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IF, and here is where the beer cuts in, the Injector Pulse is AWOL, then there is NO fuel INSIDE the cylinder to go BANG.
To prove this get some Ether in a p/pack can, and give the thing a SHORT sniff of that, and go for start. If that gives a cough, or even runs for 1 - 2 seconds, Injector Pulse is your culprit.
Probe the RED wire going into the Crank Angle Sensor, turn ON the Ign, and note the volts. You SHOULD have battery voltage.
This is memory???, and its way past Beer O'Clock, but on the X300 (4 door late XJS), there is a fuse in the RH engine bay fuse group that controls that RED wire, and that same memory is fuse #1, but that was many years ago, so might be wrong, but there will be a fuse in there for that I reckon.
I had the same problem with mine, where I tried everything that I could think of and in the end it was down to Blocked Injectors, which I removed and then Cleaned by making a simple home made rig and then I blew through all of them with some Injector Cleaner
And though I got her running I decided to replace all 6 Injectors with New ones to try and avoid any problems further down the line
But if you've got about £25 burning a hole in your pocket, you could treat yourself to a 'Noid Light' (ebay) as this is a gadget that will tell you if the injectors are firing and in doing so save you a lot of time in taking all the Injectors out of your Car
Don't delve into random detail things until you've verified the 2 key elements:
- Do you have a spark at the plugs when cranking?
- Do you have fuel being injected during cranking?
As suggested, just pull a plug and test whilst cranking. You'll also be able to see if you've got fuel squirting in that cylinder.
It's a simple test. Don't bother looking at anything else until you know whether it's a fuel problem or a spark problem. As the problem started after you washed the engine, my guess is it's an electrics problem.
So just want to take the a second and send a big THANKs to all who are contributing.
but...... still nothing. So update.
After going out and getting a spark plug ignition tester I can now confirm I have NO spark.
Fuel | Yes
Spark | No
I have the original Crankshaft Position sensor in and I have a brand new one I have swapped in and out. No change on either. So when key in “ON” position the tac hovers on 200-250 rpm and when cranking shows 300. Attached picture
Checked ECU no sign of water ever. Super clean pins are bright. Is there a power distribution for that or relay maybe I am missing. All fuses tested good. Have all new replacement to the Blue Hela Relays In place on ignition items.
Does anyone have history replacing the Camshaft Position Sensor won’t that handle the spark distribution?
My 93 had a starting issue and I found that it ended up being the ecm connectors. I should say that the connectors and pins looked fine, but I found that if I spread the two connectors slightly apart while plugged in it would start everytime. However when I would move them slightly together it would shut off and not restart until I slightly spread the connectors again! And I mean like maybe 1/16th or so at most. I ended up putting a piece of foam between them with a zip tie around them. I haven't had any issues since! I'm thinking it may be a small crack in either some solder or the motherboard. Either way, I know it's rigged, but it works. Might be worth a try
The Crank Position Sensor on your Car is a 2 Wire Inductive Pulse Sensor unlike the CPS on the V12 which is a 3 Wire Hall Effect Sensor
So if the CPS is off the Car and on the Bench Set Your DVM Meter to Ohms and put the Meter Wires onto the 2 Pins inside the CPS Plug and you should get a reading of 400 to 1200 Ohms which is an indication that the CPS is Good
Next: put the Crank Position Sensor back on the Car (But don't connect the CPS to the Car leave the CPS connected to your Meter) and Set your Meter to AC Volts then Crank the Engine and you should get a reading of 2 volts AC Minimum
As the Inductive Pulse Sensor is generating its own Magnetic Pulse to Trigger the ECU
If that isn't happening then that is an Indication that you've either got the Gap wrong (should be 0.042 or less) or the Reluctor 'Cog Thingy' may be covered in dirt or grease and need a Clean or something else is wrong that we haven't Sussed out yet (lol)
The other thing you Can also do if the CPS is off the Car is to connect the Wires from your Meter to the 2 pins of the Sensor inside its little plug and then Set the Meter to AC Volts but instead of Cranking the Engine (As it is no longer on the Car) get your Cordless Drill or Cordless Screwdrive and put in a Flat Blade 'Wood Bit'
Then Spin the Flat Blade 'Wood Bit' in front of the Magnetic Probe on the Crank Position Sensor (as close as you can without the probe getting hit with the bit) where once again you should get a reading of around 2 volts AC
DON'T use a Mains Powered Drill to do this, as that could be DANGEROUS on many different levels, as for one thing you may not have enough slow speed Control
The other thing that needs looking at are the 2 Blue Relays inside the Passenger Knee Panel Fuse Box where they are over the Top of the Fuses almost out of sight, these may be the 'Thin Blade' ones that 'may not be making good electrical Contact, so worth unplugging and re-plugging them or even swapping them round
In addition to my earlier post on the connector I have also replaced the cam shaft positioned.
Original situation
Car would normally start on first or second rev....all of a sudden it was taking many seconds to start.
Afcter several discussions with Grant Francis and others, he walked me through the entire process.
