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lt1 swapped in...not running?


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First off, i am not working on a Z car, instead its a 69 landcruiser but you guys seem to know alot! I am finished my LT1 swap and it cranked right up on the first shot but it will only run for about 3-5 seconds then die. I did a reprogram of the PCM with tuner cat and kept the stock harness. I thought that it had to be a fuel issue so i removed my filters and just ran a straight line to see if it was starving the engine, still same thing but i think it runs a tad bit longer. I am using a MSD inline fuel pump. When i depress the shrader valve pressure seems to be good. I am leaning towards PCM programming or electrical, i am not a good troubleshooter. It will crank up perfect everytime but won't stay running. THe pcm turns the fuel pump on for 3 seconds before starting and the pump stays running for a few seconds after it dies.

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just an addition...There is no oil making it to the top of the heads up on the lifters. I peaked through my oil fill cap and noticed it looked pretty dry so i removed it and even cranked up the motor and no oil is comming in. However, my oil pressure guage shows almost 50 psi when i start it?

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Kenai,

Check the settings in TunerCat again, my engine did the same thing when I first started it. I have an LT1 from a 95 Caprice 9C1 which is not supposed to have VATS but I had to program it out anyway.

 

If you can't get it running post your bin file and I'll take a look at it, or I can send you one I use.

 

Wheelman

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I checked it again and even reprogrammed to make sure. Still the same thing. I also enabled the vats and i didn't have any changes. However, i think i have much bigger problems now! My motor let out a big puff from the throttle body and it has siezed. I don't understand, it seemed to be in great shape and is low mileage. I have been getting 50 psi of oil pressure but like i said before, no oil up ontop of the heads. I think i am gonna have to tear into it!!

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Guest Grenade300

Just a thought, could there have been a clog in one of the oil passages? Arent there some engines that won't keep the fuel pump running without oil pressure. I know your gauge reads ok (that's really puzzling). I'm just throwing ideas out there.

 

Really sorry to hear about your engine.

 

Scott

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i dont know if it helps at all but your oil pressure may be fine but the volume might not be there i know this is what was wrong with my envoy but it was a fuel pupm not oil i dont know if it could do the same thing with and oil pump. this stumped the poor guy trying to fix it and then he happened accross a volume gauge and sawit had pressure but no volume just my .02

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okay latest update. I drained the oil and it was full of coolant. I could also see some coolant coming out between the cylinder head and block. So i pulled the whole top half of the motor off. There is coolant in everything, intake, oil and cylinders. Everything else looks good though, actually the motor is pretty freaking clean. I think it was seized because the cylinders were hydrolocked with coolant. I think that the head gasket blew because the cylinder was full of coolant. How in the CRAP could coolant be getting in! Also, i still don't have oil making it up to the top of the engine on the right bank. where should i look for a clog? thanks for everything!

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Guest Grenade300

Kinda sounds like a cracked head. May be? By the way make sure to inspect your connecting rods. I hydrolocked and engine once at 1200 RPMs and bent 2 rods and cracked a piston.

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latest update....Both heads are off and look great. Even the headgaskets look fine, i think that the coolant coming out of the block was being pushed out a spark plug hole. I am beyond confused. There was so much coolant in the cylinders, and throughout the intake. The rotating assembly seems fine, very smooth, just coolant everywhere!

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Did you drain the engine before pulling the heads? If not that would explain why you have coolant in the cylinders(when you pull the heads it pooled into the heads.

 

If your engine was hydrolocked that would explain why you had coolant in the intake(it probably got pushed back out the intake valve, atleast thats the only think I can think of). The big question would be why did both banks have coolant in them? I could see one headgasket going but not both at the same time(I mean its possible but highly unlikely).

 

You probably should have pressure checked you coolant system before pulling it apart to see if its leaking down internally and where if it is. It's just a guessing game now unless you have your block checked and your heads checked for cracks.

 

Guy

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Thanks for all the suggestions thus far! I think my problem may be somewhat more simple and a mistake on my part, tell me what you think.....There are steam vents that come out of the back of the heads. I connected a tube from the steam vent tube to the throttle body. On the TB there 3 ports on the right side. I connected the tube to the middle one. After further inspection i noticed that any fluid running through the this port would go straight into the intake. So, perhaps the coolant just ran right in. But, the engine wasn't even warm.

 

Even if this is the problem, how could i get coolant in my oil?

 

Also, for my oiling. Is there any special way to prime the LT1 oil pump? I only get oil to the left bank lifters. After further inspection the right bank lifters are dry. I don't know how it routes, does it take a real long time for the oil to get to the right side?

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