Paul,
The CTS is new and since you first recommended frequently cleaning the spark plugs, I have done so. I have disconnected the battery and removed the wire connectors from the ECU. I cleaned the pins and the plugs, even though they looked clean, and I will not reconnect the ECU till tomorrow. The ECU will deenergize and hopefully reset itself when reconnected. Oh! compression is good, as when the head was off I clean the valves and hand lapped them back into the head. I am old school!.
John

 

John,

I'm sure it's possible, but if you've got 6 spark plugs firing and 6 injectors squirting a nice spray pattern of fuel when the engine is cranking, then I would be surprised if the ecu is malfunctioning.

Was the old CTS malfunctioning? Is the new CTS a genuine Jaguar part or an absolutely guaranteed OEM? We know of a number of pattern CTSs that just give the wrong signal, If the old CTS wasn't defective and the car doesn't start tomorrow, I'd put the old CTS back in or try the bridging bodge and just see if you get a difference.

Paul

 

Paul,
Old cts was just buggered up, and I do not remember if new cts is oem. I will try your suggestion.
John

 

Saturday update: reconnected the ECU and jumper wired the CTS plug. Reconnected the battery and immediately got fault code 14 for cts out of range. Cranked engine and residual fuel in cylinders fired briefly and then just crank, no start. Reconnected the cts and still just crank, no start. I can think of no other option, but to get a used ECU.
John

 

John,

I'm sure this is proving massively frustrating for you!

From all the things you've described, specifically:

- all spark plugs are firing well on cranking
- all injectors are spraying properly on cranking
- the plug leads are in the correct order and in the right position
- there's sufficient air flowing through the throttle butterfly (have you checked that and tried different throttle pedal positions on cranking?)

I'm minded to think there must be a massive ignition timing error happening somehow. But an ecu firing the sparks but at completely the wrong time still seems rather strange.

The spark timing is derived from the crankshaft position sensor. Failing CPSs are common on XJS. The simple basic test is whether the car shows about 200rpm when cranking. If it does, the CPS is USUALLY working. I would check that first. Failed CPSs often cause no spark rather than mistimed sparks.

Although annoying, because you've taken them apart, you'll understand why people will question the valve timing definitely being at TDC on the right stroke, setup of distributor and leads etc.

I'm sure you don't need any more suggestions! But if it were my car, I would:

- check throttle butterfly
- check the tach bounces on cranking
- check the valve timing (again!)
- check the distributor position (again!)
- check the position and connection of the plug leads (again!) and compare to pictures of similar XJS online, or post here
- pull all 6 spark plugs and watch them all sparking together on cranking
- replace plugs, pull all 6 injectors, carefully position in glass jars and watch all 6 spray patterns together on cranking

- take a large drink!

Paul

 

Thanks Paul,
Just had a friend over and tried to spay some starting fluid while cranking, no start and the tacho only bounces to about 100 rpm. I was not able to previously get the CPS dead on center to the toothed sprocket, as the woodruff key started to tip in the slot on the crankshaft. It would be a PITA, but should I pull the crank shaft sprocket and reposition? I am getting spark, but it may be a weak spark. What are your thoughts?
John

 

If there is no coughing etc, at the very least, on cranking with ether, you do not have a spark. Even if the timing was 90 degrees out you would get backfiring and coughing.

 

Hi miamijohn

Since you are still having problems in getting your Car going

Have a look at my Thread 'Carmen won't Start'

Where I tried almost every single 'Trick in the Book' to get her going, which I eventually did!

Its all here with Photos, including removing the Fuel Rail and Testing the Injectors as well a Cleaning the Pins on the ECU and even replacing the Fuel Pump, which is a Total PIA Job to do

So maybe you could pick something out of this Thread, that you haven't tried yet

Which includes a Photo of the 'Paper Clip Trick' for the CTS as was suggested by Paul (ptjs)

Almost every 'Trick in the Book' to get my XJS 4.0L Started which it eventually did

 

Hi John,

As with similar threads that get quite protracted and detailed, it's easy for us all to miss previous comments and responses. So I've re-read the whole thread to try and recall the observations you've made,

If I've interpreted correctly:

- All 6 plugs are sparking well when the engine is cranking - Can you remove alll 6, crank the engine and show us a quick video of that?
- All 6 injectors are spraying well when cranking - again, can you show a video of that?

Based on that, like Greg, I'm surprised it's not trying to start even if the ignition timing is somewhat out of kilter?

- You mentioned the CPS gap is correct and you said the tach bounces at 200rpm, although you mentioned yesterday it's now only 100rom? However, you also stated you were "not able to previously get the CPS dead on center to the toothed sprocket, as the woodruff key started to tip in the slot on the crankshaft." I'm not quite sure what you meant by that. Do you mean the crank sprocket is disturbed or misaligned? If that's the case, then this could be really important. Perhaps you could clarify that with some photos?

Notwithstanding my thought that the car would TRY and start even if the ignition timing was out, it could be that the spark timing is being massively adjusted by the toothed sprocket being out of line and causing an incorrect signal to the CPS.

I know it's a pain, but humour us so we don't make suggestions that may distract you from a clear analysis. Show us a video of all 6 plugs sparking on cranking , and one of all 6 injectors spraying when cranking, a pic of the spark plug leads on the distributor and a pic of the alignment of the CPS to the toothed sprocket.

The answer is there somewhere!

