Lt1? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Wootdog · 01-09-2004, 02:52 PM

Went to fire up the LT1 for the first time and no spark out of the coils. I measured the resistances on the coil pack and they were good. But I went and bought a new coil pack anyway. Saw that the ignition module had a crack in it, so I got a new one. Still no spark. I have the 12 vdc on pins A and D like I am supposed to going to the module I replaced. I do not have a pulsing voltage above 0.7 vdc.on pin B. According to sources it is supposed to have at least 4 vac pulsing. It is supposedlly wiring or the computer. I tried to acquire a new computer here locally. I was told the computer would be slicked and I would need a VIN to load the program. I don't have a VIN because it is not in the Corvette the engine came from. And of course no one around here can bench test the computer. It has to be in the vehicle. The vehicle is not possible to move at this time. What to do LT1 experts? Thanks in advance Wootdog

71Rat · 01-09-2004, 03:17 PM

i haven't had an lt1 in a car that it didn't come with but my friend put one into a grand prix and when he tryed to start it, it wouldnt start later to find out that the crank position sensor was bad. i am sorry i don't know of anything to help you besides that little tid bit or try to find someone who also has an lt1 that is still computer controled and try and swap the computers....... my friend also did that, his motor came out of a camaro and his dad had a 96 caprice classic. best of luck!

Locutus · 01-09-2004, 03:57 PM

You might consider an aftermarket computer such as the Holley Commander 950 or the numerous other options. It eliminates security features such as VATS. It also comes with wiring harnesses and instructions for wiring it into the car. Thats how my friend put a TPI engine into a 1978 Datsun 280Z. He wired it in a day and started the car that night. Played with the fuel maps and had it tuned in a week. The other BIG advantage is you can tune it with a laptop no need to pull a chip and burn a new map. You can store different maps. One for street, one for long hauls and gas mileage, and one for high performance. Its all up to you.

Mike

meathead95 · 01-09-2004, 04:44 PM

Locutus
do you have a link where to get this computer and harness your friend used? I am getting ready to put a tpi 350 in my 72 and you just made it sound awfull easy

Mark540 · 01-09-2004, 04:57 PM

What wiring harness are you using? Do you have the Factory Manual for the car the engine came out of? If not it will be very helpful to the swap cause. The Holley Commander is great, but you'll spend more on that than you do on your engine. Goto ImpalassForum.com, these guys will help you through it. Bryan Herter can check your PCM and program it cheaply for you as well, link is on the Impala site PCMforless.

Wootdog · 01-09-2004, 06:19 PM

Street and Performance. I sent the computer back to them an hour ago (It is one of theirs). They told me they would check it out. Will keep you all posted. Man I was so close to getting it running it is kind of frustrating. Wootdog

mcmlxix · 01-09-2004, 06:34 PM

I will be doing the same thing. I already have a stock harness and computer out of a 96 Caprice. S&P is one of the vendors I was thinking of having mod my harness ... keep us posted on their work ...

PS. they shoudl have programmed it for VATS .. Vehicle Anti Theft System .. if it wasn't disabled ... it shuts the system down .. kills the injectors i thought .. but not sure ...

Mark540 · 01-09-2004, 07:15 PM

With VATS not working properly the car will start, but die after a few seconds.

Quagmire · 01-09-2004, 07:57 PM

Will I need to modify my stock computer or change chips?

Since 1989, most GM fuel injection systems incorporate a Vehicle Anti-Theft System programmed into the stock EPROM or PCM. This means the engine will not run if it is transplanted into a vehicle without the original vehicle steering column and decoder module.

http://www.painlessperformance.com/catalogframe.htm

will the motor start at all?

Wootdog · 01-09-2004, 08:57 PM

on a street and performance computer if you want it that way. This engine was in this truck before. but all the wiring but the computer harness has been upgraded via painless wiring. Wootdog

Wootdog · 01-17-2004, 01:02 AM

got it running after work. Even after I got the computer back this morning, I still couldn't get it to fire. I then called them back (Street and Performance the guys name is Lambert) and he helped me out big time. You have to have a keyed 12 vdc input that doesn't drop below 10.5 vdc for the computer to work when you crank the engine. After I found a spot in the fuse panel that wouldn't dip below that voltage, the truck fired right up. It is so close to being on the road. Thanks to all of you good people who have helped me out with answers to my many questions. Time for a Budweiser. (Why do you think they call them taste buds anyway). Wootdog

01-09-2004, 02:52 PM	#1
Wootdog Senior Member Join Date: Jan 2001 Location: Virginia Beach, Va, USA Posts: 1,676	Lt1? Went to fire up the LT1 for the first time and no spark out of the coils. I measured the resistances on the coil pack and they were good. But I went and bought a new coil pack anyway. Saw that the ignition module had a crack in it, so I got a new one. Still no spark. I have the 12 vdc on pins A and D like I am supposed to going to the module I replaced. I do not have a pulsing voltage above 0.7 vdc.on pin B. According to sources it is supposed to have at least 4 vac pulsing. It is supposedlly wiring or the computer. I tried to acquire a new computer here locally. I was told the computer would be slicked and I would need a VIN to load the program. I don't have a VIN because it is not in the Corvette the engine came from. And of course no one around here can bench test the computer. It has to be in the vehicle. The vehicle is not possible to move at this time. What to do LT1 experts? Thanks in advance Wootdog __________________ 1969 Chevelle 1990 IROC Z Convertible 2002 Silverado LT

