Well said.

 

Hi all, sorry for the lack of updates on this thread. I am currently in the process of packing up the family (including the Jag) and moving across the country.

Long story short, she is still not wanting to start up. I will provide a brief summary of everything that has happened.

-Was running fine all winter. Sat in a garage for a month, had to jump start. Ran for about 5 minutes, then died as I closed the boot. Tried to start it again, would crank and attempt to start, but would not run.

-It will crank for about 10 seconds, then act like its losing power (or drawing a lot more power, i.e. dash lights dim, starter doesn't turn as freely) then make an initial "whoosh" or "roar" like it has started but will instantly die. RPMs go up to about 10 during this "whooshing" period. (Sorry for the poor terminology.)

Things I have done:

-Battery tests good under load.

-I have installed a new primary coil. I have spark AT the plugs. (Blue spark with a spark tester gapped to .025''.)

-Installed a new distributor cap.

-I have checked both relays in the boot. They are in working order. The connectors do not push out when the relays are inserted. The fuel pump does run for about 3 seconds when the ignition is turned on.

-I have continuity on the shielded wire from the ignition amp to pin 18 of the ECU.

-ECU ground on pin 1 checks out good.

-The 2 spade connector wires off the battery earth ground are properly seated.

-Inertia switch is functioning properly.

-Cleaned any ground connector I could find with contact cleaner and a wire brush.

-Swapped in an ECU from an '87 XJS, no change.

-I have proper fuel FLOW (checked from return line). I performed a very rudimentary pressure test on the supply line (thumb over plastic tubing connected to supply line) and seemed to have good pressure but have yet to check with an actual pressure tester.

-Fuel cap on or off does not make a difference.

-TPS voltage STARTS at .6 volts and slowly advances to 5v as I turn the capstan.

-Injectors audibly click when ignition is switched on, but not when the gas pedal is pressed. I'm guessing this is due to the TPS starting at .6v.

-Cleaned all connectors on EFI resistor pack.

-Air temp sensor was reading as constantly open, which appears to be wrong according to Haynes Manual. I jumped the plug with a paper clip. The coolant temp sensor tests fine.

-Probably some other stuff that I can't think of at the moment. I have tried just about everything mentioned in this thread so far.


What I am currently working on:

-Due to the repeated attempts to start the engine, all of the spark plugs are pretty much coated in carbon, so I am in the process of installing new plugs and wires.

-While I had access to the V, I figured I would go ahead and pull the FI harness out and rebuild it. While I did have approx. 12 volts on the injector plugs I could access, the cracks and pops it made while I was removing it let me know it was long overdue for replacement. Once I get all the parts for the harness, I will replace it and the plugs/wires.

I tried using some starting fluid a few more times and it really sounded like it was trying to fire with that stuff, but only for MAYBE a quarter of a second, and always accompanied by the weird power drain/load thing I described in the second bullet of this post. This can be heard in the sound file I posted earlier in this thread.

I guess all signs are pointing to lack of fuel getting to the spark. I threw in a new plug and turned it over then took it out to see if there was any noticeable fuel on it, and there wasn't really, although it did smell of fuel. Perhaps that is simply because it was in the combustion chamber to begin with. Each time I attempt to start it I DO smell fuel.

-I have only used high octane, non-ethanol gas since buying this vehicle almost a year ago.

-I tested the gas in the tank for water and it was negative.


As I said, I am kind of at a standstill until I get the harness rebuilt and the new plugs installed. I am loading her up on a trailer next week and hauling her 1200 miles to our new home in Oregon, so I probably won't make any huge strides until that adventure is complete.

In the mean time, any suggestions/recommendations/guides on rebuilding the harness would be much appreciated. My background is in electronics, but as finicky as this thing seems to be, I want to make sure I don't make any mistakes. Also, if someone can point me in the direction of some good electrical diagrams that would be great, as the Captain Jaguars Electrical Diagrams site seems to no longer exist.

As always, thanks so much for all the help so far. I will do my best to be better at providing updates as they occur.

Cheers.

 

I rebuilt mine early last year, not that much to it. Look at this site all the information you need is here.
FI Harness Rebuild
Good Luck.

