Hi, I have a XJ6 1996 model and I am told that I can not touch the accelerator to start or it would flood and I would have to change the spark plugs if so. Does any one know if this is true or not. I am having problems starting, in fact it will not start at all right now. It started after two cranks three days ago, then starts fine with in 15 to 30 minutes after driving but any longer time it will not start easily ten to 15 tries. Today not at all though. Any thoughts.

 

Welcome to the forum holiday,

I've moved your question from Jaguar Forums Advice / Feedback & Suggestion Center to X300 forum. The Advice / Feedback & Suggestion Center is for posts about the forum and NOT for technical questions.

Members here with the same model will be able to help.

Graham

 

Welcome to the forum, Ziggy.
Could be a number of things; There are a ton (metric tonne?) of threads here in the X300 section on hard-starting / no-starting. From your post, it sounds like it cranks but does not start? That'll be the first issue to nail down. Reading in just a little bit deeper, and maybe making stuff up that you didn't say or mean, but sounds like it ALWAYS starts within 1/2 hour or so of being run? If both these are true, I'd steer you toward the posts about the fuel pressure regulator leaking internally rather than a faulty CKPS. But you can check that easily enough, while cranking, your tach should register a couple-hundred turns - if not, a failing CranKshaft Position Sensor may be indicated.

Have you tried flooring it while cranking? I understand the reticence given what you've been told....but on rare occasions, mine will light for a few seconds, miss a lot and run very roughly then stall.....after that; endless cranking until I hold the pedal to the floor which will get a good start and smooth running. Others here have reported similar occurrences. In any case, Search the X300 section for the word "start" and that will get you "started" on understanding the issue until some more knowledgeable members happen along to help you diagnose it.

 

In addition to the good advice from aholbro, I might add that I know of no such anomaly and I am sure I "touched" the pedal at least a few times in my 190,000 miles with the XJ6! The cars have a known failure mode with the Crank Position Sensor (known as the CKPS) and they apparently can fail intermittently. Rule this out by observing whether the tach shows abot 200 to 300 rpm as you crank.

 

Hi ziggydrives,

Welcome to the forum!

Sorry to hear about your starting issues. aholbro1 and Ross have covered the most likely suspects (FPR and CKPS are very common issues). But I wanted to add that since your car is 18 years old, it is possible, if not likely, that multiple issues are contributing to your hard starting.

First of all, when you hold the accelerator pedal all the way to the floor while cranking, the Engine Control Module (ECM) shuts off the fuel injectors to help clear flooded cylinders. It’s an intentional aspect of the design, so it’s worth trying as suggested by aholbro1 and Ross. Also, I don’t know of any reason that flooding will ruin your spark plugs as long as they are given a chance to dry off so they can spark again. If anyone knows better please correct me.

Regarding the fuel pressure regulator (FPR), a simple test you can perform is to pull the vacuum hose off of the FPR, crank the engine, and watch for the presence of fuel at the vacuum fitting. If present, the diaphragm has failed and unmetered fuel is being inhaled into the intake manifold, causing an over-rich air-fuel mixture that the ECM cannot measure or correct. Since there is no Schrader valve on the fuel rail, actually testing the pressure and leak-down after shutoff requires a cobbled-together adapter for a pressure gauge.

Have you had the computer scanned to see if any Diagnostic Trouble Codes (DTCs) are stored in the computer? Lots of owners are using an inexpensive ELM327 OBDII Bluetooth scanner in conjunction with an even less expensive program called Torque that runs on your smartphone. I paid about U.S. $17 on ebay for my Bluetooth scanning adapter and around $5 for Torque to run on my Android phone. Most DTCs will trigger the Check Engine Light (Malfunction Indicator Lamp), but from what I understand, not all codes will.

You also don’t mention how long it has been since the car had a tuneup. At the very least, I would recommend a new fuel filter and air filter, and that you pull one or two spark plugs to check their condition and that they are still properly gapped. Use zero-residue MAFS cleaner spray to clean the Mass Air Flow Sensor and its electrical connector. Allow to dry and reassemble.

