Simply put. I injected a gas/rust/rust cleaner/water/wd40 mess through the fuel system. Needless to say it died and would not start. I replaced the fuel filter/pump/ drained lines before the engine. clean gas is at the engine and it starts. As it gets up to around 14k rpm then sputters reduces rpm then recoups rises 10 14k and repeats. When I hit the gas it sputters, I let off the gas then the engine recoups.


The secondary tank is destroyed. I have not removed the fuel rail. It seems that it would be good to drain/clean the fuel rail as it could hold rust chunks.
Oh new injectors I fear for you.
The fuel return is forward too It ran for a long time that way and I'd hate to start compounding problems changing it back. I should say that it had this problem to a MUCH less degree. Generally only when I gave it lots of gas.

Btw running that mixture cleaned my heads/fuel lines heavily. Im curious if the reason the fuel return was changed may have been fixed by this cleaning agent. Seriously its unholy the amount this removed 12-14 grams.

The fuel filter has another 12grams of rust


Any ideas why it can't get up to rpm.
I'll check back.

 

Do you have a fuel pressure gauge?






Secondary tank? What kind of car is this? An XJS or a Ser I-II-III sedan?





Yeah, maybe some crud made it to the injectors




Sorry, I don't understand what you're saying



Let's start with year, model, and engine size and go from there ! :-)

Cheers
DD

 

As Doug says, a hint on the model, year etc would help get the ball rolling on this one.

The thread title is a bit vague. I'll change it to something like 'Need Help - Contaminated Fuel System' once we know you're in the right section. This way more owners of the same model with relevant knowledge will respond.

Graham

 

1983 S3 4.2V6 DAC
It has the lucas air/fuel system
Fuel injection.

I do not have a pressure gauge. I'd hate to try the gauges made for co2.

As for: "The fuel return is forward too"

The engine has to and from gas lines. The return normally bleeds from the regulator then goes through the fuel cooler (yes air conditioned model) and returns to the tanks.

On my car the pump pushes fuel to the engine through both lines. So the regulator is basically nullified as a relief system.

 

I am sure there is gas at pressure at the regulator. To what degree im unsure.

 

V6 ? the 4.2 Jaguar XK engine is an Inline 6, not a V6.

 

The detail makes all the difference although, as Jose points out, it will be an Inline 6 DOHC?

I've edited the original thread title to make the plea for help more specific.

Graham

 

Then somebody has been in there monkeying around with fuel lines and re-routed things somehow. Obviously this needs to be corrected.

But equally obvious is that you still have crud in the system ("the fuel filter has another 12 grams of rust") so it needs to be recleaned. I also wonder if the fuel pump has been damaged from contamination? It happens all the time.

I'd re-clean the tanks and lines, add a fuel filter between each tank and the pump so the pump is protected (assuming it hasn't been hurt).

You may have to buy a fuel pressure gauge so you can check regulated/unregulated fuel pressure but we already know the system is still dirty so might as well start with re-cleaning and see what happens.

Did this car sit unused for a long period of time?

Still don't know what you mean by "seconday tank is destroyed", though. Can you clarify that?



Cheers
DD

 

*cough inline 6 so I6?

I'm new at this.

Secondary Tank (R) is destroyed because of large amounts of rust. Its drained and I evaporated the contents of the tank. Put a screwdriver in the gas cap to keep the little vent open. 3 days later my screwdriver is yellow,green, and mostly rust.

The primary tank(L) is clean,flushed,new screen. Lines bled to engine. Old filter had 12 grams of mostly rust. The new filter has less than 2 hours of running time on it, so its ok. New fuel pump too. Fuel is pumping

Im going to test/clean the old fuel pump to see if it still works. (screen looks 80% blocked) If it does I will swap back to rule out underpowered new fuel pump.



The overall condition of the car is ok. He said it sat for 5-6 years. He has been restoring/driving it off and on for 2 years. 1600 or so in work. The AC system is replaced, but a small freon leak has drained it. I would test the cruise control, but im afraid the car would explode.

 

There are no "Primary" and "Secondary" fuel tanks on a Series 3 XJ6, only a left-hand and right-hand tank. Either tank can supply fuel to the pump in the trunk, via a switch-over valve also in the trunk, but not both tanks together.

At the fuel rail, there is a pressure regulator which allows fuel to return to the supplying tank via a pipe with a T-piece in it at the rear connecting a pipe to each tank via a valve. It is not entirely clear to me what has been done to your system, but is doesn't sound good to me !

I am afraid it is very difficult to assist if the system has been altered from stock. However it sounds like you don't have decent fuel pressure at the fuel rail. There is enough to start and tick-over but not pull. Other thing could be the coolant temperature sensor is duff, so there is no enrichment when the engine is cold. However, if you can start this implies enrichment, but there is a cold start injector too, and it's too long ago since I fiddled with a Series 3. Do you symptoms occur with both s hot and cold engine ?

