Good Morning. I am new here and in need of some help, as i can't seem to find much related to my issue
i have a 1983 XJ6 that has starting issues when the engine is anywhere from warm to operating temperature. i'd say like 70% of the time if i shut the car off when its hot, i have to let it fully cool down otherwise it takes quite a while and lots of cranking (and then jump starting) to get it running.
Last night while sitting at a light, the engine stalled on me, no rough idle, no surging, just shut off and would not start back up. the battery died and my portable jumper only lets you power it up so many times. my friends father came to help and by the time he got there, the engine was cooler, after hooking up the jumper cables the car fired right up.
while waiting, someone did pull over to help me but was unsuccessful at jump starting.

im not really sure where to start. when cold will start right up, idles fine, even idles fine when its hot. will give no indication if it will stall, just does it.
i have fuel, i have spark. i have been told it could be the coolant sensor for the fuel injection or the thermo time switch. a friend also suggested that if my grounds aren't great, that could give me issues. changed the fuel pump last summer, all the tune up parts are also new.
any help would be greatly appreciated

there is no modifications made to the car other than a removed air pump which never worked anyway. about 86K miles

 

both the Thermotime sensor and the Coolant Temp sensor are suspect.

if you don't know the history of those two sensors, I would replace them starting with the Coolant Temp Sensor.

Doug has a trick to test the Coolant Temp Sensor.

 

Just to make sure, you have tested for fuel and spark when the engine is in no-start mode, correct?

Did you check actually check fuel pressure? And, when in no-start mode, do the injectors click while you are trying to start the engine?

If you have an ohm meter I can give you the specs to test it.

Or, for $20 and 10 minutes time you can replace it. As guesses go, that's rather painless.

Or, next time the engine is in no-start mode remove the plug from the sensor and use a paperclip or similar to jump the terminals. If the engine now starts, bingo. Jumping the terminals sends 'fully warmed up' signal to the computer.

Maybe.

The TT grounds the cold start injector which itself operates only with the key turned to 'start'. A fault here could indeed cause impossible starting by flooding the engine but it wouldn't cause the engine to stall when running.

Next time the engine is is no-start mode unplug the cold start injector and see if anything changes

Yup !

The grounds you're most concerned with for the running/stalling/no start issue would be the bundle of ground wires at the rear of the water rail. About 5-6 black wires. These are the grounds for the fuel injection system

For the difficulty in getting the engine to crank over, read this:

Engine Will Not Crank Checklist

Cheers
DD

 

thank you for the advice Jose and Doug. i plan on ordering the coolant sensor when i get home from work. i have found a thermo time switch (why so expensive )
pretty sure those are original given the mileage and how long the car sat before i bought it.

yes. checking with spark tester, and at the last time testing i sprung a fuel leak....plenty of pressure there...big mess but i will dig out my pressure tester, may have to make up something to connect it to the rail because mine is mostly for GM and Ford. as for the clicking injectors i cant remember off had. im going to say yes only because there are times while the engine is up to temperature when not starting, it does try to fire. sometimes accompanied by a faint odor of fuel.

i didnt think about this. i will certainly try it.

i know of these grounds i will check the condition of the connection. i thought about maybe adding some to the engine block or intake, cant hurt right?
i also wasn't sure if the ignition amplifier was case grounded because it bolts to the intake manifold. figured if it was and it was dirty, with the heat and resistance i may not be getting enough spark?
. i have also read about adding a ground to the single wire o2 Sensor. not sure that would make it stall but of course any improvements i can make i'll certainly do.


hopefully i can get some of this done tonight or soon. between the engine tear down of my pickup and wiring on my Camaro, having time...and patience...is difficult lately.

i appreciate all the advice so far and i will definitely try these

 

as to the fuel odor, check under the right side front fender just below the headlamp bucket with a flashlightwhen it happens

that is where the Charcoal Canister is. Sometimes they clog and or you get liquid fuel in them. Getting near it might tell you if the odor is coming from the canister.

 

 

Jose, the charcoal canister has been disconnected. One of those valves stopped working a while ago and the fuel tanks started over pressuring but Thank you

Sov 211 thank you. I will look into the amplifier. I have read that was a major cause of issues. Perhaps as the engine gets hot, the module overheats and builds up resistance.
unfortunately tonight was a disaster so I didn't get much of anything done.

I appreciate the help from all of you this far

 

do you know exactly how the charcoal canister was disconnected? The tanks need to vent fuel vapor somewhere, or was the system left open to the atmosphere?

if yes, there's the fuel odor.

all you have to do to prevent the tanks from over pressuring, is to remove the inline check valve found near the canister in the fuel vapor line, splicing both hoses with a connector. Or you can push a drill bit through the check valve membrane and pull it out the other side of the valve, then reconnect the valve.

this issue has nothing to do with the start-no-start problem, but I bet it has to do with the fuel odor.

