Projects SBC TPI swap wiring harness

A little OT but youngest Dau has a 56 F100 that I swapped a SBC/T400 in for her 20+ years ago. Its tired and time to update and make a little more economical and reliable for her and the little one that will be here any day now. Anyway, have been given a wrecked 86 Camareo with 350TPI/700R4. Was a great running car prior to it getting T Boned, minor injuries but insurance totaled the car. Fast forward, I'm old time traditional guy and have not swapped any TPI motors, not big into EFI. Question is, if you were doing the swap, whose wiring harness/kit would you use, there are lots out there and all claim to be better than the others. Would prefer to use an Alliance vendor if possible.
Am looking for ease of install and above all, RELABILITY for her!!! Will modify tank for fuel lines, etc but want to use an external hi pressure pump to ease in changing in the event of failure. Hate pulling fuel tanks to replace internal pumps. Any recommendations will be greatly appreciated. Thanx in advance, Dave

 

I would use the stock one. Stock fuel pumps last longer than aftermarket ones, IMHO. hardest part will be sorting out which electrical gizmos from the camaro aren't needed. while it is out, have the 700r4 updated to 87-up specs, they improved the front pumps and a few other goodies.

 

http://www.hotrodlane.cc/08%20catalog/08onlinecatalogMAIN.html Street & Performance out of Arkansas has the most experience of anyone I know.

 

I'd rebuild the sbc/th400....fix whatever about it is unreliable so it's reliable again.

20 year old efi stuff is also unreliable, and there are a heck of a lot more parts that can go bad.

 

Another vote for stock harness. It's by far the easiest way to go. Just take some tape and write down on the harness what each plug goes into. If it's smog crap, just strip those wires out when you get it home. A good trick if you can pull the harness from a running car is to fire it up and grab your wire cutters. Start snipping what you think are not needed. If the car is still running, you don't need it.

EFI is different, but imo easier than a carb once it's in. The ECU will tell you what's wrong half the time by flashing a code, and it works the same everytime. The older systems are not as capable as new ones, but they work very well once it's been freshened up.

 

I'm all for "mechanical" instead of electronic stuff too. How about a carb and early distributor on the 86 engine and use the 700R4. I've converted a couple of cars over and it's no fun figuring out what you need and what you don't with a stock loom. If you're gonna go TPI, I'd use the Street & Performance loom. An interesting deal, the manuals I used specifically stated that if you're going for gas milage, the TPI didn't help much unless you used the OD transmission. Something to think about.
Larry T

 

What all would "freshened up" include?

injectors? maf sensor? tp sensor? coolant sensor? O2 sensor?

How many miles on the camaro? 80s efi engines typically last 200k or so with maintenance...how tired is it?

If I were doing the swap I'd use the original harness too....but it definitely isn't plug and play, you ought to figure out at least the basics of how it works before you start cutting wires.

 

A properly working carb will get about the same mileage/performance as efi. the neat thing about efi is that it will run the engine nice and smooth under load at low rpm...it's great with overdrive

 

And overdrive itself is a VERY big improvement for most cars. A 400 is nice, but you have to choose rear gearing that is too high or too low for some conditions.
I too agree on converted stock...there is or was an excellent book on this from "Jaguars that Run"...the '86 setup is the good one with Mass sensor, able to adapt to whatever you do with it, unlike the cheaper system that replaced it a couple of years later. I actually looked over all this stuff and bought parts for a swap before coming back to my senses and getting back into flatheads...The Arkansas people had everything (but remeber this system is now ancient history for streetrodders), but in my opinion they took out too much and left significant functions out. Don't remember just what, but it seemed functionally inferior to a full system. The streetrod suppliers also pushed to convert all of these to a non-MAF system because it was simpler and did not require figuring out how to mount the stuff in the air duct...again, I think, making for a less capable system. The stock system is quite a wad of wire, but all of that is between computer and engine and is all snap fit. Actual wiring from car to computer is very simple. I think most wire deletions will be non-FI stuff that just happened to be wrapped into the harness, like connections for Camaro gauges.

 

Newer version of book I liked: http://www.jagsthatrun.com/Pages/Chevrolet_TPI_TBI_V-8.html

 

It's been my experience that those early GM efi wiring harnesses are separated out pretty well...the stuff to run the efi is on the pass side of the car, the stuff that runs the "normal" electrics on the engine comes in from the driver side, they are separate harnesses.

 

If you're dead set on using the TPI and stock harness, You might get this book. Chevrolet TPI &TBI Engine Swapping by Mike Knell. It was written before all of the harness kits were introduced and is a pretty good read on the subject. You'll need a factory wiring diagram for the 86 Camaro too.

I still like carbs myself. (G)
Larry T




Looks like Bruce was posting the same thing while I was scanning and typing. Oh well. LOL

 

You just need to make sure everything is working right. Injectors should be cleaned and balanced, or outright replaced if they're really bad. O2 sensors wear out, and need to be replaced from time to time. MAF, t/p, and temp sensors are pretty durable, but if you're grabbing stuff from a junkyard it's good to have spares.

