hey guys,

Need some guru help here. I posted this on the ENGINE SWAP forum, but now that I have pics up, I figure that this might be the right forum for it.

Did a TPI swap into a 91 V8 TBI RS. The donor motor, wiring harness, and ECM came from a 90 Pontiac Firebird.

Rest assured, I did my searches, looked through my 92 shop manual, borrowed a Chilton's manual for Pontiac Firebirds, and I've come up with nothing.. here are the pics.







The black harness is from the original car (the 91 RS) and has been unmodified in any way/shape/form. The "clear"/white harness is from the 1990 Firebird TPI harness. As you can see from the first picture, the harnesses are not directly plugged into the ECM.

From the rest of the pictures, you can see that the black harness has A LOT more wires going into it... the clear/white harness from the donor TPI only has a couple of wires...

As of right now, the car will prime the fuel pump, but she won't crank at all. Lights on, but noone's home.

Could someone please help me with some insight as to where to go from here? thanks!

Or does someone have the wiring diagram/schematic for the clear/white side portion of the wiring harness?

 

This is the schematic for the harness taken from my 92 Camaro Service manual.

Would anyone have the same one from a 1990 Pontiac Firebird 305 TPI? It's the C207 connector. thanks!

 

someone please help!

 

First thing that comes to mind is the VATS system. Are you using the key from the Firebird? If not , it most likely won't start because it's not reading the correct resistance to activate it.

 

how would you use the key from the firebird anyways?

best i can come up with is removing the vats completly with a prom tune

 

You'll have to do that. The ECM needs a signal from the VATS module to enable it to start. Get a chip that deletes the VATS and it will crank after that.

 

thanks

 

Keep us posted on the results .

 

the things that you have to make sure that connector is doing is giving you power to the ecm, make sure the wire to the brake switch that works your lockup convertor and the neutral saftey switch are all going to the same place.

Oh yeah do not forget the aldl conector wires. all you have to do is trace the wires to the clip in the 90 harness and write it all down. I think it is an ABCD connector.

then look at the end of the wire that goes to the brake swich, aldl, fuse box for computer and injector power and neutral saftey switch.

get that all straight remove the VATS and you should BE AG

I just bought the Painless harness its cheap and its made of all new wire and connectors

 

you dont have to remove the vats, the module that reads the resistance mounts behind the dash on the pass side. the computer chip and the lock cylinder can be replaced without vats issues, because all the computer sees is an ok to start signal on the wire from the vats module.

he needs the pinout for his stock harnes on c207 and i think c232 (the one the fuel injectors go thourgh) and those for the year of his tpi harness. then compare and re-pin the wires that are in the wrong place.

good luck

 

i would just get the vats deleted completly from the prom, so it doesnt need a resistor code.


thanks for the other info though!

 

it is the easiest route to go, but...............................







all someone has to do to steal your hot and sexy ride is bash the right side of the steering column in and use a pair of pliers to start the car.

just a word of warning.

 

Too bad his ride's not hot nor sexy :P

Anyway. I'm the guy who's working on this car, (just logged in on Mike's account at the shop). I think it's the c207 connector giving us grief. Well, i know it is, but there may be more. I know it's not the VATS system, we didn't change the column or the VATS box, and the key is the same, so theres no reason that it should be the VATS.

The C207 connector looks like this

Body side -
A - Brown
B - Pink / Black
C - Brown / White
D - ---
E - White / Black
F - Pink / Black
G - Pink /Black
H - Tan / Black

J - Orange
K - Brown
L - Dark Blue (Vats Signal)
M - Orange
N - Orange / Black
P - ---
R - Purple / White

ECU side -
A - ---
B - Pink / Black
C - Brown / White
D - Brown
E - White / Black
F - Pink / Black
G - Pink /Black
H - Tan / Black

J - Orange
K - ---
L - Dark Blue
M - Black / White
N - ---
P - Red
R - ---

I've switched a few wires on the ECU side of the harness.
I switched D to A so the browns line up.
All the injector wiring seems like it is fine, it all lines up. I know there pink/black.
The ECU gets a signal when the key is on, the fuel pump primes, you can hear it. But it won't crank over when you turn the key to start.

Unsure what other wires to switch around on the other side of the harness. I know the black/white is a ground, because the before i pulled the wire, when you connected the plug, it matched up to the orange wire, and would blow the ACC fuse.

Any help would be appreciated.

