1998 LS1 not starting ?
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From: Kansas City
1998 LS1 not starting ? Hello my fellow Forum members, most of you know me as " Henry " and I am in need of help !
1998 T/A LS1 V8 into a 1978 Caprice 2 door "Aero Coupe "
The car is still not getting any spark/fuel signals.
- The PCM is good ( VATS and Emission removed ), and ran Prefect in a friends Trans Am.
- The Crank Sensor was Replaced with a known good one.
- The Tach is hooked up yet it doesnt show RPM when motor cranks ?
- Harness wires all check out ok.
Its like the engine doesnt know there is any RPM's so it doesnt fire Spark or Fuel ?
Any ideas on what we could have missed or over looked ?
1998 T/A LS1 V8 into a 1978 Caprice 2 door "Aero Coupe "
The car is still not getting any spark/fuel signals.
- The PCM is good ( VATS and Emission removed ), and ran Prefect in a friends Trans Am.
- The Crank Sensor was Replaced with a known good one.
- The Tach is hooked up yet it doesnt show RPM when motor cranks ?
- Harness wires all check out ok.
Its like the engine doesnt know there is any RPM's so it doesnt fire Spark or Fuel ?
Any ideas on what we could have missed or over looked ?
Do you hear the fuel pump run for the usual two seconds when you first turn on the ignition? Have you checked to see if there is voltage going to the coil packs when the ignition is on?
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From: Kansas City
Originally Posted by LS1MCSS
Do you hear the fuel pump run for the usual two seconds when you first turn on the ignition? Have you checked to see if there is voltage going to the coil packs when the ignition is on?
- The Ign Coil Packs have voltage when the Ign is on.
- From what the installer is saying its like the PCM isnt recognizing the engine is rotating, because the Signal to the Tach isnt showing RPM either, and if the PCM doesnt know see RPM's its not going to Fire the Coils/Injectors.
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From: Kansas City
Originally Posted by Kamin
then that would be a crank position sensor problem. either with the sensor itself or the wiring.
- Harness wires to and from the Crank Sensor all check out ok.
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From: Kansas City
Originally Posted by Rodder
Actually, most swaps do fire right up on the first try...
what codes are you throwing? do you have power to the coils and injectors?
what codes are you throwing? do you have power to the coils and injectors?
The Coils and Injectors are both getting Power, but from what the installer has told me, they are powered all the time, but only "Wire" when the PCM sends a Ground to the Coil or Injector. The Tach isnt showing RPM's so its like the PCM doesnt know the engine is turning over and that it needs to fire the Coils/Injectors. He replaced the Crank Sensor with one from a running car, and the wires two and from the sensor checked out ok.
Its very strange.
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What tach are you using? Where are you getting the signal?
In my '02 SS with the factory tach I don't see anything register until after the motor fires. My thought is that it may be normal for it to not register until a specific event happens.
In my '02 SS with the factory tach I don't see anything register until after the motor fires. My thought is that it may be normal for it to not register until a specific event happens.
have you had the pcm benched tuned??? That and the crankshaft pos. senser was my problem in my swap,,, look at the coil grounds and the camshaft pos. sensor, just over look all your grounds dubble look the wiring you might have some thing crossed over..
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From: Kansas City
Originally Posted by Rhino
What tach are you using? Where are you getting the signal?
In my '02 SS with the factory tach I don't see anything register until after the motor fires. My thought is that it may be normal for it to not register until a specific event happens.
In my '02 SS with the factory tach I don't see anything register until after the motor fires. My thought is that it may be normal for it to not register until a specific event happens.
Originally Posted by greenfbodyracer
have you had the pcm benched tuned??? That and the crankshaft pos. sensor was my problem in my swap,,, look at the coil grounds and the camshaft pos. sensor, just over look all your grounds double look the wiring you might have some thing crossed over..
We suspected the Crank Sensor too, but we removed one from a car that runs, and it still didn't work. We also suspected it was the PCM and it started up a friends 98 T/A and ran perfect with no lights or codes or anything. They have traced and checked the grounds. Will a car run/start with a bad Cam Sensor ? One of the people that has been helping on the project has also said that sometimes the Crank Relcutor Ring can get damaged/falloff/break causing the Crank Sensor not to work ? The installer looked and its on the crank but he said it is scratched up and such. Whatcha think ?
Originally Posted by KC Henry
I never really thought to ask a LS1 owner about that before. ha ha
I guess I can't say my car takes too long to start (maybe half to a full second?) but I don't remember the tach moving.Unfortunately, the easiest diagnosis would be pulling codes. Have you tried any of the u-pull it's in the area? Another thought is finding someone parting out a car. There were a few people parting out cars on the mofbody forum. Surely someone would take $5 for the OBD port. You can't even get a burger value meal for that anymore. I'd be happy to try to walk you through getting it wired up if you're feeling up to it.
I think that money will be well worth it in the long run.