Cheers

Paul

 

Thank You Paul, I appreciate your knowledge and suggestions. So i am going back to the beginning, and pulled the crankshaft pully and ordered a new woodruff key. So I will start with getting the pully properly installed and the CPS gapped as well. The old woodruff key was in bad shape and prevented the pully from being properly positioned. As I progress I will post results.
John

 

Paul,
installed new woodruff key on crankshaft and installed harmonic balancer and CPS is aligned with a .032 air gap. tried to post photos, but I didn't know how. So while I was already working on the engine front, I also put in a new alternator. No change, I get good crank but no fire. the only remaining problem I think, is the ECM.
John

 

I am stumped! I have replaced all parts, which you guys thought could prevent a no start. Recap, new working ecm, coil, cap, rotor, plug wires, plugs, oem cps air gap .032, water temp sensor, starter, fuel pressure control valve, fuel pump, fuel filter, alternator, idle air control valve, fuel injectors. Pulled the fuel rail and all six injectors are spraying, pulled each plug and grounded to engine and getting spark. Cranks great, plugs getting wet but no start. Disconnected the maf and got error code 12 so the maf may be OK. TPS and O2 sensor replaced not long ago. All fuses and relays are good. Cleaned all grounding points. Any suggestions please.
John

 

Also, tested voltage at the coil, with key in on position 11.63 volts. I am going to test voltage at the coil and test the tps while cranking
John

 

Hi John,

Like others on here I'm sure, I'm struggling to think where is the problem. You've suggested an ECM problem, but with the symptoms you've said, it's somewhat difficult to conclude that the ECM is the fault. That's because you've said:

- all 6 plugs are firing (strongly?) when cranking
- the injectors are all spraying (a good spray pattern?) when cranking

As I see it, on an AJ6 engine, the ECM does "relatively" little:

- It determines whether to initiate the ignition side. But the distributor determines the timing sequence etc. And you've said all the plugs are sparking (strongly?) when cranking which seems to eliminate the CPS and that side of the ECM being at fault

- It determines the pulse width of the injector cycle. Yes, that side of the ECM could be at fault but you've said that all injectors are spraying (well?) on cranking which implies it would at least stutter even if the pulse width was not ideal.

So if you assess that, I'd not start with assuming an ECM problem. So where would I look first?

- Fuel
- Air
- Compression
- Ignition Timing

If I looked at each of those, I'd question:

- Fuel. Can the fuel ignite? Is it definitely fresh fuel? Why not drain it all (save it for the lawn mower) and put some fresh 99 octane fuel in it and pump it through

- Air. Are the inlet tracts clear? No rags left stuffed inside from the head work? Does the throttle butterfly operate correctly and does it have the appropriate air gap at idle? Is there a massive air leak, perhaps on the inlet manifold, or exhaust manifold?

- Compression. Is the valve timing right? Are the valves operating correctly? Have you confirmed compression on all cylinders when cranking?

- Ignition timing. Is the distributor positioned correctly? Is the rotor arm positioned correctly? Are the plugs in the right order on the distributor cap and positioned on the right spark plugs?

- Residual Fuel. Every time you've unsuccessfully tried to start it, have you then removed all the plugs, disconnected the fuel pump and cranked it through to clear any unburnt fuel from the cylinders before the next attempt?



Yes, I know you can intuitively answer Yes to all the questions. Why not pretend that you've just bought a non-running car and that you don't trust any of the above and check very single item, and get someone to check and tick off every step that you're taking. There is a problem somewhere and it must be possible to ultimately find the problem. But if you assume any of the above checks don't need doing, then you'll possibly miss the one that's at fault.

We share your frustration, John, although we know it's 10 x worse for you!

Cheers

Paul

 

Thank You Paul for your support. I will do a compression test first and methodically progress through your other suggestions and report back. Today I rechecked all fuses, and tested for voltage at every relay connector, so fuses and relays are OK. Is there any way I can test the MAF and the TPS?
John

 

MJ
I may have asked you already; but does it try to fire on ether (EEZEE START)?

 

Greg,
I have tried to spray some starter fluid in thru the Maf to the throttle body, but I do not know if I am doing it properly.
John

 

Best to have someone doing the starter while you continuously squirt the stuff down the intake. WELL worth doing to be 100% sure before you do anything else; for if no firing, no trying to start, no even popping and banging, you can be SURE that the spark is not doing its job.

 

Hi John

We all share your frustration at not being able to Start her because 'When' you eventually get her running then we will all learn something that we didn't know before and as such may then be able to then help someone else with similar problems

Having been there and done that as many of us have, its all too very easy to overlook the obvious that can have us 'kicking ourselves' for ever

So what I would suggest is to take the Plastic Cover off the Fuel Pump Cut out by the Passenger Door Jamb and actually have a look to see if it is working

As this is a Magnetic Switch (at least it is on my 95) so it would pay to make sure that when you Push the Button Down it Stays Down and also Check the Wires to this are Clean and not Corroded and even put your DVI Meter on it to make sure

The other thing that could prevent her Starting is a Failure of one of those Blue Relays over the Top of the Fuses behind the Passenger Side Knee Panel (UK) Car where these have earned a bit of a reputation for the Prongs not fitting 'Tightly in their Holders'

Have you tried spraying Starting Fluid into the open end of the Air Filter and while I'm not a big fan of using that stuff, sometimes its a case of needs must so could be worth a try?

 

Greg,
You are correct. It is early morning here, so before doing a compression test, I removed the plugs and put a small amount of oil in each cylinder. Replaced the plugs and cranked the starter and the engine fired up (roughly) and was burning off the oil. At least all the smoke chased away the mosquitoes. So when it seemed the oil burned off it didn't want to stay running. So I pulled the plugs and cleaned them off, as the engine is probably flooded. I will wait a couple hours before reinstalling the plugs and try again. So yes Greg thanks for the tip, I will have someone squirt the starter fluid in, as I do the next crank
John