No Power
Thread Starter
4th Gear
Joined: Oct 2005
Posts: 4
Likes: 0
From: Texas
No Power
1986 corvette has been parked 3 yrs car started right up after charging battery and ran fine for a few days then fuel pump went out replaced fuel pump and filter car ran fine a few more days then I got a ses light pulled codes 22 & 33 replaced bad throttle position sensor for code 22 and found a vacuum leak that cleared code 33 car ran and performed very well for about 1 day then all of a sudden it would hardly move maybe 20 mph and it sounds like i am at full throttle will only change gears if i let of gas pedal. Could this be caused by a vacuum problem and if so any clues as to where to look I did find a missing vacuum line on the power assist booster but could not figure out where it goes someone told me it goes to the vacuum modulator on the transmission does anyone know for sure any help would be greatly appreciated
Race Director
Joined: Sep 2005
Posts: 10,878
Likes: 1
St. Jude Donor '07
3 years, eh? First thing I'd do is let it idle up to operating temps and change the trany fluid & oil. There might be some trany & oil cleaners that you could add beforehand to remove the gunk. Maybe even idle it around the block a few times to get everything moved about well. Then try it all again with fresh fluids and hopefully the trany will behave better. Get a vaccuum guage and test for leaks.
Did everything work properly before it was mothballed?
Ya know, 3 years might have even attracted some 'house guests.'
Did everything work properly before it was mothballed?
Ya know, 3 years might have even attracted some 'house guests.'
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
It doesn't particularly sound like a vacuum problem. It sounds more like a fuel problem, again. Check your fuel pressure. Besides the filter, did you replace the sock on the fuel pump? If it isn't a fuel system blockage, then I vote for a clogged exhaust system, specifically a catalytic converter.
RACE ON!!!
RACE ON!!!
Racer
Joined: Nov 2005
Posts: 456
Likes: 3
From: Sumner Texas
I think that CFI-EFI is on the right track. Even though you changed the fuel filter, you may very well have stirred up some junk in the tank.
You can verify that this is the problem by removing the outlet line on the fuel filter and connect a hose that leads to a jar or something. Turn on the ignition for 15 seconds and then measure the fuel in the jar. If it is not at least a pint, then that confirms CFI-EFI's suspicion.
Good luck,
You can verify that this is the problem by removing the outlet line on the fuel filter and connect a hose that leads to a jar or something. Turn on the ignition for 15 seconds and then measure the fuel in the jar. If it is not at least a pint, then that confirms CFI-EFI's suspicion.
Good luck,
Burning Brakes
Joined: Feb 2000
Posts: 824
Likes: 2
From: Camden SC
"it would hardly move maybe 20 mph and it sounds like i am at full throttle will only change gears if i let of gas pedal."
OK, just want to make sure about the symptoms. Does the engine sound like it is developing power, ie no misses or hesitations, makes RPM but doesn't seem to be transfering power through the transmission. Is this correct. Then, you let off the gas pedal and the transmission shifts. What happens after the shift.
These are interesting problems. Sounds like you are doing a good job of jumping on the problems and gettin' things fixed.
dlmeyers 90 coupe zf6 3speed shocks
OK, just want to make sure about the symptoms. Does the engine sound like it is developing power, ie no misses or hesitations, makes RPM but doesn't seem to be transfering power through the transmission. Is this correct. Then, you let off the gas pedal and the transmission shifts. What happens after the shift.
These are interesting problems. Sounds like you are doing a good job of jumping on the problems and gettin' things fixed.
dlmeyers 90 coupe zf6 3speed shocks
Thread Starter
4th Gear
Joined: Oct 2005
Posts: 4
Likes: 0
From: Texas
after it shifts if i apply the gas it downshifts again. the car seems to idle ok but when you press the pedal it just seems like all it does is suck air there is no umph. This problem happened right before i pulled the codes 22 & 33 repaired both codes and reset system car ran like a charm for about a day then this problem returned and i swear i hear a hissing sound like air but could only find the missing line on the bottom of the power assist booster but not where it goes as the whole line is gone was just a little piece hanging almosy flush with end. i caped this hole and the car seemed to idle a little better but still has no power. Will check the fuel pressure today and see what volume is being delivered..starting to think the cat is clogged as suggested. But would it unclog for a day and then clog baCK UP...luckily i am already bald or i would not have any hair left.....well off i go to check the fuel lines ..thanks everyone for all your help will keep you posted as to my findings also any more suggestions will as always be greatly appreciated.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Have you used anything like propane to try and isolate any vac leaks?How about air filter? Did you add anything to the fuel like Heat to remove any water-water in the tank can act like a marble in the fuel system. The cats won't go out from just sitting-but your exhaust could have gotten plugged somewhat from a rodent-
Last edited by rick lambert; Nov 25, 2005 at 08:01 AM.
Burning Brakes
Joined: Feb 2000
Posts: 824
Likes: 2
From: Camden SC
[ The cats won't go out from just sitting-but your exhaust could have gotten plugged somewhat from a rodent-[/QUOTE]
Hmmmm, guess I'd go with fuel flow/pressure and Cats. I'd start with whichever is easiest. If you have a Factory Service Manual, the trouble shooting list should help organize the process.
Now, on the WAY outside, I've seen an occasional coil windings fail in this mode. Very rare, but tough one to pick out. An occilliscope would help. Spark, air and fuel. Darn physics.
Let us know.
dlmeyers 90 coupe zf6 3 speed shocks
Hmmmm, guess I'd go with fuel flow/pressure and Cats. I'd start with whichever is easiest. If you have a Factory Service Manual, the trouble shooting list should help organize the process.
Now, on the WAY outside, I've seen an occasional coil windings fail in this mode. Very rare, but tough one to pick out. An occilliscope would help. Spark, air and fuel. Darn physics.
Let us know.
dlmeyers 90 coupe zf6 3 speed shocks
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Racer
Joined: Nov 2005
Posts: 456
Likes: 3
From: Sumner Texas
You don't have vacuum to the modulator. Trace the line from the modulator up to the engine and use a vacuum gauge and your eyeballs to find the vacuum leak. You will have to hook up the booster line that you can't find where it goes. That will likely fix the problem.
Good luck,
Good luck,
Thread Starter
4th Gear
Joined: Oct 2005
Posts: 4
Likes: 0
From: Texas
Fuel volume delivered and pressure seem to check out ok...but my fuel looks really strange like there might be water mixed in with it. I have a head cold so i cannot smell but there seemed to be no gas odor. Will find someone without a cold to smell a little gas i saved from my car. Will try to find modulator line on transmission and see where it goes or if it is even connected as I hear air from under the car also.
Racer
Joined: Nov 2005
Posts: 456
Likes: 3
From: Sumner Texas
If there is water in the fuel, pour in a can of Berrymans B12. It will emulsify the water and burn it. Get rid of the gas quickly and get some good, dry gas in there before you stick an injector.
Good luck,
Good luck,
