Hello All,

I took my 1997 Jaguar XK-8 Re-Animator project outside of the confines of my Industrial Park and it let me down.

Just had new/used transmission installed.

After about 15 minute drive, engine idled rough.

Reached destination (auto parts store !) and shut off car.

When I returned, car would barely start, but not rev, with rough idle. Plugs were wet. At one time I got spray from fuel rail Shraeder valve, other times not.

Had car towed home.

No start. No codes. No apparent fuel pressure.

Measuring zero volts at fuel pump with ignition switch on, but can't tell if pump cycles on and off because have misplaced continuity light (and working alone). Will have helper or trouble light avalable in day or two.

1) Should fuel pump always be energized?

2) If not, where to look? Have checked fuses and swapped fuel pump relay.

3) Could it be switches in shift console or wiring ?

4) Shift lever adjustment?

5) Bad fuel pump?

What am I missing?

Thank you for reading.

 

The starting sequence for Jaguar is that when the key is first turn to the on position the vehicle performs system check and energizes the fuel pump for 3 to 5 seconds to charge the rack then shuts down. As the key continues to the crank position the engine turns over, the crankshaft position sensor sends a signal to the ECU that engine is rotating and the ECU turns fuel pump back on.
You should be able to turn the key on and wait 5 seconds turn it off and have fuel pressure. If not check circuit for energizing initially and check for clogged fuel filter. If it is energizing and the filter is clear then it is most likely the pump.

 

If you have fuel pressure and the plugs are wet you almost certainly have bore wash. Then there is the issue of running rough. Could be a chain tensioner failure, so it would be a good idea to remove the cam covers and be sure the cam flats line up.

 

Got someone (angry wife...I kid sort of) to turn the key and measured voltage at the pump, but can't hear or feel the pump running. No visible fuel pressure...a little dribbling at the valve. Interestingly I (borrowed a gauge and) measured about 40 psi about a week ago, but was having some hot starting issues. This is a car that sat for several years, so a fuel pump failure isn't out of the question.

...I appreciate your interest RJ237, but please, please don't say any more about chain tensioners, because that could invite the bad mojo. I've spent many a late night in the garage tackling that bear and if I ever see the insides of this AJ26 again, it will be too soon!

So it's likely I will have to order a fuel pump, but first it occurs to me that the crankshaft position sensor was spliced in place (by me). I'll check that and if the splice is ok, will then order a fuel pump. Already replaced the fuel filter. Will let you know of the results shortly.

On the positive side, the fuel pump made no noise, but, while I was in the trunk, the CD deck started clicking. I wiggled it and now the radio works !

Finally, let me say how much I appreciate the folks on this forum. Whether I'm completely lost or have an idea on how to solve a problem, the advice I have received always lets me generate a plan to solve the problem. And when you own a car that is so problematically challenged, it lifts my spirits to know that there is (almost) always an answer !

 

Replaced fuel pump. (That was interesting.) Car starts strongly, then dies. Sprays gas from the Shraeder before cranking. Nothing after car dies. So from Avern1, it seems the fuel pump isn't getting the signal to keep going. No codes. I'm going to re-visit the crankshaft position sensor...but after that, I got nothing. Ideas?

 

It can only thusly be , clean the sensor face first as metallic debris clouds the signal out .

 

You have 2 fuses and one relay that feed the fuel pump. See if this information helps.

Link JagRepair.com - Jaguar Repair Information Resource

 

Here is what I wrote a couple hours ago:


Thinking this could be a vacuum problem as there is some backfiring...

...And I was right (finally after going on every other imaginable tangent !) though I am not yet sure how to fix the problem...and it's too late to try...

I removed and plugged the vacuum line that goes to the fuel pressure regulator diaphragm on the right side fuel rail (at least I think that is what it is).

Lo and behold, the engine revved up. Not all that smoothly, but it produced some power.

Now, is the problem in the vacuum lines or in the diaphragm, I have no idea. Last week I had my Indie mechanic repair a lack of brake vacuum. He might have routed a hose incorrectly...Or the fuel pressure diaphragm may have given up the ghost. Or both. No idea yet.

If anyone has seen this, your wisdom and experience is appreciated !

 

Remove the vacuum line and pull a vacuum test / leakage test on the fuel regulator and see if it holds vacuum. A brake bleeding tool works well for this test.

Link https://www.harborfreight.com/automo...le/brakes.html

 

As it works you have more fuel pressure when you bring engine RPM up ( not by much ) so by removing the line you will have underfueling injectors unless the ECU adjust the pulse time to compensate for the lower fuel pressure to keep your STFT at 0.0 . Just a thought . :icon_shrug

As the RPM comes up a vacuum leak is compensated by the larger supply of vacuum .

The vacuum hose fitting in the intake to the brake booster is suspect in my inline 6 different then your V8

EVAP valve stuck open or line off ?

 

Hello all. Still working on the problem...(Removed the throttle body...found a couple bolts missing (not of the four that hold the throttle body in place) and a nick in the line to the fuel regulator. Checked wiring on the crankshaft position sensor, but car runs with cksp attached not without....and the part is almost new, so I don't think that's it but could be wrong.)

So after replacing the throttle body, hooked up my ELM 327 and got Pending: P1000, P1336 (cksps), and PO358. Also PO358 in the Active area. P0358 is an ignition coil problem.

Still, the car starts, but won't rev up, at least not smoothly.

Also, I found this plug with Yellow / Red / Brown / Blue wires attached, but not the other end of the plug. It's near the throttle body, but I can't find the other end.

