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HI. I have joined the forum and am hoping for some help with this issue.
I have Jaguar XJS-V12 from 1990. It is hard to start and I need to give it gas in order to keep it from stalling. If I do that for about 30 seconds or a minute it then idles smoothly on its own.
Any idea what could be wrong? Is this affecting the performance once it gets warm?
HI. I have joined the forum and am hoping for some help with this issue.
I have Jaguar XJS-V12 from 1990. It is hard to start and I need to give it gas in order to keep it from stalling. If I do that for about 30 seconds or a minute it then idles smoothly on its own.
Any idea what could be wrong? Is this affecting the performance once it gets warm?
To clarify, does this occur only on cold starts; ie, after sitting over night? If so, one of the usual suspects is the coolant temp sensor...which pays a major role in controlling fuel mixture on a cold engine.
Actually, the coolant temp sensor can cause starting problems on a warm engine as well, if it erroneously sends a 'cold' signal to the ECU (computer) when the engine is cold at all.
How's the general state of tune? Spark plugs, distributor cap, etc?
The status of the tune is good with new plugs and rotor but not wires. This happens when the car is cold and I never had the opportunity to start it when it was warm.
The reason I ask is you have a 27 year old car with only 29K miles. How much has it been driven recently? When was the last time the gas tank was filled? When was the last time it started without issue?
I'm guessing the axillary air valve is stuck closed and isn't letting in enough air for cold idle. It's on the water rail, left side of the engine at the rear.
It's somewhat similar to a thermostat, except the wax capsule moves a piston that covers or uncovers a port to allow air through. Over time the piston can corrode and quit moving. There used to be rebuild kits available, but I don't think so anymore. If you search here under "AAV" or the full name you should find lots about them.
I purchased the car in May of 2015. The car starts but it takes a few pumps of the gas to get it going and you need to hold down the gas to keep the RPM up for about a minute. Then it runs fine. I drive the car in the summer but only put about 1000-2000 miles a year on the car ( I have 2 other collector cars so I just don't have the time to run each of them a lot). It also is not my daily driver. I keep the gas tank full with premium all the time and put in a gas stabilizer during the winter when it is a closed storage facility. I start the car every two months and bring it up to normal operating temperature throughout the year.
This is a Pic of the AAV Valve and as Jagboi says they can get Stuck through lack of use but having said that some people either disable them or else take them off the Car altogether.
All those higher Start up Revs, just help to guzzle Gas, as if She wasn't Juicy enough already!
This is the AAV Valve, which can get Stuck and cause 'Hunting' through lack of use.
Next on my list would be the "black goo" that builds up around the throttle discs. Simply wipe them clean with a solvent soaked rag at each oil change period.
Hard Starting XJS V12
