Exactly what I was working on this afternoon. I have assimilated 2 complete fuel rails and 4 more injectors that I plan only to use as cores.

 

Thanks Don. I plan to change out a set of injectors first and see what that gets me. After writing that last, I got to thinking and realized that bad regulator or not, the fuel should not be getting past the injectors without the car running. At least, I don't think it should.... I will of course keep us posted.

 

Hi Jerry,

I may be misunderstanding the above statement, but if you are still referring to the pool of fuel in the intake manifold, if the FPR diaphragm has failed, then any time there is pressure in the fuel rail, fuel can squirt into the intake manifold via the vacuum fitting, whether the engine is running or not. And when the engine is running, the vacuum in the intake manifold helps pull even more fuel through the failed FPR.

If you are referring to fuel getting past the fuel injectors into the combustion chambers when the engine is not running, that is certainly possible if one or more injectors are sticking open and leaking.

Cheers,

Don

 

Right, I have checked the vac side of the FPR multiple times by lip suction and hardly got poisoned at all. The injector(s) sticking is what I'm aiming at .....

 

Quick update... changed out the injectors with some 94 model year ones which I simply backflushed with a small jig I built and some carb cleaner. First test drive engine light off, second drive has trans light off. Still have surge. Checked newly replaced (with new) coolant temp sensor, found resistance to be high and have got another to try. Will also be looking at possible cracking or other leakage directly into manifold .......that is all. Over.

 

This is Paul Harvey with... The Rest of the Story. This morning I stopped off at my parts warehouse and picked up another coolant temp sensor- the 2 pronged one. Along with it I bought 2 bottles of "Heet." After installing the sensor, I Attempted to remove the gas cap in order to install the "Heet" but found it to be Very Suctioned Down. I actually had to pry it with my fingers to let the vacuum bleed down. "Huh." I thought...."That aint right." I then consulted the Haynes Book Of Lies and saw that it said clearly "remove the plug from the 3rd port on the Evap canister or else your fuel tank will collapse. I consulted my parts department and found that my spares have had their 3rd caps removed. "Lies," I thought. But I tried it. AND NOW! (drumroll)..... It worked!!!!!!! I drove it about 10 miles, stopping, starting, turning, slowing, coasting. Yada yada yada. No hint of surge. NO LIGHTS, No stumbling... I have been dancing while clearing the flotsam from my workbench. Does it rate a "Dopeslap heard 'round the world?" I am honestly not sure, considering the car went 25 years with that plug in place. Ill just say that after replacing the coolant sensor twice, finding 2 large and 1 small vacuum leaks, replacing fuel injectors with Newly FOUND ones that were higgledy piggeldy rinsed and installed, swapping both the TSP and the IAC to no good end, and most things done twice or thrice, I feel a huge weight off- one of at least 287KG.
I thank you all for your input. This has been a brain-frying experience.
Conclusion: Remove plug on 3rd port of Evap canister.
WOOO HOOOOOOOOO!!!!!!!!!!!!!

 

See? Tenacity (not stubbornness of course) does have its reward ... good on ya Jerry, nailed it at last!

ATB

Larry

 

Congrats, Jerry!

I've been on a journey almost exactly like yours for the past four years or so with my '92 Sovereign as well. Stumbling when decelerating, surging, etc. I've pretty much had the whole intake off and examined, checked all the vacuum hoses, replaced the intake hoses and accordion, fuel injectors with rebuilt ones, replaced EGR solenoid, EGR valves, cleaned the EGR tube and adapter, adjusted the throttle plate and idle speed about a dozen times, replaced the 02 sensor, coolant temp sensor, IACV, cleaned grounds and connectors, cleaned and adjusted the TPS, etc etc etc.

I still have the surging and stumbling on decel anytime the EGR vacuum hose is connected. I don't think the issue is with the EGR itself, but rather, I think there's some other issue which is noticeable only when the crappy EGR gasses are burnt. So I've plugged the line and left it as-is, pulling the Facia Pack Memory Fuse when the FF 39 code eventually sets.

I will check that EVAP canister ASAP! Mind telling me your sequence number? I'm 656772. Maybe they had a bad week and left the plugs on both our cars. My car was reacquired by Jaguar in 1994 due to some Fuel Fail codes... Who knows?

