LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Engine swap almost done but engine dies???

Old 07-18-2004, 02:53 PM
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Engine swap almost done but engine dies???

I have almost completed my engine swap in my mercedes but as i started it for the first time it cranked over a few times fired up and then about 2-3 seconds later it dies? I does this every time i start it. The amount of throttle % doesn't change it and the fuel pump turns on when i go to ignition then when i crank it over and stays on, so i don't think its a fuel problem.


Thanks,
Maurice
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Old 07-18-2004, 04:21 PM
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Re: Engine swap almost done but engine dies???

Checked for vacuum leaks?
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Old 07-18-2004, 05:09 PM
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Re: Engine swap almost done but engine dies???

Vats?
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Old 07-18-2004, 06:00 PM
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Re: Engine swap almost done but engine dies???

I checked all the vacume lines, but even if i give it gas it'll just rev when i start it then die.

I was thinking VATS , but wouldn't vats not let the car fire at all???

my hanes manual doesn't go into any detail it just showes how the starting system working through the vats, no details of the system itself.

Thanks,
Maurice
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Old 07-18-2004, 06:49 PM
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Re: Engine swap almost done but engine dies???

If you do not have the vats system disabled through a vats bypass box, or by a computer tune, then that is the problem.
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Old 07-18-2004, 11:43 PM
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Re: Engine swap almost done but engine dies???

After a year waiting for my motor to get done, my car did the exact same thing, fired right up then died a few seconds later. Damn injectors were screwed up from the fuel drying on them from sitting for so long. On a hunch, I replaced the injectors with some used ones I bought off the board and VROOM!, fire right up and runs like a bat outa hell.

If the injectors have been sitting for more than a few months, this can happen.
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Old 07-18-2004, 11:48 PM
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Re: Engine swap almost done but engine dies???

Might also wanna screw the throttle stop screw out some. I had a similiar problem once and that fixed it. Throttle blades just might be closed too much thus no air, thus dying.
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Old 07-19-2004, 12:57 PM
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Re: Engine swap almost done but engine dies???

I had the exact same problem when I fired my 94 LT1 in my 240Z for the first time. Had me puzzled for days. Long story short, I had missed plugging one of the vacuum lines to the throttle body. With the MAF unplugged, it would run...try that. With the MAF unplugged it relies on the MAP, which will take a vacuum leak into account when measuring air/fuel requirements.

Tim
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Old 07-20-2004, 03:01 PM
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Re: Engine swap almost done but engine dies???

Thanks, i have tried unhooking the maf, that didn't work, i then today called the company i bought the engine from and they said the VATS is the problem and that i can buy a bypass box from the aftermarket, they have this problem with all of these setups but they never told me until i asked, and they didn't send the original vats system from the car so i have done some resurch and found a project page on how to make my own module. it just pulses the blue wire to ground 30 times per second and then the car starts, simpler than i thought, also they said in the meen time to tap that wire to ground manually and the car will start just the same.


Thanks for all the quick replys!!!

Maurice
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Old 07-20-2004, 03:13 PM
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Re: Engine swap almost done but engine dies???

Sincity; What year is your LT1? I may be able to give you some pointers as i did an LT1 transplant into a german car as well!
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Old 07-20-2004, 03:51 PM
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Re: Engine swap almost done but engine dies???

Originally Posted by SinCityLT1Benz
Thanks, i have tried unhooking the maf, that didn't work, i then today called the company i bought the engine from and they said the VATS is the problem and that i can buy a bypass box from the aftermarket, they have this problem with all of these setups but they never told me until i asked, and they didn't send the original vats system from the car so i have done some resurch and found a project page on how to make my own module. it just pulses the blue wire to ground 30 times per second and then the car starts, simpler than i thought, also they said in the meen time to tap that wire to ground manually and the car will start just the same.


Thanks for all the quick replys!!!

Maurice
I have seen those modules for sale on Ebay, also. Have a link to the page you found on how to make one?
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Old 07-20-2004, 03:56 PM
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Re: Engine swap almost done but engine dies???

If you have a programming cable easy to do VATS and VSS as well as any AC disable you may nead. Tuner from CATS makes it real easy. Take out VSS, VATS, EGR, EVAP, AC, Air pump with the click of a mouse! Makes it very easy for us transplant guys.
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Old 07-20-2004, 05:50 PM
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Re: Engine swap almost done but engine dies???

I agree with the above!! Go to http://www.tunercat.com/ and download the software, buy the license and the definition file ($EE), and get a cable from Andrew at http://www.akmcables.com/. You will be miles ahead of the game then. While you're at it, download freescan. It will allow you to see DTCs and reset them, among a bunch of other things: http://www.andywhittaker.com/ecu/ecu_software.htm
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