Ideas?

 

EGR stepper motor?
It was dropped from 98:


Colours mostly match what you've reported

 

Hmm MichaelH.... those colors - the yellows match a plug that never attached to anything, even when the car was running right...

So I'm at a crossroads. Before I was looking at vacuum and fuel as the source of my problem...But I wonder if the problem isn't electrical...(However, I am discounting P0358 as I found a disconnected sparkplug wire.)

Re Electrics: There is more than one electrical plug - now four in fact - that don't seem to have an connection. However, I do have the schematic so serious study is in order.

Observations and Questions:

1) MichaelH...Do you have any idea what a stepper motor looks like and where it goes? Or is it even necessary, since Jaguar got rid of it.

2) I smell a lot of unburned fuel and think the O2 sensor, or its heater may not be attached on the driver's side. Almost sure of it.
Does anyone know if a bad O2 sensor would give me the symptoms I am seeing....currently back to a bad idle and very poor throttle response.

3) Going back to the vacuum issue...I noticed the throttle body was oily inside. Also seeing some leakage on my left side cam cover...Related? Vacuum issue?

4) Issues started after transmission was replaced. Engine ran reasonably well beforehand but occasionally threw codes. It idled nicely but sometimes had trouble re-starting when hot. Putting it in neutral to start seemed to help.

5) I can't be sure...but when the engine is popping and backfiring, it seems that the VVT sometimes audibly snaps into position with an awful slap towards the front of the engine. Chain tensioners and chains have been replaced, top and bottom. Is this a clue to bad engine management?

6) Engine doesn't smoke. I've never measure compression and I'm not going to, because what's the point. I'm not taking this engine apart again! (But I will fix the wiring if necessary.)

7) I hope that reading of my situation is of some value. Of course XK8 problems aren't unique, but it seems this car may be missing parts, which isn't all that common.
Thank you, readers, for your patience and interest.

 

I've not seen one in the flesh - but here's a pic (LCA1550AE):





I think it attaches at the back of the TB:- the location is blanked off in the later cars. I'm only aware of its existence because that is one of the differences in the 98-on ECM (although the electronics appear to be carried through, but not connected to anything).
I doubt its being disconnected would throw any codes as there's no feedback loop & as you say, Jaguar obviously decided it wasn't adding any value.

Poor idle can be air leak - what are the fuel trims saying?

When I last had the TB off there was some clean oil in the elbow, and cam cover leaks seem to be common.

Perhaps post pics of the orphan connectors together with their locations - we might be able to identify them?


edit: FWIW, I can't find any reference to the EGR in JEPC

 

The 97 did not have a egr valve.

 

Thank you michaelh and RJ237. So fuel trims should be less than 5% and 20% is bad (no need to answer unless I am incorrect). Let me have a look. That might be the change I am looking for ?!?! Making a living will probably interfere with my Jaguar schedule, but I will be back soon.

(The location of the non-existent egr valve would correlate to the location of the connection-less plug. Will survey other plugs in the interim as well.)

Thanks again !

 

I believe that I have located the problem and, with a bit of time this weekend, will be able to fix it. Had I listened to Gus two weeks ago, I would be that much closer to a solution.

The problem lies under the dash. When I re-wired the brake lights (which had been re-wired once before) I set it up so that they only activated when the ignition switch was on. That way, when I was making out with my girlfriend in the park with the engine shut down, and my foot pressed the brake pedal, I wouldn't run the battery down.............................................. .....................................





And have to call my wife to pick me up.

Bah dump bump.

Anyway, I jumped pins three and five on the fuel pump relay as per the link Gus provided and the car ran pretty well...Until I started poking around under the dash. Then the car ran better. Then it ran worse. Then the dash lights came on when I pressed the brake pedal.

The schematic indicates the ignition switch is tied into the fuel pump (which you all pointed out to me as well) and to the security system which also has some sort of control over the fuel pump. With the CAN system it sort of has a mind of its own. There are probably other electrical pathways too. So, most bets point to a short.

I'll have to take the dash apart (again) this weekend. Will avoid the ignition switch when I do my re-wiring. Not looking forward to it, but has to be done.

No more time during the week to mess with it.

I don't know why I didn't inspect the relay and the dash earlier. I had a suspicion, and an aversion to looking in that area. Perhaps I knew deep down what I would find, and didn't want to re-visit those regions.

Thanks Gus. Thanks everyone. This has been a wild goose chase. Still is. I'll let you know when she purrs like a kitten - and roars like a Jaguar.

 

Weeks later...I'm still lost....Last thing, I cut the brake switch wire that I had connected to the engine run or accessory (red white or orange white) and ran it directly to ground.

Ran the car. It ran fine.

Put the dashboard back together.

Same symptoms. Starts, but won't stay running.

Now, no tachometer and no lights on the transmission lever.

Code 1638 (CAN error). Car runs the same without the dashboard (CAN junction) connected however.

Dash reads Transmission Fail, Engine Fault, sometimes incorrect part fitted.

Transmission recently replaced. Thinking the Indy who did it might have left something loose. Might try to limp it over to him.

Any ideas?

It's a mystery and I know you folks are brilliant detectives.

Thank you.

 

Jusr throwing some ideas out their with little detail ;

1 ) Transmission ECU correct match with the correct software .

2 ) Transmission electrical connector on transmission body clean as the the engine and transmission talk to each other and will stall the engine alone .

 

Have you checked your grounds?



Link JagRepair.com - Jaguar Repair Information Resource