Before I ramble on with my story I wil ask my question: Do the OEM fuel pumps fail intermittently before they completely fail?

I am new here and I searched for a couple of hours on this topic but I have only found a couple of related threads so I though I would ask this anyway. Sorry if this s a little long.

I have owned my XJ8 for two years and packed almost 50,000 miles on it in that time. It has started every time I needed it to for that whole time in temperatures from -10F to 110F. It now has 115,000 on the clock.

Two weeks ago I drove the car to a meeting for work and it would not start. Cranked fine, tried to fire and would sometimes make a few revolutions before dying. It seemed like a classic case of no fuel delivery to the rail. I called my dealer and their service department helped me trouble shoot all of the obvious relays and we finally decided the fuel pump had failed. After the tow truck arrived we gave it one last try and it fired right up.

I drove the car for the next two weeks daily. On average I would say it goes throug about 10 starts a day. I had absolutely no problems until last Friday. I had parked the car in my driveway the night before and it would not start the next morning or for the next 4 days. I went to push it into my garage tonight after work to do some diagnostics and gave it a try just in case. It started and has for 10 tries in a row.

I'm at a bit of a loss here. Since it's all working now I can't test it for an electrical fault. I took tomorrow off to replace the pump I was sure had failed but now I don't know if I should go ahead with it or not. At this mileage it could use a fresh pump anyway but I want to actually solve the problem while I am at it. Anyone have a similar issue in the past?

Any insight would be appreciated.

 

I am dealing with this very problem right now on an '86 SAAB SPG. According to my Mechanic, the machine is equipped with a "vehicle rollover" sensor which cuts fuel flow to the engine to lessen the fire risk in a crash. The Jaguar may be similarly protected. This sensor may be the source. The intermittant nature of the start fail though is enough to kill your confidence in the vehicle, until it's truly repaired. I replaced both pumps thinking I had fixed the car, but it happened again. I would indeed recommend replacing the pumps for the reason you mentioned.

 

Swap the fuel pump relay with some other relay or take the brown cover off and check to see if the contacts are BURNT. The fuel pump draws alot of current so I replace the relay (or at least check it) when I replace the pump.

bob gauff

 

Change the fuel filter while you're at it. People tend to neglect them. It's located inside the left rear wheel well, or a bit inboard of the wheel well. I just did mine recently and it wasn't a bad job. Just be careful of the o-rings inside the filter couplers. It's my theory that the filters get clogged and eventually kill the pump. But then again, I could be wrong.

 

BigCat - There is an inertia switch in the vehicle. Jag calls theirs the Inertia Fuel Shutoff (IFS) and my JTIS says its in the "right-hand footwell behind the footboard carpet". I think that means behind the right kick panel in American but it could be just in front of the rear seat. It would stop the pump if it was tripped that is for sure. The manual says it will also kill the automatic door locks. They worked when I pulled the car in the barn last night but I will find it and test it anyway.

Bob - I did replace the relays when it wasn't working. I have spent years around Ford fuel injection systems and that's always the first place I go if I don't have a multimeter with me. I had ruled out the relays earlier but was planning to test them again when I had some help and my meter. My real concern is that the ECM is intermittently sending the fuel pump signal to the relay. If I was still in the no start state I could just check for the relay signal at the fuse box to rule this out. Since its starting now its clear that all of the electrics are in order. Thats why I was looking for some feedback on the typical failure fuel pumps themselves.

Thanks to both of you for the replies.

 

I tend to believe this too. It's on the shopping list for this morning.

 

I was able to do a little trouble shooting this morning. The car would not start. I have 40 psi at the fuel rail when I turn the key. The fuel pump is definately not the issue here.

My code reader will not connect to this car. Does anyone know what specific protocol it requires? I have a universal VAG/CAN OBDII scanner that should be current through the 2010 model year. It is my understanding that it should work with this car but I am getting nowhere.

 

Any OBDII scanner should work. What is the problem ? My OBDII reader has an auto detect for the protocol, but if you have to set it it's ISO 9999 - some numbers for the "9999" maybe "9161" ? I assume you found the connector under the dash. So, fuel is not the issue. I have heard that the crank position sensor (CPS) can cause intermittant problems like this. Maybe you could search for info on that. I'm just guessing though. It would be good if you could get a diagnostic code or two.

 

My scanner should auto detect as well. It tries to connect with several different ISO protocols and then just reverts back to the start screen. I was watching it work but it seems like every ISO protocol it showed was 10000 or above. I have never actually used in on an non-VAG car before so maybe its the scanner that does not work. All of my other stuff is based on Ford EEC-IV technology so I rarely use this scanner. I will run it on my wife's Jeep tonight and see if it works.

I did some other tests. I have consistent fuel pressure. I have consistent spark. I removed the MAF sensor and cleaned it. Then I tested compression and only got 60 psi on he cylinder I checked. I wasn't convinced that I cranked enough so I went back and tried again the car started immediately in failsafe mode. I had 160 psi on that cylinder after that.

This is probably a Nickasil engin based on the car's VIN (I have not checked the engin serial number yet). Have I fallen victim to this issue? Does the no-start from this happen after the engine has been run for long time periods?

 

Since the situation has once again magically fixed itself I found a code reader that will communicate with the car and have found the folowing:

P102 - MAF circuit low voltage - this is obviously from the failsafe start where it was not connected so I have erased it from memory
P112 - IAT high voltage - Interesting, but I would not think this would prevent a start. I will test the circuit.
P1111 - System checks complete - I undrstan this to mean that a valid drive cycle has been completed.
P1642 - CAN circuit malfunction. I need some help with this one. The section in the JTIS I have does not indiate that the engine controls are part of this network. Could this have something to do with the no-start problem. Maybe in the security system o something?

