Car Stut..tt..tte..ering

  • Thread starter Thread starter Anonymous
  • Start date Start date
A

Anonymous

Guest
Ladies and Gentlemen, Boys and Girls, Children of all ages..

For the last fortnight the XF has been stuttering/bunny hopping/jumping etc. when ever i get off the gas.

When the problem occurs the revs dont change and the engine seems to be running as per usual, so i was thinking maybe clutch or gearbox issue?

Only occurs when i get off the 'go-pedal' . Does not occur when i have the foot on clutch.

Its very annoying/frustrating to say the least.
banana.gif


Any ideas would be great....

-Mike
 
hmm. I'm thinking either ignition or EGR. Does it backfire at all? when it stutters, does smoke come out the back?

Might want to run the engine at idle at night with the hood up, see if any sparks arc from either the coil, or any of the leads...

I doubt its the gearbox or diff though..
 
Actually now that i think of it, it hasnt really been backfiring but it has been very tempremental with its idling.
Eg. Idle often drops very low, close to stalling (has stalled a few times) and then trys to counteract this and revs high (if that makes sense)

As for smoke, none that i have seen.

Mike.
 
hmm. In my mind, I think that'd rule out ignition - now I'm thinking Vacuum Leak or Head Gasket.. Is there water in the oil? like is it a milky colour? With the engine running, take the radiator cap off (when its cold, mind you!) and put your hand over the radiator filler hole. If you can feel a strong pulse on one of the cylinders firing, theres a good chance you have a leaky headgasket.

If not, get a can of WD-40 or other spray oil, and spray around the intake manifold bolts, and around the carby. if it starts to run much better, and then blows out blue smoke, youve just sprayed the leak :D

good luck!
 
Mike,
is this the EFI XF that is run on LPG?
If it is it does sound like the lpg mixer is playing up.
Have agood hard look for vacuum leaks.
See if adjusting the idle mixture makes any difference.
Noel
 
Noel, nope no LPG over this way. Im running a fuel-Carbed XF.
As for playing with the mixtures, i had a bit of fiddle with the idle-screw on the carb, but to no avail. Even on a very low/high idle it would still miss/stutter/rough idle.

Hmm, im kinda with disco on this one, may be a vacum issue.

Any other ideas gents.

Mike.
 
Ok guys, im offically stuck for ideas...
So far i have..
-replaced plugs
-adjusted idle screw
-checked for vacum leaks (for ages)
-removed and cleaned EGR valve.
-removed dizzy cap to check for cracks etc.
-Radiator doesnt pulse (disco's idea)

Im in dire straights here lads..

Any more suggestions/ideas
 
MIX,
Looking at your carbie from the front of the car. There is a round valve, it has two vacuum hoses connected.
One runs down to the intake manifold and the other runs backwards to the side of the carbie.
This is a throttle lifting devise and is designrd to lower exhaust emissions.
Press on the front if you have the correct valve, with the engine idling the engine speed should increase.
If this is correct, disconnect and plug both ends of the vacuum supply.
Try the road test again.
Hope this helps.
Noel
 
Noel.
I tried your suggestion, still to no avail.
Although i did notice, when i pushed the valve there was no difference in idle/engine speed.
Any other thoughts.
-Mike.
 
have you tried checking the compression yet?

I think its safe to say we've exhausted the easily checked easily fixed things...
 
Dang it..
looks like im going to go and get myself a compression gauge.
 
have a look on the side of the carb ,the idle cut off solenoid is a dodgy bit
of work at its best .simetimes you can wiggle the wire and here a small click when the solenoid activates. they normally break just under the terminal.also the vacuam transfer port the little pipes break.

might be worth a look.

cheers dave
 
Ok, went and got a comp-gauge.
The results are as follows:

cyl 1 - 180
cyl 2 - 180
cyl 3 - 182
cyl 4 - 190
cyl 5 - 181
cyl 6 - 180

*all figures are in PSI

Although cyl4 is a tad higher than the rest, the compression seems pretty spot on.

*sigh* Where to now?!

-Mike.
 
hmm. Interesting.

Heres a thought, is it an '85 XF? if it is, it'll probably have a vacuum advance on the dizzy.. try disconnecting that, see if it'll stop stuttering.. :)
 
Can we take those figures as hot, dry readings? Hope so. They are great then.

Did the pressure pump up evenly per stroke, per cylinder? Guessing it did. Now try this.

Take off the dizzy cap, and crank the engine until the rotor button is on #1 and the balancer notch is at TDC. Don't turn the engine back to achieve this, just forwards. Now grasp and turn the balancer backwards until the rotor just begins to move. Not the degrees read. Halve this to get your timing chain slop in °.

Have you checked your mechanical advance is functional? Do you feel a springy resistance when twisting the rotor button in the direction of rotation? They get sticky with age and often lock up. The vacuum advance gets sticky, too.

LOL, I must be trying to sell you a rebuilt distributor...

Check this stuff, anyhow.

Adam.
 
You must log in or register to reply here.
Back
Top