85 series III won’t start

1985 xj6 series III
Won’t start. Went out one morning to start car to make sure it would start later for wife. Car hadn’t run for two weeks. It started up quickly and I thought I’d let it run for minute or two to warm up a bit. Then it started chugging and died. Couldn’t restart then or since.

Bought fuel pump (it was making noises), fuel filter( cause I was in there), and fuel regulator because I figure it’s never bad to replace a crucial part on a 35 year old car.
Also new main relay on firewall.
Some facts:
Never starts normally. Not a puff.
Always starts with starter fluid. Immediately.
I’m 90% sure fuel pump doesn’t run while I’m cranking. If I “hot wire” it (in trunk), it runs but car won’t start. If I hot wire it up front by relay, pump runs, car doesn’t.
All relays on firewall work properly. I took them off, cleaned them up, tested by hot wiring them and they all actuate, checking with ohmmeter they go from OL to zero properly.
I have fuel at injectors. I just loosened a hose and fuel started leaking out.
Couldn’t test pressure but as I said earlier, new pump, new regulator.
I’m thinking it has to be fuel problem as it always starts with starter fluid, never with gas.
Ignition system obviously works as starter fluid works. Car ran nice previously. I’m sure it’s not in tip top tune but this is the middle of summer and everything is dry.
I haven’t checked for fuel at injectors. That’s next. Not real sure how to do that, gotta research that a little.
Any help on this problem would be greatly appreciated.
It’s getting to the point where I’m thinking I could check for fuel carelessly, fire might start (accidentally of course) , give it a few minutes before finding fire extinguisher and insurance will get me a different one.
Now that I think about it, it’s parked next to my house which is a frame four square pushing 100 years old. It could use some refurbishing.
Have to get wife, dog out first I guess.

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Can’t help with the the no start, and I’m sure that this was VERY tounge in cheek but now its on the inter web………………….

A crucial factor in easy starting is that the idle settings are correct, Tom - an engine that cannot idle won’t start easily. The complete checks are; throttle gap set to 0,002" (and the throttle clean), the AAV verified half open when cold, and closed with the engine hot. Then the idle is set, with the engine hot(!), using the idle screw to some 800 rpms…

The engine should idle cold at some 1200 - 1400 rpms cold - dropping to set idle as it warms up. This is basic indicator that the set-up works as it should.

And the the xk is a ‘feet off’ starter - using the gas pedal during cranking; the engine will baulk and may refuse to start.

You should also verify that the CSI sprays for the required time - and certainly check CTS for correct resistance relevant to engine temps…

You do not mention testing ignition? That it starts with start-gas, which ignites easier than petrol, may indicate weak ignition - or indeed an air leak, responding to more fuel. Use a spare spark plug triple gapped - to verify spark quality. Connected to any plug lead; it should show strong, blue sparking while cranking - weak/yellow may prevent normal starting…

As a matter of routine; have you tried starting on the other tank…?

xj6 85 Sov Europe (UK/NZ)

Thanks for reply. The weak spark has been a problem in the past. When I replaced main relay it seemed to go away. I remember reading somewhere, that the cranking of engine draws so much power that voltage to coil can drop to 4-5 volts and you get a weak spark. Something about how some cars run an extra wire to coil from ??? to give it adequate voltage while cranking?
I like ideas though and might try today. Have to golf first though. First things first. I’m in Chicago. I fell asleep on couch, woke up to end of Olympic golf. It’s 3:50AM. Don’t golf till 10 so hopefully I’ll get some sleep, golf, back to car to try your suggestions. However more likely golf, too many gin and tonics, come home to nap back on couch.
I like weak spark idea. And it’s easy to check.
I think I’ll buy 6 plugs and just replace them. That will give me a look at them too. And that’s easy, cheap.
Thanks again.

Welcome Tom, you will find a wire that runs along the wiring loom where the injectors are. The wire leaves the loom and goes to the ignition coil.
This wire has a bullet connector and if you turn on the ignition and tap the bullet connector together, the injectors will click every third time (it is so sensible that it can feel like every time or sometimes every fourth, the important thing is that they click at all).
Give the injectors five or ten clicks and then try to start the engine.
Also check if the new regulator hisses, passing excess fuel back to the tank when the pump runs. You can leave the pump hotwired at the relay, which simplifies troubleshooting. I hope this helps.


