Please help. EFI problems LS1 to LS2 swap
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Joined: Apr 2010
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From: Jacksonville FL
Please help. EFI problems LS1 to LS2 swap
I am currently building a FFR GTM kit car and I am using an LS2 engine and a converted LS1 engine harness. I have done everything that I have read about doing an LS1 to LS2 swap. I am having a few problems.
when I try to start the engine the furl injectors will all spray twice and then stop. They wont spray after those two quick sprays.
and
My fuel rail pressure is about 20psi and I believe its the regulator because I kinked the return from the new filter and the pressure shot up above 80. I believe it has to be above 58.
My fuel pump gets only about 9volts and will only run when the key is in the start position. I am pretty sure I wired everything right but, I could be wrong. I have been rechecking everything.
I didnt know if anyone could give me a list of potential reasons why the fuel injectors only fire twice and then stop.
let me know if you need any more info
when I try to start the engine the furl injectors will all spray twice and then stop. They wont spray after those two quick sprays.
and
My fuel rail pressure is about 20psi and I believe its the regulator because I kinked the return from the new filter and the pressure shot up above 80. I believe it has to be above 58.
My fuel pump gets only about 9volts and will only run when the key is in the start position. I am pretty sure I wired everything right but, I could be wrong. I have been rechecking everything.
I didnt know if anyone could give me a list of potential reasons why the fuel injectors only fire twice and then stop.
let me know if you need any more info
Race Director
Joined: May 2005
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From: West Norriton PA
St. Jude Donor '08
An Ls2 motor uses a 58X reluctor and a LS1 motor uses 24X reluctor. Unless the LS2 motor was a 2005 motor that could be part of the problem.
Also there are some problems with the converter harnesses wires in the "A" and "C" positions being backwards.
Voltage is too low ? and should be at least 12.5 volts.
Also there are some problems with the converter harnesses wires in the "A" and "C" positions being backwards.
Voltage is too low ? and should be at least 12.5 volts.
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Joined: Apr 2010
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From: Jacksonville FL
I have checked to make sure it was a 24t. and the conversion harness I kinda did myself. I has an LS2 and LS1 engine harness, cut and splice them together the way they should go. I have been double checking the crank position one a few times because that seems like it could be the cause.
And ajg1915 you offered an LS3 to me a little late. if I would have seen that offer before I got the LS2 I would have went for it instead, thanks you are a good man.
I am seeming to having another little issue with my obd2. I decided to try it to see if it will help. It gets power but no connection. I have it connected to a wire that goes into the number 58 spot on the PCM. Its for serial data on the pinout. I checked everything. power grounds and connection, but it still wont work. The OBD2 just lights up and says it couldnt connect, ensure car switch is in the on poistion.
This is getting troublesome.
And ajg1915 you offered an LS3 to me a little late. if I would have seen that offer before I got the LS2 I would have went for it instead, thanks you are a good man.
I am seeming to having another little issue with my obd2. I decided to try it to see if it will help. It gets power but no connection. I have it connected to a wire that goes into the number 58 spot on the PCM. Its for serial data on the pinout. I checked everything. power grounds and connection, but it still wont work. The OBD2 just lights up and says it couldnt connect, ensure car switch is in the on poistion.
This is getting troublesome.
Race Director
Joined: May 2005
Posts: 15,960
Likes: 21
From: West Norriton PA
St. Jude Donor '08
What year harness did you use and what year PCM did you use ?
If you used an early 97-98 harness and a later PCM that could be your problem. There are so many variables that you have to deal with when you build these kit cars and the information provided is not always the best.
The LS3 ended up going to a good home.
You should also be using a LS2 throttle body and not a LS3 one.
If you used an early 97-98 harness and a later PCM that could be your problem. There are so many variables that you have to deal with when you build these kit cars and the information provided is not always the best.
The LS3 ended up going to a good home.
You should also be using a LS2 throttle body and not a LS3 one.
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Joined: Apr 2010
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From: Jacksonville FL
I bought the harness and pcm used from the same car. I read somewhere that the crankshaft position indicator will cause the problems that I am having and may somehow cause the obd2 not to work on some vehicles. I am going to buy a new one and see if that does it.
Burning Brakes
Joined: Mar 2008
Posts: 983
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From: Middle Of Kali CA
I have checked to make sure it was a 24t. and the conversion harness I kinda did myself. I has an LS2 and LS1 engine harness, cut and splice them together the way they should go. I have been double checking the crank position one a few times because that seems like it could be the cause.
And ajg1915 you offered an LS3 to me a little late. if I would have seen that offer before I got the LS2 I would have went for it instead, thanks you are a good man.
I am seeming to having another little issue with my obd2. I decided to try it to see if it will help. It gets power but no connection. I have it connected to a wire that goes into the number 58 spot on the PCM. Its for serial data on the pinout. I checked everything. power grounds and connection, but it still wont work. The OBD2 just lights up and says it couldnt connect, ensure car switch is in the on poistion.
This is getting troublesome.
And ajg1915 you offered an LS3 to me a little late. if I would have seen that offer before I got the LS2 I would have went for it instead, thanks you are a good man.
I am seeming to having another little issue with my obd2. I decided to try it to see if it will help. It gets power but no connection. I have it connected to a wire that goes into the number 58 spot on the PCM. Its for serial data on the pinout. I checked everything. power grounds and connection, but it still wont work. The OBD2 just lights up and says it couldnt connect, ensure car switch is in the on poistion.
This is getting troublesome.
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Joined: Apr 2010
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From: Jacksonville FL
I just found this forum. Doc99ss was having the exact same symptoms I was having.
