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Pierre
If a GOOD spark to the dizzy and a POOR spark from the dizzy to the plugs, then it MUST be one of:
Cap, Rotor, HT leads. Try a new cap and rotor and if no change, leads.
Check that the sprung graphite connector to the rotor inside the cap is there and good, too, before you fit the new cap.
Last edited by Greg in France; 10-28-2021 at 08:44 AM.
Hi
I made couple of adjustment on the timing, air intake gap, and other tweak. I was able to make the engine run for few seconds then it dies. It is running for about 3 4 second erratically very slow then dies. It small gas and fume. So I have fire and gas going to the spark plug but there seems to be some misadjustment with either timing or air flow calibration. The engine giggle a lot and want to start but when does it run very slow and shakes . I feel that I am close but there is something out of whack I can t figure out. Getting very discouraged over this stupide engine. ...
Frustration is normal, and we have all been there. Even worse when trying to sort out what some other person/s have done, can be soul destroying.
My suggestion, NOW that it runs sort of:
Remove the cap and the rotor. Find a Fibre washer that is about 1 MM thick. Used extensively on fuel piping on Carby cars. It is an Insulation material. Read on, please, and it will fall into place. You need one that will just fit inside the rotor. I had to file one smaller in diameter until it fitted, then cut a slot for the rotor locating peg.
Fit the washer and the rotor.
NOW, I suggest going back and double checking that timing, and ensure that the plug leads are correct, both at the start of cycle (1A), and so forth. I know you have done it, but while the cap is off, check it again.
LOOK carefully at the carbon brush inside the centre post of the cap. Is it there?, is it in good shape?, THEY FALL OUT, so pay attention. The engine will start, and run, sort of, with that missing, but not run well. That I know from 1st hand experience TWICE.
Fit the cap, refit the leads as mentioned before.
The reason for that washer, and it is used by me on ALL my V12's, is that the HT (BLUE spark) from the coil, comes down the lead to the cap, through the spring loaded carbon brush, to the rotor brass strip, and then distributed out the tip to the related spark plug.
I have found "leakage" of that BLUE spark through the rotor insulation material TO the distributor shaft, thus earthing that spark, and leaving near NO spark for the tip to spread around. Fitting that washer to my Red Beast sorted the hard starting, backfiring, etc etc in a heartbeat. Hence that extra insulation is now part of what I do without thinking about it.
REASON, Spare Parts these days, OE or Aftermarket, are basically crap at best. Its just the way of the world in Auto Spare Parts, where I have spent 55 years.
Hi,
Today i went back and checked evreything again and replaced some more parts.
Remove TPS, main coil and base under the TPS.
Check the volt on my TPS, all good at 0.34 volt
Clean the engine "valley" some old grease there.
I replaced all the spark plug leads with high quality lead.
I removed, cleaned and check the gap of 10 spark plugs. they were all in good condition. (did not remove 1A and 1 B were to hard to get too lazy to remove AC) .
I checked the gap on the new pickup coil (.022 inch) and check the resistance between the two wires, all good there.
Check again the amplifier to ensure wires are not broken. I put a new GM gismo inside.
Check resistance on the two ignition coils together (0.90 Ohm).
Ensure the wires from the amplifier are connected correctly, two to the coil, on to the dashboard and the other one to the ECU.
Ensure battery is fully charge.
Check voltage on new main coil with ignition on: 12.6 volt. Crank engine and voltage went down to approximately 9.9 volt
Put a new distributor cap. check little spring and pin. all good.
Insert a fabric washer in the rotor.
Fuel pump is working ok. wet spark plug.
Injectors working ok as I can hear them with a screwdriver on my ear clinking when the engine is being cranked.
Fuel pressure is around 36 lbs.
ensure inertia switch is off.
Tried to start it again, same old. The engine giggle every second or two like if there was a spark but does not start.
I checked the timing and it looks pretty close. I did started the car few weeks back and took a ride with it. th\e only problem then is that the idle was kind of fast at 1500RPM. so if it ran, then the timing must be ok you would think?
from here I have not idea where to go. did everything I could. Very disapointed. thinking of letting the car go for part or putting a 4.2 in it which would be sad..
Last edited by Jean Pierre; 10-30-2021 at 03:26 PM.
Do you have an inductive timing light? The type that clips onto a spark plug wire? As a test, you might want to clip the light to each plug wire and then crank and see if the light flashes. If it does, then you know you have spark.