Also, you have to make sure that ALL the wires are hooked up, including the little stuff on the car side. If the ECU wants a VSS signal (not sure if this one does), you need to have it. It will trip codes at the least, and make the car run poorly or cut out at worst.

I've stripped down a few harnesses in my day, it's really not so bad if you pull it yourself and label as you go. It's only when the thing is sitting in a pile and you have to figure from scratch that it gets to be a PITA.

 

Some stuff to wade through but a good TPI swap site that helped me.

http://www.chevythunder.com/

Now, I'm an anti-electronics car person.

I used to always own old cars, when they broke down, I'd fix 'em on the side of the road. The last few electronic cars I've owned including several new ones ALWAYS have $ensor/$ystem i$$ue$.

I'm done with them. When my current driver goes tits up, I'll be buying a 60's Nova station wagon with a straight 6.

Oh yea, I'd use the stock wiring harness and cut out or unplug what you don't need. A Haynes manual is handy for wiring schematics or I'm sure you could find them on a Camaro site.

I used a modern (non EFI) harness in my 1951 F1 but didn't want a bulkhead connector going through the firewall. So, made this and hid all of the wiring.

 

I've always used Street and Performance, one thing about them they will work with you on the phone until it's fixed, a lot of times that is Mark the owner. I never thought I could strip the harness down and make it work due to the VATS system, is this not true?

 

I swaped a 1987 iroc tpi 5.7 ltr and trans in my 1986 chev truck several years ago. I used the factory harness and fuel system, it was the cheapest, easyest and cheapest way to go. why spend money on parts that you already have in the doner car that work fine? there is no need to re-engineer it

 

If you are into electronics, it's pretty easy to make a LM555 timer circuit that will put out the required low frequency square wave....or get a chip burned....

 

Well, LM555 is way beyond me , but I'm eager to learn. Looks like a chip, how to wire the circuit? Or where cam I find info on the web. Thanks

 

google is your friend...

http://images.google.com/images?hl=en&q=vats+555+schematic&btnG=Search+Images&gbv=1

 

I have to agree that http://www.chevythunder.com Lenord knows his stuff and he will talk to you about your project

 

Squirrel, Again, you are the man!

 

I bought the JTR/Suncoast TPI swap manual years ago when I was contemplating a TPI swap into something. It was a good book, broke down the harness wire by wire and told you what you could eliminate, how to trouble shoot, etc...

Also, FYI, unless the motor was swapped, the 350 TPI motor wasn't available in an F body until 87'. The 305 TPI motor will still get up an go though...

If you want to switch to full serpentine belts, check a 91-93 Caprice or Roadmaster out. They have the correct brackets to make an 86' TPI motor full serpentine with the offset tensioner. Also, the 91-3 9C1 Caprice copcar's longblock is the same motor as the 87+350 TPI motor, cam & everything...

 

that is my experience. I'm also a fan of the 200r4 over the 700r4 if you're looking at overdrives, less power to run it, better gear spread.

 

If VATS is a problem Painless wiring has a wiring thing to go around vats. I have Vats for security but keep the wiire thing in the tool box just in case one of those little wires breaksare the module goes south.

 

if you are going to use all of the emmisions I say go with the oem harness and ecm, but if you pull all that off i would go with a howell harness. I got one for my wifes aerocoupe when I did the swap and it was pretty much plug & play very easy install and it's all wrapped with ends on. the only other thing to remember is that you will have to get the mem-cal reburned (howell does that also)Good luck, Tom

 

guys i can reburn the chip remove all the on road emission equipment and vats ... i can do TBI TPi Lt1's etc... very good reasonbale pricing

 

Probably is a 305, its an all orig Z 28 with less than 100k on it. Was given to us about 3 years ago, cant get it started now, set to long in the AZ sun and with the "ADDITIVES" in AZ gas, the in tank hi press pump is inop. Local parts folks here tell me, due to AZ additives, that gum up the pumps that they only warrenty them for a year. I should have started it a little more often to keep pump working. Even mechanical pumps dont last long unless you use them regularly. Thanx, Dave

 

A friend in town here (sv) likes TPI engines, I've helped him troubleshoot a couple that wouldn't run...first one they tried everything, it seemed to me like it cranked kidna fast so I suggested a compression check,it had hardly any compression! engine from a wrecked F body.

Other was kind of the same deal but it was in his 48caddy, no start, discovered all the injectors were plugged up.

EFI is fun....good luck!

 

Larry's Electric in Ruma Il. can fix you up with a harness for a good price. I know him & he does good work.

 

Thanx HAMBrs for all the good input, will use a lot of it. I know several folks that have had good luck with TPIs over the years. (I have a couple of factory TBI vehicles that stiil run great pretty good economy too). I'm sure I will too. A lot of it is just good preventive maintenance to keep them running as designed as it is with any gas engine.