I have been having a problem with my 78 XJS. It wants to cut out after a few minutes when started from warm. It starts fine but while driving along, especially when you take your foot off of the gas, it cuts out. It doesn't want to restart normally. However, it can usually be restarted by putting the foot full on the gas and eventually it catches. My garage man thinks its is the AAV but it seems more like fuel or electrics to me. Any thoughts please?
Peterjohn77
Engine cut-out
Moderators:davidr, BigCatXJS, dhdove
Engine cut-out
Hi, does the car idle over at approx 750 rpm?
The AAV is supposed to close when warm, thus reducing the idle speed. When started from cold the AAV should allow more air to pass thus raising the tickover.
The coolant temperature sensor on the nearside of the car has an influence on the cars running. However it usually causes overfuelling which causes the engine to stop. When I had this problem the exhaust belched white smoke.
Obviously you can adjust the AAV with the bolt protruding from it. Do you have the throttles set to 2 thou gap? also check the bushes as the outer ones are notorious for disintegrating.
Keep us informed as to progress. Regards Kels.
The AAV is supposed to close when warm, thus reducing the idle speed. When started from cold the AAV should allow more air to pass thus raising the tickover.
The coolant temperature sensor on the nearside of the car has an influence on the cars running. However it usually causes overfuelling which causes the engine to stop. When I had this problem the exhaust belched white smoke.
Obviously you can adjust the AAV with the bolt protruding from it. Do you have the throttles set to 2 thou gap? also check the bushes as the outer ones are notorious for disintegrating.
Keep us informed as to progress. Regards Kels.
-
peterjohn77
- Posts:19
- Joined:Thu Jan 31, 2008 1:12 pm
Engine cut-out
Kels
Thanks for the insights. I had guessed that if it was the AVV, it would have coughed & sputtered before stopping and not been so sudden. My mechanic also advises that the AVV is seized and he has restricted the air flow down that route
When newly started and idling, it tries to drop out but usually catches itself and comes back. Every now and then it doesn't come back.
Peter
Thanks for the insights. I had guessed that if it was the AVV, it would have coughed & sputtered before stopping and not been so sudden. My mechanic also advises that the AVV is seized and he has restricted the air flow down that route
When newly started and idling, it tries to drop out but usually catches itself and comes back. Every now and then it doesn't come back.
Peter
Engine cut-out
It is possible to dismantle the AAV and free the piston, I have done so on two ocassions succesfully.
It is a bit brutal but if you hold the top in a vice with the AAV removed from the car, it is possible to drift the funnel off the main body. usually the piston has just stuck.
you require a torx screw set to undo the screws.
Once freed off, test it after reassembly by placing it in a pan of boiling water. it should close as it reaches boiling.
After all what have you got to lose. regards Kels.
It is a bit brutal but if you hold the top in a vice with the AAV removed from the car, it is possible to drift the funnel off the main body. usually the piston has just stuck.
you require a torx screw set to undo the screws.
Once freed off, test it after reassembly by placing it in a pan of boiling water. it should close as it reaches boiling.
After all what have you got to lose. regards Kels.
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