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Trying to help a guy out. . . . 78 280Z possable head crack ???

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Old 04-04-2012, 05:24 PM
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Trying to help a guy out. . . . 78 280Z possable head crack ???

Got a guy on craigslist been doing small jobs for fellow z owners have a 78 with 56,000 miles. . . . I did not to get to hear it run since he already took the intake off and yea a mess. . . . . Complaint was the car lost power and stalled when it warmed up. . . . No fluid swaps nor gas fumes in radiator . . . . Radiator was full on inspection. . . . . How ever # 4 cyl is 13 lbs lower on compression than the other 5 cylinders that are within a pound of each other. . . . Now a head crack with out gasket failure? Or a wireing issue. . . . Hate to turn the guy away car is way to sweet to be covered by camping gear and paint buckets. . . .
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Old 04-04-2012, 05:43 PM
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Now before sarcastic remarks. . . . . 13 lbs could be a crack iin the head a ring issue ect ect. Im just confused why it loses power warm and stalls. . . . . Heat would pump up a leaky ring . . . . . Car sat well going off inspection stickers 6/91.. now a problem with the EFI could also cause the issue too what would you guys do? Buy all new gaskets and hoses to put the car back together to trubble shoot. . . Waste of $$$ if its a head. . . . . Or just tell the guy to tow it to a garage?? He has the money for a new engine he wants me to swap but if its a simple efi problem HUGE waste of $$$$ been haveing. Good luck did two swaps this month for 500 a peice of course being the zx models. So I may just pass on this car?
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Old 04-06-2012, 12:38 AM
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Originally Posted by Lesnocker
Now before sarcastic remarks. . . . . 13 lbs could be a crack iin the head a ring issue ect ect. Im just confused why it loses power warm and stalls. . . . . Heat would pump up a leaky ring . . . . . Car sat well going off inspection stickers 6/91.. now a problem with the EFI could also cause the issue too what would you guys do? Buy all new gaskets and hoses to put the car back together to trubble shoot. . . Waste of $$$ if its a head. . . . . Or just tell the guy to tow it to a garage?? He has the money for a new engine he wants me to swap but if its a simple efi problem HUGE waste of $$$$ been haveing. Good luck did two swaps this month for 500 a peice of course being the zx models. So I may just pass on this car?
Rust in the gas tank or in the fuel lines??
You always can do a presser test....
Just start from there.
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Old 04-06-2012, 08:03 AM
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update on the 78. . . . Thermo time switch?? hell is that??

Well worked on the guys car last night. . . . . Installed the manifolds / fuel rail/ exhaust. . . . Now this car has a new fuel tank / pump/ filter and lines / dizzy . . . Now since no fluids have mixed and no fuel is in either the cooling or oil systems I'm safe to say the head should be fine that and the owner stated the car came home with all fluid levels full and never over heated. From what the owner said sounds as if it vapor locked. So I would say the electronics would a bad amf cause this? Since the car dies warm the book also shows air temp / water temp/head temp and a "thermo time" hmmm to an average joe sounds as if would change the timeing with engine temp ?? Now on my ZX half the sensors are doing nothing at the moment since well I HATE tiny things that always snap off. What would make a 280 z die warm? Car I found has been a polterguiest since new has always had a nasty habit of leaveing people stranded. . . . . So its a lil bastard! Guess why it only has 56000 miles
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Old 04-06-2012, 10:55 AM
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Not really sure what you are asking or saying...

I've yet to see someone prove that a 280z / 280zx is having vapor lock problems... Vapor lock is a problem with carbs because the fuel pressure is 3-10psi. EFI systems run at 35psi+ . . . (I've ranted about this MANY times).

Are you doing all this work without a manual? Because all sensor info is in the FSM.

Originally Posted by NismoPick
There are 3 sensors...

#1: Water temp sensor for dash gauge
#2: Water temp switch for the aux fan
#3: Thermotime switch for the cold start valve.

From the FSM (you should download it here: www.xenons130.com/reference if you haven't done so yet).

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Old 04-06-2012, 02:40 PM
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Im useing the manual...... Just trying to figure out what sensors will actully kill the engine. I belive its the amf I know my zx wount fit to test. . . So I wount know anything until its put back together. So next saturday ill be going over and finishing. Then we can start digging deeper. Now on mine I can pull every sensor except the amf / oil pressure sending unit and the tps and the car will drive fine....
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