Jag refusing to start puzzle.
Discussion
Evening all,
After finally completing the head-rebuild on my 3.6l XJS, and after finding several damaged hoses and replacing those, I got into a position to start the car up. She'd not been run since the end of October, but had been laid-up for longer before and started without complaint.
Turn the key: No joy. Engine turns slowly, and nothing else happended. Enlisted help of a neighbour with a running car (for a jumpstart). Engine turned a bit quicker, and after a few hiccups, sprang to life but rather roughly. After running for about a minute, she died, and since then (Sat 3pm) she's refused to do restart.
To get over the slow turn-over on starting, I bought a new battery. Car turns over better, but doesn't fire. Spark is present, as is fuel (plugs wet when pulled after start-attempt). I've tried the old leads and dizzy cap as well as the new ones I'd fitted; I've tried a new coil as well as the old one.
One thing I've noticed is that if I pull the plugs out, the rear four are blackened, and the front two are clean. If I clean the plugs and try restarting, I get the back four dirty again. All smell of petrol which suggests the front two cylinders either aren't getting a spark, or are getting it at the wrong time. I've checked the connections on all six HT leads.
I've yet to check the timing accurately. I thought it was "about right" because the marks I made on disassembley all lined up when I replaced all the bits.
Beyond that I'm stumped. I can hear a snapping noise (spark noise) when I try starting. The noise occurs frequently (not fast enough to be all the cylinders losing spark, maybe just one). Engine turns over better (and more constantly) when the coil - dizzy HT lead is removed.
So anyone got any suggestions?
A rather puzzled Sheepy
After finally completing the head-rebuild on my 3.6l XJS, and after finding several damaged hoses and replacing those, I got into a position to start the car up. She'd not been run since the end of October, but had been laid-up for longer before and started without complaint.
Turn the key: No joy. Engine turns slowly, and nothing else happended. Enlisted help of a neighbour with a running car (for a jumpstart). Engine turned a bit quicker, and after a few hiccups, sprang to life but rather roughly. After running for about a minute, she died, and since then (Sat 3pm) she's refused to do restart.
To get over the slow turn-over on starting, I bought a new battery. Car turns over better, but doesn't fire. Spark is present, as is fuel (plugs wet when pulled after start-attempt). I've tried the old leads and dizzy cap as well as the new ones I'd fitted; I've tried a new coil as well as the old one.
One thing I've noticed is that if I pull the plugs out, the rear four are blackened, and the front two are clean. If I clean the plugs and try restarting, I get the back four dirty again. All smell of petrol which suggests the front two cylinders either aren't getting a spark, or are getting it at the wrong time. I've checked the connections on all six HT leads.
I've yet to check the timing accurately. I thought it was "about right" because the marks I made on disassembley all lined up when I replaced all the bits.
Beyond that I'm stumped. I can hear a snapping noise (spark noise) when I try starting. The noise occurs frequently (not fast enough to be all the cylinders losing spark, maybe just one). Engine turns over better (and more constantly) when the coil - dizzy HT lead is removed.
So anyone got any suggestions?
A rather puzzled Sheepy
Just thinking things over whilst making breakfast and 
I think I've just worked out why the car doesn't fire.
v8guinness is right, it sounds like two HT leads are swapped. But
the six leads are numbered from 1 to 6, so how could that be wrong?
Because the 
mother piece of dog previous owner has used lead 1 for cylinder 2 and vice-versa 
I copied the dizzy cap connections (hey it worked before, so must be right
) but wired the cylinders properly. I did have this nagging thing in the back of my mind wondering why 1 and 6 were so close on the cap, but hey it worked before, so must be right No it's not right. The paired cylinders are meant to be opposite each other on the dizzy. What a basic and stupid mistake. My only excuse it that I've never completely stripped a car with more than four cylinders before 
I'm now wondering if I have enough time to put the plugs back in and try the car again before I go to work (otherwise I'll do it this evening).
Sheepy
I think I've just worked out why the car doesn't fire. v8guinness is right, it sounds like two HT leads are swapped. But
the six leads are numbered from 1 to 6, so how could that be wrong? Because the mother piece of dog previous owner has used lead 1 for cylinder 2 and vice-versa I copied the dizzy cap connections (hey it worked before, so must be right
) but wired the cylinders properly. I did have this nagging thing in the back of my mind wondering why 1 and 6 were so close on the cap, but hey it worked before, so must be right No it's not right. The paired cylinders are meant to be opposite each other on the dizzy. What a basic and stupid mistake. My only excuse it that I've never completely stripped a car with more than four cylinders before I'm now wondering if I have enough time to put the plugs back in and try the car again before I go to work (otherwise I'll do it this evening).
Sheepy
Bugger!
The leads are right now, but the car still won't fire. I guess I'm going to have to check the timing too. I've now got two flatish batteries as well!
Ah well, guess it would have been too easy for it just to have been a case of swapped leads.
Back to the drawing board! I'll leave it until Saturday, because working in the dark (and rain) ain't fun
Sheepy
The leads are right now, but the car still won't fire. I guess I'm going to have to check the timing too. I've now got two flatish batteries as well!
