misfire

[menostig]

So we hit a slick wet road and then within a few hundred metres the car didn't feel right and I could hear a misfire on and off with the car slowing then jerking faster on a constant throttle. when we stopped at the junction it almost stalled and didn't want to pull, it definitely wasn't on all the cylinders. But it wouldn't clear with a blip either - not that it's ever suffered this before but I thought that might work. However, on moderate acceleration it would suddenly fire all cylinders and thrust the car forward again. But then backing off due to traffic it would be misfiring again. I sprayed the Sport's ZZ4 distributor, ignition leads and plug area with wet start once we got home, but a restart revealed the same misfire. So... could it be a blocked jet or something in the 750cfm 4 barrel Holley ?
cheers
Roger.

[eliot]

If you have a condensor (points) then that would be No.1 to change. Cant believe that they would be running points on those engines though.

[gtrclive]

Does it run a Hei coil ontop of dissy type ?

My MSD Dissy didn't like being wet or moist under neath the Cap.. Had this problem a coupe of times after hosing down the engine bay....

[GTRene]

I think you have to dry all again and wait till al moistre? (water) damps away...in some cases it is the distrubator? cap and sometimes when you spray the engine with water the plug hole fills with water and that way the spark is no longer crafty in the engine when low idle, you can see this when you put the lights out in your garage and start the engine, all the lights you see then outside the engine aint good?
Mostley the next "dry" day all works again as normal.
Difficult to explame in English for me I'm from the Netherlands...good luck finding the problem causer...
René

[craig-ultima]

Oddly enough I had maybe a similar problem today. I was driving for about 10 minutes in very light drizzle, and as I moved away gently from a stop, when I got to 3rd gear, the engine suddenly died.

I pulled over to the side of the road. Oil, fuel, coolant, electrical all looked good. (About 90 seconds earlier, the rpm dipped and then came back up while I was driving at highway speeds.)

I waited 20 seconds, then restarted the car. It took a lot longer to crank, but eventually caught and I was able to drive home just fine.

Weird... something is up. I suspect that the battery is bad since it cannot stay charged for more than a few days. Maybe water spray getting in somewhere to a connection that is not sealed properly. But the top end of the engine bay was bone dry, so I know that it wasn't a problem with the distributor.

But if anyone has any ideas, I'm all ears.

[steve_D]

When you say the 'rpm dipped' do you mean it actually dipped or the gauge dipped?
If it was primarily the gauge then the problem is likely to be early in the ignition circuit i.e. switch, fuse, battery. This would give loss of current to the gauge and the ignition system but you would see it on the gauge first.

Steve

[GTRene]

I don't think its a bad battery or altenator, also because I think you used new ones?
And with a bad battery the car goes slower and the lights too and finally short after that the car has no spark power annymore and runs dad...
But in your case it runs dad a while, and after a while it works again? so its probebly not the battery...think you got a bad link in your elek circuit? does only the spark power goes dad or also the elektrical say light radio power went down at those moments...feel the difference, so you can sort things out..?
I know it does'nt feel good, when you can't trust the car, hope you soon find the "minor" problem, I say its something small..

>> Edited by GTRene on Monday 26th September 09:52

[ultimarobert]

I had a similar problem.
The car suddenly lost power occassionally, but then regained it. I tracked it to the distributor wire leading to the coil. It had somehow cracked near one of the ends. Factory sent a replacement quite quickly.

Now I have a battery problem. The charge only stays a couple of days. It also never seems to get fully charged according to the CTEK Multi XS 3600 charger.

[menostig]

Ok so it dried out over 24 hours and this evening started and ran absolutely fine.

Good job because the in-laws are over this weekend which means I can go for looong drives without worrying about depriving the children ! And I can take my wife out for her first ever go. And I can escape from work early on Friday yeeha.

Rog.

Note there was no obvious sign of moisture on the distributor, but moisture had got somewhere, probably on the inside.

[GTRene]

menostig said:

Ok so it dried out over 24 hours and this evening started and ran absolutely fine. Note there was no obvious sign of moisture on the distributor, but moisture had got somewhere, probably on the inside.

it only takes a very smal amout of damp or moisture? on the inside of the distributor! not always seen by the eye, but when doubt...dry with cotton or a tissue
then all works fine again...
good luck

[craig-ultima]

Thanks Steve... The dip in RPM was really quick, and not very deep, and surprised me that I wasn't paying attention to the engine for that split second. You are right in that anywhere along the way, a flaky connection could cause an interruption. It might be the power to the MSD since the tach input comes off the MSD.

I did notice that the voltmeter was reading only just over 12, whereas it normally reads about 14. After the car stalled and started up again, it read 14.

I need to get a proper charger for the battery too. So, clearly some gremlins... but that's half the fun!