 

Setting the TPS


Well this is ironic my truck started running rough after topping up the gas with fresh high octane gas last week, I did some messing around with the timing and went for a run it was bogging down so I checked everything again tried to pull off the drive and it died first time since I built the truck.
Now I have the "Autob syndrome" engine cranks and cranks then fires up and dies straight away didn't have time to mess with it but will check this out at weekend and report back, mean while my modified TPS worked out great.

 

Its funny, NOT! that this seems to be happening more and more often now, My theory is the fuel is rubbish, and must have some particulates that make it through filters but not injectors. I am be totally Wrong but lets just join the dots, how often do you read, "car was fine filled up with fuel and soon after just died", what do you think?
Maybe just coincidental?

 

Well had a big fat spark at the plugs and it ran on starter fluid with the fuel pump disconnected so its not ignition I thought it was fuel related because of when it started acting up will check the fuel pump and injectors tomorrow my pressure gauge shows 40 psi at the rail so some more fault finding to do

 

Great news. The fuel side is much simpler to fix. May I suggest you start at the tank outlet and check everything from there? The list to check is:


Tank outlet flowing freely for 1 minute under gravity only.
Tank outlet to sump tank hose not collapsing; this fault does NOT show from the outside, as the inner lining seems to collapse and block. It is best to renew this hose
Sump tank: clean out and renew the filter inside it
Pump: run connected to the upstream system for at least a couple of minutes flowing into a container and check fuel delivery stays strong throughout. Pumps do fail after they have run for a bit sometimes.
Filter: renew, they do spontaneously block under pressure sometimes
Pipe from filter to fuel rail, disconnect at the rail inlet and blow it through with compressed air
Tank vent: make sure the tank vent system breather valve is working 100% both letting air out and letting it in. Not as bad idea to replace the OEM Rochester valve arrangement with a modern aftermarket one.


If all this does not cure it, you just may have a duff B bank fuel pressure regulator as well. The A bank one can be done away with, or make sure that it is not somehow blocking fuel delivery.


Greg

 

Thanks Greg good advice but its funny in my case as I made the tanks and designed the fuel system to rum my V12 in a 1940 Chevy pickup truck

 

This is getting interesting I usually split a non start in two, Ignition or Fuel but this has got more involved. I noticed the engine was kind of hydro locking like the timing was to far retarded then the odd smoke off burnt fuel in the inlet makes no sense. I am starting to suspect the ignition amp or the internal component's has gone faulty. I have fuel and I have a spark but they are not happening at the right time. I am thinking maybe the zener diode or one of the capacitor has gone bad and I am not getting the signal to fire the coil or turn on the injectors in the right order. Anyone got any ignition amp experience or care to chip in?

 

I found this for the GM HEI unit

 

Moff
Do you have a Lucas ignition engine or a Marelli ignition one?


Greg

 

Its the Lucas ignition as fitted to a 1986 XJS has the GM type amp as pictured above, a friend from the Jag club is lending me a spare amp to try I hate swapping out parts but I guess this type of fault has sent many a Jaguar to the breakers yard. There is no doubt I will find the fault just takes some time.

 

Moff,

Did some catching up just now.

We are still on the Jag are we not?, or the Truck?

The Zenor and the Condensor inside that amp are fine. If either is faulty you got NO spark.

The injectors are NOT timed to anything related to the Spark system. They really do not communicate in the true sense of that word. The only communication, if you call it that, is the pulse (tacho type pulse) down that shielded wire TO the fuel ECU #18, to indicate that there is in fact ignition activity of sorts, so that is enough to have that ECU keep the pump circuit, injection circuit, ALIVE. Failure of that pulse will basically "switch off" that ECU.

That .6v, and the "click" at ignition ON, is not correct. That .6v will have the ECU "shut down" partially. That is why opening the throttle during cranking of this system has a very "hard to start" scenario.

The discussion about fuel quality is becomong VERY common on here and elsewhere. The storage life of said fuel is also questioned. I have read often of people with similar issues after a Winter lay up, and the fuel simply lacks the OOMPH to go BANG, and a simple drain and refresh with "newer" stuff has the beast in question alive.

