When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Al, I will give you the same advice that others have mentioned. If you have not cleaned the injectors and to the TB it is time ti do so. I had date exact same issue as you and the cleaning did the trick Besides it also upped my fuel economy.
Al, I will give you the same advice that others have mentioned. If you have not cleaned the injectors and to the TB it is time ti do so. I had date exact same issue as you and the cleaning did the trick Besides it also upped my fuel economy.
Thanks, I did a complete tear down and cleaning of the TB and intake track early in 2017, which included new Bosch fuel pressure regulator, Jaguar air temp sensor, new Jaguar SC intake boot, Jaguar SC intake track seals, Jaguar intake gasket, fuel injectors rebuilt by the Jaguar fuel injector guy, Jaguar fuel filter and various other bits.
My independent mechanic friend is suspecting the ECU at this point since I've changed just about everything except the IACV, TPS and MAF. We really don't suspect the TPS or MAF at this point, although the IACV is debatable and may be on the list to test based upon the techniques laid out in the previous posts.
The mechanic's son has a similar XJR6, and we're likely going to swap ECUs next weekend to see what happens.
In addition to the work above in 2017, so far in the last few months:
- New Autozone "lifetime" Denso(ish? ..who knows anymore) alternator
- New Jaguar engine ground strap
- Additional engine/alt ground strap
- Cleaned and tightened multiple significant power and ground locations
- New Jaguar relays: both fuel pumps, ECU, RH engine ignition on, RH heelboard ignition on, trunk ignition on
- New Jaguar crankshaft position sensor
- Rebuilt and timed camshaft position sensor, new sensor electronics
- New belts, all
- New Jaguar coolant temp sensor (ECU)
- New Denso fuel pumps, twin
- Extra fuel pressure drainback/check valves, one per pump
- New QYL coils
- New Champion copper plugs (changed yearly) with little to no oil in coil/spark plug wells (only shows up in well 3 if ever)
Some other tidbits:
- EGR valve is 4/50k miles years old, replaced as part of the EGR/TB-return-spring recalll
I feel like I'm forgetting something else, but that's what comes to mind off hand.
I'm tired today after a 24 hour adventure driving over to Knoxville, Tennessee to buy a 1994 XJ12 and trailering it back at 4am
Al, you may have addressed this earlier, But does it stall on a cold or hot engine or both? Does it matter what the ambient tempos are? How is the restart? more cranking than normal? Any smoke with the restart? When it does start after a stall, is it as if it never stalled in the 1st place?
Al, you may have addressed this earlier, But does it stall on a cold or hot engine or both? Does it matter what the ambient tempos are? How is the restart? more cranking than normal? Any smoke with the restart? When it does start after a stall, is it as if it never stalled in the 1st place?
Yes, thanks, covered in more detail in previous posts but in order of your questions:
Hot engine, coming to a stop when dropping to idle, dies. Doesn't not normally occur with a cold engine, but has a few times when first starting the car.
Doesn't seem associated with ambient temperatures, this has been happening since winter and continues now into summer.
It did take more cranking than compared to other cars in good working order, but I think that was an unrelated issue with the camshaft position sensor. Now that I've rebuilt the camshaft position sensor, it starts on first key turn. However, when the car is exhibiting this problem, it will take 2 or 3 tries to get it started, I will have to feather the throttle to keep it running then the idle will settle and will run fine until next incident.
No smoke that I'm aware of, no rich fuel smell that I'm aware of, but I'm usually in traffic so can't tell. It is possible.
Yes, each incident is unique and no better or worse than if it died recently. In other words, it doesn't seem to "get worse". But once it has started to be a problem it is likely to happen again.
I am relatively convinced it is some sort of heat soak related issue, but not yet proven.
These were the photos the seller had taken. It was a 24 hour odyssey driving the truck & trailer out to TN, loading the car, and back to NC. Very tired today, so really haven't done anything other than unstrap and unload the XJ12.
Try giving the EGR valve a wack with big screwdriver... that does it for mine about 90% of the time. after a couple whacks it starts right up and idles fine. Also sometimes revving the engine up will cure it.
Steve may have point. The EGR would cause a stall if it is sticking.
Hrmm, I'll put it on the list.
I'd be surprised since it is relatively new, but on the other hand it does have 40-50k miles on it.
I wonder what the easiest way to test it's operating in a good state would be though. For example, could I unplug it's electrical connector at a particular point in it's movement (e.g. closed) and if the problem disappears that would indicate the EGR? If so I assume I'll get a code for the EGR while testing, but other than that the car would run fine?