 

Ok, so it cranks now, and i have no idea why. Only the side of the plug that matches is plugged in (A through H). It cranks over and gets spark now. Gets fuel pressure, haven't gotten it to fire, but i dont think there's much fuel in it, so once i give it a few bucks worth of gas, we'll see what happens.

 

I looked at this car today,

burned a chip with vats disabled just to eliminate that as a possible problem, no change
checked fuel pressure, got 45 psi but falls off to 30 in like 30 seconds, no fuel in the oil, a leaking regulator or injector shouldn't stop it from starting,
got spark,
engine cranks,

heres the weird part,
I tried to datalog with Tunerpro and my autoprom, wouldn't connect, with the key on

I also have a snap-on scanner, I tried hooking up with that, as soon as I roll the key to on, the scanner turns off, this I've never had this happen in 1000 cars I've scanned, the scanner uses a ground in the aldl so I'm guessing where its supposed to ground something is getting powered when the key rolls forward,

 

pin m is your problem. on the tpi car pin m is the ground, which is suppose to be the case according to my motor wiring diagram book for your 90 rs as well, but it is suppose to be blk/wht, not orange. if you remove the orange wire out of pin m and install a ground to that pin, it should start.

pin k is not used, on the tbi car it is the pin that supplies the vss signal to the pcm from the buffer box, on the speed density cars, the computer buffers its own signal. you will have to run a splice off the speed sensor wire before the buffer to the pcm on pins C1- B18 (yellow) and B9 (ppl). this will tell the pcm how fast you are going, but u need to leave the buffer box installed and functional or your speedo will not work.

also, i looked through my books and could not find anything for pins A and pIN R, which are the crank signal (pin r) and aldl pin c (pin a) on your tbi harness. these might need to be changed but i would leave them unless it runs wrong.

KEEP IN MIND THAT THESE ARE COMING OUT OF A MOTOR DIAGRAM BOOK, AND MAY BE DIFERENT THAN THE ACTUAL WIRES ON YOUR CAR!

i checked all the other pins and other than the ones i mentioned, everything looks good.

if you need more help, let me know and i will see what i can come up with.

good luck
anthony

 

damn the server is runnin slow today.

DOUBLE POST

 

thanks alot!

 

car still wont crank...

 

if it wont crank then you need to see if the purple wire down at the starter relay is receiving the start signal. if not then you need to look at the relay that cuts the starter signal when the vats is active. if you need to bypass it and put a wire on the starter itself and energize it to see if it will crank and fire up.

you still need to make sure the ecm is receiving the proper power and ground signals.

if you have any more questions i will be back later tonight, so just post them and i will do what i can.

good luck

 

@zzkker: thanks for helping us on this one so far, your advice has/is much appreciated. We located the starter relay and physically grounded it. The car cranks with the starter relay grounded, but she still does NOT fire. It IS getting spark, and we can smell gas as it keeps on cranking. Now, it sounds like it WANTS to fire up (it'll cough a couple of times really quickly), but fails to do so in the end.

I've double checked the plug wires, and they are all in order. We didn't monkey around with the dizzy, so timing shouldn't be affected.

 

i know you are not going to like this answer, but you need to pull the fuel rail off and check all the injectors to make sure they are not clogged.

i had this problem with a set of lt1 injectors on my lt1 intake conversion. the injectors had sat around so long that all but 2 of them were not squirting, and the 2 that were looked like they were taking a ****.

i could smell fuel out the exhaust and it would stumble then just crank like you said yours is doing.

i could not figure it out till it hit me, i had never used this set of injectors before.
so 4 bolts later (much easier on the lt1 to change injectors) and i turned over the car to see what was the lack of injector spray. a friend of mine had an extra set of known good injectors laying in his garage so i put those in and it fired up the first time.

moral of the story, check the injectors before installation (this is more so true on a super ram or the tpi).

good luck
thanks

 

nm car runs now!

thanks for the help!

 

what did you do to finally make it run? was it timing, or just somthing simple overlooked (these are always the ones that bite me lol).

glad you got it running

thanks

 

Turns out the timing was off alot, either the distributor was a tooth out or cocked sideways for some reason, i had to swap the plug wires one position.

Grounding that pin in the C207 plug didn't seem to do anything tho. I had to check the books and kinda go through it logically, and test for power along the different spots that send a signal to the starter. Turns out the starter relay was getting power from the car, and gettting a power signal when you turned the key to start, but wasn't grounding out. In the book it said the ground signal goes through the VATS, but Steve (89Vert) disabled the VATS with his chip, so i dont know what's going on there. Possibly still a bad ground somewhere.

But we got it running and driving, so that's a big step ahead.