V8 Missfire - Back Again!

i went for an Aldon ignitor and have not looked back sicne. More responsive, starts quickers, smoother, what can I say. it an easy install - recommended :D
no modifications required, just plug in and play (more or less) :LOL:
 
Hi all,
finally got the kit from maplins and fitted it yesterday. Fired the car up first and let it run for a few minutes to see how it ran. Then switched over, ran for about 15 seconds and started to misbehave again. Changed back to the original setup, got about 30 secs before it cut out. Think the coil, or possibly the rev counter?? (my 'running' coil feed is from the rev counter) is to blame. Will replace the coil, and failing that rig a temporary supply to the coil next weekend when I'm home again. Same symptoms, runs sweetly for a while, then the rev counter needle jumps around and the engine dies. Will restart perfectly with no hesitation after about 2 minutes standing.Doesn't really missfire as such, just refuses to rev and then dies, or can just stall with no warning.
Regards,
Dave
 
Swap the coil first as it does sound coil related, certainly easier than messing with the wiring.
Are the dizzy cap and rotor new ?
 
webmaster said:
Swap the coil first as it does sound coil related, certainly easier than messing with the wiring.
Are the dizzy cap and rotor new ?
Click to expand...
Thanks for the reply Richard, will try the coil first. The dizzy cap and rotor were replaced at some point before I bought the car and look fairly new. No signs of wear or tracking. The car has always fired first go, even in wet conditions, which makes me think they should be ok. To my mind it seems like a LV problem rather than HT. The rev counter become erratic just before the engine misses and stalls. As the rev counter works off the LV side of the system, I would imagine the problem is here. Though having said that, a sudden short on the HT side might also effect the current flow on the LV. I went through the ignition in a mini several times for a friend, it was a non starter, and eventually found the rotor arm was going to earth through the dizzy shaft so I won't rule it out!The coil is a 2 minute job so i'll try that saturday. Failing that I'll eliminate the supply to the coil with a direct feed off the battery. Can rob the other 2 cars for parts to eliminate the cause (hopefully :LOL: )
Regards,
Dave
 
That rotor arm earthing problem stopped the wife's 820, rotor was only a couple of weeks old too, but this is the problem with a lot of the new parts. But that was a straight fail, it didn't work for a while then stop, just dead. Your problem does sound more like the coil breaking down / shorting etc.
 
Hi all,
I can't believe I'm revisiting this post again, but :( . The car had been running perfectly since last November, the last action being to change the plugs, the rest you are probably all well aware of (cleaned the tank, carbs, fuel lines, rebuilt pump, facet pump installed, filters, Ignitor II, all other ignition components, rewire of the ignition etc etc. Yesterday I completed the second wedding I had to do this year. The car, as per the last few months fired up instantly, ran like a dream all day, and didn't miss a beat, until luckily on the drive home. When cornoring on an uphill section the car 'coughed' a few times, but ran faultlessly for the rest of the trip. It had done this enroute to the first wedding last month under similar circumstances (cornoring uphill at about 1800 rpm in 3rd - under no real load). I got back, parked up outside my other halfs place, then moved the car just up the road to mine, no issues. My place is on a hill in the estate, with parking spaces at right angles to the hill. The car was reversed in, nearside lower than offside, all still well. Just before I had to leave for London I decided to move her slightly, fired her up, and once again (for the first time in about 12 months, she sounded like she was a 4 cylinder (V8 sound gone, struggling to rev but none of the usual popping of a missfire, i.e. trying to pick up cylinders). I had to leave before I had a chance to investigate. Car was half full of fuel. I was thinking about the issue as I sat on the flight and something struck me, this problem always seems to arise when I park it in that spot, and it almost always leaves that spot on a transporter :( . I think it must be something moving out of position, or sticking when on the slope. It never has an issue when parked lengthways on a slope, up or down, and the problem start when I attempt to start the engine, and on occassion disappears with no work. Now my solution, if it has disappeared when I get home is not to park there again :LOL: , and I'm moving soon so I'll get a house on level ground, but what the hell am I missing here??
Regards,
Dave
 
dave , im having the exactg problem with my p4 its basically been unused for a year and starts well enough but very quickly runs like a bag of @@@@ then cuts out , im wondering if its down to the unleaded that has gone off, i too ordered new points,condensor ,coil and ht lead, i seem to be forever replacing these components lately, maybe try first draining off the old fuel and replace with fresh crap,good luck,rich
 
rover100rich said:
dave , im having the exactg problem with my p4 its basically been unused for a year and starts well enough but very quickly runs like a bag of @@@@ then cuts out , im wondering if its down to the unleaded that has gone off, i too ordered new points,condensor ,coil and ht lead, i seem to be forever replacing these components lately, maybe try first draining off the old fuel and replace with fresh crap,good luck,rich
Click to expand...

