LT1 swap in my 91 RS
08-20-2012, 04:45 PM
#41
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yeah if the opti was flipped i would have had some cylinder blow out, which i had none. I was thinking the same thing but the guy who did me harness has a very solid reputation for building ls1/lt1 harnesses so Id like to think its not wiring, but one connection being loose or spliced doesnt seem too far fetched so im going to check that out tonight
08-22-2012, 08:43 PM
#42
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Now I have no spark, went to do some testing today and ive got nothing to the plugs and still no pulse on the injectors. Im going to get my ICM tested tomorrow just to rule that out, then Im going to inspect/replace my crankshaft positioning sensor. Ive been doing some reading and it seems that the CPS failing can cause no spark or injector pulse. I looked over the wiring for splices and loose wires but didnt find anything. I havent given it a thorough inspection yet but I want to beleive its not my harness. Ill let you guys know what happens, but im open to more suggestions lol. Im getting frustrated.
08-26-2012, 06:57 PM
#43
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Just tested my wires to my ICM according to shbox.com's diagram. Im getting over 12V to termials "A" and "D". But when I put terminal "B" to ground and crank the engine I get a slight burst of 0.02 V then back to 0.
Then I tested my Opti harness and it reads:
A- 5V
B-5V
C-12.3V
D- 0.05 ground continuity
So according to shbox.com its either my PCM or Opti(or a loose connection/bad wire. But ive checked all those). So I just emailed my tuner to see if he can tell if a PCM is bad while hes tuning it, seeing as I dont have an extra one to test it with, this week im going to take off my opti to see if its lined up on the cam pin correctly.. and i guess well go from there.
Then I tested my Opti harness and it reads:
A- 5V
B-5V
C-12.3V
D- 0.05 ground continuity
So according to shbox.com its either my PCM or Opti(or a loose connection/bad wire. But ive checked all those). So I just emailed my tuner to see if he can tell if a PCM is bad while hes tuning it, seeing as I dont have an extra one to test it with, this week im going to take off my opti to see if its lined up on the cam pin correctly.. and i guess well go from there.
09-07-2012, 07:44 PM
#44
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ok... today I rented a noid light to see if i had fuel injector pulse. Sure enough there was no pulse, so I tested to see if I still had spark so I could narrow it down.. and now I have no spark.... Wtf is going on?.. I took out the optispark and spun the cam sprocket on the opti, and the coil fired and I could hear the injectors firing one by one. So I know it cant be the opti. This is the second time ive had spark and lost it so Im just baffled. Im thinking maybe the PCM but I dont know anyone that has one that would let me borrow it.
Any one have any more suggestions?
Any one have any more suggestions?
09-08-2012, 04:44 PM
#45
Only the 96-97 LT1 has a CPS FYI Your MAF & PCM plus other sensors need to be from the right yrs too OBD1 vs OBD2 My guess is that if all the VATS & other crap is deleted in your PCM, Theres a wiring Gremlin somewhere 
Triple check every last detail
Triple check every last detail
09-09-2012, 09:08 AM
#46
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MAF and PCM are from the donor motor, so both 97, the only thing i have from a B-Body are me PS lines, and Intake manifold, but my rail is off my 97. Im in the process of checking wires but havent found the bug yet.
Yesterday I checked the following pins at the PCM connections with KOEO(key on engine off)
Connector A-
Grounds at A18 & A2: Both were good.
Connector B-
Battery feed @ B15: Good
Ign Feed @ B30: Good
Connector C-
Ground at C32: Good
Connector D-
Engine ground at D1: Good
Ign feed at D3: Good
So it seems my PCM is sending the signal so I dont think its bad. Someone said to check my oil pressure switch because it can cause a no start condition. And if I apply 12v to pin #87 it by-passes my fuel pump relay and also acts as an oil pressure switch. So ill give that a shot next although i dont beleive thats my issue. So what else can cause no spark, and no pulse if its not the opti, and no the PCM?
Yesterday I checked the following pins at the PCM connections with KOEO(key on engine off)
Connector A-
Grounds at A18 & A2: Both were good.
Connector B-
Battery feed @ B15: Good
Ign Feed @ B30: Good
Connector C-
Ground at C32: Good
Connector D-
Engine ground at D1: Good
Ign feed at D3: Good
So it seems my PCM is sending the signal so I dont think its bad. Someone said to check my oil pressure switch because it can cause a no start condition. And if I apply 12v to pin #87 it by-passes my fuel pump relay and also acts as an oil pressure switch. So ill give that a shot next although i dont beleive thats my issue. So what else can cause no spark, and no pulse if its not the opti, and no the PCM?
