Hey, i had a question about the injector wiring first off. When i unplugged one, both sides(wires) had 12v when the key was in the on position. I thought the ecm grounded one side? Is this what is causing my car to only be able to start for like 2seconds with some starter fluid? Its a 86' TPI with a 400ci under it. Car was converted to TPI with use of a 86 harness.

 

After testing my dads injector wires for 12v on his 91 corvette they both had 12v as well in key on. So apparently that isnt the problem. It seems to me that the ecm isnt grounding the injectors. What should i check to confirm this?

 

Just put a noid light on one of the injector connectors. Cranked it over and it didnt light up or flash at all. Tryed the two front driver side ones when i did this. Im pretty sure the ign module is good because the fuel pump kicks on with just a bump of the starter. Meaning it is getting the rpm referance pulse. Anyone have any ideas?

 

Fuel pump has nothing to do with the ign module; runs directly off the ECM key on before the engine even cranks over
or the OP switch once 4psi is reached
if you have no dist ref signal when cranking ;pump will still be running from the OP switch

Was engine running before or is this a fresh start?

Pull the ECM codes and see if anything is showing.
Check TPS voltage ; too high and it will shut down injectors

 

Its a fresh start. Bought the car without a motor. Put the 400 in with the tpi on it and installed a 86' wiring harness. I will go attempt to check the codes and check the TPS voltage. Im not 100% sure if i can check the code since there is still one wire i need to run to the Aldl connector from the C221(i believe thats the right one) connector. But i will go try that now and get back to you.

 

Ok, just checked the ecm. It isnt connecting. Most likely because of that wire i still havent run to the aldl connector. But i went ahead and made some jumpers and checked the TPS. It looked to be right around .5_ and was smack dab on 4.0 at WOT. So that appears to be fine.

 

That is correct. If the ECM re-enables the FP for 2 seconds with the starter being bumped the ECM is receiving reference pulses from the distributor.

Which MEMCAL is in the ECM may be the issue. In '89 f-bodys got VATs which will prevent the injectors from firing. The y-body's received VATs in earlier years.

RBob.

 

I had a 87 corvette prom in it first. But I read up on it and they got vats in 86' so I put the prom that came with the ECM. It's a 86 305 prom so no vats there. Last night I read to take the distributors 4 pin connector off and on the harness side apply 12v to the purple/wht wire with key on to check the injectors. Sure enough the passenger side injectors sounded like they were clicking. Popped the noid like in and they were blinking if I tapped the 12v to the wire. But the drivers side wasn't clicking or blinking??? So I double checked the DS and made sure they had 12v and both sides on the connectors did. So now this morning I'm going to try and crank it over with the noid light on the passenger side to confirm if the dizzy is giving the refference signal.

Any thoughts on why the driver side didn't blink when I did the test?

 

So the passenger side injectors are all firing, or trying to. The noid light blinks on a passenger side injector connector when the engine is cranked over. So I assume that rules out the distributor having any problems since that means it is sending its reference pulse for sure now.
As long as i am right on my assumption, what is making only one bank of injectors fire? They all test out fine when i check them with a ohm meter. They are above .10 and are all right around eachother. Im using an analog multitester so i dont know for sure exactly what they are at, i just know its above .1 and closer to .2 so lets go with .17-.18ish.

 

bad injector driver in the ecm. check connector d15 and d16 and your grounds.

 

The grounds are fine. Ive checked all the ecm grounds at the ecm connector. What do i need to check on D15 and D16? Also, with one side of the injectors working doesnt that mean the injector driver works as well? Or are there separate drivers for both banks? Thanks for the response

 

Check the connection at d 15 and d 16, I think the 165 has two quad drivers u3 and u6. I'm not sure if a bad icm could cause this even though you have pulse on one side. I'm always learning and mr rbob is a wealth of knowledge on gm ecm's. check both injector fuses.

 

I just check both those connectors, D16 has 12v and D15 doesnt. Thats with the key on. Both injector fuses are good. I also did an ohm test on every injector to see if there was a break in the line. All of the driverside injectors ohmd out fine on D15 and all of the Passenger side injectors ohmd out fine on D16. Why doesnt D15 have 12v?