Thanks Rich, I don't think the fuel is to blame for this though as she has been driven about 300 miles in the last few weeks, and I've got fuel a few times. This is something far more random, and has been cured in the past without replacing fuel. Sounds like you have been a victim of the dodgy condensors, or else coil, or you have crud in the tank. I've been through alot of those recently. I had replaced the points and condensor in my red car a few months ago and she wouldn't run, got her going the weekend by changing them again. To me it seems something is sticking/moving when the car is parked at an angle. It's not something blocking the fuel pickup as I've tested the flow from both the electric and mechanical pumps in the past, in the same position and they have been fine.
Regards,
Dave
 
I wonder, Dave, if you are actually out of fuel, as far as the car is concerned, when parked in that position? The fuel pick up in the tank is on the extreme off side of the tank. On Lucky, 1/2 tank is deceptively empty. There's only around 50 miles before I need to pull the reserve at around 1/4 full. If yours is the same there may not be enough petrol to cover the pick up when parked at an angle like that. Certainly Lucky's way of announcing it's ime to pull the reserve is to quite suddenly run like a bag of old nails.

Chris
 
chrisyork said:
I wonder, Dave, if you are actually out of fuel, as far as the car is concerned, when parked in that position? The fuel pick up in the tank is on the extreme off side of the tank. On Lucky, 1/2 tank is deceptively empty. There's only around 50 miles before I need to pull the reserve at around 1/4 full. If yours is the same there may not be enough petrol to cover the pick up when parked at an angle like that. Certainly Lucky's way of announcing it's ime to pull the reserve is to quite suddenly run like a bag of old nails.

Chris
Click to expand...

Thanks Chris, however, I got fuel about 15 miles before this problem arose (about 20 litres), and one time it happened I pumped around 8 gallons out of it. The fuel filter always shows fuel as well on both pumps. She is on reserve constantly with the last few months as the facet pump is on the reserve line and I use it to prime the system before starting if she has been parked for a while to avoid cranking. Also, returning to level ground or adding fuel doesn't instantly solve the problem. Any other thoughts? Chances are she could fire up next time and be fine, but I won't find that out for another two weeks :( .
Regards,
Dave
 
The only other thing i can think of, is whether you are flooding the engine by using the facet? They have been known to force fuel past the float chamber needle valves so that it spills out of the jet and fills the inlet manifold / engine up. But that doesn't really explain the cough on a left hand corner. Presumeably the latter is when only the mechanical pump is in use.

Chris
 
Totally random thought , and i've got the excuse of being a woman so can say stupid things , but has it got or ever had an alarm / immobiliser fitted ? they can make strange things happen ! ( the type with movement sensors )
I'll get me coat !
stina
 
chrisyork said:
The only other thing i can think of, is whether you are flooding the engine by using the facet? They have been known to force fuel past the float chamber needle valves so that it spills out of the jet and fills the inlet manifold / engine up. But that doesn't really explain the cough on a left hand corner. Presumeably the latter is when only the mechanical pump is in use.

Chris
Click to expand...

Chris,
I usually only use the facet (posiflow - it's low pressure, high flow) when starting the car after a lay up of more than 3 or 4 days. The latest problems have arisen using the mechanical pump alone. The pump is really only there as a backup to the mechanical one.

stina said:
Totally random thought , and i've got the excuse of being a woman so can say stupid things , but has it got or ever had an alarm / immobiliser fitted ? they can make strange things happen ! ( the type with movement sensors )
I'll get me coat !
stina
Click to expand...

Good suggestion stina but unfortunately not on this car :( .

Regards,
Dave
 
OK then, abandon clutching at straws and back to basics!

We can eliminate vapourisation as it does it from start up.

Fuel surge is still a possibility as all the regular locations are on cross car slopes.

We need to know what the fuel situation is like in the engine when it does it, so a plug cut whilst it is misbehaving is a must. (ie turn the ignition off and disengage drive, then have a look at what colour the plugs are.)

Then there are the usual suspects of duff plug/coil/distributor cap/fuel filter.