01-09-2004, 03:17 PM	#2
71Rat ran out of money Join Date: Apr 2003 Location: northern, NJ Posts: 925	i haven't had an lt1 in a car that it didn't come with but my friend put one into a grand prix and when he tryed to start it, it wouldnt start later to find out that the crank position sensor was bad. i am sorry i don't know of anything to help you besides that little tid bit or try to find someone who also has an lt1 that is still computer controled and try and swap the computers....... my friend also did that, his motor came out of a camaro and his dad had a 96 caprice classic. best of luck! __________________ Modify everything, leave nothing alone!~

01-09-2004, 04:44 PM	#4
meathead95 computer illiterate Join Date: Jan 2001 Location: Des Moines, IA Posts: 6,446	Locutus do you have a link where to get this computer and harness your friend used? I am getting ready to put a tpi 350 in my 72 and you just made it sound awfull easy __________________ 72 2wd blazer 72 swb 4x4

01-09-2004, 04:57 PM	#5
Mark540 Registered User Join Date: Feb 2003 Location: Fairborn,OH Posts: 203	What wiring harness are you using? Do you have the Factory Manual for the car the engine came out of? If not it will be very helpful to the swap cause. The Holley Commander is great, but you'll spend more on that than you do on your engine. Goto ImpalassForum.com, these guys will help you through it. Bryan Herter can check your PCM and program it cheaply for you as well, link is on the Impala site PCMforless. __________________ 1970 GMC Burb 4x4 - 68 Chevy Front, FI LT1, 4L60E 1970 Chevy Impala 47,000 miles 2001 BMW 540i 6-speed 2002 Dodge Ram 1500 4x4 w/20's

01-09-2004, 06:19 PM	#6
Wootdog Senior Member Join Date: Jan 2001 Location: Virginia Beach, Va, USA Posts: 1,676	Wiring harness is a Street and Performance. I sent the computer back to them an hour ago (It is one of theirs). They told me they would check it out. Will keep you all posted. Man I was so close to getting it running it is kind of frustrating. Wootdog __________________ 1969 Chevelle 1990 IROC Z Convertible 2002 Silverado LT

01-09-2004, 03:57 PM	#3
Locutus Registered User Join Date: Jan 2003 Location: Santa Fe, Texas Posts: 250	You might consider an aftermarket computer such as the Holley Commander 950 or the numerous other options. It eliminates security features such as VATS. It also comes with wiring harnesses and instructions for wiring it into the car. Thats how my friend put a TPI engine into a 1978 Datsun 280Z. He wired it in a day and started the car that night. Played with the fuel maps and had it tuned in a week. The other BIG advantage is you can tune it with a laptop no need to pull a chip and burn a new map. You can store different maps. One for street, one for long hauls and gas mileage, and one for high performance. Its all up to you. Mike

01-09-2004, 06:34 PM	#7
mcmlxix Collector of Projects Join Date: Apr 2003 Location: Las Vegas Posts: 3,106	I will be doing the same thing. I already have a stock harness and computer out of a 96 Caprice. S&P is one of the vendors I was thinking of having mod my harness ... keep us posted on their work ... PS. they shoudl have programmed it for VATS .. Vehicle Anti Theft System .. if it wasn't disabled ... it shuts the system down .. kills the injectors i thought .. but not sure ... __________________ Rich 1972 K5 Blazer CST Click HERE D60 BIG BRAKE UPGRADE Click HERE

01-09-2004, 07:15 PM	#8
Mark540 Registered User Join Date: Feb 2003 Location: Fairborn,OH Posts: 203	With VATS not working properly the car will start, but die after a few seconds. __________________ 1970 GMC Burb 4x4 - 68 Chevy Front, FI LT1, 4L60E 1970 Chevy Impala 47,000 miles 2001 BMW 540i 6-speed 2002 Dodge Ram 1500 4x4 w/20's

01-09-2004, 07:57 PM	#9
Quagmire A splendid one to behold Join Date: Jan 2004 Location: moore, ok Posts: 251	Will I need to modify my stock computer or change chips? Since 1989, most GM fuel injection systems incorporate a Vehicle Anti-Theft System programmed into the stock EPROM or PCM. This means the engine will not run if it is transplanted into a vehicle without the original vehicle steering column and decoder module. http://www.painlessperformance.com/catalogframe.htm will the motor start at all? __________________ 67 swb 02 wrx

01-09-2004, 08:57 PM	#10
Wootdog Senior Member Join Date: Jan 2001 Location: Virginia Beach, Va, USA Posts: 1,676	vats is turned off on a street and performance computer if you want it that way. This engine was in this truck before. but all the wiring but the computer harness has been upgraded via painless wiring. Wootdog __________________ 1969 Chevelle 1990 IROC Z Convertible 2002 Silverado LT

01-17-2004, 01:02 AM	#11
Wootdog Senior Member Join Date: Jan 2001 Location: Virginia Beach, Va, USA Posts: 1,676	IT LIVES got it running after work. Even after I got the computer back this morning, I still couldn't get it to fire. I then called them back (Street and Performance the guys name is Lambert) and he helped me out big time. You have to have a keyed 12 vdc input that doesn't drop below 10.5 vdc for the computer to work when you crank the engine. After I found a spot in the fuse panel that wouldn't dip below that voltage, the truck fired right up. It is so close to being on the road. Thanks to all of you good people who have helped me out with answers to my many questions. Time for a Budweiser. (Why do you think they call them taste buds anyway). Wootdog __________________ 1969 Chevelle 1990 IROC Z Convertible 2002 Silverado LT



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