When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So,long story short, I bought this blind, as it were.It had been laid up for about 6 months and the keys had been lost. Always up for the challenge. The car arrived on a trailer last week and with VIN in hand I ordered a key from our local dealership (£15 bargain). I had prepared as much as I could,clean off the plugs,dizzy cap and rotor arm,fresh petrol,topped up oil and coolant.
Anyway,she turned over but wouldn't fire up. Pulled the main HT lead off the cap turned her over but there was no spark. Two questions. The battery I have temporarily put on is from an X300 (The boot has been locked until today,so I couldn't get the old battery off) are the XJ40's particular when it comes to different batteries? I'm assuming not but I've assumed before,to my downfall.
Secondly, my gut feeling was to goto the crank sensor,removed it and tested OHMS, only to find the reading was sporadic so I'm not certain I was making a good contact with the probes, it ranged from 689 upto 1800. So I'm thinking that's the culprit. I have a spare from an X300 but the connectors are different and I don't want to start butchering it. Any thoughts so far? and has anyone got a spare sensor? I've ordered one through Ebay but it won't arrive until after the weekend. Any input appreciated. For reference it's a 1993 XJ6 (XJ40) 3.2S. Many thanks.
The crankshaft position sensor (CPS in XJ40 jargon) is definitely a suspect when you have no spark, and could be the reason the car stopped running some time ago. I assume the electrical connector is clean and dry and you're sure it is connecting securely?
Another possibility is low battery voltage while cranking. If the voltage falls below about 10.5V while cranking, the engine control module (ECM) will not trigger the ignition to fire. An X300 battery should be able to start an XJ40 with no problem.
Problems with the ignition coil and amplifier (the flat electronic component mounted directly under the coil) are known - check for deterioration of the plastic around the electrical terminals or signs of arcing.
There are a number of fuses and relays in the starting/ignition/engine management circuits. See the schematics in the Electrical Guide, which you can download here:
Thanks for the reply and link Don,much appreciated. I shall have a look through and try and locate anything relevant. Someone has been at it before me by the looks of things,there is a bank of relays on the passenger side firewall of which two have been rewired as the holders are badly water damaged,two others are very poor also,so will need repairing. I've pulled every fuse available today and found one blown,which means we now have left hand windows working.The crank sensor won't be with me until next week so I can only do rudimentary checking for now, unfortunately I broke the old crank sensor whilst seeing if it was possible to use the x300 one. Both footwells were damp when she arrived but I have checked the main CPU area and that shows no signs of water ingress, which is a bonus for now.
Is that corrosion in the relay sockets or is it grease? If someone has added grease to try to help seal out water, you may be able to clean it away with a small wire brush and repeated flushings with zero-residue electrical contact cleaner spray.
Just disconnect the negative battery cable first, because some of those contacts in the sockets carry battery voltage at all times and you don't want to short anything with your wire brush.
Unfortunately it is corrosion. I was first cleaning out the terminals with a fine bradawl but chunks of metal were just falling out. I'm going to replace them all one by one as I don't trust the previous handiwork.
So the crank sensor arrived this morning. The bracket was slightly different but I had a longer bolt which fitted nicely. Moment of truth,turned the key and she fired up,what a rush. There is no downside but she is running poorly. There is no accounting for what has been done before and the fact that I have no idea what has been played around with previously whilst she wasn't running. Still one step at a time.
Unsure whether to continue on this thread or start one for 'Running badly' Let me know if that would be best. So finally started but as posted not running well. Unable to get the revs above about 800rpm. As a matter of course I purchased a new cap and rotor arm,you can see from the pictures the old ones weren't the best. Put them on this morning but it made no difference. Still think it was worth doing as at least it rules out another area for relatively little expense. I have a spare set of new spark plugs which I will put in tomorrow before moving onto some more in depth fault finding. Like I have said before, there may have been underlying issues I am not aware of which caused the car to be laid up in the first place...I'll see where we are after the new plugs go in and then maybe move onto to the fuel side. If I didn't know better it smacks of HT leads in the wrong order but I have double and triple checked and they are in the right place. Enjoy the photos'.
Can see why the rotor arm didn't want to come off.
Finally gave it up after a little persuasion.
Cleaned.
The old and the new.
This was after I'd tried cleaning it up before replacing the crank sensor and starting her up.
Definitely a good choice replacing ignition. You say it won't rev over 800. Does it respond to throttle at all? Or does it try and then get bogged? It seems like an injection issue. I would be checking fuel pressure and proper injector action. Maybe have a look at the throttle position sensor on the bottom of the throttle plate shaft. I recently spent a lot of time there. Have a look in the stickies at top of this forum. The info is probably there. Good luck.
Hi Jerry,
I agree and that will be my next stop after putting a set of plugs in. There's a definite 'note' change to the engine when the throttle is depressed and if you try very very gently it feels as though it wants to pick up but just doesn't. My guess is that it hasn't run for longer than the six months I've been led to believe so who knows what condition the fuel side is in. I'll rule out the plugs and then move on to the fuel and take your advice and have a look though the 'stickies'. Thanks for the advice.
So here's out it all turned out. Last night I was pondering the next step which in turn led me think about the crank sensor bracket I had recently fitted. We had gone from a non-starter (no spark,nada) to a very poor runner but a runner none the less. This in itself was a bit of a red herring. The bracket and sensor I had removed were the same as the spare I had from an X300 (except the connector was a 2-pin on the x300 and a 3-pin on the xj40, which was why I didn't use it in the first place) The one I ordered was listed as being for AN XJ40 from 89-94 but was of a different design,which I didn't pick up on in the pictures. I just assumed it was a design change, no biggy,found a bigger bolt and away we went,fitted without a hitch...and the car started. Well after an hour so last night trawling Google for any info I could on Crank sensors it turns out different ones were for different models and although the bracket/sensor I had purchased will fit some XJ40's it will not fit my 1993 3.2s. Those in the know will undoubtedly be aware of the criteria.
So...I could wait and order another sensor or go with what was still a hunch and cobble together something workable with what I had. In trying to remove the newly aquired sensor from its bracket, it broke...not being put off I cut the connector off with a good few inches of wire. Put two female connectors on the ends of the red and blue wires (the black one I had to leave redundant) and connected those to the two connectors on my x300 sensor/bracket. Bolted it on,connected it up. Turned the key and all six cylinders sang in unison. I realise it is only a temporary fix and I will have to get an original one sorted but for now she is mobile and the rest of the work can commence.
Happy days.
The one on the left is the larger one (EBC1253) <br/>that will not work on my 1993 3.2s
The lower,smaller bracket was from an X300 3.2 and although fits the connectors are different and required some fudging.
In '93 the alternator was upgraded to a higher-output unit and if I recall correctly the pulleys and belts were changed from 4 ribs to 5, which meant that the CPS bracket had to be redesigned to position the sensor correctly over the reluctor wheel. Or something like that!
Well done twack and thanks for sharing . . . especially your pics. Thanks also to DonB for explanation on alternator change. Having both an '87 and '94 XJ40, 3.6L vs 3.2L, I am constantly learning they are very different cars.
Well done twack and thanks for sharing . . . especially your pics. Thanks also to DonB for explanation on alternator change. Having both an '87 and '94 XJ40, 3.6L vs 3.2L, I am constantly learning they are very different cars.
Cheers,
Ken
No worries,thanks for that. It was some pictures I came across in a forum (Via Google images) that helped, which gave me the idea and a happy ending.So if in the future it helps anyone then all is good.
05-09-2017, 12:03 PM
XJ40 3.2S Non-starter