And I guess at this stage we ought to add, fuel line defect allowing air to be drawn, LT wiring fault causing intermittent open circuits.


Sorry not to be more definite

Chris
 
chrisyork said:
OK then, abandon clutching at straws and back to basics!

We can eliminate vapourisation as it does it from start up.

Fuel surge is still a possibility as all the regular locations are on cross car slopes.

We need to know what the fuel situation is like in the engine when it does it, so a plug cut whilst it is misbehaving is a must. (ie turn the ignition off and disengage drive, then have a look at what colour the plugs are.)

Then there are the usual suspects of duff plug/coil/distributor cap/fuel filter.

And I guess at this stage we ought to add, fuel line defect allowing air to be drawn, LT wiring fault causing intermittent open circuits.


Sorry not to be more definite

Chris
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Thanks again Chris. You have the right plan there I think. The problem with all this travelling is I have to spend the next 2 weeks thinking about it but can't do a thing :( . My plan is to 1. Check the timing. 2.confirm the spark at each cylinder 3. Check the plugs as you said. 4.check the fuel flow. 5. Get her to level ground and hit everything with a hammer :evil: , if a float etc is sticking this may move it. (although she has never thrown fuel out the overflow, though I suspect instead one float chamber could be dry.

The only electrical problem I've had is my rev counter reading low and behaving a little irratically at times, which I suspect is due to the Ignitor II. I have, however, fed her with a direct supply from the battery before with no improvement.

I know I have to follow the above and not clutch at straws, but I do have a couple of uneducated theories in my head which include;
1. Float sticking in the closed position (not open as I have no fuel coming from the drains.
2. Piston sticking
3. Something sticking within the distributor.

Thanks again,
Regards,
Dave
 
Just to add insult to injury I've just discovered my camera phone had a big piece of dust on the lens, must get proper photos from the weddings from the photographers, but in the mean while.

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Regards,
Dave
 
Maybe a bit of a long shot, but what about the float levels in the carbs, maybe you've got a very low level in one carb and when on an angle there isn't enough for the pickup.

You can also test the tank fuel level issue by simply trying the reserve position and see if that works.
 
webmaster said:
Maybe a bit of a long shot, but what about the float levels in the carbs, maybe you've got a very low level in one carb and when on an angle there isn't enough for the pickup.

You can also test the tank fuel level issue by simply trying the reserve position and see if that works.
Click to expand...

Thanks Richard, good point, but she stays the same after she returns to level ground, otherwise I'd just roll her down the hill :D . I checked the float levels the last time the carbs were apart and all was well, still well worth a punt though. She is also running on the reserve at the moment, as that is where the electric pump is located - only used the odd time but I tend to leave it in that position. I'm still thinking something is sticking, but what :? . Just hoping it is one of those occassions she cures herself, then I'll park somewhere else!
Regards,
Dave
 
webmaster said:
maybe you've got a very low level in one carb and when on an angle there isn't enough for the pickup.
Click to expand...
Seconded, it sounds like one of the carbs fails to get and deliver fuel when the LHS is lower than the RHS (if I have the nearside/offside translated right). Have you checked the fuel lines for blockages? Do you know for a fact that the pumps are delivering to both carbs when the car is tilted? I forget if the fuel passes through the LHS carb first or they have separate feeds :roll:

Other than this, do you still have a funny tacho and electrical cut-outs as before?
 
Tor said:
webmaster said:
maybe you've got a very low level in one carb and when on an angle there isn't enough for the pickup.
Click to expand...
Seconded, it sounds like one of the carbs fails to get and deliver fuel when the LHS is lower than the RHS (if I have the nearside/offside translated right). Have you checked the fuel lines for blockages? Do you know for a fact that the pumps are delivering to both carbs when the car is tilted? I forget if the fuel passes through the LHS carb first or they have separate feeds :roll:

Other than this, do you still have a funny tacho and electrical cut-outs as before?
Click to expand...

Tor, I'll certainly check both carb supplies. Fuel line and tank were cleaned out fully about 2 years ago or less. I confirmed the fuel supply, with the car in it's current position, from both pumps by removing the pipe from the top of the fuel filter and cranking/switching on the electric pump and all was well. I even elevated the pipe and still got flow. The fuel lines do run from LHS to RHS (viewed from inside the car) carbs. I had the tacho reading low that morning but was behaving normally when the car started acting up.
Regards,
Dave
 
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