1989 XJS fuel injected, no modifications, all stock, professionally maintained. Out of the blue this morning, the engine wouldn't start. The starter turns the engine over very well. The engine just doesn't start, like no spark or no fuel or ?

Are there basic spark fuel tests I can perform before I call the tow company? I'm somewhat mechanical. Thanks very much.

 

So many possibilities.

You can check for spark the same way as you would on any other car...except for the plug wires are harder to reach :-). Post back if you've never done this before.

Turn off the radio, fan etc. and turn the key "on". Do you hear the fuel pump hum for 2-3 seconds? You should. If not, post back.

If the car has Marelli ignition it couldn't hurt to pull the distributor cap and see if the rotor has burned through. If it has, well, you're lucky it didn't happen while you were driving.

Do you have a test light? Volt meter? Fuel pressure gauge?

Cheers
DD

 

First check the simple stuff...like the Coolant temperature sensor, and the Intake air sensors are plugged in good.

Plenty of gas in the tank etc. ...

Dave

 

Thanks Doug, Dave, I appreciate your replys. I have a test light and a voltmeter...no fuel pressure gauge. The fuel pump does click for a few seconds when I turn the key to the first position. I haven't tested for spark yet.

While looking under the hood, I noticed one of the wires was pulled out of the electronic part that sits just an inch or so rearward of the mechanism where the two throttle linkages cross and fit into, along with the throttle cable. The part has a small arm on it and is adjustible. The plastic on the electronic part is broken, so the wire can't be plugged back in to it. The part was made by Burgess and has the number VBFYR1.? on it. The number is a bit hard to read. I'd post a picture, but don't know how.

What is that part called? Is it the reason the engine isn't firing?

 

Yes, that is almost surely the reason, and that, I believe is your TPS (throttle position sensor).

Dave

 

That sounds horribly like the "full fuel" micro switch, on the throttle capstan. It is a common "broken" bit, and NO it will not stop it from starting. It is purely a fuel enrichment device for acceleration purposes, one of 2 on that engine.

That indicates to me that yours is a Lucas ignition engine, being an "early" '89????. Is there a "black box" looking thingy bolted to the LH inlet manifold, slightly larger that a packet of smokes??.

let us all know that answer, then answers will flow thick and fast totally related to the engine system on YOUR car. 1989 is when Jaguar introduced the Marelli system (as Doug said), and that system has its own very specific issues, not related at all to the Lucas system.

 

Just got through with my '92. Went to the store and she wouldn't start. Funny, I've only had the car for about 2 months, never had AAA before but something told me, "you own a jag now, you'll need AAA", so I got it. Had the car towed home, free!! and fairly quickly also.

I didn't hear the pump run on first key-up, plus the car seemed to try to start, which told me that it probably had spark. Pulled the relays from their hidey-holes, removed them so I could read the terminal numbers, wrote the terminal numbers on them in sharpie so I could see them (old eyes) and reinstalled them. Tried the car again and it started. Figure I'm going to replace both the main and fuel relays....should be cheap (fuel relay on my wife's old Taurus she used to have was 10 bucks last year...even if the Jags are twice that it's only 40 bucks).

howlinowl

 

Grant Francis, Howlinowl,
Thank you very much for your comments. They're most reassuring.

Grant, there is indeed a black box on top of the LH inlet manifold. It's identified as Lucus AB14 Electronic Ignition Amplifier. Wires and ground to it seem to be secure. I did find the second Full Fuel micro switch, also on the throttle cable on the other side (throttle pedal side) of the throttle capstan.

 

mine would run without a TPS. (long story how I know that) ran like a POS but still was able to drive. Finding your problem is just a matter of narrowing the massive list down into a smaller one. 1st. is the problem fuel or spark? 2nd. narrow that down to your problem.

I had the same problem, turned out to be the distributor pickup. It does't seem like anyone maintains the distributor on these cars like they should. It's an important bit.

 

OK, Lucas system car, info now able to sorted.

That 2nd micro you found has nothing to do with the fuel system. It is the transmission kickdown micro switch, and also may be broken, and again, NOT related to NO start.

The 2nd full fuel switch is a vac operated switch (commonly known as the "blue/white" switch). It is generally tucked into the inlet manifold space around the 5A area.

I would pull a plug lead, any will do, and plug a spare spark plug into the end, any old spark plug will do also, and crank the engine, see if you got a GOOD FAT BLUE spark. That will eliminate the ignition system somewhat. A crappy yellowish spark is NO GOOD.

Then CAREFULLY (FUEL SPILLAGE WILL OCCUR), crack the 2 nut setup that is the fuel hose connection TO the rail and observe the presence of fuel. If you got "pressure" in the system you will get a good spurt, or just a dribble if the pump/filter/relays are not working as they should.

Once the problem is reported, a fix will be sorted, and quite quickly I reckon.