In all the research I've done, I do recall reading that the 93+ fuel injectors are different from the 90-92 ones. The older ones have a pintle tip that emits a single cone-shaped spray of fuel.

The 93+ injectors are of a plate-type, twin-spray variety, and have a green band. The injectors have a different clip than 90-92 injectors to keep them oriented correctly to aim the twin-spray at the intake valves.

Not sure if there were any ECU adjustments for the later injectors, but just wanted to make sure you were aware.

-Nick

EDIT: Also, by third, are you talking about the far left port "Purge Air Inlet"?

 

Good info, Nick! Your research agrees with mine.

I do think there must have been a change in the ECM fuel map programming for the '93 and later cars because the fuel flow rate of their injectors is just 210 cc/min, compared to the rate of the earlier injectors of 240 cc/min. It seems obvious that a primary goal of the revised double-orifice plate-type injectors was to improve fuel economy by aiming narrower cones of atomized fuel more directly onto the backs of the intake valves. This had the benefit of reducing waste and unburned fuel, improving efficiency, and giving the ECM increased control over dynamic fuel management. Here's a link to some information I collected several years ago as I was researching Jaguar fuel injectors:

Fuel Rail Overhaul Part 2 of 3 - Injectors

Cheers,

Don

 

Hi Nick, thank you. I wish though, that the fix had held. Those 10 miles were all I got and its back as bad as ever. I mostly get my symptoms at cold start, and when slowing at the shift from 2-1. Stopped and warm it's "Usually" fine. My cars number is 655170, so you may well be onto something there. I appreciated your listing of what you did because, while I did already do most of it I have not tried cleaning out the crossover pipe ( but I thought about it) or tried just plugging the egr vac tube. My associates have suggested I delete the valve but I doubt that would solve anything and I don't want to. My next attempt will be to remove the Evap canister and check it for flow along with checking its electric valve- I've already replaced the vacuum valve there. The plug on mine was on the left hand port. I have also tried swapping gas caps with a 94 but got no effect. Sorry this seems scattered, I'm writing it on my phone and can't refer back to your entry. I'll check it later and see what I've missed. Again, thanks.

 

Thanks Jerry. I have had three similar situations where I finally thought the problem was solved and over with, just like you, but only temporarily.

I did try pinching off the vacuum supply hose to the Canister Purge Valve, but same stumbling with EGR active. I haven't accessed the canister yet because the fender liner screws at the bottom seem to only want to spin...

I have narrowed my symptoms down to this one easily testable scenario:

-Engine at operating temperature
-Park brake on, transmission in Drive
-With service brake on, rev engine 1100 RPM then quickly release the accelerator

With the EGR vacuum hose connected, the engine shakes and stumbles for a couple seconds before it settles at idle.

I removed the vacuum hose to the Fuel Pressure Regulator and did smell gasoline, unlike the last time I checked a couple years ago. It certainly could've been gasoline residue in the intake causing the smell, but I ordered a new Bosch FPR today and will install it then run my "test".

Its getting to the point that I'm even considering swapping in another ECM... There was no issue until I got a FF39 due to an EGR valve with a bad diaphragm. I replaced it with an OEM Jaguar valve and it's never been right since. I've ordered a second new OEM Jaguar EGR valve and it's done the same. I've swapped vacuum solenoids out as well with no results.

I'll be keeping an eye on your progress as we both search for solutions.

Nick

 

I haven't done any more work yet, other than to move that car to a larger space for more swinging room. The comment on the injectors has me wondering though. The ones I put in it are from a 94- they are the green stripe ones. The ones I took out were correct for 92, at least if i am reading the descriptions correctly. I now have a code ff26, o2 sensor lean. I have to assume this is caused by the newer injectors. Does this seem reasonable since I haven't had a code 26 before?and is there a way to adjust the ecm? Larger hammer maybe......

 

That makes perfect sense, Jerry.

The fuel flow rate for the '93-'94 green-band injectors is significantly lower than for the earlier injectors. Perhaps your ECM cannot adjust the AFR rich enough to compensate, so the O2S is correctly reporting a lean mix.