 

Doug and Fraser are giving you great advice. As Fraser says, there is no primary/secondary, just L/R. Sounds like your L tank and filter are at least in decent condition, but the R tank is bad. First thing to make sure is that your switch on the dash (the rectangular button with the green and red arrows all the way on the left in this picture above the temp setting knob that is next to the radio (ignore the red circle this was the first pic I found Image Detail for - AutoTrader Classics - 1986 Jaguar XJ6 Sedan Black 6 Cylinder ...)) is pushed such that the LH tank is selected and don't switch to the RH tank until you've been able fix that part of the system.

As Doug says, there is still crud in the system allowing the car to get enough gas to idle, but not actually rev. If we assume the LH tank is good and the LH filter is good then you need a pressure gauge to check if your pump is able to run at the correct pressure (looks like it should be 36psi, if I am wrong someone will chime in). If the pump is pumping properly the pressure regulator could be bad and/or the injectors could be clogged.

Hope this helps and good luck.

Eric

 

Yes. Hot and cold conditions are the same. It idles for a long time, so its injecting apart from the cold start system. I should mention that the problem appeared and got worse over 24 hours. Im going to have to put my money on:

flush fuel rail
check injectors.
I'll see if i can get a hold of a fuel pressure gauge.


Would a taxed oxy sensor be a potential. Likely is the same one factory installed. Perhaps the gunk got there too. I'll do the other things first though.

 

The O2 sensor is in the exhaust system and could not possibly get gunk in it from the fuel system. Could the O2 sensor be bad? Sure, but given what you've described so far, I doubt it. I'd focus on the fuel system for now if I were you.

Eric

 

The XJ has two tanks the the check vavles and switch over valves are subject to clogging with debris. If it was my car i'd start with a actual fuel pressure gauge which can be bought at any good auto parts store. You should get about 42 PSI at the rail. If you get low pressure then go through the supply side and check valves. If you partially pinch off or dead head the return line you should see 90 PSI or higher but dont let the PSI get over 80psi or something could burst. IF you cant get to 80 psi then your pump is failed. If one tank is rusted then remove the problematic check and switch over valves and plumb the clean tank direct to avoid accidental usage.

 

 

Ok. The max pressure was 32 psi and it varies between 28 - 32 as it rev/sputter cycle.

the insertion point is between the main input into the fuel rail and the out of the regulator.

 

Update:

Replaced fuel pump again with a higher quality/higher pressure rollervayne. It idles quite terrible but once you give it gas it goes well. Even better than the beginning.

When I start it the fuel pressure hits 40 psi, but fades and holds at 30.

When i rev it dips to 28 then increases to 34ish.


Its so close to perfect yet idles nearly to death.

Perhaps adjust idle setting or run a ground further back to decrease the fuel pump - electrode. It would make the fuel pump run harder, but afraid to push the original wiring.

 

geez, if you keep on butchering the system with a non-original fuel pump which is not calibrated for the car's fuel system, you can't expect normal anything. An original-style fuel pump is no more expensive than the one you just installed. With these cars you need to stick with the original parts, especially the fueling system.

you can clean the passenger-side tank without removing it; Look under the tank and you'll see a plastic black plug (assuming it is still there); Move the plug aside if still there and then you'll see a large bolt; remove the bolt and that tank will drain through that hole.

On a hot day, take a garden hose with sprayer, with the tank's drain bolt removed, and start spraying water from the top down and from the bottom up until all the crud comes out. A dirty messy job but someone has to do it. After it fully drains, use a blower to blow air from the top and bottom until that tank is 99% dry, then let it drain and dry some more overnight. Leave the top filler cap and the bottom drain open overnight without starting the engine. Next day, reinstall the bolt and fill with gas and add a bottle of STP Fuel System Cleaner. And don't add WD-40 to the tanks.

 

Best to keep it as near stock as you can. Did you replace the pressure regulator on the fuel rail ? This acts as a pressure "weir" and returns excess fuel to the tank it comes from. Pressure in the fuel rail will vary depending on manifold vacuum, thats what the pressure regulator detects as part of its blow-off function.

Idle is adjusted on the Mass Air Flow (MAF) meter using a fairly large Allen key to vary the bypass on the MAF.

MIght help if you bought the Workshop Manual if you are going to keep the car, (a goldmine of information): -

 

I at first did buy a poor pump, but the last one I spent 240.00. Orileys suggested it for my car. They only offer 3 pumps recommended for this car.

My car has no fuel return system as of now and only still barely manages to breach 30 psi. The setup I have now, I should actually be getting overpressure, but alas I am not.

In the first few seconds the psi is good. When I give it gas it is good.

I'm going to play with that idle key. Frankly it might be the last piece of the puzzle.


As for sticking to original specs. Where is your sense of adventure?


I do have the Haynes red book for xj6 1-2-3