I see no reason not to test it the way you mentioned. but It would be best to just remove it and check to see it sticks when you manually move the plunger...I know... you dont want to remove it... neither would i. But, it may be worth the effort. By the way, I had one go wonky at 50K
I see no reason not to test it the way you mentioned. but It would be best to just remove it and check to see it sticks when you manually move the plunger...I know... you dont want to remove it... neither would i. But, it may be worth the effort. By the way, I had one go wonky at 50K
Oh I don't mind removing it.... of all the things I've been removing/replacing on this car in the last year, the EGR is a piece of cake, just right on top, out in the open!
I'll check it out.
Question: How does the EGR behave at idle, versus open throttle? Is the EGR normally doing something different at idle that would correspond to my "dies at idle" scenario? Just trying to understand it's operational modes.
Al, yes you are right it is not hard to get at. Why engineers put some replacement part in places no one can get at is beyond me. Just wait till you see the x351.. you cant even see the engine. LOL
Fortunately the EGR valve has a followup sensor inside so you can see where the valve position is at unlike the IAC valve . There is also the EGR temp sensor . All of this can be read at the ECU connector once you have the engine warmed up in the area of the fault , and tapping is a good suggestion that has helped me find faults with a meter on different things . There is no other connector in between .
Your ECU connector inspection may visually point to a bad socket before getting a meter out .
With the ECU connectors off you might be able to drive the valve motor through it's positions with a 9 volt battery and read the position change in the other sensor wires at the ECU .
The Black / Light Green wire on Black 24 which is also tied into Red 17 and the power output on the ECM controlled relay that powers the EGR motor and another tap on the Black / Light Green wire is the power to the EVAP valve and MAF sensor and can be sucked down in them having a fault . One of the more important taps of this wire is the power source for all 6 fuel injectors .
On certain non SC engines this Black / Light Green wire also powers the fuel tank canister close valve and is located by the fuel filter .
The Black Green wire on Red 30 is tapped into by the Cam position sensor and Inlet Air temp sensor so their connector can be removed after starting and see what you get .
In theory , with both ECU connectors off you should read 0 resistance to any ground at socket Red 30 or Red 17 to any ground . And if not you can disconnect one blue or yellow device at a time depending on what the red or blue wires are attached to .
Editing
Last edited by Lady Penelope; 06-11-2018 at 02:29 PM.
The EGR valve should be closed at idle and also wide open throttle. It should only be open at part throttle. An EGR valve that is open at idle will give a very poor idle if it even runs. Carbon buildup in the valve or a defective valve itself can cause this.
Would you be able to tell at idle if the EGR valve is open based in the lines temperature vs. the surrounding block as this would be a easy verification that it's open when not suppose to be . This would be easier then a meter if not up to speed with a meter .
Would a cheap infrared temp meter give you a real set of temp values you can use to compare .
We used them at work on the flight line but 9 / 11 ended that
Last edited by Lady Penelope; 06-12-2018 at 01:26 AM.
OK, here was my EGR test, not sure if it validates anything, but...
Car was cold, has been sitting without being started for several days. Before starting I unplugged the electrical connector to the EGR. Car started right up with no problem and settled into the correct idle RPM. The RPM remained normal when put in gear, and the car drove away normally with no issues stopping at several stop signs and stop lights. I drove the car a couple miles to Autozone (parts for the XJ40.... and so it begins ) and let it sit for about 30 minutes.
At this point this is typical behavior where the car exhibits no issues until it has been driven and/or sat and heat soaked for 15+ minutes.
After coming back to the car from Autozone, EGR still disconnected, the car started well but RPM dipped to 500 briefly. After driving the car another approximately 3 miles at 55mph the idle dropped below 500 and died upon turning off the highway and decelerating to turn into a parking lot. This is the normal problem scenario.
As usual, I was able to put the car in P or N and restart while feathering the throttle, at which point the idle returned to normal RPM and I could drive away with no issues.
The car didn't die again at three other stop signs, but repeated problems are hit/miss, although the idle did dip dangerously close to 500RPM at one point when decelerating.
Again, the EGR was disconnected this entire time. Also interesting is that no CEL was lit, but I don't know if EGR will light the CEL and how long the DTC must persist before the CEL will light.
So I'm thinking EGR is not related to this problem since it ran fine with the EGR valve disconnected, then still disconnected exhibited the problem. Thoughts?
It sure it odd though that it will die, then I can start it right back up with a little throttle feathering, and it will drop right back to a good idle. If purely heat related, one would think the low RPM problem would persist even upon restart and not instead act like "nothing happened". So odd.
06-10-2018, 10:41 AM
) and let it sit for about 30 minutes.