My car began stalling again as it did in the past before I replaced the egr tps and iacv. So after being very frustrated I tried something radical, I disconnected the iacv. Not only has the car never stalled out again, but it's running better than ever! Anyone else had this experience? Is this a sign that something else is inherently wrong?

 

im having the same porblem, so your saying if i remove the control valve itll run steady? where exactly is this control valve located?

 

You might need to use WDS to do an engine setup. The TPS calibration and Oxygen Sensor Orientation sometimes fixes running/idling issues.

You might also have a faulty IACV????

bob gauff

 

I have had a simular problem with my 95 XJ6. Sometimes it will just shut off when starting off from idle. What is an iacv?

 

Idle Air Control Valve. Aka Idle Control Valve, or Stepper Motor. Check out the fault code and iacv calibration info here: AJ6 FAULT CODES AND IDLE SETTING / AJ6 Engineering

And if you want to buy a real Lucas replacement, I think you'll find they're cheapest here: 1992 Jaguar XJS Fuel Injection Idle Air Control Valve in Canada - Canada 1992 Jaguar XJS Fuel Injection Idle Air Control Valve

It's the same one for your car.

 

Heed what motorcarman told you!

 

Marco,
Etaent didn't remove the idle speed control valve. He simply diconnected the electrical connector. If this was done after the ignition had been turned on and off, with the engine cold, the the stepper motor will be left "parked" in the position ready for a cold start. This will result in a higher idle speed than normal when the engine temperature is fully warm. The higher engine speed means the engine has more momentum, to keep the engine running, if there is an intermitent problem.

 

Ok, here is what I tried today. Before first start up in the morning I disconnected the iacv. Temp was about 50F in garage. Idle was about 900 rpm which was OK with me. Drove about 30 miles. Car ran alright but idle got too high. About 1400 rpm. This presented a load while stoping and I could feel the transmission down shifting which I had never felt before. Didn't like it. Plugged it back in. Have a new iacv and will try it next.

Finding the stalling problem is difficult in that it does it very infrequently. Everytime you change something you think you fixed it but no. It stalls at a very bad time.

 

EZ driver, you couldnt be more right! I am still dealing with the issue, my solution has been to leave the IACV disconnected until i get some funding to resolve it.

 

I just bought one off ebay. Haven't tried it yet, but it was only $36+. It is such a simple function (as most of these sensors are) I felt it would probably work. More available at the below address.

</title><meta name="description" content="New Idle Control Valve Jaguar XJS Vanden Plas XJ6 95 94 92 91 90 XJR 97 96 1995 in eBay Motors , Parts Accessories , Car Truck Parts , Exhaust , Other |eBay"><meta name="keywords" content="New Idle Control Va

 

Let me know what happens, i purchased one for 250 and nothing changed unfortunately. Maybe the one i bought is an expensive knock off

 

It will be a couple of days. My other vehicle with wings needs attention tomorrow. The only thing I can think of is that the IACV is not the problem. I still have the stall. It seems to me that there is a starvation of fuel when coming off idle for just a split second. I'm going to talk to my indy and see if I can't if I can rig a way of monitoring the fuel pressure in the fuel rail.

 

Let me know what happens, currently my baby doesnt stall since i dont have the iacv plugged in. No high idle issues either. But i dont want to leave it that way since it seems my mpg has dropped from 15mpg to 12.4mpg

 

First off. Your mileage bothers me. I think there is something else wrong. My XJ6 with 122K miles never gets less than 20-22 mpg with mixed driving. Highway driving it gets 25-26. And that is with regular gas ( let's not start on what gas to use). Your mileage sounds way to low.

One thing I don't like to do is change parts to see if it fixes the problem. For one thing my car does the stall from stop idle very infrequent. I might go several days with no problem. So I can't just change a part and say that fixed it. I'm trying to gather data and do research along with testing to understand the problem.

One thing I do to avoid the stall from idle start is to add throttle very slowly and carefully when starting out from idle when stopped. It almost never stalls when I do that. What you might do is use that technique and reconnect your IACV.

The next thing I will try, if I can figure out how to do it, is monitor fuel pressure at the fuel rail. It almost feels like a vapor lock at times.

The other thing I have been doing is research on the throttle position sensor tps. That might also be the problem and I am trying to find out if a Ford part will work since they are a lot cheaper and look exactly the same. Or find the cheapest OEM Jag part. They are very expensive and if that is the problem that information will be handy for me as well as other members. That thread is just above this one in the list and the address is below. You might review that.

Don't expect a quick solution right now. I'm not very fast but determined to sort something out. I think I will start a new thread to ask members that have had to change the IACV or the tps what was the reason for the change, what were the symptoms, how did they discover what part was the problem and did it fix it.

Keep cool. I'm working on it. And your mileage looks way to low.


https://www.jaguarforums.com/forum/x...-sensor-89513/

 

Hi Bob,

How does one go about running a TPS calibration and Oxygen Sensor Orientation? Is that something a specialty shop would have to do?

Thank you,

John

 

The calibration and orientation are initiated with dealer level software, including IDS, WDS or other high end diagnostic packages. A dealer or Jag specialist should be willing to doi it for about 30 minutes minutes or the minimum hourly labor charge, assuming they just run the diagnostic.

 

Hey Ross - I guess you are a lot more optimistic on this - Man I wish I could find someone local with more experience than I have! I was just told by my local Jag dealership:

"I just talked to service and they where saying you could unplug the battery for ten minutes and that would reset the O2 sensor. To re calibrate the TPS would start out at two hours about $230.00. He would have to hook it up to the computer and then manually recalibrate it."

So much for 30 minutes... sigh... But thanks for the heads up - it helps!

Thanks again,

John

 

my xj6l gives me 18 to 18.5 avg miles per galon. i always tought that is so poor cause i had read about 20-25 avg from users here. but my car doesnt missfire or has any problems i can feel with engine. i have a less restrictive air filter too that in any case that would give a tad better mileage. and i have removed the lower catalitic converters, and since reseting the computers ive only drove like a grandpa, barely touching the gas and cruising at 50-60mph. I do notice however a light smell of fuel or unburnt fuel from time to time inside the car. could a fautly fuel evaporative system reflect as low MPG in the trip computer? i have no check engine light either. and no codes present.

 

Johnny's
Drive it over to Atlanta and bring me a cup of coffee and we will do it for free! In the mean time, check the TPS for smooth operation and repeatable position (voltage output) near closed throttle . Do that with either a voltmeter at the TPS terminals or watch the throttle position on a suable scanner.
BTW, the service guy you spoke to either is misinformed or gave you a less than complete answer. There is no manual settup. You simply confirm the throttle is fully closed, then push a button on the screen!

 

I'm pretty certain it's misinformed.... Gawd I wish I could get this solved!

Every tidbit is appreciated - thank you-