One clue I spotted is you said wet spark plugs. The engine could be flooded, and then it won't start. One time I had to move my car only one car length. I started it, moved it and shut it off. Then later in the day it simply would not start, not matter what I did. Had the car towed to the shop, they removed all the sparkplugs, dried them and put compressed air into each spark plug hole to blow out the residual fuel. Reinstalled the plugs and the car started and ran fine.
Are you 100% sure that the HT lead for cylinder A1 (front RHS cylinder, as you sit in the car) is connected to the dizzy cap post that has the tiny (but visible) "1" cast into the plastic?
Last edited by Greg in France; 10-31-2021 at 02:35 AM.
Are you 100% sure that the HT leads are in the correct order going ANTI-clockwise? Yes
Have you cleaned up very carefully the resistor block pins and connector? I will inspect and clean it today.
Are you 100% sure that the HT lead for cylinder A1 (front RHS cylinder, as you sit in the car) is connected to the dizzy cap post that has the tiny (but visible) "1" cast into the plastic? Yes i double checked the all the lead twice. all in good order. 1A is connected on the distributor cap with a "1" and going anti clockwise after.
I will check again today the timing to ensure it is right on the nose.
As I said fuel delivery is not an issue as I hear the injector when I stick a screwdriver on them and stick it to my ear. Fuel pressure is perfect at 36-38 lbs.
However, how sensitive is the motor to flooding? Will wet spark plug prevent it from starting?
How precise must the timing be to make it start? I rotated the distributor using the flat screwdriver in the slot in different positions with no success.
Reading the last post by yourself, and it appears it was running and you took it for a drive, but the 1500rpm idle was a concern. That is the AAV most likely, and can be sorted by you easily once we get it running basically as it should.
That voltage drop at cranking is LOW, and could?? be contributing to the issue. I suggest as a temporary measure a jump lead from the battery to the coil +ve terminal. I suspect an Ignition Switch electrical section issue, also, easily fixed.
Cold start Injectors, I suspect you have 2, one each side. They dribble fuel, flood the engine, and that COULD be the cause of the "giggle" in my opinion. Unplug them, electrically, that is usually all it takes. I have had ONE only Injector continue to dribble mechanically, so removing them from fuel supply was needed. Fiddly, but not hard.
Jaguar fitted these, removed them, fitted them again, removed once more, then deleted them totally.
With all that cap and rotor work is the spark AT the spark plug end of the lead any better, as in Blue, or still weak and yellowish?
The wet spoark plugs indicates fuel, maybe too much, and a weak spark, oops, no good on a HE engine.
this morning I cleaned the resistor block. It was pretty clean with shining prongs no rust.
I put a timing light on a spark plug and it is funny I get the light flashing off and on, not regularly.
I checked agin the spark at the end of the lead and it is a poor yellow light. nothing blue at all.
How fast doe the starter turns on these motor? i feel it is not turning that fast compere to my 4.2.
also I checked the spark coming out of the lead in my 4.2 Jag and the spark is strong and almost 3/4 inch long, on my 5.3 L the spark is much smaller.
I still believe the probem is with my fire or lack thereof...
thanks,
Last edited by Jean Pierre; 10-31-2021 at 05:25 PM.
JP,
Cold start Injectors, I suspect you have 2, one each side. They dribble fuel, flood the engine, and that COULD be the cause of the "giggle" in my opinion. Unplug them, electrically, that is usually all it takes. I have had ONE only Injector continue to dribble mechanically, so removing them from fuel supply was needed..
I don't think the Canadian cars had these. My 1992 Vanden Plas didn't
Jaguar deleted the cold start injectors on the V12s circa 1984...for most markets, at least. I recall a couple odd exceptions. The "D Emission" cars, maybe? Whatever that is?
You do not say that you have installed a new rotor. The fact that you have a poor spark at the end of the HT lead and a good one at the coil to dizzy lead, MUST mean a fault in the HT circuit. Therefore a new rotor, as the cap is new and so are the HT leads, must be the cause of the poor spark.
Also check that the engine earth strap is good and that the battery earth lead connection to the body is good.
Then do the 12 volt direct to the coil and report back.
Last edited by Greg in France; 11-01-2021 at 11:26 AM.
10-28-2021, 02:37 AM