 

d15 and d16 should have 12v koeo and 13.9v or so engine running. the ecm grounds d15 and to fire the injectors

I know this pic is for a 89 but it's the same 86-89

http://home.earthlink.net/~gellett/89wiring.gif

 

So if both D15 and D16 should have 12v key on, then what would be the cause if only D16 had the 12v but D15 ohms fine with all the DS injectors?

 

sounds like a open in the wire from the injector #2 fuse pink-black to the ecm pin d16. There is a grey connector by the ecm if I recall correctly that the injector power wire run through.

 

http://www.chevythunder.com/fuel%20i....%20pg%20C.htm

look at the picture at the bottom of the page.

 

I had to add fuses for that. On the fuse side, both have 12v.

 

Well i got it to start firing all the injectors. Or at least the noid light...it still doesnt want to start. It trys so hard and can here it trying to fire and live but it just cant do it. Im thinkin its dirty injectors since they had sat for several years. Im hoping if i put some seafoam in with the gas and tap them some maybe it will get clean enough to start up. I will also be getting a fuel pressure tester while im at oriellys returning the noid lights just to make 100% sure i have enough pressure. Even though its a new pump i want to know for sure that it is working correctly.

 

What size injectors are you using 30#hr with a adjustable fuel pressure regulator?

 

I want that size lol but its still running the stock 22?# with the stock regulator. This setup minus the harness/ecm/prom ran in my dads 79 blazer. I just want to get it to the point of running, then i will start getting the afpr and bigger injectors plus a tune. It wants to start sooo bad right now. But its only firing on 1 cyclinder on the PS and 2 on the DS. Im leaving for a bit but when i get back i will be checking the plugs for spark and cleaning them all up.

 

they would be #19 from a 305 #22 from a 350, when you go to buy new ones check out southbayinjectors.com the give a 10% discount to members. What was the injector power issue?

 

Thats exactly who i was wanting to go through for the injectors. I guess that means it has the 19# injectors to unfortunately.But anyways I had been underneith the dash on that side of the car checking some things and my head disconnected the wires i have running to that little grey connector for the injector/fan power. Well i plugged it back in not really thinking and i guess i misjudged the color making one of them going to the fan. Well since i havent wired up my fan yet that left that bank of injectors to not have power. Little mistakes like that are what get you every time lol.

 

do you need may address to send the six pack too, lol

 

stuck injectors are a very good possibility. sitting without fuel they can start sticking in just a couple of months. when i put my TPI motor in my Monte Carlo the motor sat for less than 6 months and most if not all of the injectors were stuck. i used an injector tester to fire the injectors while i tapped on them.

 

hi im new here but long story short ive done everything previously said my d16 no power koeo d15 ok both grounds are fine also power to fuses and fuses check out where is this grey plug? other then the mysterious grey plug im going to trace the light green wire for open then its ecm? what did i miss????

 

Are you asking about c207 ? Where is power lost ?

 

im not sure what c207 is but yes this is the diagram im working off of d16 is passenger side no injector pulse no power to d16 lt grn/blk koeo plug probed off of ecm

 

Power at the injector plugs ? Or just at the fuse ? C207 is the plug next to the ecm that power to ecm, injector power etc

 

power at both pins each injector all 8 engine runs only on bank 1

 

Have you checked the splice if you don’t have power back at the ecm ?

 

im guessing the splice is tracing the light green/black wire back from the injectors? lol the car in question is a 1987 corvette my info is from a shop manual from a 1987 trans am (my wifes) she bought it new is c207 actually a grey plug? i looked pretty good and didnt see it

 

This is a 3rd gen f body forum. I don’t think c207 is the same connector on a Y body. The splice is by the distributor in the loom. If you have power there ohm the wire it probably has a break .

 

ok thx so ohm the wire? im green on this

 

yes ohm the wire checking for continuity

 

ok thx my next move is to do just that i need to get into that harness im hoping to find a break

 

thanks for the info i appreciate it so yup it was the splice in the loom under some black duck tape totally disconnected so the light green/black (D16 ) broke off from the injector cluster i crimped it quick just to see and it fired right up! so if your still with me one of the injectors ohm at 8.2 the rest were 16 ohm is this my slight miss/running slightly rough?

 

Contact Southbayfuelinjectors, I’d get their Delphis . Good plug and play choice