If anyone has any ideas I am open to suggestions.

 

Past
You have it right so far. The P-1642 is usually just a artifact of connecting the OBD scanner. I used to believe it almost always was, but there have been several folks report actual CAN bus failures to the TCM module. I don't believe it would usually cause a no start even if it was a real CAN bus failure.

In addition to Nikasil, there is a known cylinder wash issue with these cars. There was a recall for the throttle body to correct this, but we are long past them honoring it now. The other cylinder wash issues may very well be Nikasil related, and lots of different theories have been espoused on the subject

The IAT is integral to the MAF, as I recall, so that and the MAF are related.

I think you should do the compression test and maybe a blowby test on all of the cylinders- 60 sounds awfully low. When you have the marginal condition that you described as running a few revolutions, try the ol "hold the throttle to the floor" routine and see if that clears it. It has worked for me once when I flooded it.

 

Glad Ross chipped in. i agree with the compression check and the possibility of cylinder wash. You could kill two birds while checking the compression - check it dry, then check it wet with a squirt of oil in the plug holes, then maybe the compression will come up enough to start. Also, if you do a search on "cylinder wash" on here you should find a bunch of posts.

 

Ross & Jim -

Thanks for the input, particularly on the 1642 code. I have been driving the car all afternoon and it hasn't skipped a beat. I broke one of the air bleed lines to the expansion tank first thing this morning so I drove it down to the dealer to get a replacement and took the opportunity to BS a little with my service adviser. He didn't know what that code was so I am grateful that I won't have to lose sleep over it.

He did tell me that his shop has had another XJ of my vintage in for the same mystery no-start issue recently. They also believed it to be the fuel pump and replaced it only to find that it was actually the ECM relay that was intermittent. I have discounted this as my issue simply by the fact that my fuel pump gets a run signal during my no-starts. If the ECM relay was not working the ECM couldn't send the signal to the fuel pump.

He also fessed up to the other cylinder wash issue or "flooding issue" as he called it. He said that he had a car in about a week ago that had that problem and they had to put a squirt of oil in all of the cylinders to get it to fire. He suggested that I change my plugs based on my mileage and he also suggested the "hold the pedal to the floor" method and some persistence with it if it happens again.

I will do a compression test when I change the plugs. I agree that 60 psi is very low, even at my altitude. I am not overly worried here though since that cylinder did produce 160 psi after the engine fired. The blowby test may reveal some issues though so I will work on that as well.

Any suggestions for the best set of plugs to install? I picked up a set of platinum plugs that my local AutoZone said were the right ones but they just don't look anything like the set that is in there. These aren't quite as easy to change as the ones on my small block Fords so I would just as soon have the correct ones to start with.

 

So what's so hard about changing the plugs?

heh, heh. Actually they are a lot easier than most Fords these days!

I understanfd your angst aout the plugs. Some folks claim it makes a difference which you use, but the standard issue AutoZone platinums of several different brands have worked for me.

Oh, and join the club on those no good S*& hoses. Make sure you put the two on the front of the tank on the right ports. They look backward- the top one goes to the wheel well overflow tank- sorta crossed up looking.

 

I would have to agree with you on this. I was referring to my trusty 1970 Bronco. You know.. pull the plug wire, turn the plug out, turn the new plug in and reattach wire. It probably takes me less than two minutes a piece including application of anti-seize.

At least I have finally received some good news. My friendly, local service adviser talked me into bringing this car in for an upper tensioner service tomorrow. I pulled the driver side valve cover this afternoon to find.....that this engine has the complete upgrade kit already installed. The uppers are certainly the metal units and as far as I can tell by peeping down from the top of the timing cover the lower guides are the newer ones as well. Maybe the PO actually had some maintenance done after all. I'm going to look for an engine serial number now. Maybe the whole block has also been replaced.

 

Wow, that serial number is difficult to read with the engine in the car.

The serial is 9909291648 so there's no doubt about this being a Nikasil block. I guess I will have to learn to live with that. At least I can still feel good about the tensioners.

 

Past, the Nikasil should not be a problem. There are many that say it will outlast the steel-lined blocks. I've got it too. If you really want peace of mind, you can change your water pump and dump the plastic thermostat housing for a metal alloy one. Unless of course the PO beat you to it.

 

Jimmy- I am hearing you on the Nikasil block. I have had this car for two years and routinely did every no-no I have found listed without incident. I took the car in for an alignment yesterday and the techs at the shop took the time to talk me through the no-starts. The consensus is that it was washed but that it probably occurred due to a dirty MAF or plugs in need of replacement or some combination of other minor problems. I will still get around to a blow-by test sometime but for now I am just going to drive it some more and see what happens.

I am confident that the tensioner change is a fluke. The PO did very little maintenance on this car that was not absolutely necessary. I had the opportunity to change the thermostat last winter and cracked that silly plastic lid on the housing. changing to the metal one would make good sense. Is is also possible to get an all metal water pump?

 

Past, yes you can get a water pump with a metal vane, I guess it is all metal, I did this replacement. The description says "non-OE" if I recall correctly, but I would check and see if the parts guy knows for sure. FYI - I did hear an opinion that the metal ones may cavitate, by a learned Jag man - I think it was Motorcarman. I'm okay though with mine.