Hey y'all, need quick help again. My every day car '11 jeep liberty just pooped out on me and went to fire the jag up and now it won't start. I've had it about 3-4 months. Bought it pretty cheap and just wanted a project car. Ive only really worked on the interior and taillights. I haven't messed with the engine. I did change the oil. It seemed to run good except for the codes is been throwing, which seem to have to do with the O2 sensors. P1138, P1187, P0132, P0152. Would a bad O2 sensor cause it not to start? Also one of the fuel trim readings are way off. I think it read 24.2. I'm trying to think of there's any other details that could help. When i opened up the fuel door there was alot of dirt and leaves packed in there. I took the plastic piece out (i think is like a pressure release valve) i cleaned it real good but this was after it wouldn't start. I appreciate any feed back i can get. I need this thing running. If there's any other info that i could get to help out let me know. Thanks

 

Hi salP3082,

The most common causes of a Jaguar that will crank but not start are probably the following:

1. Low battery voltage while cranking. If the voltage falls much below 11V while cranking, the Engine Control Module (ECM) will not trigger the ignition to fire.

2. A failed crankshaft position sensor (CKPS). A simple test that is usually reliable is to watch the tachometer while cranking the engine. If the tach reads about 200 rpm, the CKPS is probably not your problem.

You might try jumping the car with another vehicle (allowing the Jag's battery to charge up for 5 or 10 minutes before attempting to start the engine). If it will start while jumped, it's time for a new battery.

Low battery voltage is also a known cause of multiple random fault codes, so if you decide you need a new battery, try clearing the codes and only concern yourself with the ones that reappear.

A bad O2 sensor should not cause a no-start because the ECM doesn't even refer to the O2 sensors until they have reached full operating temperature, which I seem to recall is about 20 seconds after startup.

There are lots of other possibilities which you can learn by perusing this thread, compiled by our fellow member aholbro1:

https://www.jaguarforums.com/forum/x...ngines-120221/

Cheers,

Don

 

So it's pouring rain here so i tried waiting it out but there's no end in site. I don't mind getting a lil wet. When i first turn the key but not all the way to stay it, the battery meter reads 12v. I did noticed the tactometer isn't moving at all. So from reading the thread I'm assuming it's the crankshaft sensor. Is it an easy fix that i could do myself and is there a certain kind i need to get?

 

I forgot to mention when i crank it the battery voltage meter drops way down. Is this supposed to happen or is it supposed to stay at 12v while cranking it? Again thanks for the help

 

The gauge on the dash may be temporarily disabled while cranking, so I don't know if you can take that as an indication of actual battery voltage. Perhaps one of our other members can confirm.


If the tachometer needle doesn't move at all while you are cranking the engine, then the primary suspect is the crankshaft position sensor. Replacing it is easy. It's mounted on the front of the engine above the crankshaft pulley and is secured by just one screw (8mm hex off the top of my head). Its wiring harness connects with just one electrical connector.

It does take a specific sensor, but they are widely available from all the good independent Jaguar parts specialists like Coventry West, Welsh Enterprises, SNG Barratt and Jagbits, as well as many of the chain auto parts stores like O'Reilly, NAPA, AutoZone, Advance, Carquest, etc. Here are a couple of examples:

http://www.welshent.com/advanced_sea...1640AA&x=0&y=0

http://www.oreillyauto.com/site/c/de...s!angle+sensor

Cheers,

Don

 

Ok. Again thanks for the help. I'll get that ordered and let y'all know how it goes.

 

It would be a good idea to check the battery while waiting for the sensor. The V8's will not fire if the voltage is too low, but I'm not sure about the 6.Get a full charge on the battery and make sure it holds the charge.

 

RJ,

Yes, it's the same with the 6-cylinders. See my post #2 from yesterday.

Cheers,

Don

 

My XJR always ran rich and was not keen to start. When starting it would misfire and chug away and blow foul smoke. Then one day I could not start it at all, so it sat for ages while I did other things. Eventually I got round to replacing the exhaust manifold-to-header gaskets as one had been leaking a bit and while the header was off I fitted new O2 sensors (there are only two on my car, at the bottom of the header). After that the car starts easily and idles and runs cleanly. So I would say yes, the O2S can cause or at least contribute to difficult starting.

 

As Don stated earlier, the O2 sensors are not referred to directly by the ECU on initial start-up - the system would be in Open Loop.

However, a bad O2 sensor is likely to cause the LTFT (Long Term Fuel Trim) to go out of kilter. LTFT is the baseline that the ECU uses for fueling map and therefore what it would use in Open Loop. So yes, indirectly I would expect a bad O2 sensor can cause starting issues.

 

So i just got someone to crank it while i put the multimeter to the battery. It read 12v when i put the leads to the battery. Then when she went to crank it dropped to 10v. So it must not be the battery? I have ordered the crank sensor and am now just cleaning up the interior. I'll let y'all know when it arrives. Thanks again every one. I think I'm gonna go ahead and order the down stream O2 sensors to take care of that problem cause i noticed the LTTR was off last time i had it out

 

The battery is definitely a problem. If the cranking voltage falls to something like 10.5V the ECM will not trigger the ignition to fire. Have you tried boosting/jumping the Jag with the battery of another vehicle?


Don

 

Oh ok lol. Yea i was a lil confused on that. I did the other day when it was raining but i got tired of getting wet so i didn't leave the cables on there very long lol. I'll try again here in a bit. Thanks. Another thing, inside the fuel door, there were alot of dirt and leaves. I went to clean that out and a plastic piece fell off. I think it's like a pressure release thing. It was all dirty so i cleaned it up but I'm not sure how it goes back on. Plus you think if a lil of the dirt fell through the whole, it would cause any harm?

 

I don't know how similar the fuel filler latch box and gaiter are between the X300 and XJ40, but here are some views from our '93 that may give you an idea of the arrangement of fuel filler door latch, the rubber gaiter that seals the fuel filler neck, and the drain hole that is supposed to channel rainwater down to the underside of the trunk/boot but can't whenever leaves and seeds collect inside the fuel filler box (and they do, constantly):

Welcome to Jag-lovers - Members Photo Viewing Page


Don

 

Oh ok. Thanks for the info on the fuel filter latch box. Well i tried jumping it earlier. It still wouldn't start. Rpms did not register. Battery voltage meter was up to like 12-13v but again it looked to do down when i was cranking. You think it could be both the battery and ckps?

 

I got my ckps in today. I already went down and installed it and sure enough she fired right up. I had a lil problem getting the old ckps wiring connector off. It was clipped to a metal bracket or something but finally got it off. I had to remove the top radiator house to get access to it. I got the new connector connected but i didn't get it clipped back on to the bracket. Is it easier to go from underneath or does anyone have a good idea how to get it back clips? Thanks again to everyone! I'm stoked to get er back on the road