hi everybody, I recently purchased an 86 jaguar xj6 that had been sitting for a couple years, and i was wondering if anybody could help me figure out some issues i've been having. fortuneatley when i got it both gas tanks were practically empty, and i filled them with fresh gas and added some fuel sytem cleaner and replaced the fuel filter, but it still seems i am having some fuel issues that i think may be linked to the fuel pump or injectors, but i'm no epxert (not yet atleaste haha) and this is my first jag (so excited) anyways, i know there could be other contributing factors to my problem that are beyond my knowledge, and i would really apriciate the advice of some epirienced jaguar owners.
here is my issue: overal the car seems to run quite well (it only has 66000 miles on it) accelerating gradually i have no apperant issues, but if i punch the accelerator the engine gets stuck at around 2200 rpms, and it sounds as if its not getting the fuel it needs, its like its just spurting, only getting enough fuel to maintain its rpms, but will not continue to accelerate. my wife also said that it randomly died on her a couple times, and i'm thinking the problem is related, does anybody know what could be causing this? any help is much appriciated.

 

Welcome to the forum stellar-warior,

Sorry to hear about your XJ6 problems.

A 1986 could be either a Series III or an XJ40 -two very different vehicles. From the reference to twin tanks, I'd expect it's Series III?

If you confirm this, I'll move your tech question to the right section to get advice from members with the same vehicle.

Graham

 

thank you so much Graham! it is in fact a series III =)

 

( moved from General Tech to XJ6 & XJ12 Series I,II & III section )

Let's see what the resident experts can come up with.

Graham

 

thanks again Graham!

 

does the engine start easily after sitting overnight? or does it struggle? It should start from the first crank if the Cold Start Injector is in order.

I don't think it is the fuel pump; After the car sits overnight, do this: place the shifter in 1, turn your right ear to the rear seat, turn the key to Start, it won't start but you will hear the fuel pump whirring. If the pump whirrs when you try to start, chances are it is a good fuel pump.

have you checked the transmission fluid after driving the car for al least 25 minutes?
(check it with the engine running, park the car on a level surface, after driving it for at least 25 minutes, and not before).

I suspect it's the Coil, but I can be wrong too. Could be a number of other reasons.

 

The "could be" list is long but IMHO is does indeed sound like a fuel issue. These running-poorly-after-storage problems are almost almost fuel related, it seems.

The tanks having been empty doesn't prove much. They're best kept full when a car is being stored.

Let's start with something easy: remove the fuel filter you just replaced and empty the contents into a clear, clean jar. What you see in the jar will determine your next steps.

Cheers
DD

 

thanks Jose! I just went out to start up the jaguar for the first time today. It didn't start on the very first crank, but didn't seem to struggle too bad, about three cranks and it started. Still, its a hot day, (I live in southern Idaho where it can easily reach onehundred degrees in summer and fall below zero in winter) and with fall and winter upon us, I imagine it will struggle to start as colder temperatures set in. What do you suggest i do with the cold start injector? do you think it may need to be replaced, or can it be effectively cleaned and tuned up?

I checked the fuel pump as you suggested, and as you expected it seems to be in fine working order.

The transmission fluid is one of the first things i took care of after purchasing the vehicle, so i doubt that is the culprit, but the more its narrowed down the better thanks sooooo much.

 

Thanks Doug! i'll get right on that and see what i find!

 

well doug, i removed the fuel filter as you suggested, i poured the contents into a clean clear jar. the fuel looked great as far as i could tell: clear and light yellow in color, no sings of rust and no derbres. I would speculate that the tanks are not rusty or full of sediment, what do you think? and what do you suppose i do next?

 

Ok, good. Looks like you've dodged the rust-in-fuel problem bullet. Most don't, so count your blessings :-)


Anyhow....

What comes next depends a bit on your tools and experience level. I'm now thinking the fuel system is *probably* OK but, still, if you have a fuel pressure gauge now would be the time to haul it out. It would be nice to know of the pressure falls off at the same time that the engine acts up.

To eliminate a possible problem with the fuel pump circuit run a jumper wire from the battery "+" post to the white/green wire in the socket of the fuel pump realy. This bypasses the entire control circuit. Of course this doesn;t telly ou anything about the pump itself....which can be operational but not up to par. That's whre a fuel pressure test comes in.

A "sputtering" symptom as you originally describe could be an old fashioned ignition misfire, either secondary ignition (cap, rotor, plugs, plug wires, coil) or primary ignition (wiring to the coil and the primary side of the coil itself).

If you have an ohm meter you can check the coil. You want about 1.0 ohm primary resistance and about 8k ohm secondary resistance. Coils are known to give problems on these cars, as I think Jose mentioned, and the symptoms can be a bit strange.

Check your engine wiring and connections with particular attention to the wiring at/near the coil. It's often cracked/broken/loose. At the rear of the water rail is a bundle of ground wires for the fuel injection system. Very important that the connection to ground is clean and tight.

Ignition switches often give trouble, interupting voltage to the coil. For testing run a jumper wire from the battery "+" post to the coil "+" post and see if anything changes.

Well, this should give you some choices to mull over. Post back for more details, if needed.

Cheers
DD

 

sounds like great advice! thank you! i'll get to work and post later how it goes.

 

Has anyone considered the carbon purge canister? Or how about the vacuum advance on the distributor not working properly?

 

i replaced the coil, problem solved! talk to you all later =)

 

Bingo! I knew it was the coil!. Here's an even better tip:

order the coil for the 12 cylinder engine for more ooommphh! Doug has the part number. I forgot it. SHHHHH, do not reveal the secret!

 

Lucas DLB170 :-)


Cheers
DD

 

wow thanks guys! I never even thought about that, you guys a brilliant, I just might have to go order that coil. goodness I didn't even see this post till just now ha-ha thanks!

 

Wild card, just for fun!!!

The coil was fine, but the mere act of replacing it cleaned questionable connections. result, all is well, sorta.

Carl

 

hahaha anything's possible