TPI wizards only, enter at your own risk

[donnj]

Go easy on me please, thanks.
Another post showing my age here. First and foremost auto electric is like black magic to me. I know its easy for most just like following a road map, but for me I always seem to end up in some foreign land and very frustrated.
The first car TPI car I built recently became available and I was able to buy it back. The motor and trans now reside in my vert. Before I go and start pulling wires and take 10 steps back is there anyone willing spend a few moments on the phone or willing to make a house call that knows this stuff like the back of there hand and could help me out for a few hours. The car I originally swapped the TPI set-up into was a carbed car and the internet wasnt around back then, so I had a NIGHTMARE getting the wiring, fuel pump, learning batch injection, all to function properly amongst so many other lovely things.
The vert is a TBI car so I think the body harness will work with some small mods. AC is gone, AP is gone, im running a alt. and PS pump thats it. I want a simple clean engine bay. No wires from either harness have been cut so you can get a visual of what im up against. I know all the info is out there on the forums but I get so lost its not funny. I just want the wiring for the TPI to be done right once and for all, and to understand what actually does what.
Im in North Jersey / Wayne area and not looking for charity, I know time is money so if you need to be paid just say the word. Im honestly looking to get past this hurdle and finish the build.
Thanks in advance guys

[stealth355tpi]

Not sure I follow but your trying to swap tbi to tpi? If so I must say its not worth the hassel. I've been down that road and wasted a lot of time and money. I wish I would of just gone carbed.

[Kat]

What year tbi?

And read this. I've done a few conversions over the years using this and helped with some of the wiring crap back in 2004. Wow. Damn.

http://www.thirdgen.org/techboard/tp...d-density.html

Basically the hard part it swapping the ECM connectors from the tbi ECM to the tpi one, then adding the 8 injector connectors, lengthen the cts connector and I think that was it.

[greenformula92]

If you have a intact tpi harness I would use that. What you absolutely need are the following connectors: throttle positioning, idle air control, 8 injectors, coolant temp, egr temp (unless tuning out), intake manifold temp, speed sensor, MAF/MAP, O2, and knock sensor. Whatever you don't use just clip off or stuff it back into the harness. The routing is up to you. You can lengthen/shorten the leads as necessary but you need all the engine/speed sensors connected for it to run right.

[Mark B]

Wouldn't a factory TPI harness plug right in?

[stealth355tpi]

Originally Posted by Mark B

Wouldn't a factory TPI harness plug right in?

Yes, but that didn't work for me. I had all the donor parts from an 87 and when I put it all into my 92 it didn't work.

[donnj]

thanks guys, so far still the same. Where im lost is the harness coming thru the firewall on the drivers side. I dug out a 1988 GM wiring diagram book last night and was able to start labeling a few things. I will post up some pics of what im up against in the engine bay later so you get a visual, stay tuned.

[Kat]

Originally Posted by stealth355tpi

Yes, but that didn't work for me. I had all the donor parts from an 87 and when I put it all into my 92 it didn't work.

Not surprising. In 87 the engine side was basically two separate harnesses. The lights, starting, and charging was one and the ECM stuff was another. In 88 they combined the two to make a cleaner engine bay

Seriously tho, you have a known working TBI harness and a scrap TPI one.. I rather spend a few hours adding a couple of connectors and repining a few vs a few days chasing problems and cursing life. Been there done that. Haha

[V]

When i did a SD tpi swap into an 87 Monte ss, i bought a custom stand alone harness off ebay. the seller was very helpful even a few months later when i had questions. i only had to hook up power acc ground and then i used vdo gauges since the gauges run separate of the ecm (except vss). People over complicate wiring swaps imo. i love electrical wiring but then again i had started taking electrical engineering in college now im going for mechanical. There is one great website i used. i think it is like chevythunder .com or like that. It had info about all year tpis and what swapped or could be made to work.

oh and of course id be willing to come by and give a hand here and there depending on my schedule. i could also possibly draw up diagram and instructions as to what wires to connect or splice.

[donnj]

exactly the problem, one monster harness coming from firewall instead of 2. One engine and the other the body harness is what the old car had

[maroman88]

been there done this, went TBI to TPI and now ive got a Carb, if i could do it all over, it would have stayed TBI lol

[greenformula92]

is this a MAP or MAF harness? I would just ditch the exsisting body harness and use the combined harness. I know it's more work but it will look cleaner. Or source a MAF harness that is engine only and sell the harness you have

[LTb1ow]

Why not swap in an LS1?