Thanks. That’s new stuff on me and sounds crazy to me.
Sure your real name isn’t Dorothy and you have red shoes and you can’t find Kansas.
I’ll try it.

Bought new plugs because who knows when I changed them last. Car doesn’t get driven 500 miles a year so I figured how bad can they be.
Turns out, really bad. Pulled first plug and center electrode was almost gone. Looked like the end of a toothpick. So I’m thinking, great that’s the problem. Replace all the plugs and try and start it and it acts the same. Not a puff with fuel starts immediately with starter fluid.
Never did check for spark as I thought for sure it was the bad plugs. It got dark, so tomorrow another day. I’m starting to think the fuel system is never getting turned on.
The fact that I never get a puff from gas and starts immediately with starting fluid makes me think it’s not getting gas. Too much of a night and day difference. Even if the settings are off, bad plugs, etc., you should at least get a puff.
Thanks for all your help I’ll try a few other things tomorrow.

Are you sure it was worn out or perhaps they are platinum or iridium plugs? They are just like a needle.
Let us know what the plug number was that you took out.

Just check battery voltage before and during cranking, Tom - a drop of a volt or two won’t interfere much with sparking. If battery voltage drop significantly; either the battery is discharged or defective - or the starter draws excessive current…

An extra wire won’t cure this - it it cannot deliver more voltage than the battery can provide. However; you should indeed test starting with a jumpwire directly from batt pos to coil pos - this will bypass any connectivity problems between battery and coil. In the same vein; do your coil have an external resistor? If so; it should be bypassed - it may interfere unduly with ignition…

A weak spark may or may not be able to start and run an engine - but it is a signal that the ignition is impaired. Nothing prevents having more than one fault - each must be detected and remedied in turn. As a ‘final’ ignition test; remove spark plugs, dram each cylinder with a teaspoon of fuel, reinsert the plugs - and crank. With ignition working; the engine will start and run briefly - and if it continue to run, it has fuel, but idle settings are likely off…

Since you have experienced starting problems over time; whatever the fault(s) might have worsened over time - and something finally gave!

With the mentioned fuel items replaced; your fueling is likely OK - you just have to verify that the fuel pump actually run in ‘crank’. Easy enough by setting gear lever in ‘D’ and turn key to ‘crank’ - you should hear the pump ‘buzzing’. Beyond that; fuel can only be verified by a fuel pressure test - and of course; verifying that the injectors are actually ‘clicking’ while cranking…

For all I know; your only problem may just be incorrect idling set-up - and the engine is unable catch during ordinary cranking…

Go through the idle set-up as described - it costs nothing, but will confirm or refote vital points…

xj6 85 Sov Europe (UK/NZ)

The bullet connector as I described proves if there is a connection from the coil to the working ECU and back forwards to the injectors, also shows if all 6 injectors click at all and whether they pass some fuel or not.
It also drams the engine a little.

Next up would be looking at false air (leaks beyond the air flow meter, misfires can blow off hoses) and then spark.


Only if the fuel rail is kept pressurized, David - and pressure drops very rapidly when injectors open and the pump not running. And if the system is leaking, like a failed one-way valve, pressure drops to 0 as soon as the pump stops…

xj6 85 Sov Europe (UK/NZ)

Yes, Frank, I thought of that!

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Ok, that gives me a lot of things to try. The comment about Itidium plugs is probably correct. I put them in so long ago I forgot what they looked like. Like I said this car is only driven 500 miles a year so nothing like plugs should be worn out before 20 years or so. Oh well, like I said before, never hurts to replace a part on a 35 year old car. $18 and <hour of easy labor. And now I have a spare set of plugs that are probably better than the ones I put in. I’ll check the #. I do like the way this engine has the plugs running right down the middle, on top, no other wires, hoses, or anything in the way. Could probably do it with eyes closed.
I’m at work now try some stuff a bit later.

I think I may be missing something. You describe that the engine will start when primed with ether. but, does it continue to run or just for a bot, then quit.

  1. No fuel enrichment at cold start. The ether shot does that.

  2. If it does not continue to run, it is clearly a fuel delivery issue. Got to find a way to determine if the injectors are actually squirting. Others can aid best there. Or check the archives. Much on injector issues there. Might be gummed up from lack of use.

I’m with Mr Hutchins.
Engine only runs two seconds. I’m doing this by myself so half the ether probably evaporates by the time I get around and crank it. I’ll do the checks people suggested and get more info.

