Hi All.
The Moneyfunnel has been running quite well lately. On a whim I dumped 2 cans of R134a in it and now not only does the heat work but the A/C as well! Woo Hoo!!. As a related aside, I found and pillaged a 93 for Many Many parts in 2 separate trips. These parts include most of the intake and fuel rail, taillights and controllers, lots of electronics, and brake m/c/ abs controller- Etc...
This thread is for Roger though. I took cap and rotor off it to test and repair Moneyfunnel after having It towed home for No Start (see that thread). Proir to this all, this car had developed an engine surge which only happens while the car is moving, and after it is warmed up- a mile or so. It is such that at a steady 50 to 60 mph I can feel it in my seat. It doesnt show on the tach, but it is there. It is most problematic at about 10 to 20 mph while coasting or braking to a stop. It then becomes quite visible on the tach also. The rpms will go from a comfortable 800 to 1100 or 1200 and then back in a cycle of about 1 second intervals. Once I stop though, the surging stops and all is good with the world until (I am suspecting here) I get past 2nd gear. All shifting is as normal so I have ruled out trans problems. Last time I checked, I did not have any codes at the VCM.
Heres is my current thought though- I built an adapter cable (for the different plug) and mounted the 93 throttle position sensor to this car. There is improvement but it is only minimal so I conclude this was not part of the issue. It was only this morning that I realized this is only happening with the car In Motion. Could this surge be caused by a bad wheel speed sensor? When I noticed the clues this morning, it occurred to me that it may not be an engine sensor at all, but an output sensor- either at a wheel or at the transmission output (if there is one). I can imagine a way to test this theory but I thought I would put it before the committee to get approval of suspicions. Thank you for any potshots or head clearing jolts!

 

Jerry - surge is usually an air leak somewhere in the intake plumbing, check all vac hoses are tight - cut 1/2" off the end and re-fit nice and tight and check all the usual suspects (hoses cracked on underside etc.)

if it ain't one thing ....

anyway good news on the A/C ..just in time, right?

cheers

Larry

 

I'll have another look. I did the start fluid spray test a while back, but got no results.
It really has been one thing after another this season- all compounded by the 3.8S rear end being strewn across my countertop.

 

I poked around for a while today (not too long- you don't want to make it feel babied) looking for a hose off or a crack. also checked the vacuum solenoids located at either end of the fuel rail- both seem fine. I'm thinking of trying a different fuel regulator at the low pressure end of the fuel rail since I have extra. Whatever the case, I am 100% certain that once I figure this one out there will be a dope slap "heard around the world." If anyone would care to point me to a complete vacuum diagram I would really appreciate it since there is so much invisible "hos-iery." Thanks!

 

Jerry, another idea ...I read a thread on an XJS forum that talked about surging and attributed it to a slight "flap" of the throttle plate and or throttle spring sometimes caused by a worn bushing in the linkage ...there was also some discussion pertaining to a "sticky" IACV so it might be an idea to de-coke the thing too ...

ps when you get a vacuum diagram, don't forget to share it with the rest of us!

cheers

Larry

 

Throttle linkage. hmmmm. 178000 miles.... Could be.... I ruled out the fuel regulator, and need to dig back down to the vapor canister again and check there. I also was going to try my spare IAC since that was involved in adjustments last episode- I didn't have a spare at the time. I guess the positive here is that very few miles are accumulated.

 

Time for an update. My last poking around got nothing. I tried spraying "volatile fluid" on and around the throttle area with no results. I then changed the IAC valve to my recently acquired spare. It works but made no change. So, happy and sad there... I then tried lip suction on the evap can valve (the discontinued one). It didn't hold vacuum, so (heres where it really pays to have something to compare) I tried the same action on the Moneyfunnel and found that vacuum would hold there. I put a cap on the engine side of that line and took a test drive. It made an improvement though still not perfect. Maybe the evap system being faulty is still a problem. I dug down to the evap can and found the top off of the pressure control valve- an open vacuum port, go figure. Reassembled it with silicone and found the diaphragm bad to boot. I searched the forum for reference to the valve CBC7714. I found a thread where the writer (sorry, I don't remember his name) said he successfully used a GM part 214552. I have it on order from Rock Auto for about $21 -a far cry from unobtainium. It looks to me like the difference may be a slightly different spring resistance. My valve has a "15" where the replacement has a "20" stamped right next to the vacuum port.
While I wait for that I plan to re-install the original throttle valve and sensor but may leave the IAC as it doesn't have a huge knot of extra wiring on it.....
More later....

 

By the way, in my searchings I found multiple clear vacuum diagrams at Jaguar Heritage. The drawback being they only show the lines and parts in them Not the locations of the ports on the motor.

