My '86 xj6 is hard to start so I cary a can of starting fluid…and a squirt of staring fluid and it ALWAYS starts. Lately less hard to start cold (Phoenix) and when running temp usually will not start without starting fluid. Putting it in reverse and turning the key…I can hear it run the pump but does not change the hard starting.
I have multiple extra parts so I can swap parts to solve problems.
It runs very well and smooth…level idle and no cut out…just runs well…
Lately, I have been enjoying the xj6…it is very comfortable and a great ride…
Any help with starting ?
Also, is there a way to "hot wire the cold start injector?
Also, can we define all these acronyms ?
CSI= cold start injector
AAV=automatic air valve
AFM=air flow meter…a barn door that opens and closes to tell the CPU the afm
CPU=
afm=air flow mixture
Mitch
More to add…my xj6 is an '87…as far as I know it is the same as an '86
More to add…it has the resistor…if that is the thing attached to the coil
More to add…how do you measure the .002…is this the gap in the “barn door” in the AFM
More to add…What is idle gap?
More to add…How do you check the CSI
More to add…ballast or coil or external resistor…all terms for the thing mounted on the coil
The Cold Start Injector (or valve (CSV) as it is sometimes called) is powered by POSITIVE from the ‘50-power’ the same as the starter solenoid and GROUNDED by the Thermo-Time-Switch.
I remember when I worked at a Volkswagen dealer in the 1980s that there was a TSB for energizing the CSV at certain times for a HOT START problem. A vapor lock issue in some cars was improved by ‘pulsing’ the CSV with a additional electronic relay added to the start circuit.
I have a push-button switch in the cab of my 1980 VW pickup so I can GROUND the CSV when the Texas summer heat causes a hard hot start after a short rest/engine restart. (usually about 10 to 15 minutes sitting in the parking lot)
I just installed a wire from the earth side of the CSV to the push button so I can ground the valve during cranking if the engine seems vapor locked.
You can unplug the CSI (or CSV) and apply 12V while the engine is running and if the engine starts running RICH, the CSV is operating.
You can test the circuit by putting a test light in the CSV connector and crank the engine with a cold start.
Motorcarman…thank you…I prefer to"do it myself" rather then rely on some CPU…on my '85 saab I installed a momentary button…worked
Besides, I will not have to Lock the xj6…it won’t start for the thieves…
The only technical change I know of is that the '87 has a 3-wire oxygen sensor versus the 1-wire sensor of an '86. This change includes elimination of the oxygen sensor light and its tripping device, the Intervalometer (sp?). This almost certainly has no bearing on your problem.
For the heck of it you can bypass it and see if anything changes. Run a wire from the battery “+” directly to the coil “+” post
No, it’s the gap between the throttle blade and the throttle bore. Checking with a feeler gauge after cleaning the throttle bore. Accessible by removing the ducting to the throttle body
Have not heard of that.
Cheers
DD
In my experience a failed CSI will not cause a “no start” condition. Extended cranking, yes. The normal injectors, if working properly, will eventually provide enough fuel
I went for who-knows-how-log with an inoperative CSI and never realized it.
Cheers
DD
Thank you Doug…So it is the throttle…the accelerator cable attaches to the throttle…this is supposed to have a .002 gap…you are kidding me…how does the mettle stay stable thru cold to hot??? And we have a problem…what I call a throttle body is labeled by LUCAS as “2 AM air flow meter”…this being the part that monitors by way of a 'barn door opening and closing telling the computer how much air is being drawn in thru the preceeding air filter.
Frank uses the term “idle gap” …I have not understood it for years…
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Oy, Mitch; what you call ‘a throttle body’ is in fact the Air Flow Meter, AFM - which indeed tells the ECU how much air is passing to the throttle body proper…
Follow the air duct from the AFM and you find the throttle body - which contains the throttle butterfly, operated by the gas pedal. The gap between the closed butterfly and the body is the ‘throttle gap’, not the ‘idle gap’. And should be adjusted, by the tiny throttle stop screw, to 0,002"…
Now for the hard starting. First the procedure; the xk is set up for a ‘feet-off’ starting - any pedal input will cause the engine to baulk, difficult starting.