I am going to see if the cause is the pcm not correctly grounded. It seemed to fix it for him
http://www.ls1tech.com/forums/pcm-di...t-start-5.html
I am going to see if the cause is the pcm not correctly grounded. It seemed to fix it for him
http://www.ls1tech.com/forums/pcm-di...t-start-5.html
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St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
I just found this forum. Doc99ss was having the exact same symptoms I was having.
I am going to see if the cause is the pcm not correctly grounded. It seemed to fix it for him
http://www.ls1tech.com/forums/pcm-di...t-start-5.html
I am going to see if the cause is the pcm not correctly grounded. It seemed to fix it for him
http://www.ls1tech.com/forums/pcm-di...t-start-5.html
Thread Starter
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Joined: Apr 2010
Posts: 58
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From: Jacksonville FL
Well I moved some Battery power connectors on the starter and now the OBDii and the Fuel pump works perfect.
The only problem now is the fuel injectors. Does anyone know what will cause the injectors to pulse twice and then stop?
the only thing I can see wrong with this car is the MAP sensor. its reading 31 "HG when the car is not running. I took it out and blew in it and it read 31.7
I plugged it in my friends GTO and is it worked fine. I dont think it would cause the car not to start.
thank you for helping me with this. I need my FFR GTM to come to life
The only problem now is the fuel injectors. Does anyone know what will cause the injectors to pulse twice and then stop?
the only thing I can see wrong with this car is the MAP sensor. its reading 31 "HG when the car is not running. I took it out and blew in it and it read 31.7
I plugged it in my friends GTO and is it worked fine. I dont think it would cause the car not to start.
thank you for helping me with this. I need my FFR GTM to come to life
Pro
Joined: Mar 2004
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Did you have VATS disabled in the PCM? Your symptoms sound a lot like VATS kicking in and shutting down the injectors.
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From: Jacksonville FL
I would think it would run for a few seconds first before it would shutoff do to VATs
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From: West Norriton PA
St. Jude Donor '08
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From: Jacksonville FL
well I am pretty sure that the VATS has been removed. I am trying to see if I can find someone with a 98 vette so I can see if my pcm is the culprit. If it doesnt work in their car, then either the vats has not been removed by the people who I sent it to twice or the pcm is bad. I dont think either of those cases are likely.
I think that the wiring for the fuel injectors maybe be backwards. I am double checking that now. I had to reverse the intake manifold and the valve covers. I am running out of ideas.
I think that the wiring for the fuel injectors maybe be backwards. I am double checking that now. I had to reverse the intake manifold and the valve covers. I am running out of ideas.
Pro
Joined: Mar 2004
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On my 2001 harness, the injector connector hoods have a number stamped and colored on the intake-facing side of each hood...1 through 8. Hard to see while they're in place, but clearly visible when the connector is unclipped from the injector.
Check yours, maybe the '98 harness has this too.
Also, I have read posts where people had the coil harnesses + coils installed on the opposing cylinder banks and it caused problems. Not sure if your '98 can do this but it might be worth checking or testing by swapping the harnesses side-to-side.
Check yours, maybe the '98 harness has this too.
Also, I have read posts where people had the coil harnesses + coils installed on the opposing cylinder banks and it caused problems. Not sure if your '98 can do this but it might be worth checking or testing by swapping the harnesses side-to-side.
Race Director
Joined: May 2005
Posts: 15,960
Likes: 21
From: West Norriton PA
St. Jude Donor '08
well I am pretty sure that the VATS has been removed. I am trying to see if I can find someone with a 98 vette so I can see if my pcm is the culprit. If it doesnt work in their car, then either the vats has not been removed by the people who I sent it to twice or the pcm is bad. I dont think either of those cases are likely.
I think that the wiring for the fuel injectors maybe be backwards. I am double checking that now. I had to reverse the intake manifold and the valve covers. I am running out of ideas.
I think that the wiring for the fuel injectors maybe be backwards. I am double checking that now. I had to reverse the intake manifold and the valve covers. I am running out of ideas.
Have you plugged a code reader to the OBD port to see if you're throwing any codes ?
Hopefully its just the wiring is backwards.
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Joined: Apr 2010
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From: Jacksonville FL
http://www.supraforums.com/forum/sho...504-IGF-signal
Does the ls2 in the corvette have anything like this?
I see other cars with a similar problem and they say its lack of an IGF signal.
I just dont see an igniter.
does anything tell the computer that there has been ignition?
Does the ls2 in the corvette have anything like this?
I see other cars with a similar problem and they say its lack of an IGF signal.
I just dont see an igniter.
does anything tell the computer that there has been ignition?
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Joined: Apr 2010
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From: Jacksonville FL
I am getting absolutely no codes. I was getting one for MAP sensor. but that is fixed. Is there any codes for VATS?
I sent it to have it removed twice but you guys are right, it is the same symptoms.
Is there anyway to verify its off vice plugging the pcm in another car?
I sent it to have it removed twice but you guys are right, it is the same symptoms.
Is there anyway to verify its off vice plugging the pcm in another car?
Thread Starter
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Joined: Apr 2010
Posts: 58
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From: Jacksonville FL
What year harness did you use and what year PCM did you use ?
If you used an early 97-98 harness and a later PCM that could be your problem. There are so many variables that you have to deal with when you build these kit cars and the information provided is not always the best.
If you used an early 97-98 harness and a later PCM that could be your problem. There are so many variables that you have to deal with when you build these kit cars and the information provided is not always the best.
