911 2.4 power failure
 

Hi I have a problem with my 911 2.4 S (1972).
Sometimes (more usually when engine is cold) is impossible to speed up. :mad:It´s occurs when I try to acelerate, RPM is like “enganged” in 1.500 line and do not go up. The car seems to be a power failure.:eek:
In this case, pressing the acelerator quickly several times, suddenly acelerate and all works “correctly”. I put “correctly” as the car over 2.000 RPM works, not correctly but not so bad: At least without power failure, but going up 5000 RPM has a a power failure again..:confused:
Acelerator linkage is ok. Distributor, rotor, sparking plugs & Ignition cables, are ok. Sparking plugs have 4.000 Km. MFI has been rebuilded a year ago.
Any suggestions to have this problem fixed?
Thx & rgds

Hello, I'm no expert, but it looks like a rotor problem to me.

when you say that the distributor is fine, do you mean that the shaft spins freely and distributes spark, or have you looked at the mechanical advance portion, as well?

if it was a fuel pump starvation problem, i think you would notice the knocking/pinging/popping as you would try to accelerate. since you didn't mention this...

it sounds like the timing is not advancing. if the centrifugal weights and associated springs are stuck, broken, missing, etc, you are most likely not getting the correct advance.

take off the distributor cap and gently turn the rotor by hand. it should be against the stop in one direction, and have spring tension against it in the advance direction. take the rotor off and look at the springs/weights underneath it. anything look amiss?

MFI guys will have to contribute if a similar situation occurs with the MFI pump...

Hi boys, thanks.
kucharskimb, you are right. One of the associated centrifugal spring is broken. That is the problem. But I´m afraid would not be easy to find another.:confused:
Thx & rgds

Two things, just buy a whole new rebuilt distributor if you can afford it. Second, How do you have a 5.0 liter in your Grand Cherokee? I have heard of 4.7, 5.2, 5.7, 5.9, and 6.1 liter V8's.

This is a possibility. Not cheap but a possibility... I will check my budget for next year ;-).
You are right my cherokee has 5.2...It was a failure just fixed;-). A big machine in Morocco dessert.SmileWavy

im having the same problem with my 2.4 could a valve adjustment and maybe some carburator tuning be in order also?

Is the hot air connection to the left heat exchanger in tact?
The MFI pump needs forced hot air when the motor is cold.
Bill K