Troubleshooting these things really requires a scan tool of some sort (not just a code reader, but an actual scan tool). You're shooting in the dark without one... a code reader would be better than nothing though.
My money is on a wiring problem... either a problem in an aftermarket/modified harness, or something your installer screwed up. Is this a complete aftermarket harness, a modified harness, a stock harness with an aftermarket adapter, or what? some of the cheap adapter harnesses that were on ebay for a while were notorious for having wires mixed up.
My money is on a wiring problem... either a problem in an aftermarket/modified harness, or something your installer screwed up. Is this a complete aftermarket harness, a modified harness, a stock harness with an aftermarket adapter, or what? some of the cheap adapter harnesses that were on ebay for a while were notorious for having wires mixed up.
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From: Kansas City
Originally Posted by Rhino
I'm just throwing out ideas. I guess I can't say my car takes too long to start (maybe half to a full second?) but I don't remember the tach moving.
Unfortunately, the easiest diagnosis would be pulling codes. Have you tried any of the u-pull it's in the area? Another thought is finding someone parting out a car. There were a few people parting out cars on the mofbody forum. Surely someone would take $5 for the OBD port. You can't even get a burger value meal for that anymore. I'd be happy to try to walk you through getting it wired up if you're feeling up to it.
I think that money will be well worth it in the long run.
I guess I can't say my car takes too long to start (maybe half to a full second?) but I don't remember the tach moving.Unfortunately, the easiest diagnosis would be pulling codes. Have you tried any of the u-pull it's in the area? Another thought is finding someone parting out a car. There were a few people parting out cars on the mofbody forum. Surely someone would take $5 for the OBD port. You can't even get a burger value meal for that anymore. I'd be happy to try to walk you through getting it wired up if you're feeling up to it.
I think that money will be well worth it in the long run.
I will have to find time to put one on though, I bet it would make things much much easier.
Originally Posted by Rodder
Troubleshooting these things really requires a scan tool of some sort (not just a code reader, but an actual scan tool). You're shooting in the dark without one... a code reader would be better than nothing though.
My money is on a wiring problem... either a problem in an aftermarket/modified harness, or something your installer screwed up. Is this a complete aftermarket harness, a modified harness, a stock harness with an aftermarket adapter, or what? some of the cheap adapter harnesses that were on ebay for a while were notorious for having wires mixed up.
My money is on a wiring problem... either a problem in an aftermarket/modified harness, or something your installer screwed up. Is this a complete aftermarket harness, a modified harness, a stock harness with an aftermarket adapter, or what? some of the cheap adapter harnesses that were on ebay for a while were notorious for having wires mixed up.
I really hope its something like a bad wire or something cheap/easy and not something that would mean tearing apart the motor like a bad Crank Sensor Reluctor Ring on the crankshaft.
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From: Dover Arkansas
It's only a serial data wire to plug in to the pcm plug and a constant battery power and 2 grounds to connect the scan plug. You could get all that at a junk yard cheap, with wires attached. Just mount temporary in engine compartment to get your problem fixed. Good luck.
A little more information on this swap since I saw the car the other day and went over the wiring to help double check everything.
Coil packs have power, pcm has power, injectors have power, sensors have power. Checked continuity from the pcm to the CPS, coil packs, etc, checked all grounds and everything has a good connection. Car has no signal(purple wire on coil packs and ground wires on injectors). We did try a different CPS that we know was from a good working car and am working on getting a cam position sensor. If Henry can come up with the money for a ALDL connector it wouldn't take anytime at all to wire it up and would probably make troubleshooting this issue a lot easier.
Coil packs have power, pcm has power, injectors have power, sensors have power. Checked continuity from the pcm to the CPS, coil packs, etc, checked all grounds and everything has a good connection. Car has no signal(purple wire on coil packs and ground wires on injectors). We did try a different CPS that we know was from a good working car and am working on getting a cam position sensor. If Henry can come up with the money for a ALDL connector it wouldn't take anytime at all to wire it up and would probably make troubleshooting this issue a lot easier.
Originally Posted by skinnies
A little more information on this swap since I saw the car the other day and went over the wiring to help double check everything.
Coil packs have power, pcm has power, injectors have power, sensors have power. Checked continuity from the pcm to the CPS, coil packs, etc, checked all grounds and everything has a good connection. Car has no signal(purple wire on coil packs and ground wires on injectors). We did try a different CPS that we know was from a good working car and am working on getting a cam position sensor. If Henry can come up with the money for a ALDL connector it wouldn't take anytime at all to wire it up and would probably make troubleshooting this issue a lot easier.
Coil packs have power, pcm has power, injectors have power, sensors have power. Checked continuity from the pcm to the CPS, coil packs, etc, checked all grounds and everything has a good connection. Car has no signal(purple wire on coil packs and ground wires on injectors). We did try a different CPS that we know was from a good working car and am working on getting a cam position sensor. If Henry can come up with the money for a ALDL connector it wouldn't take anytime at all to wire it up and would probably make troubleshooting this issue a lot easier.