 

My vacuum control valve showed up and ended up being The Same, down to the Rochester stampings even though it was in an Airtex box. I happily installed it and got.... No Change! GRRRRR...
I got some time today to try for a fix, but only made things worse. Previously I re-installed the original-to-the-car IAC valve and TPS with its throttle body. When I put them back in, I tried to set the TPS (I had removed it from the housing to try swapping sweepers or such like) and got myself a trans light and a service engine light for my efforts. I have since tried again to set the TPS. My last result with a known good meter was .53v at closed throttle going to 4.6v at WOT. I have also re-done the IAC reset using the key on and unplug procedure. I think this last was my downfall since when I TRIED to start it the last time to plug the valve in, it surged badly and died as a result 3 times. I had to nurse it and although it would run, it was neither even nor convincing. Plugging the IAC in made little difference and now I have a nasty surge and the 2 lights. I don't know where to go from here and I feel like I am going in circles with this problem, each fix makes a different complication. I have inspected as many vacuum hoses as I can find, and all seem solid and at least reasonably flexible. It could be a vacuum leak but a cant begin to guess where. Throttle cable is firm and shows no wear.
I would chop the 2 plugs from my TPS's and make a 3rd, but at this point I don't think it would help. Color me stumped.

 

Hey! Real quick! Can anyone tell me if the steering column itself- sleeve and shaft assembly only will swap from 94 to 92???? I'm at the yard and there are 2- a 93 and a 94, both have tilt but my 92 does not!

 

It's update time. I have gone over every centimetre of vacuum line that I can find. I have found 2 or 3 things lacking and corrected them including the "Rochester valve " on the Evap can and a tee that was not broken but had a hole worn in the center. I have changed a couple of questionable hoses but all to no avail. The car runs like there is a 2 cm opening somewhere in the intake. The idle goes from 600 to 1200 at 1 to 2 second intervals more or less evenly - such as it might be. My next thought is water in the gas. Comments please? Thanks

 

Hi Jerry,

At this point in your saga it's hard to recall everything you've done in your attempts to resolve the issue. Could you maybe post a list of everything you've done to help us think of anything you might have overlooked?

We're with you and want to help!

Cheers,

Don

 

Did you get the trans and check engine light to go out?

 

The trans and check engine light are still on.
This all began this spring with an egr fail code. At that time I Rechecked the egr valve (its nearly new) and removed the intake end of the crossover pipe and its housing from behind the throttle plate to clear the carbon plug in the little tin tube in it. It was completely plugged and I was suspicious at the time that there should be some sort of..... airflow control... something... in that tube. I then put it all back together. Immediately after that I had the high idle problem where the car would start and idle well, but then the idle would slowly increase to about 1200 over the several minutes as it warmed up (just sitting- car not moving). I adjusted the TSP, IAC valve and stepper motor to compensate. I had it set to a good idle and it would run well cold in the garage through warming up. However upon driving 3 to 4 miles the surge would become apparent at speeds above about 35 mph (3rd gear accelerating and then upon slowing at the 2 to 1 shift causing several mis-shifts I.E. 212121 shifting). At that point in time the surge would stop once the car was stopped and I was suspecting a wheel speed sensor but did not act on it. Over the last couple of weeks I have replaced a bad "Rochester valve" on the evap can- and tested IT too, and replaced a bad vacuum tee up at the front solenoid vacuum valve. I also changed out the rubber elbow going from the oil fill tube to the plastic intake elbow. All summer I have been checking and rechecking where I could have messed up but I can see nothing ((Schultz) I know NOTTING!). In fact just now in the shower I was pondering a way to partly plug or somehow slow the airflow in the egr housing tube as that is the only other thing I can point to(maybe temporarily block it off). I have considered a bad MAF sensor (Its been on and off enough times!), a failing fuel pump (starting problems at high ambient temps last year), or possibly a failing crank sensor..... but it will still run,.... sort of.....
This is my story and I'm sticking to it.

 

I think you are getting further and further away from the root cause. Believe me, I've been there. Let's remember that the throttle position sensor provides the crucial information source so that the engine and transmission computers can work together. There are dual potentiometers in the TPS that provide the same output ranges from the same shaft but are electrically isolated from each other. As you are aware, there must be a correct reference voltage at closed throttle, and the closed throttle must be set to something like 2 thousandths of an inch. I would ensure that the TPS is the correct on, that the throttle body is set up correctly and then if things are still the same, diagnose the mass airflow sensor. You can also try to see what happens with the MAF unplugged.

 

I took your suggestion and a bit further, took the throttle body off. The throttle plate is set just to where I can see light round the edges. So I Think that's fine. I am not ruling out the TPS yet but inside the manifold I found a good 2 to 3 ounces of dirty gas laying in the low spots. I was planning on doing a temporary block off plate for the egr tube but now I will wait for further comments on wether or not there should be pooling gas in the intake and which fuel pressure regulator might be to blame!
Fuel injectors!

 

Did I not see a listing somewhere for an injector rebuild kit that includes a screen? Also, apologies to Don B, but could you send a link to your photo shoot of injector cleaning? I cant seem to ...... make the new JagLovers site work FOR me- only against. Thanks!

 

Wow, old fuel in the intake area. That's a new one for me. I've never seen that before!

 

Jerry - could you grab the injectors/fuel rail off that parts car you've been raiding and swap 'em out?

Larry

 

Hi Jerry,

That fuel in your intake manifold could certainly be coming from the FPR if its diaphragm has failed and it is allowing raw fuel to be inhaled into the manifold.

Here are the links to my fuel injector cleaning photos - sorry Jag-Lovers still doesn't have the large photos back up. The filter & O-ring kits are available on eBay and the same parts fit the XJ40 and X300 injectors:

Fuel Injector Cleaning - Filters & O-rings Part 1 of 2
Fuel Injector Cleaning - Filters & O-rings Part 2 of 2

Cheers,

Don
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