 

Grant, EcbJag,
I pulled a sparkplug wire, put a sparkplug in it as suggested and grounded the plug to the manifold. No spark at all when turning the engine over, turned the room light off to be sure. I haven't done any fuel tests at this point.

If I do need to crack the 2 nut setup on the fuel hose connection TO the rail, to observe pressure, do I do it with the engine cranking or not?

What is the distributor pickup?

 

OK, forget fuel for the moment.

Just to NOTE, NO for the cranking to check fuel. Once the ign has been ON, the system is deemed "primed", and that will provide sufficient for that test.

Since this is "out of the blue" as you said, I will stay on that track as best I can, and from my experience of items that just go legs up out of the blue.

Now you will require a DCM (digital volt meter). Turn the ign ON, the Black lead of that meter earthed, and probe the +ve coil post with the Red lead. The meter should be set on DC Volts of 12 or larger, and you should see battery volts (about 12V or so).

If no volts, then I suggest the "electrical section" of the ignition switch has gone hissy.

If you got volts, GOOD, to a point.

If you have volts, then I am heading for the module "inside" the AB14 amp has failed, they do that. That module is readily available, and I use an Echlin (made in USA) part number TP45B (the B being for "blister pack").

The coil itself may also have died, but since you have 2 it would be rare for both to fail, and the spark should be present.

Another issue I have had 3 times is the carbon brush "inside" the distributor cap has failed/worn away. I buy them here from the local GM dealer for about $5.

The pick up inside the distributor body can fail, but it is quite rare in my opinion.

Once you establish spark, the engine should start.

The inertia switch is fuel pump related, so lets not confuse things until you establish SPARK.

 

Thank you Grant. Your experience and familiarity with Jaguar automobiles exclusively since 1968 is very impressive. They are beautiful and wonderful machines, frustrating at times, but worth it.

I've been a bit under the weather today. I'll follow your instructions and report back Wednesday. Thanks again.

 

the car will run without a TPS.

it wont hosever run with a burned out CTS.

neither of these things would explain why you have no spark.
try doing your spark test again, but instead of testing from the Dizzy to the plug, test from the coil to the dizzy. you could have spark from the coil but no contact inside the dizzy, or Vise versa

 

I am sure if you carefully follow Grant's advice you will get it going fine. It seems very likely that the plug change has somehow disconnected a vital wire.

Just in case this has not been checked, there are two wires that run from the AB 14 unit to the base of the distrubutor at the front side of the dizzy. These wires are connected to the wires exiting the dizzy base by a white, flattish rubber plug about 3 inches after they exit the dizzy. The wires from the dizzy base to this plug can be very fragile and break. It would be worth checking them carefully, too.

I am not sure what the electrical test is to check that they are functioning correctly, but Grant will know!

greg

 

YEP.

The first page of the owners manual should state;

JAGUARS ARE ALL FEMALE, SO TREAT THEM AS SUCH.

They are awesome cars, and even super reliable.

The many, many years of neglect is what we enthusiast types need to take care of, and that can be long and frustrating, but luckily they are simple, basic cars.

Gregs mention of that plug out of the distributor is very relevant, and there is NO easy way to test it, but I will go thru it, if the other checks I mentioned prove fruitless.

JD on the bench, looooong plastic hose to the mouth, suck at will, EVERYTHING clears up real quick, and best of all, FUN is had, Jaguar heaven.

 

If I remember correctly there is a shielded wire that fails causing no spark. I don't have a wiring diagram handy at the moment.

 

I've had a similar problem with my '89 in the past.

If the car has the Marelli ignition like mine, they use two crank position sensors, One is near the flywheel and the other on the timing case at the front, near the crank pulley. The wiring coming out of those sensors can go brittle and become intermittent.
After pulling my hair out for hours, I found simply jiggling the wire to the front sensor got her started.
The wiring to each sensor is shrouded in plastic loom, and both run from the main loom in the valley. The front one runs under the A/C compressor then down in front of the B bank cam cover (With the Oil filler cap).

Apparently without a signal from these sensors, neither ignition nor injectors will work.

Hope that helps!

 

Yes, something that beautiful can only be female.

Thank you very much Gentlemen for your help. I'm most grateful.

With the voltmeter's black lead earthed and the red lead on the +ve of the coil, as Grant said, the meter showed about 70 mV in the ON position. When we tried to start the car, it jumped to 11.46 V. When I pulled the wire between the coil and the dizzy, as M90power and Grant suggested, and held it close to the dizzy (3/8"), there was no spark when we tried to start.

Greg, I checked the four wires out of the AB14 unit. Two go to the coil, and the other two go to their connectors and dive down in to what look like wire looms, they may end up at the base of the distributor, I can't tell.. What I could see and tug at seemed secure.

I figured out Dizzy, but JD has me puzzled. What does JD on the bench mean?

Don't you just love these machines!

 

JD= Just Drink. (my experience anyway..lol)
I won't add anything to this, as Grant seems to have you headed in all the right places!