Battery voltage: Jaguars are very sensitive to poorly-charged or failing batteries. If battery voltage falls much below 11V while cranking, the ECM will not trigger the ignition. Most of the chain auto parts stores will run a basic test of your battery and charging system for free. Be sure to have them check the battery voltage sag while cranking, since Jags are more vulnerable to low cranking voltage than many other cars.

On a related note, poor battery charging is often caused by corrosion on the many battery power connections and ground points throughout the car. Search the forum for many posts about cleaning and maintaining these connections.

Contaminated fuel: If your problems began shortly after purchasing fuel, or after the car had been sitting for a few months, it is possible the fuel is contaminated with water.

Ignition Switch: The electrical switch mounted on the end of the key barrel is known to fail with age. If the ignition contacts open when the starter contacts close, the engine will crank but not start. Wiggling the key while cranking may help diagnose this issue, or you can test the switch with an ohmmeter at its electrical connector inside the steering column cowl.

Coolant Temperature Sensor (CTS): The ECM refers to the CTS signal in order to determine the degree of fuel enrichment required at startup (more enrichment is needed in cold ambient temperatures). If the CTS is failing, or if there is a problem with its electrical connector or wiring harness, the ECM may provide too much enrichment (or too little), contributing to hard starting. A common symptom of CTS failure is reduced fuel economy.

Camshaft Position Sensor (CMP) or Engine Position Sensor: The ECM uses the CMP signal to establish initial ignition timing within 2/3 revolution; after startup the CMP is ignored and the ECM refers only to the Crankshaft Position Sensor (CKPS) for ignition timing. If the CMP is failing or has an intermittent (perhaps temperature-dependent) fault, the ECM must rely on the CKPS instead, but since it doesn’t know which orientation represents Top Dead Center for Cylinder 1 on the compression stroke, it has to use trial and error with different timing schemes until the engine starts, leading to very long cranking times (how long, Ross?).

Fuel non-return or check valve: The check valve is built into the evaporative flange on top of the fuel tank, and its job is to prevent fuel pressure from escaping back into the tank. The check valve works in partnership with the FPR to maintain pressure of +/- 40 psi in the fuel rail. Over time, both the check valve and the FPR cease to hold pressure, so the fuel pump must provide sufficient fuel flow through the rail not only to keep the fuel injectors primed, but to atomize the fuel injected into the intake ports. If the fuel is not properly atomized it won’t ignite as easily as it is supposed to, contributing to plug fouling and starting and running issues. If your check valve has failed, the easiest solution is to add a new check valve in the fuel feed line.

Idle Air Control Valve: This fills up with carbon gunk that reduces its ability to open and close properly for starting and idle control. Search the forum for instructions for cleaning the valve and stepper motor.

Sorry for the long laundry list, but once I get started it’s hard to stop.

Please keep us informed or let us know if you have more questions.

Cheers,

Don

 

Hi guys, thanks for the reply's. I guess I have left out a bit of info. I had a new crank sensor put in recently, and a complete tune up. also a new battery. I will give it a try with the pedal to the floor while turning over, I hope that will work. I also wonder if it matters, that when it does start I have no accelerator response until the car warms up approx. 2 to 5 minutes. Will this make a difference if I put the pedal to the floor before it starts?

 

When you say "no accelerator response", do you mean it lacks power, or truly "no response"? I would assume you have a CEL? If so, you need to get the codes read- it will help pinpoint the problem. And, as a direct answer to your quetion, it is hard to imagine that anything you do to thepedal while cranking would only affect operation for a few seconds after startup.

 

Hi Ross, yes I mean no response at all when I start the car it will not accelerate until about 2 to 5 minutes. I can put the pedal down and there is nothing, then when it warms up it clicks and then I have acceleration. Is this a normal thing or some thing wrong?

 

Hmmh! I went back to look to see if you really had an X-300, since what you say sounds like a "drive by wire" problem, which the X-300 does not have. I am really waiting to hear the outcome on this one, since I have no idea in the world how that could happen!
Good luck.