Make sure to jump the fuel pump for now. The air flow meter has contacts inside that will power the pump as long as the engine consumes air. It is possible that in the end your fuel pump is running during crank, but not powered in ‘run’. That would explain if it ran for a few seconds only, each time.

News from the front:
The old plugs were NGK BPR5E GP. And they’re supposed to look like that.
Spark seems fine
Pump runs while cranking.
Hard to tell if injectors are triggering while cranking. Too much noise and vibrations.
I don’t feel anything.
Tried that bullet connector thing. I hear a noise but it seems to be coming from under coil and it doesn’t sound like a click. Thought I felt “click “ at injector but only once.
Can’t hear hissing at regulator.
Had wife crank engine while I sprayed bursts of ether in throttle. Ran for several seconds, stopped spraying, engine died.
To me that kinda proves fuel problem.
Removed one injector fuel hose and fuel dribbled out. Like a really bad water faucet leak.
Then I ran fuel pump WITH hose off and it still just dribbled out. Turned pump off.
Put that hose back and removed main? hose from pump. The one attached to end of fuel rail. Some gas dribbled out.
Ran pump and I was expecting strong stream got nothing. So I don’t know what’s up. Gas is being blocked some how. There a real rat’s nest of hoses by fuel filter that I don’t understand.
Pump running backwards?
Fuel filter in backwards?
Should have changed tanks when I had hoses off. That might indicate something. I’ll try that tomorrow. I have tried changing tanks before without any good results. Could one of the solenoids back by fuel tank changeover be blocking things?
Thanks to everyone for help so far. Seem to have it boiled down pretty much but not completely. Obviously no fuel at fuel rail is a big problem. They don’t call it a fuel rail for nothing. There is some fuel in there though.
Should I run fuel hose directly from pump to fuel rail?
Thanks again.

A good diagnosis process, Tom - did you try on the other tank as well…?

Failure of fuel feed to the pump will be similar; clogged in-tank filters or changeover valve - or, as you have changed the pump; you may indeed have connected the pump wires wrong…:slight_smile:

The filter would work either way, but there is a faint possibility that the one-way valve, the brass hexagonal ‘thingie’ is the culprit - the piston inside once reported as ‘tumbled’. But the more likely is a blocked feed - the hose lay-out is easily identified; one hose from each tank to the changeover valve, one hose from valve to pump, one from pump to non-return valve, one from that valve to filter, and one from filter to fuel rail…

Hoses should be clamped before disconnection, if not clogged you don’t get a trickle - you get a flood from the tanks…

xj6 85 Sov Europe (UK/NZ)

You should have heard all six injectors click distinctly with the ignition on.

You don’t have fuel pressure so start there. With the tank selector switch pushed in, fuel flows from the left tank to the three-way valve next to the spare tyre. Then it goes to the pump and then to the fuel filter as well as another device that is supposed to purge the air and hold pressure when the pump is off. From there it goes forward to the fuel rail, regulator, then back and to two valves that return to the fuel tank selected.
The return is visible if you open the flap inside the filler neck and peer down; should be a steady stream. Send a picture of all your fuel hoses in the boot and we’ll tell if any hoses are wrong.
But most likely your pump is bad, or the wiring is backwards, or the feed from the tank is clogged; how is the other tank?

Had to work this morning but took a couple of pictures. Don’t think I could have hooked up hoses wrong as they’re old and stiff and not long enough to reach anywhere else.
Changed filter and pump. The old pump worked but who knows how old it was. With it in the boot, everything looks brand new back there.
I changed pump and regulator because they were old and to take a couple of variables out of trouble shooting (though they could be faulty).
Then I figured I’d check pump. Took hose off pump and hot wired it. NOTHING.
So wired wrong? Possible since pump wasn’t exact replacement. Had to change terminals.
Bosch pump, looks nice but they all look nice.
Don’t think I could have installed backwards as I think hoses are different diameters and the wiring would then be on the bottom and very awkward.
I tried changing tanks and got nothing.
So must be a problem upstream of pump. Probably in tank changeover. Probably not pump as that would be two pumps, one new, going out at same time. And they both whirred so they are turning.
Maybe I’ll pour a little gas in a can and see if pump can suck fuel out of can. And start car?
Might be asking for too much.
In unrelated but another possible problem.
Do injectors fire, click, if there is no fuel pressure? Seems like they should.
I’m at work now, I’ll be back at it this evening. At least it’s now a cut and dry, simple problem.
Famous last words.