Here's a link to some info on the injectors (sorry the large photos are still not working):

Fuel Rail Overhaul Part 2 of 3 - Injectors

As far as I know there is no easy way to reprogram the ECM with the correct fuel maps for the green band injectors.

Cheers,

Don

 

Ok, thanks Don. Plan is to clean the originals in the same cheesy cheap fashion I did this set, and reinstall.
I have my Evap canister off and am applying vacuum to the various lines and not learning much but it smells of gas. I am also hatching an idea. On which involves installing a 1/2 or 1/3 or 2/3 blank plate over the port at the intake coming from the crossover pipe. Has anyone tried this?

 

I have 'decided' that the Evap can is not the problem. I put that all back on- including the plug on the 3rd port (we will see if it stays). I changed the throttle plate off for the replacement one that I used previously. Then this morning I made a partial block off plate for the EGR at the exhaust manifold. It is made from Exhaust gasket paper. I gave it a hole with a 15/64 drill bit. I ran the car this afternoon with good results. It worked well until I entered traffic and apparently blew the paper out. I will be trying the same again with something more stable than paper. I also need to change the injectors out yet too..... I am encouraged though...

 

I may be on the up side now that the season is nearly over. My exhaust- paper- gasket of yesterday worked well until it blew out. Today I found some aluminum sheet slightly thicker than a pop can and made another restrictor plate of that. Nicks suggestion that blocking the EGR off didn't help much made me think I should not block it Completely. I put a 1/4 inch hole as a first attempt fully planning to adjust up or down. I also removed the plug on the 3rd port of the EVap can again. I put it back earlier as a test which failed. Today I drove the car 9 miles with steady speeds of 45, 60, 70, and a short distance of about 83 mph. I see no damage, and more importantly no change in behavior from what it was beforehand. The idle is high at 1100, but I was messing with the IAC screw so not much concern there. Tomorrow after it is cooled down I will work on changing the injectors back to clear the code 26 and then install new plugs and wires. Then put it away for the season...... (grrrrrrr)

 

Hello Jerry,

I'm not sure if you've tried putting a rubber cap on the outlet of the EGR solenoid, but that would effectively disable the EGR system to isolate whether or not that's causing the surging.

If I leave the EGR vacuum hose connected, I get lots of stumbling and erratic engine speeds when decelerating and noticeable stumbling when cruising at steady speed.

With the EGR solenoid outlet plugged, the car essentially runs just fine, aside from the eventual FF39 after the ECM realizes the EGR is disabled. My 92 has been operating this way for the past 3+ years.

It only takes a few minutes to locate and block the hose. This would rule out the EGR system causing your surging.

-Nick

 

Thanks Nick, I did tinker with that valve thing but only to make sure it was working. Theses last 2 drives have me hoping. I still have a lot to do- injectors, plugs& wires and then assuming all is still well I want to try putting the correct Tps back on it. I am using a 94 MY throttle valve with a correctly set tps and a short adapter cable at the plug to avoid the cut and splice pitfalls..I'll keep that in mind as an option, but we all know how I despise that light!

 

Stay Tuned! For this weeks episode of Roger and the Vacuum Leak!
I have made a "tin" restrictor plate and installed it between the exhaust manifold and the EGR valve base. It has a 1/4 inch hole in it. I would say the full diameter of the tube is about 1/2 inch. Otherwise the egr system is complete and functional as far as I know. I have cleaned and reinstalled the original fuel injectors. I started it, let it warm up fully and then drove it about 20 miles at varying speeds holding steady at 40, 45, and 55 for a mile or more each. I felt no surge or stumble, had good shifting up and down. When I pulled back in, I found that I had an idle of about 1100 rpm. I adjusted the IAC screw and got it down to 800. I waited a few minutes and tried a hot restart with good result. I then let the car rest for about an hour. I came back and started it again, It started very well and the gauge showed still warm. Drove it to the parts store for a Water Pump for The Buick (GRrrrrrr) and found that the idle had settled to 600. Then later put it back away. All with good results. The O2 sensor code cleared, but was replaced by ff14. I think I know what that will lead to. Beyond the code..... all seems swell today.....
Tune in next week for another exciting episode of Roger! and the Enormous
Vacuum
Leak!!!!!!

 

So any update on this problem(s)