 

Gregory is 100% correct, of course, regarding the ignition module. The most common failure mode is 'when hot'. The ignition coil trails close behind for hot failures.

But you report having spark when in no-start mode. With a failed ignition module, you wouldn't have spark. A failed coil might result in no spark or weak spark.

Cheers
DD

 

Jose, it is disconnected before that check valve before the canister.
could be possible that's what the fuel smell was but.I can't be sure, I just don't remember. I don't ever recall seeing fuel coming out anywhere in that spot. I do recall some fuel vapor coming out of the air cleaner. I will.keep an eye out for it next time.

doug, gregory, while doing some research, I learned that the ignition module inside the amplifier box can be changed our so I used the part number he gave. They're pretty much available anywhere so I wound up ordering it from the same place in getting the parts to put my Silverado engine back together. Wasn't too much so it can't hurt to change. And at the same time I'll check out all my grounds.
oh and the coil is also fairly new, changed with the most recent tune up, with a Beck/Arny coil. The original one used to get screaming hot. If I what brand it was but this one doesn't get nearly as hot.

depending on when the order comes in maybe I can play around with it this weekend.

hope this solves my problem. You all have been a great help in giving me a direction 😀

 

1. I was going to say that the cannister disconnect, just might be an issue. The tank/s must vent. To the atmosphere as in days of old or into the engine via the purge. As I read it, you have reverted to the olden method. But, is it enough? X's vacuum in the tank vs the pump's effort to remove fuel !! Long shot, I think, but worthy of a thought.

2. The Jaguar grounds are many and just fine if, clean, tight and lubed. Oft ignored is the one down under. A braided strap on the right side between the chassis and transmission at the engine.

3. The amplifier is indeed heat sensitive, whether in a Jaguar or GM car!!! On the fuel rail is not a bad location. Well worth removing it and cleaning it and the mount point. A heat transfer goop is needed between the housing and the rail. Were it my car, I'd consider moving it to the wing wall or adding an air defector to enable more air going across it.

4. Way out muse. When it stalls, be prepared to cool the module. Liquid nitrogen comes to mind. Simpler means might be as good.

5. In high temps and slow speeds, pop the bonnet to the safe latch. Added air escape mean lower bay temps and the issue be relieved. More of a limp home than a real fix...

Carl .

 

Replacing the GM module in the amplifier is an easy procedure: remove the bolts holding the amplifier to the block, and disconnect the amplifier. You will see that the amplifier case is held together by several (4?) very small hex bolts. Remove them. Now you open the case and you will see the GM module; note the orientation. disconnect it and remove. Take the new module, smear the grease provided with it on the metal plate on the module back and on the amplifier case. Fit the new module, put the case back together, reconnect, and bolt the case back to the block: but NOTE: the bolts must be firmly seated so that there is no air passage possible through the bolt holes/threads.

This may well fix the problem but at thevery least it eliminates the possibilty of this being the culprit.

 

Good evening everyone. Been pretty busy with this car and one of my others. But an update
I changed the ignition module with a new AC delco one and upon starting the car, it would barely run, like on 3 cylinders and die. Did this repeatedly. As a suggestion from a friend to put the old module back in. Car started right up and ran just fine.
after that I changed th coolant sensor for the fuel injection.

car has been running fine all week, starting cold, starting hot. Just earlier I went to go start the car while the engine was warm and it wouldn't start.

a random though went through my head of a video I watched once when having starting issues. There is a bullet connector on the water rail. In the video the guy, turned the key on, disconnected that connector and reconnected it, hearing a sparking sound. When turning the key to crank it starts right up.
that's what I did and the car fired and ran.
it is a white and black wire. I'm not sure where it goes or comes from.

Anyone have any ideas or experience this?

 

my '84 does not have that, but it looks like a Coil wire. Where does it lead to?

 

I'm not entirely sure, I'm not able to get out and look at it this moment. I know it comes out of the connector pack at the fire wall. When I get home I'll grab a light and see if I can find where it goes

 

It goes from the coil "-" post to the ECU. In the S58 manual it's called the "engine speed" signal. I call it a 'trigger' wire.

I've seen the video you mentioned and was never quite sure what to make of it.

Cheers
DD

 

Possibly a dud.

Or.....

If inclined, compare the grounding point on the two modules. My memory is foggy at the moment but it's been an issue for others from time-to-time. I'll try to find some pics to illustrate

Cheers
DD

 

Hmm, I wonder if there is something in the ECU that's getting stuck? Or something that's not waking up when the key is turned, and retouching that wire wakes something up?
I would assume there's no way to test that other than sending it out somewhere.