Staring cold the engine has 3 sources of air; the throttle gap, the idle screw and the AAV - which all must work properly for easy cold starting. And to give engine proper - idle - without proper idle the engine will not start.
Idle should be set hot by the idle screw; when hot the AAV is closed, and air is provided by the throttle gap and idle screw. The first set to 0,002" the latter adjusted to the desired hot idle - 800 rpms. When cold, the AAV is open and adds enough air for the engine to idle at 1200 - 1400 rpms (200 to 400 rpms above hot set idle).
So what is the hot and cold idle? Unless complying; the engine may/will be hard to start. If your engine runs OK once started - idle anomalies may provide a clue…
To aid starting; the ECU enriches the mixture, the colder the engine the fatter the mixture - ECU reads the Coolant Temperature Sensor for engine temp. The Cold Start Injector also sprays extra fuel while cranking cold - but as Doug says; it may delay starting but not preventing it…
One problem may be an air leak, which leans out the mixture. Carefully inspect the air duct between the AFM and the throttle body for tight and secure connections and tears - as a first leak test…
As an aside; spraying start gas into the air intake is courting disaster. As engine cranks and you spray; you fill the air duct with a highly volatile mixture - a Fuel Air Explosive. If the engine backfires; the mixture will explode with a mighty bang…
Not good; attend properly to your difficult starting…
Frank
xj6 85 Sov Europe (UK/NZ)
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OK…Will trouble shoot the suggested areas…
Of note, it usually will start cold… Phoenix is never freezing.
Any one know where to find a DIAGRAM OF VACUUM LINE ROUTING…been looking for years…and the sticker on the bonnet is completely inadequate.
I never spray starter fluid while cranking only before…then “strep” back. I learned, by having the starter fluid can blown from my right hand with a backfire…I considered myself lucky to still have a right hand…indeed it is dangerous
Thank you Doug and Frank
Thank you for researching so well so far;
CSI= cold start injector, adds fuel via the frontmost switch on the water rail and only for a few seconds, while cranking, temperature dependant. Bimetallic, heated switch and 12v valve. Nothing to do with the ECU!
AAV=automatic (or auxiliary) air valve for idle control, the aluminum casting with a 2 pin plug (it is also heated)
AFM=air flow meter…a barn door that opens and closes to tell the CPU=ECU the air volume.
CPU=Probably the ECU, Engine control unit/computer in the trunk that translates temperatures, AFM and Lambda information into fuel injection times
More to add…my xj6 is an '87…as far as I know it is the same as an '86 (likely as Doug said)
More to add…it has the resistor…if that is the thing attached to the coil (yes)
More to add…how do you measure the .002…is this the gap in the “barn door” in the AFM
No: the throttle body is on the air intake plenum. The cables from the throttle and the transmission attach, as well as the distributor’s vacuum line: if you remove the cast ‘elbow’ you see a brass plate: The throttle. It must not fully close, so you will need to be able to slide a .002 feeler gauge through the gap. To adjust, there’s a little bolt on the outside where the two springs are that acts as the stop.
More to add…What is idle gap? The .002.
More to add…How do you check the CSI? As said, or remove it and look at the spray pattern, but if it starts well cold…? If it has a hard time cold, look into it.
More to add…ballast or external resistor…all terms for the thing mounted on the coil? I guess so.
David
I just spotted this. I am intrigued. I have exactly that problem on my XJ6 here in Florida in the summer. Always starts fine cold but after a run, it will not start hot after 10-15 minutes sat parked. I have to wait for the engine to cool down - for 30-40 minutes usually. I have fitted the thing that increases fuel rail pressure when the engine is hot ( I think it is standard on later cars but not on my 78 FI model) with no improvement. So I may try your trick of manually triggering the CSI to give it extra fuel.
