hello i hope this is the right forum I'm new to this. so i got this 97 xj6 4.0 liter with no signal to injectors verfied with noid tester. any ideas where to look? thinking maybe cam sensor . wiring seems tight any help would be appreciated. thanks . oh car will start if i spray some starting fluid in that little port in the back

 

Hi audionut,

Welcome to the Jaguar Forums! It's great to have you with us.

I have moved your post from the forum for the X350/X358 to the forum for the X300, which is the Jaguar factory project code for your 1997 XJ6.

Here are several questions I can think of:

1. How long will the engine run when you start it using starting fluid?

2. Are you certain there is sufficient fuel in the fuel tank? Fuel level senders are known to provide an incorrect fuel level reading.

3. What is the battery voltage at rest, and what is the battery voltage while cranking? Jags are notorious for requiring a very healthy battery in order to start and run properly, and low voltage during cranking can cause all manner of odd behaviors.

4. Have you scanned the car for any stored OBDII Diagnostic Trouble Codes (DTCs), and if so, did you find any codes stored? If so, please report them here.

5. When you first put the key in the ignition switch and turn the key to Position II (Ignition ON) without starting the car, do you hear the fuel pump run for a couple of seconds? The pump is in the fuel tank behind the rear seat.

The fuel injectors on your car are controlled by variable-width pulses from the Engine Control Module (ECM). Fueling is enriched or enleaned by widening or narrowing the signal pulses.

Under certain conditions, the ECM cancels fuel injection, so one possibility is that the ECM believes one of those conditions exists. For example, one such condition is Wide Open Throttle (WOT) while cranking, which the ECM determines from the position of the Throttle Position Sensor (TPS). The TPS is a potentiometer (a type of variable resistor) mounted on the Throttle Body (TB). The ECM applies 5 volts to the TPS and monitors the resulting voltage across the TPS output pins. If the voltage is low (just above 0 volts), the ECM understands the throttle to be closed. If the voltage is high (just under 5 volts), it understands the throttle to be wide open. It is possible your TPS has developed an internal short or it's wiring harness has a short or corrosion is bridging across pins in its electrical connector or at the ECM connector.

The ECM refers to the Camshaft Position Sensor (CMP) signal together with the Crankshaft Position Sensor (CKPS) only at startup to establish initial ignition timing within less than one full revolution of the engine. From the moment the engine starts the ECM refers only to the CKPS signal for engine timing and the CMP is no longer relevant. In fact, the car will start with the CMP disconnected - it will just take longer.

You can download the Electrical Guide for your car at this link, courtesy of our forum member Gus:

http://www.jagrepair.com/images/Auto.../jagxj1997.pdf


There are other helpful documents at the same website, including this 1996 Model Year Update, which will probably apply to your 1997 also:

http://www.jagrepair.com/images/Elec...jm18159960.pdf


There is also a wealth of info available from the Jaguar Forums, such as documents posted in this thread:

https://www.jaguarforums.com/forum/x...k-links-20088/


One such file is this 1996 Technical Guide:

http://www.mediafire.com/download/ol...18151257tg.pdf


Hopefully other members will respond with suggestions that will help you diagnose the problem. In the meantime, please visit the New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum and post an introduction so we can learn something about you and your Jag and give you a proper welcome.

Cheers,

Don

 

You don't have a location set. If you are outside the US this could be due to the security system which disables injection.

 

Hi Don thanks for quick response. car has a new high end battery and there is fuel in tank and fuel rail . with good pressure. i only sprayed enough fuel in port to verify that it will in fact start. it definitely has no pulse at injectors. it does have a check engine light on and i am trying to find a scanner that will read jaguar codes. as i can't drive it anywhere to get it scanned. most i see on cragslist only read domestic and asian cars. i will report back with codes when i get them . thanks again Brian

 

Audionut,
What is the back story here? When was the car last running satisfactorily, and what were the circumstances leading up to the current problem?

