Join Date: Dec 2009
Posts: 1


odd issue on 89 xj6
hello, sorry for the long post but I have an issue with my 89 xj6 which is driving me up the wall.
I was driving, when all of the sudden I lost engine power, pulled over to the side of the road, the engine turns over but won't run.
my buddy helped alittle we confirmed that I have spark and fuel pressure.
when we tested the injectors it was found that pulse signal is missing.
I installed a new crank sensor....
no results so I took a vohm meter and found that if I disconect an injector both sides of the plug have power with key on, but according to chiltons manual only one should have power the other should be pulsed signal...
if I disconect the next injector then I get power on one side of both injectors but no pulsed signal.
I have removed the engine harness in order to check for any shorts or melted wires, all seems clean, have tested nearly all sensors and have received ohm values similar or in range of my manual.
the only sensor I have not tested is the throtle position sensor.
according to the engine diagramm all injectors have a common power wire and two cylinders share a pulse wire, that is 1& 2share pulse signal so do 3 & 4 as do 5&6 .
does anyone have a suggestion for this issue? thanks
carlosz

 

Could it be some sort of emissions thing? Some sort of solenoid shorting out, Air flow meter shorting/going out?

Just about the same thing happend to me the other day, car worked fine and then all of a sudden broke. So I will be following this and if I find anything on my end ill post it.

 

progress update, since I dont have much time to devote to the vehicle.... visited ny local pick a part and found a 1990 model mine is a 1989.
the ecu connector is a bit different but with a little custom work I made it connect.
after alittle bit of finger nail biting I finally got the engine to run but only if remotely fired from under the hood.
once engine started, injector number 1 failed to fire so I ran connection jump wires from the adjacent injector and it ran well until I cut if off some 2 hrs later.
I tried starting it from the drivers position and it revertted to the original issue of crank but no start.... I went to the engine bay and used my remote start and voila it fired and ran again..... this led me to believe I may have an issue with my ignition switch... I obtained a replacement unit but due to time constrains I have not been able to install and retest... will keep on posting as I get to it.....

 

Sorry, no help here, but I am eagerly following this thread.
Your explorations have already given me some things to check in my efforts to get my '90 model running.
Good luck to us both ....!!!

 

Subscribed, so I can follow with interest and remember to bump every 9 months or so

 

Subscribed!

 

All right gents, possible final up date on getting my xj 40 running again.
long story short, I finally made the time and effort to move this thing from its location to the shop where I could dedicate my spare time on it.
I had installed a 1990 ecu, as soon as I installed said unit the vehicle ran, but once I cut it off It had difficulty starting again.... if it started cyls 1 and 2 would not fire and thus engine would run rough on 4 cyls. at this time, I used a jump wire from injector 3 to the 1-2 connector and then it ran good but rich and had trouble accelerating.
as mentioned in prior post all the sensors checked out with in op range but never got around to the throtle sensor, this time I did... it failed.
I left the sob sensor disconected and it started inmmediately and ran well but the miss was still present so the jump wire stayed in place, in order to drive in and out of shop, the throtle had to be feathered as soon as engine loaded it would backfire.
the task of locating the throtle pos sensor was easier said than done due to the age of the car....a buddy at the local dealership located one, it took a month and 250.00 bucks to get.
during this time I attempted at installing the later throtle body and sensor to go with the new ecu, but the pin out is different and difficult if not impossible to find.
the new old stile sensor arrived, I installed but the newer ecu would decline to learn so it ran with out it connected and the jumper still in place...
ebay became my friend, I searched nearly 2 months before someone posted the proper nunbered ecu I needed for an 89. I did not bickered and paid the "buy it now" price of 50.00 bucks.
thru all this time I was visiting local pick a parts and found many 89's butnone had the ecu with matching #'s I needed... called all over the country and received ridiculus sales prices, from 350.00 to nearly 800.00 with a max of 15 days exchange warranty, the guy on ebay gave me 90 days warr, with choice of money back or exchange what ever I preffered.
some time during all the testing saga I reinstalled the original ecu and it smoked as soon as I turned the key.... that went into the garbage.
installed the ebay unit and it started and ran wonderful, set the throtle sensor and let it run for some 30 min to make it learn idle and clear plugs from rich running condition.
Im glad to report, it drives in and out of shop every day until the day I decide to make the time to tow it back home (tags are dead and it's un insured).
turned out that jag is the only manufacturer who installed the throtle sensor at the bottom on the throtle body, at the same time the pcv is at the throtle booth before the sensor, these engines have lots of blow by and oil settles at the bottom of the throtle body then it leaks into the sensor and it shorts it out, thus fooling the snsor into flood mode and this in turn kills the injector pulse to allow the engine to "clear" excesive fuel which is non existant....thus no start as no injector pulse but spark is present. as to why my factory ecu smoked it is a mistery..
I have a 1990 4.0 ecu left over, if anyone thinks they need it "pm" or email me rovertech2@hotmail.com we will work out something.
I hope you do not get bored with all the details of the post, at the same time I did not mean to insult your intelligence with all the details, I felt I owed it to all non mechanically inclined or savvy do it your serlfers to report steps.
if you have the same issue I described, start by disconnecting the tps. if it starts with out it install a new one.
best of luck..
Carlos...

 

I appreciate your taking time and postin' back on your updated issues , it's long but not boring at all , I like detalied posts a lot , this was an old thread but updates are new lol

 

Thanks for the update. Same here, the more detail the better.

 

I'm another who appreciates the details. My car is now running, but not well, so I've sorta put it on the back burner.
Reading your experiences and results gives me new things to check out on my own car. Maybe there's hope yet!
Keep up the good work!

 

I guess whe you make a living working on english cars you need to make details to be able to explain to the owners of what is going on... lol.
it took lot of patience and decation, specially when parts are rather pricey and difficult to source, in addition that customers cars came first.
I had to be sure of a diagnosis on a suspected failed part before locating it.
that being said, I attemped to have keyless entry installed on these bad boy and 3 alarm shops told me it was impossible... I proved them wrong and got it installed and working fine...
"I ain't afraid of no ghost"..... lol
Carlos.