I got a used distributor from ebay, removed the cam shaft positioned and replaced it with my original distributor. Based on some guidance from Grant got it together and in and back to firing up on 1st rev.
Maybe Grant can discuss the cam shaft positioned and exactly what it does.
I had replaced the crankshaft positioner .....no difference. By the way the positioner is pretty fixed as you mentioned.
I will go through my scribbles, drink much coffee, and work through that Cam Sensoe.
I doubt it is at play for the complaint you have, as yours has NO spark.
Cam Sensor failure, or out of time, simply cause the engine to crank excessively (10 - 15 seconds) before firing. This is due to the ECU gathering other information as to where #1 TDC Compression stroke is, then the engine will run fine, BUT, that search mode takes place EVERY time you shut it down, hence the need to sort that before the starter motor fails. AGAIN< I doubt it is the problem here at the moment.
12V in that RED wire to the Crank Sensor is from the Blue relay closest to the engine, RHF behind the RH headlight IN the engine bay on the X300, and I imagine these 1996 cars would be same layout. NO 12V in that RED wire, DEAD engine, no exceptions.
You washed the engine, so I will focus on that only, and come back later tonight (our time) after more thoughts.
Played around with the Relays and replaced both units with NEW black relays made replace the light blue Hela ones. Still nothing.
Went back to the NEW crankshaft position sensor and still nothing.
Keep forgetting my multimeter tester but will have it tomorrow.
What’s yours or anyone’s take on a
bad Temp Sensor. I have read that that is known to cause a NO start and no spark. It tells the ECU that it has no temp so it will cause the ECU to stop a spark. Thoughts?
You could try 'The Paper Clip Trick' on the Coolant Temperature Sensor, as in your situation nothing to lose by giving that a go
Just Bridge the Wires in the Coolant Temperature Sensor Plug with a Paper Clip or a Piece of Wire and who knows you might get lucky
How wet did that Engine actually get?
As its very possible and possibly more likely that water got into the Coils in the Spark Plug holes, so before you take some time out it may be an idea just to pull the Coils off the Plugs in the hope that they might dry out (if they got wet) or maybe give them a bit of the Hair Dryer Treatment
Taking the Coils out is easy if you leave the Spark Plugs behind for the moment
Last edited by orangeblossom; 04-25-2021 at 05:40 AM.
OK, my suggestions, and I will not leave out any that have been mentioned, my brain simply wont keep up, so I reckon you be smart enough to "tick off" the ones that do not apply.
Washing the engine, and assuming it got WET.
Unplug and dry, then WD40 spray:
TPS (Throttle Position Sensor) connector.
CTS (Coolant Temp Sensor).
MAF (Mass Air Flow) Sensor, in the sir intake trunking near the air filter box,.
CAS (Cam Angle Sensor),
CPS (Crank Position Sensor). You have been at this a few times. It is a MONGREL connector at best.
Coil Connectors, ALL of them, one by one.
Lift the coils, ensure there is no moisture up inside the rubber boots.
Relays, OK you have attacked them, but the sockets could be holding residual moisture, blow them out good.
Remove the "tin lid" of the CAS, blow it out, just for the sake it is there.
Your market may have other things with connectors, we were very basic down here.
The only item that I believe (I may be wrong) that causes loss of spark is related to the CPS. When that voltmeter turns up, check that RED wire. If NO 12V, there be your problem.
Bridging the CTS is a good FREE diagnosis trick.
Having that Tacho read anything but zero with the Ign ON and the engine NOT rotating is bizarre to me. Also indicates that MAYBE there is 12V in that RED wire, to give nay signal, mmmm.
Shimming, I have never done it, BUT that does NOT mean it is a thing to be dismissed. With the quality of parts these days, OE or not, anything is possible.
Look at the toothed wheel on the rear of the crank pulley, make sure there is NO foreign stuff obliterating some of the teeth, Washed down from above. There will be ONE missing tooth, that is normal, and that is the timing key for much later setting up, after its running, so as NOT to confuse things now, I have NOT attached that PDF here.
All this is about 12 beers, have fun.
Last edited by Grant Francis; 04-26-2021 at 02:37 AM.
You should feel Honoured to have 'The Wizard Of OZ' Grant Francis on board and KOF 'Greg'
'The Wizard' most normally only turns up in situations where 'All Hope Is Lost' and way back in 'The Mists Of Time' when I first joined the Forum and was in a similar situation with my V12 although I had totally lost myself in the mass of wires and pipes that were under the Bonnet, they helped me Fix my Car and got her running!
What these two guys don't know about Jags and XJS's you don't need to know
But never ever ever, let any Water get near the engine of a Jag!
So before I even put items up on the forum I did go through all the engine connections and dried them out and used some dielectric grease. Also blew all connections out..... even used a hair dryer.
No luck on the temp sensor. Didn’t do anything.
The CPS is reading 2.945v so guessing that is a problem.
Also the Tac shows 200ish RPM just with the key on run. I even have the CPS no connected and it shows that?
So I have the wiring diagram shows the CPS has power and connected into black connector of the ECU.
04-23-2021, 06:10 AM