[OG]

Originally Posted by LTb1ow

Why not swap in an LS1?

why waste an LS1 on a turd...

[donnj]

ok, was at at it all day, Thanks Chris again. MAF harness. It runs and I will be at it again tomorrow. 2 major issues. The car was a auto that is now a stick. Trying to fiigure out the wiring for the starter to work as it should. I jumped the blue and purple at the shifter harness and it started. Need to see what wires need to be cut and spliced. Other major issue is the fuel pump is on all the time, the relay is not working to keep it on for 2 seconds then off, its running with key turned on all the time. Black magic....

[chrisfrom nj]

don im glad i could help you out i havent worked on a tpi car in years i forgot how many wires the wireing harness has the car is looking great im looking up what wires you need to hook up to get the car started with the key instead of the jumper wire

[donnj]

need some help here, all is working but the 2 second relay for the fuel pump prime. With the key on its the pumps always on. I can hear the relay turn off and the green/white wire from the ECM shuts off after 2 secs, but the tan/white wire still has 12 volts. I swapped the relays and cant figure it out. i know, should have went with a Holley...

[L695speed]

Originally Posted by donnj

need some help here, all is working but the 2 second relay for the fuel pump prime. With the key on its the pumps always on. I can hear the relay turn off and the green/white wire from the ECM shuts off after 2 secs, but the tan/white wire still has 12 volts. I swapped the relays and cant figure it out. i know, should have went with a Holley...

Not going to be much help... But I do have a couple thoughts.

Are the relays sticking? My fan high speed motor relay sticks. Fixed via a whack with a flashlight.

My brother put in a switch for his fuel pump. Requires a lil hacking, and a lil more work to get it started, but his Fiero has one to manually turn on and off the fuel pump. Naturally gotta have it on to start it. But I don't think you want to do that.

I have an 88 myself, that is a running driving car (admittedly needs work but its saving my ass now...), love the low end torque of it, but I don't envy what you're dealing with. Electrical is black magic to me too. I do have a Factory Service Manual for the 88 TPI. Wouldn't hurt to take a look at it. The 2 second delay relay.....hmmm.

From GM service Manual
"FUEL PUMP RELAY
To control fuel pump operation, a fuel pump
relay is used.
When the ignition switch is turned to "RUN"
position, the fuel pump relay activates the electric fuel
pump for 1.5 to 2.0 seconds to prime the injector(s). If
the ECM does not receive reference pulses from the
distributor after this time, the ECM signals the relay
to turn off the fuel pump. The relay will once again
activate the fuel pump when the ECM receives
distributor reference pulses."

So you're saying its not turning off like it should correct? I'm looking at the flow charts for the pump relay circuit, most of them point to the relay. It may be worth it to pull the fuel relay when the car is running. Reason being. The oil pressure switch is tied into the same circuit as a back up. Get it up to temp. If you pull it and it quits, the OPS is bad. If it keeps running the whole circuit checks out.

The other thing that is throwing me off, is you say there is 12V to the black and tan wire. According to the wiring diagram there shouldn't be 12V on that wire. There is a black and pink wire as well as a dark green and white wire that should have 12V running through it, ditto for the orange ones. The Black and Tan wire is a fuel pump signal wire. Possible you have them mixed up?

[greenformula92]

also keep in mind the oil pressure switch is in the fuel pump circut. The fuel pump relay is used to prime the injectors. once the engine is running and has oil pressure the it keeps the pump running. the ECM does not use the relay all the time. this is why when you have a bad fuel pump relay and you crank the car till it has enough oil pressure it will kick the pump on and it will fire.

[donnj]

ok, update. before and after pics, so far. The fuel pump was being fed 12 volts from a large tan/white wire from harness going to the 207 connector slot D, from the new car it was for the fans that were hooked to that and thus feeding the tan/white all the time with key on. What a frustrating day but once everything worked as it should with the volt meter and test lights, it was time to push in the clutch and and see what would happen. She roared to life and it was a sound so rewarding....
better pics coming, going back out to keep soldering, heat shrinking and cutting wires not needed

[chrisfrom nj]

the after pic looks great don i remember seeing the before view what a mess

[greenformula92]

i now have a headache after looking at that mess lol

[L695speed]

Yikes, and I thought my brother's Fiero was bad.......

[Kat]

Just for some inspiration........

[greenformula92]

I spy spohn upper strut mounts