reorganised HT leads, car now feels lumpier and slower

[jazzdude]

Decided to tidy up the engine bay and put the HT leads into spacers as the garage that fitted them recently left them looking like a dropped bowl of spagetti. Moved them one at a time so I think they are back in the right places. I also moved the ribbed conduit hoses around the LT leads around as they were all cable tied to the top of the distributor and checked the connections to the coil and they are tight.

The car now feels lumpier at idle and seems to have a little more vibration and about 30% slower. It is not misfiring, revs to the redline, no shunting, and with my ear in the engine bay can't I hear clicking or arcing around the sparks. It does sound a little like a Subaru though as if it is running on 7.5 cylinders (is that possible?). I checked the leads, took them off and pushed them back on again and I think they are tight on the plugs and (no shrouds), sparks resistor type.

I doubt I could put 2 leads on the distributor the wrong way round as surely the car will be backfiring and sounding terrible?

Is it possible that in my reorganization I have killed a lead? If so, whats the best way to find out which one without electrocuting myself or burning my hands?

[jazzdude]

Just had a thought, I cable tied the main HT lead from the coil to the distributor to the mass of wires that are in the ribbed conduit going to the coil, as it was too long and sticking up in the air.

Is it possible that this proximity is causing the problem?

[ClassiChimi]

Anythings possible, I'd carefully check all wiring to coil and anything else you could have disturbed,, re routing shouldn't really cause this but you could have a lead breaking down etc

[jazzdude]

Is it possible that the distributor cap has been disturbed with all the pushing and pulling, would that cause the lumpiness?

[QBee]

I would move that main lead clear of everything first - three minute job, and IMHO the most likely cause of your problem.
After that it is a case of start up and check the exhaust manifold temperatures, as a slight lumpiness usually means running on 7, significant lumpiness means running on 6.

I took my car the 130 miles to London a couple of weeks ago and commented to my passenger on the way down that I wondered if I had a misfire.
Nothing more than that, it just felt not quite perfect.

As soon as we hit London traffic and were going through the gears at low speed, it felt rougher and i could hear the pops and bangs from the exhaust as the unburnt fuel exploded on down shifting.
Long story short, when the car had cooled off, we restarted it, checked the manifold temperatures with my laser thermometer, and not one, but two, cylinders were misfiring.

[blitzracing]

This is how it should be- the routing and spacing is to prevent cross firing between the HT leads. Double check you have not swapped two by mistake.

[jazzdude]

blitzracing said:

This is how it should be- the routing and spacing is to prevent cross firing between the HT leads. Double check you have not swapped two by mistake.

That is the chart I used, although the no 1 position on my distributor was about 90deg clockwise from the position it shows. The rest of the leads corresponded to the order shown on the diagram and I tried to get the under and over cables to match, but with the rotation of the distributor it didnt look the same. The cables on mine are also longer so there is some slack looping out towards the front of the car, especially cables from the drivers side bank .

I will have another look tomorrow though.

What I am not sure about is the 3-4 ribbed cable conduits snaking about above the distributor, connected to the coil at one end and then looping around under the top coolant pipe. There seem to be a long block (connectors?) there under electrical tape.

Is anything there that could have been dislodged in that lot? I dont really want to unpeel all of those cables to check it but that block under the tape, what is it?

[WOO5IE]

A good way to check for arcing is when it is dark
It's amazing how well it runs with two leads reversed ,depending which ones they are

[phazed]

WOO5IE said:

A good way to check for arcing is when it is dark
It's amazing how well it runs with two leads reversed ,depending which ones they are

^^^^^^^

My money is on a pair of leads in the wrong place!

[gmw9666]

Does sound like something is not how it's should be.........if you've checked the leads......are all the plugs tight?

Sometimes due to the tight location, number 7 or 8 are not nipped up enough and can undo a tad

I've also got a handy sticker in my engine bay.......very useful

[jazzdude]

Incredible.... 2 & 4 were the wrong way round!!!

Can't believe it to be honest, you would have thought it would have made loud noises, backfired but it was just a little lumpy, so I spent the afternoon checking for tightness in connections and not the order of the leads as I did them one at a time. Somehow they switched.

Thanks for that

[phazed]

I knew that

[QBee]

Good to have aired it here, because one's first instinct is that it would be horrible running on 6, so one dismissed crossed leads.
Fact is, it's not, just a little rough in traffic and a little down on power at full wack.

Phazed probably remembers mine at Curborough, just after my new extenders were fitted. Two new plug extenders had failed simultaneously. I was only about 3 seconds in 90 off the pace, but was seriously pissed off frustrated with it and well off the pace as far as I was concerned. He kindly tried to help me find the fault, but at that time I wasn't suspecting the new parts, nor did I have a digital laser thermometer. The latter is always in the car now.

[phazed]

My wife's ford focus has just gone on limp mode, similar effect and much safer for her to drive

[ClassiChimi]

phazed said:

My wife's ford focus has just gone on limp mode, similar effect and much safer for her to drive

good call,, easy mistake to make re the leads,,,;)

[Steve_D]

Now you have the fix it is still worth observing for others that cross firing can happen with leads touching each other and in this case 5&7 are the worst case as they are so close in firing order.

Steve

[jazzdude]

Steve_D said:

Now you have the fix it is still worth observing for others that cross firing can happen with leads touching each other and in this case 5&7 are the worst case as they are so close in firing order.

Steve

I will check that but with the leads being a bit long (Lucas original) they don't go as directly as the diagram but curve upwards, but I'll move the distributor connections around so nothing touches.