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LS1 Starting Problem. Please HELP!!!!


Guest daviprit

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Guest daviprit

I've put a 98 LS1 engine into a 53 Chevy Truck. Before I sent the Computer off to get programed it would start and run but rough. I had the computer converted to Speed Density, Vats Burned out, and set up for an adjustable fuel regulator. I have a 70psi vortec fuel pump with Professional Products Rails and Regulator. Fuel Pressure Gague is showing 58psi. The engine will fire right up but starts going dead after about 3 seconds. During that time if you try to give it gas you can hear the motor trying to suck air but it chokes down and dies. I've tried hooking the fuel pump up direct to the battery bypassing the realy but still won't stay running. I hooked a scan tool to it and its not showing any codes or history of codes. I've also stuck a screw driver to the injectors to listen to them and as the engine starts dieing the injectors clicking slowly starts to slow down with the engine rpms. If anybody has any suggestions It would be greatly appreciated. I've also hooked up a VATS module to the Painless wireing harness to see if that would solve the problem but it didn't, it also has 14 volts when running for those 3 seconds and 12.2 while not running.

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can u monitor the datastream with your scanner and see what the ecu is seeing. depending on ur scanner you could try activating different things ie idle air control valve etc until you isolate the culprit.

 

were you suspicious that it was just priming the fuel pump but not keeping the fuel pump running?

 

gl

 

Dave

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if its not vats (which it does sound like)

i'd check your TB idle screw and see if its too low.

I know for the longest time my cold start/idle sucked, i increased the idle screw a 1/2 turn or so and it fires up and runs like a top. worth a shot since it takes all of 30seconds to do.

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Guest daviprit

I wasn't sure if the fuel pump was just running long enought to prime the sys. then shutting off. Thats way I bypassed the relay to see. As far as the Vats thats been burned out of the computer and the computer isn't showing a VATS Code nor any other code for that matter. I hooked an external VATS Mod to it just throwing something at it to see. I took the Scanner back yesterday and it will be a couple of days before I can borrow it again. Maybe next time I can get my friend to come over with it seeing he uses it everyday and he can look at the data stream.

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i know its a bit of a rough way to do it but when i was struggling to get my motor started wasnt sure if injectors firing ended up pulling injectors and rails out laying them on top of motor and cranking motor over like that found that i had 4 dead injectors on one side

but at least it shows you if injectors are firing

 

mick

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