 

Just thinking out loud here, so bear with me. I can only think of a few things that could even remotely contribute to the symptoms ziggydrives describes:

1. His car is actually an XJR and there is a malfunction with the supercharger... (doubtful)

2. The EGR valve is stuck open, which, in conjunction with the Secondary Air Injection system, is allowing so much air at startup that the throttle butterfly valve is essentially swamped and irrelevant. The Secondary Air Injection can run for up to 4 minutes depending on ambient air temps, which seems consistent with the 2-5 minute lack of throttle response. A stuck-open EGR valve would also contribute to hard starting, and the problem could be further compounded if the IACV is carboned up and/or not functioning properly.

3. Could there be a temperature-dependent malfunction of the Throttle Position Sensor (TPS) or its electrical circuit? The TPS is a potentiometer, or variable resistor, wired as a voltage divider. An analog-to-digital converter in the ECM converts the voltage divided by the TPS to a value that represents the unique position of the throttle butterfly valve. Could condensation in the TPS, or oil contamination, cause a lack of throttle response until the water turns to steam or the oil warms and runs off the resistive elements so the wiper can make good contact again? PROBLEM: This could explain why the ECM would not increase fueling at first, but it doesn't explain why the introduction of more air into the intake without more fuel (by opening the throttle valve) wouldn't cause the engine to stumble and possibly die do to over-enleanment.

So far option 2 seems like an avenue worth exploration, unless someone else can shoot the idea down.

Cheers,

Don

 

For lack of anything better, I like #2 also. And... it actually makes some sense. Well, a little anyway...

 

ziggydrives,

We're trying hard to help you - I'm still suspecting that multiple malfunctions are contributing to your issues. Are there any other symptoms you have forgotten to mention? Every clue may be helpful.

Cheers,

Don

 

Like a "Check Engine Light" or an OBD code?

 

Hi and thanks for the help, no luck yet but will explore the tips. As for more info, I have replaced the crank sensor but am not getting any movement on the tac what so ever, which if im correct means it could be the sensor is faulty or its some thing else all together. Wish you guys were closer..lol. also the check engine light is on and the battery level goes below 9 while cranking it over.

 

I would sure get the OBD codes read by some method! I hope yo don't have some manifestation of the corroded wire syndrome reported by some folks recently. That's where the ECU connector pins show up corroded due to water ingress from the sunroof drains!
But the idea that the engine runs without tach pulses AND will continue to idle as the pedal is depressed really seems odd. I don't know much about the thing that limits the revs for the traction control, but could that have some part of this?

 

Ziggydrives


I hope you keep us all updated on any progress you , too often posters ask a question about a problem and get lots of great insights to solving the posted problem and when it's fixed, they forget to give us the final outcome..... Puff...... we never hear what the solution was...... So keep us posted


BigBoss in Dallas TX

 

I to am a bit confused by some of the OP's observations.

Ziggydrives,

Are you saying that when the car does start, it idles ok and that if you press the accelerator the engine does not rev up in Park or neutral? Does it do anything like run rough when you press the accelerator?

Or does the condition you are describing only happen when you put the car in drive? If so, when you put the car in gear do you feel the transmission engage or does that only happen after the 2-5 minute period? If so, I would suspect something wrong with the rotary switch or the decoder.

 

Well I'm happy to report that a faulty crank sensor was the start problem, I just finished putting in the new one and it purrs like a kitten....As for the accelerator problem it was a simple (sticky) for lack of better word cable. I played with the assembly and it seemed to be stuck until it warmed up then worked fine. Worked it a little and I had good results. As is for now all works great....Thanks for all the input and will be around for for advice when needed....Thanks guys!!!!!...

 

Thanks for that update and good to see you got it fixed


BigBoss in Dallas TX

 

Today first time ever, my 1996 XJ6 Sedan had trouble starting. Hot day and car was sitting on flight line at work all day. Tried to start and took about 3 long times of cranking before it finally started. Once I got home, I was sitting in car while it was idling and it stalled out 2x. I was able to get started, but wasnt consistent to start up immediately. Where do you recommend I start for trouble shooting?

Thanks!

Marcus