94 idi
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94 superduty 7.3
i Did some searching and found a small leak on one of the new return lines fixed that no the truck runs a little better but still has the higher rpm miss and still putting out the blue smoke. Going to do a compression test where should the compression be?
Scope Wizard
Joined: May 2019
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Ok in that case then it seems pretty obvious those injectors are leaking pretty good, I would still be interested in Compression readings or Differential readings.
it's Good that it is not Coolant
it's Good that it is not Coolant
Posting Guru
Joined: May 2015
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If you get a low reading on some of the cylinders, test it again with the motor fully up to temp. I've found a lot of times that same low cylinder might jump up to 80-100psi when warm.
I was also able to remove the gauge on my compression tester and hook it direct to my airhose and do a leakdown test.
Best of luck to you, they'll run fine down to 280-300 but 350+ is definitely where you want to be as tj said.
I was also able to remove the gauge on my compression tester and hook it direct to my airhose and do a leakdown test.
Best of luck to you, they'll run fine down to 280-300 but 350+ is definitely where you want to be as tj said.
Lead Driver
Joined: Apr 2008
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Are you sure its not missing all the time? Were the two glow plugs next to eachother? Starting to sound more like a headgasket. Miss at high rpm could be weak valve springs. Ive put 4k governors in a few different 7.3s but my 88 wouldnt even get to stock governor before floating the valves.
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Posting Guru
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Are you sure its not missing all the time? Were the two glow plugs next to eachother? Starting to sound more like a headgasket. Miss at high rpm could be weak valve springs. Ive put 4k governors in a few different 7.3s but my 88 wouldnt even get to stock governor before floating the valves.
Most likely the pump was shot and couldn't consistently deliver fuel that high in the rpm range, which is pretty common on a rotary pump.
Now for op it could be a head gasket issue, although you would notice a hazy exhaust, coolant being pushed out of the radiator and more of a knock along with the miss up high as that's exactly what mine did when the head gasket failed.
The firing ring was the actual part that failed but it was easier for it to cross to a nearby coolant port, than it was to cross through another firing ring to reach the next cylinder.
Lead Driver
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I highly doubt your problems with reaching 4k was valve spring related, the piston to valve clearance is so small on these engines that if it was then you would be pull those heads and possibly pistons.
Most likely the pump was shot and couldn't consistently deliver fuel that high in the rpm range, which is pretty common on a rotary pump.
Now for op it could be a head gasket issue, although you would notice a hazy exhaust, coolant being pushed out of the radiator and more of a knock along with the miss up high as that's exactly what mine did when the head gasket failed.
The firing ring was the actual part that failed but it was easier for it to cross to a nearby coolant port, than it was to cross through another firing ring to reach the next cylinder.
Most likely the pump was shot and couldn't consistently deliver fuel that high in the rpm range, which is pretty common on a rotary pump.
Now for op it could be a head gasket issue, although you would notice a hazy exhaust, coolant being pushed out of the radiator and more of a knock along with the miss up high as that's exactly what mine did when the head gasket failed.
The firing ring was the actual part that failed but it was easier for it to cross to a nearby coolant port, than it was to cross through another firing ring to reach the next cylinder.
Posting Guru
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Well that would be something, that was the best running NA ive ever driven. It was a single cab 2wd C6, out ran my 92 5spd with a leaky 088. I may very well be able to verify this one way or the other as soon as i figure out where that pump is hiding, planning to drop it in the 92 to do some troubleshooting.
I think it's mostly because of the rotary pump limitations. Must be a tight motor if it outruns a turbo'd five speed
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