 

hi countyjag , i dont know anything about the car really. the guy i bought it from got it from a jag dealer in exeter nh. supposedly needing a fuel pump . pump is fine. he said his son lost interest and he needed the room in his lot. said it ran great when it ran . has a reject inspection sticker from January. thats about all i know .thinking i might go back and see if he knows more . he had a copy of the title with original owners name and address .i just have bill of sale

 

The post by V126man, earlier in the thread is interesting, and virgin territory for me. I found the following link which might be helpful, as it all sounds kind of plausible from the way you have described your situation.
Jaguar XJ6; Jaguar X300; not starting; start

 

Hi Brian,

Your 1997 XJ6 is strictly OBDII with only Powertrain (P) DTCs, so I believe any decent generic scanner should be able to read all the codes. Here's a link to the DTC Summaries manual with explanations for every code and likely causes:

http://www.mediafire.com/download/q2...6_ECM96_97.pdf


Here's a link to the dealer service training manual for Engine Management Systems including the one for your AJ16 engine.

http://www.jagrepair.com/images/Trai...20-%202000.pdf

Cheers,

Don

 

The diagnosis of "no pulses" is incomplete! Do the injectors have +12 volts on the terminals which are all tied together, or is the problem thst none of the ecu channels are pulling the low side to ground?

 

Good point, Ross! I meant to mention that in my first post and completely forgot.

Brian,

The injectors receive a constant 12 volts from the ECM Controlled Relay on the Black wires with Light Green tracer lines. The relay is in the right front corner of the engine bay:



The same relay also powers the MAFS, EGRV and a few other things.

The ECM activates each injector in sequence by connecting its second wire to ground. It would be worth cleaning all the ground points used by the ECM, including the RH bulkhead ground stud, the RH "A" pillar ground stud, and possibly others. The Electrical Guide shows the locations.

Cheers,

Don

 

thanks for all the replies guys. there is power to injectors but only checked with light meter, i will check with meter and see if it is actually 12 volts . im working 2 jobs so my time to work on it is sparse. i hope to work on it tomorrow . oh and find an obd2 reader today. thanks a bunch. really appreciate it.i will try to post some pics of car as well. Brian

 

The light is a better test device than a meter anyway, since it provides load! If the TPS makes the ECU think it is at WOT, no pulses fire. Check the throttle position with your new OBD scanner.

 

thanks sparkenzap i will

 

ECM connector clean and dry?

 

so i bought a Bosch scanner , model obd1050 but having trouble downloading the info . its one of those ones that are blutooth and sync to your phone. it just keeps saying updating . so i will have to call customer support tomorrow after work. also forgot to mention "airbag" is in the little display above steering column on dash but i doubt that would keep it from running

 

As aholbro says, do check your ecm connectors (in the RH kick panel).

 

it looks like someone replaced ecm already. it is encased in a ziploc bag and the left plug on top has dielectric grease on wires going into back of plug from harness.

 

Uh-Oh!

 

The news about the ziplock bag is indeed double edged!
From what you said earlier, the car was sold by a jag dealer as a non runner, and you bought it from the person they sold it to, who had also been unable to make it run. It seems to me that the dealer would only have sold it as a non runner if they couldn't find the fault, or it was uneconomic for them to repair it. The presence of the airbag warning light would have nothing to do with the non starting, but it could have a significant bearing on the economics of repairing the vehicle. I also wouldn't mind hazarding a guess that it had something to do with how the car came to be in the dealers in the first place.
When I sent you the link earlier, I should have said that you need to scroll down it a bit, to the section on immobilisers. Following on from the post by V126 man, I was interested to discover that there are two systems for immobilising the car; the alarm system one, and one based on a chip in the key. The latter can be affected by long periods of inactivity an resultant deep battery discharge. Like might happen to a problem car sitting on a dealers lot.....
Purely guesswork, and may not be relevant if your car is a us market car, as it doesn't have the key chip.
The bagged ecu doesn't sound like the work of a dealer, so may have been the owner you bought it from, which would confirm that the problem wasn't the ecu...
A lot is hanging here on the fact that the car starts when you spray fuel into the manifold.

 

The US version of the X-300 does not have an immobiliser and does not have the chip in the key.
I would have a good look at the connector pins on the ecu wires side and see if there might be one or more that have become corroded.