The "hydraulic" feeling you are getting is typical of that fuel issue.

The small ignition module inside that amp can fail, but that usually leads to NO spark, and NO tacho movement.

The fact you had it stored, and then ran it, and shut the boot lid, and it has ceased to motivate since then kind of yells fuel quality to me.

If you had messed with timing etc, different discussion.

That EFI loom rebuild is way overdue, and a good thing to do, even just for elimination, and the warm and fuzzy feeling of knowing it is NOT causing strange happenings.

 

"Struth mate" I think we have crossed wire all over the place here Grant, I was replying to Autob original post about his no start when my truck fitted with a 1986 XJS engine and gearbox developed the same issue. I built the fuel system and made my own injection harness and rewired the complete truck ran great for 3 years, now I have this issue. My question would be if the ignition amp does not effect the pulse rate of the injectors what does? I do know the V12 jaguar engine has a lot of redundant systems that seem to overlap

 

Goodo.

In the Jag system, the ECU is purely FUEL. It is a dumb sucker really.

It is set up to time the fuel pump, tick.
When the engine cranks, it gets a signal from the starter realy, AND the ignition amp (shielded wire) that "tells" it we have activity, sooooo, it keeps the pump running, AND triggers the injectors. Tick
The TPS "tells" it where the throttles are, and for starting it must "see" 0.32-0.36v, or the pump circuit is "shut off". Tick.
The CTS is the PRIME signal for the ECU, and without a signal from it, the system is DEAD. That sensors wiring is part of that integrity also in the Jag, as wiring is Lucas???.
The ATS is a trimmer, and if its AWOL makes very llittle difference.

The Injector Resistor Pack is now proving to be quite fickle. "Greg in France" has a excellent write up on it. Basically, the multi pin plug is the main culprit, coz on the Jag its plugged from the bottom, and fills up with crud over the years.

The IGN amp modules are a normal failure item, and I use Echlin TP45B (the B being for blister pack), or Tridon IM410, with good results.

The "condensor" looking thing inside that amp, screwed into one corner, is a redundant item that will KILL the spark with conviction. I remove them and bin them. They are basically a noise suppressor, whoopee.

Inside that rubber "blob" are 2 resistors, ane for the tacho, one for that shielded wire. So if the tacho works, that resistor is OK. If the injectors fire, then that one is also OK. I have never had an issue with those resistors, and I have had some V12's here after serious engine fires, and that amp is quite sad, but it still works.

That "shielded wire" is a fickle thing, it tests OK, but when I test them I "fiddle" with that wire something fierce, as in twist it, wiggle it, etc etc, and note the OHM meter carefully. I do NOT run that wire in the engine bay of any of mine. The coax is replaced with a standard wire, and spliced back into the coax again at the bulkhead connector at the RHD gas pedal area.

Any issues with that Ign Amp will give NO spark, and NO tacho, and NO fuel pulse to the ECU.

Some people report NO injector activity when the gas pedal is opened rapidly, Ign ON, Engine OFF. This is a classic TPS out of range, or ECU issues. Again, I have never had an ECU failure. Wiring etc hell yes.

Sadly the cars I see are AFTER the fiddle factor from all and sundry. So I simply start at A and finish at Z, and then only is it finished. Works everytime.

There are other things, but they will not stop the engine from starting.

 

Did you ever get this figured out? I seem to be having a similar issue.

 

Still working the issue, CTS? and ATS? not familiar with abbreviations

 

Fair dinkum, I finally stumped an American with an acronym, wow.

CTS = Coolant Temp Sensor, located in the rear section of the LH thermostat housing, and has a 2 pin Injector plug on it.

ATS = Air Temp Sensor, located in the snorkel of the LH air cleaner cover, and also has a 2 wire injector plug on it.

DO NOT mix these 2 plugs up, it is EASY to do so, coz havoc will reign supreme if you do.

 

Bloody cheek! I am English as warm beer and fish and chips

 

DAMN.

BBQ is running, I'll chuck another Croc steak on for ya.

The Jags can wait,