09-13-2012, 10:55 PM
#49
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Well a little update, I decided to pull my relays and check them out. There are 3 right by the brake booster, which is the way I think Jon does most of his harnesses. They were labeled but I think the tape came off, but one of them has a burn mark on the relay connection and the female connector from the harness.
http://www.flickr.com/photos/8720869...n/photostream/
http://www.flickr.com/photos/8720869...n/photostream/
Its the black/red wire, Im not sure if its crossed or what, I unplugged the relay and turned over the car, and the injector pulsed for a second, then the motor backfired. And after that, even with the new relay installed, got no more pulse. And now right after I prime the pump(according to my fuel pressure guage) I loose all fuel pressure after prime instantly.
And not sure if its relevant, but one of the relays clicks right when the pump is done priming. Even if I swap it with the brand new one. I assume its kicking the fuel pump off after priming but figured id double check.
Im going to check over some wiring threads over the next few days and see whats going on. But i guess you can call that progress
http://www.flickr.com/photos/8720869...n/photostream/
http://www.flickr.com/photos/8720869...n/photostream/
Its the black/red wire, Im not sure if its crossed or what, I unplugged the relay and turned over the car, and the injector pulsed for a second, then the motor backfired. And after that, even with the new relay installed, got no more pulse. And now right after I prime the pump(according to my fuel pressure guage) I loose all fuel pressure after prime instantly.
And not sure if its relevant, but one of the relays clicks right when the pump is done priming. Even if I swap it with the brand new one. I assume its kicking the fuel pump off after priming but figured id double check.
Im going to check over some wiring threads over the next few days and see whats going on. But i guess you can call that progress
09-15-2012, 02:53 PM
#51
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homestly idk if its a wiring gremlin, im starting to think i have a bad PCM. ill do some checking over the weekend.
Anyone ever had this kind of trouble with there lt1, i swear its something small im just not seeing. Fuses and grounds are good
Anyone ever had this kind of trouble with there lt1, i swear its something small im just not seeing. Fuses and grounds are good
09-15-2012, 03:38 PM
#52
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Did some testing on the Black PCM connector on the Opti pins:
(all tested with Key On Engine Off)
Pin 2- Red/Black wire- Dead
Pin 3- Pink/Black wire- Dead
Pin 14- Solid Red wire- Dead
Pin 20- Purple/White wire- Dead
I also picked up a little scan tool to check for codes, and it wont read me the codes. The Check Engine light is supposed to pulse the codes from the dash, and it doesnt blink at all.
Im starting to think maybe the PCM took a crap
(all tested with Key On Engine Off)
Pin 2- Red/Black wire- Dead
Pin 3- Pink/Black wire- Dead
Pin 14- Solid Red wire- Dead
Pin 20- Purple/White wire- Dead
I also picked up a little scan tool to check for codes, and it wont read me the codes. The Check Engine light is supposed to pulse the codes from the dash, and it doesnt blink at all.
Im starting to think maybe the PCM took a crap
11-19-2012, 09:35 PM
#53
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Sorry its been so long since Ive updated, but ive been super super busy at work and had no time to work on it, but I managed to buy a new GM opti off 'tech and a slave cylinder. Tonight I put the opti in, hooked it up and wouldnt you know it......
She fired right up!!!! Oh my gosh I cant describe how awesome it felt to hear her take a deep breath of air!! And boy was it loudd, strait out of the shortiesand im sure the cops are going to show up any minute, lol.
Still have a few things to tie together and things to check out. I only ran it for about 20 seconds, the driver side header heated up, but the pass. side header is cool to the touch. And theres a little bit of smoke out of the pass side header so I probably have a spark problem but ill check it out later, for now im going to watch the Bears beat up the Niners
But thank you to all the people who stuck with me through this long *** process(z28ricer,89454rs thank you so much). But still have a ways to go.
Cheers!
http://www.facebook.com/photo.php?v=534479623247909
She fired right up!!!! Oh my gosh I cant describe how awesome it felt to hear her take a deep breath of air!! And boy was it loudd, strait out of the shortiesand im sure the cops are going to show up any minute, lol.
Still have a few things to tie together and things to check out. I only ran it for about 20 seconds, the driver side header heated up, but the pass. side header is cool to the touch. And theres a little bit of smoke out of the pass side header so I probably have a spark problem but ill check it out later, for now im going to watch the Bears beat up the Niners
But thank you to all the people who stuck with me through this long *** process(z28ricer,89454rs thank you so much). But still have a ways to go.
Cheers!
http://www.facebook.com/photo.php?v=534479623247909
11-20-2012, 06:34 AM
#56
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Yes when in doubt replace the opti, cant beleive thats what it was the whole time
11-21-2012, 11:45 AM
#59
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Ordered O2 sensors and downpipe. one thing is I got a slave cylinder and the clutch master resevoir cracked, and I cant find a replacement anywhere. Seems it only comes as a complete set, anyone know who has them?