Ah well, guess it would have been too easy for it just to have been a case of swapped leads.
Back to the drawing board! I'll leave it until Saturday, because working in the dark (and rain) ain't fun
Sheepy
wedg1e said:With me, anything's posssible
One of the classic cockups when reinstalling a distributor is to have no. 1 cylinder at TDC, but on the EXHAUST stroke. So the rotor arm is 180 degrees out (or whatever suits your engine).
Ir couldn't be THAT simple, surely...?
Ian
Mind you if it was so grossly out, would the car have run briefly on Saturday? I've a feeling that it may just be a case of the timing being a little bit off (enough not to run, but enough to still get sooty plugs from the sparking). Also, if the exhaust system was blocked, what would the symptoms be when trying to start?
Sheepy
Dizzy was about 30 degrees off. Removed dizzy and re-aligned.
Rotated engine. Checked timing based on number 1 at TDC, both valve-cams with notch showing upper-most (indicated valves on cylinder 1 are fully closed). Rotor arm in dizzy now points directly at the post for number-1 HT lead.
Great. Now to try starting....
No joy. Engine does turn faster and is trying to fire, but doesn't quite make it. Tried different leads, dizzy cap and coil all to no avail. She just doesn't want to run. One thing I did notice (but don't know if it's wrong or how to adjust) is that when the rotor-arm is pointing at #1, the nearest of the six spines for opening the points is still some way from operating them. By the time it does operate the points, the rotor arm is no longer pointing at #1. Is this wrong? If so, how do I adjust it on a '86 3.6l XJS?
Any advice or hints would be useful, I've pretty much exhausted my own thoughts on this bloody car!
Sheepy
numbnuts said:Did try cranking the engine without the fuel relay in. Didn't hold the throttle open (or think to clean the plugs afterwards!!). Without the fuel pump runninng, you can hear the crank note change as it goes from almost firing to not firing because there's no fuel.
Take the fuel pump relay/fuse out, crank the car over for as long as possible with your foot flat to the floor then put the fuse/relay back in and try again.
sounds like the plugs are following up on cold start.
Don't understand the "points" in this car. Unfortunantely the dizzy I have doesn't look anything like any of the opotions covered by all the manuals (typical!
). Sheepy
Sheepy said:
Take the fuel pump relay/fuse out, crank the car over for as long as possible with your foot flat to the floor then put the fuse/relay back in and try again.
sounds like the plugs are following up on cold start.
Did try cranking the engine without the fuel relay in. Didn't hold the throttle open (or think to clean the plugs afterwards!!). Without the fuel pump runninng, you can hear the crank note change as it goes from almost firing to not firing because there's no fuel.
Don't understand the "points" in this car. Unfortunantely the dizzy I have doesn't look anything like any of the opotions covered by all the manuals (typical!
Sheepy
I can try and find the number of a LB mobile mechanic who came out to look at my Golf. He couldn't get mine started, as it turned out it needed a new vernier pulley, so didn't charge me for the two hours he spent on it. Which means he is a top bloke in my eyes
Let me know if you want it, last resorts and all that...
danny hoffman said:
try www.jaglovers.org
I've already got a thread on their XJS forum
Thanks anyway. Sheepy
Am probably not going to help at all as I'm not a Jag man but if the car has a hall effect pickup on the distributor and it's faulty, it will give the symptoms you describe. Had it on the Ultima (Chevy V8) and spent ages messing around until I looked there and the fix was instant.
If I'm proved to know nothing please don't flame me!!
Cheers,
Dave
If I'm proved to know nothing please don't flame me!!
Cheers,
Dave
Dave,
Any suggestion is welcome. As far as I'm concerned, the only stupid suggestions are the unspoken ones where after I fix a problem, someone says "Ah, I thought it might be that..."
As to whether the Jag has a hall-effect pickup: No idea. Did you still get spark when you had this problem?
Sheepy
>> Edited by Sheepy on Friday 20th February 22:36
Any suggestion is welcome. As far as I'm concerned, the only stupid suggestions are the unspoken ones where after I fix a problem, someone says "Ah, I thought it might be that..."
As to whether the Jag has a hall-effect pickup: No idea. Did you still get spark when you had this problem?
Sheepy
>> Edited by Sheepy on Friday 20th February 22:36
We're up and running again!!!!
Tried the cold-start fluid this morning: No joy. After lunch, Trooper joined me in staring into the engine
I pulled the dizzy out and cleaned some dirt (and a dead-earwig) out of the body, and put the dizzy back in so that it was about one tooth further than before (making the timing slightly advanced). Also found and swapped in the original coil-dizzy lead and rotor arm. Turned the key and she fired straight up.
I've got a slight water leak (water-pump seal), so we drove in convoy to Bletchleyt and bought some leak-stop for it. I'll see if that fixes it, otherwise I'll have to pull the rad and change the seal.
Now all I need to do is clean the interior up a bit and fix the non-funcitoning horn ready for her MOT later next week.
Thanks for all the helpful advice,
Sheepy
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