XJ-S H.E. Spluttering revs cold start wont cancel,!

[glenn1411]

wonder if anyone can shed any light on this please,?? i have a 1981 model year {154th production car off the line} H.E. COUPE
the car has been stored in a dry garage since.....1997 just prior to "putting it away" -for a while,!!!! a local Jaguar main dealer had the engine out,and re did the timing chain and tensioner,!!! and i have to say the car had never run as well when i got it back, i did about 200 miles in it before putting it away,i bought a new battery 2 weeks ago ,filled it with new fuel-and fired it up-2 things were immediately apparerant, it dident want to rev beyond fast idle/cold start and the fuel pump was very noisy/and vibrating,something which had not happened prior to storage, i noticed a wire off the throttle response switch,so i sourced and fitted a new one-a feat in itself, as Jag dont make them anymore,!! however i managed to find a genuine part i also fitted a new bosch fuel pump,and metal filter .the result was the car did rev above idle,but its still very woolley, and spluttery...the fuel pump is quieter but im not sure its as quiet as it should be,ive packed the underneath of the pump with foam , and made sure its sitting off the floor in its rubber cradle, as i seem to remember,before restoring the car when i bought it in 1994 that there was a piece of foam under there anyway,from the Factory!!{we are talking B.L. here,!!} the cold start definately is refusing to cancel the car will sit on fast idle all day, it gets up to temperature o.k. and if i let it idle enough the thermostatic extra fan cuts in/out as it should thats normal,i cant road test it, as its not M.O.T.,d does anyone have any thoughts please?? i have to say that ive owned this car for thirteen years-and been...RIGHT THROUGH IT.... in that time everything has come out of a genuine Jaguar parts bag wherever possible and my total investment is now in excess of £16,000,!! before you laugh... let me say its a car for LIFE for me and will never sell it in my lifetime,so i think my investment justified,!! so you can see i havent taken any short cuts along the way,however it has been laid up untill recently for 10 years and ive resisted the urge to fire it up occassionally as i really dont think it does engines any good getting them bouncing hot then switching them off and leaving them to cool down in a cold garage -especially in the winter time, perhaps i should expect something when its not been run for a while,!!!??
any thoughts would be grateffully accepted,and appreciated
kind regards
Glenn
West Yorkshire.

[kelsham]

Hi good to hear you appreciate your car. You do know that there is a fuel filter in the sump tank that lives in the boot dont you? sometimes this clogs and causes the pump to become noisy. To reach it clamp off the hoses and using a piece of wood tap the retaining ring. This fault can cause poor running due to weak mixture. As to fast idle this is usually a sticking AAV valve sorry auxilary air valve. it is on the passenger side of the car. If you remove the near side air cleaner you will see a hole at the rear of the back plate that you have unclipped it from. with the aircleaner out of the way get a substantial piece of cloth and cover the hole. At the rear it leads into a rubber pipe. this pipe in turn leads to the AAV. once you block off this orifice your revs should drop confirming it is the AAV. If this is the case let me Know and I will post further instructions. regards Kels. P.S. hold onto rag firmly we dont want it sucked into the engine.

[davidr]

I agree with kelsham - sounds exactly like a sticking auxilairy air valve to me which is quite likely if the car has been laid up for a while. It's worth a try to block it off once the engine is warm to see if the revs drop.
It's not difficult to take it off and test - it should close when the bulb is immersed in hot water.
It's also worth persevering in trying to free it off as a new one is not cheap! WD40 to the rescue hopefully!
Another possibility is an air leak in the induction or vacuum system somewhere (although that could make it quite difficult to start).
Good luck

[glenn1411]

Thanks again Guy,s unfortunately i havent been able to investigate the sticking AAV yet because of the weather weve been having here of late in Yorkshire,!! but i did change the fuel filter in the secondary fuel tank today WHAT A DIFFERENCE IT MADE,!! unfortunately i was deluged in fuel when i removed the top of the tank by tapping it with wood, im not sure wether or not fuel had been building up in there because of the filter and boy,!! was it blocked,!!! im surprised fuel was managing to get through at all i immediately changed it for a new filter {£10.00} and replaced the top,!!! the car does not now splutter, the wooliness has disappered also or so it would seem i dident have the time to run the engine up to operating temperature but changing that filter seems to have made a world of difference,ALSO the fuel pump is now SILENT another result,..!! it would appear the engine was being starved of fuel as far as the poor reving was concerned i would have spent FOREVER trying to clean the original filter the deposits on it were SOLID im amazed any fuel managed to sive its way through at all.it must be the original one from 1981,..!! may i say a BIG THANK YOU for your suggestions gents, i would have been lost without this kind advice, will report back on the AAV once i have had the chance to examine it, and test as per suggested by blocking the hole up behind the filter
best regards
Glenn.

[glenn1411]

Today i managed to test the AAV on the car,No Rain in Yorkshire Today,!!.. i backed it out of the Garage and let it warm up for about 15mins, as it has been doing of late it was idling on cold start at around 1000/1100 RPM, i then stopped the engine when it was warm ,and went indoors to make a drink,after about ten mins, i came out and re-started the car,i noticed the revs had dropped immediately, on looking at the rev counter it was now idling at 800RPM
so with the engine still running i removed the pass side airbox cover and airfilter and held a rag tightly in place over the AAV apperture, for about a minute,...Nothing happened.. still idling at 800 revs, i then stopped the engine in order to re-fit the filter and box cover, i fiddled with it as i couldent remember immediately which way round the filter was supposed to go, and to make it easier i unclipped the sensor/switch at the top of the airbox at the front,once reassembled with the arrow on the filter pointing to front.and the sensor re-connected i attempted to re-start the engine, Nothing!!! then engine turned over but made no attempt to fire, i tried several times ,still nothing...So i undid the airbox cover and fiddled with the sensor switch i had unclipped,and then refitted,the airbox cover,tried again still nothing, so i elected to let the engine cool right down, before trying again, my garage is on a slight incline, and the fuel gauge was barely registering, so i put about a gallon of fuel in the tank, thinking it might not have enough in the tank to push the fuel uphill , once the engine had cooled sufficiently to remove the radiator cap i tried again the engine fired up then sputtered and stopped i retried and held the revs at 2000Rpm for about a minute, no problem i drove the car back inside the garage the revs again on the cold engine being 1000/1100 RPM, i waited until the car was warmed through again stopped the engine...waited 5 mins,and restarted again it started up no problem and the revs were back to 800RPM, so it would appear if i switch the engine off when warm,wait a short while,.. then re-start the revs drop,..i tried restarting when warm several times without any problem again it ticked over at 800 Rpm but im sure it should idle at 500RPM when Warm??? thats where i now am,!!!....lol any further suggestions would be appreciated i checked all the pipes i could see under the bonnet to make sure everything was connected but blocking up the AAV made no difference whatsoever
kind regards everyone
from Glenn.