4.6L (1996-2004 Modular) Mustang Technical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within.

Im stumped.

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Old Sep 23, 2008 | 10:45 PM
  #1  
Cody96gt's Avatar
Cody96gt
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Default Im stumped.

alright. i have a 96 gt and the wierdest thing is happening. if i get on it at all the oil pressure goes straight down to low. but cruising its fine. also in higher gears if you get on it the rpm's go up but the car doesnt go any faster. you have to let off and then it will speed up. its almost like something is slipping? i have no clue but if anyone has suggestions i would appreciate it.
Old Sep 23, 2008 | 10:49 PM
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Sounds like a clutch is slipping as for the oil pressure loss it could just be a bad oil pressure sender.
Old Sep 23, 2008 | 10:49 PM
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Youre way low on oil.......In a nut shell, youre low on oil. The self adjusting hydraulic lifters arent pumping up all the way so youre not getting the full valve lift that you should be getting.
Check your oil, or better yet change your oil and use a high quality filter like WIX. Put some Castrol syntec 5w50 in there and it should run fine. Check for leaks.
-P.
Old Sep 23, 2008 | 10:50 PM
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yea i guess i should have said check your oil level then go from there.
Old Sep 23, 2008 | 10:55 PM
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Originally Posted by P Zero
Youre way low on oil.......In a nut shell, youre low on oil. The self adjusting hydraulic lifters arent pumping up all the way so youre not getting the full valve lift that you should be getting.
Check your oil, or better yet change your oil and use a high quality filter like WIX. Put some Castrol syntec 5w50 in there and it should run fine. Check for leaks.
-P.
The "lash adjusters" control just what they are called, the lash. They do not have anything to do with the lift of the valve. If this was a push rod engine with hydraulic lifters then I would agree with you but its not.

The low oil pressure is either a bad sender or bad pump. You can buy a cheap mech oil pressure gauge for $20 and to see the the pressure is.

As for the no power its probably your clutch.
Old Sep 23, 2008 | 11:00 PM
  #6  
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Originally Posted by mustangman281
The "lash adjusters" control just what they are called, the lash. They do not have anything to do with the lift of the valve. If this was a push rod engine with hydraulic lifters then I would agree with you but its not.

The low oil pressure is either a bad sender or bad pump. You can buy a cheap mech oil pressure gauge for $20 and to see the the pressure is.

As for the no power its probably your clutch.

the lash adjusters will colapse if they dont have sufficent oil pressure reducing valve lift, which will cause problems. +1 on the clutch this could cause the loss of power complaint as well
Old Sep 24, 2008 | 03:45 AM
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Originally Posted by jwog666
the lash adjusters will colapse if they dont have sufficent oil pressure reducing valve lift, which will cause problems. +1 on the clutch this could cause the loss of power complaint as well
If the adjusters collapse it will affect valve lift, however that would not cause the problem the OP described of the engine speed increasing and vehicle speed staying the same.

Assuming he has a manual transmission the only thing that could do that would be a slipping clutch.

The oil pressure issue could be oil level related. A recent thread revealed that the change from the 5 qt to the 6 qt engine fill recommendation in 2002 was not related to a change in the oil pan capacity; but rather due to Ford's engineering team finding that 5 qts was insufficient to prevent oil starvation at higher revs.
Old Sep 24, 2008 | 10:26 AM
  #8  
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Lash adjusters stabilize the cam followers they do not push the cam followers to make them press on the valve tip to open it. If you lose oil pressure and a lash adjuster collapses it will not effect lift but the cam follower will now bounce around which is the ticking sound you hear when it happens. You both are thinking of hydraulic "lifters". Completely different animal.
Old Sep 24, 2008 | 01:27 PM
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thanks for all of the ideas. the car is indeed a 5 speed. actually has a tko 500. so the clutch is definatly most likely the speed problem. as for the oil pressure i dont seem to be low on oil so im going to check out the oil pump/ oil pressure sender.
Old Sep 24, 2008 | 02:22 PM
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Originally Posted by mustangman281
Lash adjusters stabilize the cam followers they do not push the cam followers to make them press on the valve tip to open it. If you lose oil pressure and a lash adjuster collapses it will not effect lift but the cam follower will now bounce around which is the ticking sound you hear when it happens. You both are thinking of hydraulic "lifters". Completely different animal.
The HLA is the fulcrum/pivot point for the cam follower, so if in normal operation it compresses fully while the valve is opening (which I suspect it does not) then it's being collapsed would not effect valve lift.

If OTH it does not fully compress during normal operation (I.e. it behaves as a hydraulic lifter, which do not fully compress under load) then its being collapsed would affect valve lift.

I have no idea as to whether it fully collapses under load or not, if it does then it's a crappy design because high speed metal-to-metal impact it never a good thing--it would also I suspect be quite noisy.

This would also not account for the "slipping" the OP reported...
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