent of the ECU right?
Thanks!
Yep. Just finished my install. Not sure about all the gauges on the f body but. Tach you can hook up to the fitech output wire or to the remote coil. The speedo can hook up to the fitech output wire or if it's cable driven then it's independent. I've got a 6 speed so the vss wasn't needed and the vss wire goes to the stock ecm then outputs speed to the gauge.
Water temp you will need to put in a T on the manifold or find another coolant passage. Fitech uses a cts sensor that can't be shared so you'll have to run an independent sensor and just plug it into the existing wiring or run an aftermarket standalone.
Thought I should make an update here since I finished my swap. L31 + 4L60E out of a '99 K1500 put into a '92 K2500. SDPC Vortec TPI base, stock TPI, 24lb Bosch injectors from Southbay, everything else is pretty much stock as-pulled. I had my fuel rails welded to accept -AN fittings from the rear, and I had to cut some chunks off the accessory drive mounts. The factory A/C compressor interferes with the throttle body but an adapter plate can be made to shift it over an inch, I went for the delete pulley just to get the swap running.
The install instructions were good, I didn't really have any problems with figuring out what goes where. It fired right up on the first try after 3-4 seconds of cranking. I'm astonished at how drivable this tune is straight out of the box. The first drive went really well. I still haven't done anything other than set the initial configuration parameters and the truck is totally drivable. Doesn't lurch or bog, never died or stalled, it shifts my trans a little firm on the 1-2 (I got the trans control one for the 4L60E). Throttle tip in could probably use a little work and the idle seems to fluctuate just a little much but it really seems like only minor tweaks are going to be needed to get this thing dialed in. AFR targets are good, full throttle, part throttle, cruise all fine.
It probably helps I have a stock cam. Power seems strong, it's hard to hear the squealing of the tires over the glasspack but I'm pretty sure I was doing rolling burnouts on the highway by how greasy the rear end felt. Adequate for a daily driver truck at least.
I haven't gotten the tach and speedo output to the gauges yet but all the others are independent and those are working. Tach and speedo are available on the handheld controller so I can get my data, it's just not ideal. I have sent an email to FiTech asking for info on the tach / speedo settings so I'll give another update once I have that sorted out. It's a little annoying those features weren't documented with the provided system, but overall my initial impression is good for the price I paid.
@Komet just out of curiosity. What's your IAC count with warm engine, ideling in park? (You'll find that on the handheld dashboard if you scroll down a little).
@Komet just out of curiosity. What's your IAC count with warm engine, ideling in park? (You'll find that on the handheld dashboard if you scroll down a little).
3-4. It was a new Standard Motor Products IAC, according to the instructions it was in the acceptable travel range out of the box and I haven't done any syncing or tuning with it.
10-04-2022, 11:41 PM