David
David
naah, keep it I get away with telling tales here that don’t really belong either…o
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You’re very unlikely to find a comprehensive line ‘routing’(!) diagram, Mitch…
There was a wide range of vacuum operated devices relating to year, market and equipment level - and routing variations. There was no universal layout; Jaguar simply didn’t provide comprehensive details - and PO actions through the years probably increased variations.
Vacuum diagrams are much like electric wiring diagrams - showing what is connected to what. The sticker on the bonnet is likely as good as it gets…
That said; since you have solved the hard starting (good work!) - vacuum routing is sort of immaterial…
Frank
xj6 85 Sov Europe (UK/NZ)
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Don’t worry Carl,
I’d rather suggest you write down a story book of “People and Cars of My Century” … well, at least the best part of it, from “Ts in Texas” over “MGs and Military” and “California Corvairs” to “Jags’n’Jeeps”. Keep them coming and get well soon!
Best wishes
Jochen
75 XJ6L 4.2 auto (UK spec)
Jochen
75 XJ6L
There has been a lot of emphasis on the fuel system, and I’m to lazy to read everyone’s post. but have you done any detective work on the ignition?
Every XJ6 I’ve purchased didn’t run. The last two videos I posted on my YouTube Channel - Jag Mods cover tuning up the ignition on a XJ6. As well as an Ignition module repair. At the end of the tune up video is the tuning specs. for an 4.2 XJ6.
I will look for a plumbing (vacuum) diagram. I know I’ve ran across one in my wonderings. but coldn’t tell you where. Also I will need to know if our XJ is a Federal Car, if not what country as well as the year and it’s date of birth. Sometimes the date of birth will be a different model year than what the car was sold at or under. Sometimes this stuff makes a difference.
Good luck
for what ever it’s worth, it’s the guys on this forum who’ve taught me were to look to fix everyone of my XJ’s 4 down and 3 to go 
Federal car
Update…I found the problem…it was a disconnected vacuum hose on the air intake manifold. It was hidden in that, “culprit” hose is cloth covered and so it appeared the hose was covered…well, the cloth was but not the rubber inside. And, it did it again today…that hose is going to be changed pronto.
Now on to fixing the fuel gauge and the duel fuel tank stuff
AND yes, without help on this forum…I would not own this xj6…I am enjoying the xj6…
Mitch
I have one of these issues too on my '86. along with one fuel gauge that doesn’t register correctly and the other that does register at all. Not on the top of my list. The suspension is higher on my list right now.
Driving this car around is what I imagine it would be like driving an electric car. Not really sure if you’ll make it to a charging station. 
Mark…“not sure… to a charging station” That is Soo funny
Wish it was a manual then I could use the starter to get off the highway to fix it.
You know crank the starter over to “yard Drive”
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That’s saved my bacon a couple of times, Mitch - getting out of the way of traffic…
Frank
xj6 85 Sov Europe (UK/NZ)
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Decades ago, that was a cop car start. Cop hid and awaited a “pigeon”. Cop car engine not running, but transmission in gear. Flip on the ignition and punch the starter button. No waste of time to clutch and engage first.
Bob and I worked together in LA. Bob an ex cop and race driver. Each of us had VW’s for the gas mileage.
Each of us very competitive. so, at quitting time, we went to the roof top garage and fired up and “raced” for the freeway. Then, I caught on to Bob’s quick getaways… Next phase of the race. Find the fastest rout via the streets to the on ramp of the infamous Hollywood freeway…
I wonder if the lemans drivers do that cop start?
Carl
Carl,
That is a great story…
I did it out of necessity (start in gear without a clutch)…when you drive a spitfire…well you get the idea
Mitch
And Frank…I thought for sure I would be admonished …3 cheers