OK so at the weekend we went to the Hotrod Holiday...brilliant do fill up on super unleaded and its fine till we get back to the site....then it coughs a bit and is abit difficult to start....clean plugs (bit sooty) and it's abit better but conclude new plugs needed...after another fill up I find out it's 99 octain so conclude again new plugs and it don't like 99 octain, It runs ok on 95 or 97!! Stop on the way home and it's having none of it...an hour later and a stray AA man collared off we go...runs brilliant once off at home its off for good. manage to get it going tlast night, ticks over for 20 mins no probs. off we go to the petrol station, coughs a bit and dies 3 times in 4 miles but manage to fill up with 95 octain. Back home push on drive. New plugs...gapped properly (see previous post!), clean out dizzy cap etc, now won't fire at all, spark seems abit intermittent.....Big initial spark then it seems to get smaller and not regular. What the hell is happening!!! is sumat breaking down....Oh it's a ZZ4 SBC and I have an MSD probillet dizzy matched coil (blaster I f I remember right) and holly control box The MSD has no points so i'm asumming it doesn't have a condenser....but I could be wrong anyone have any idea where I would find it if it does???? So....put the old plugs back in and it's trying....it has fired up but is coughing and spluttering and backfiring badly...and wont stay running for long.....it has to be ignition or fuel So....A mate has came over (to tell me he can smell fuel at his house over the road!!) our conclusion is it's not a fuel problem!! He confirmed the firing has nowt to do with me pumping the pedal like a bstard and it's trying to fire up randomly......we checked the spark and it's sparking intermittantly, as I had already found out!.... I'm gona chase it back...the plug are OK, the leads are OK I have cleaned out the dizzy but will check it again and the rotor arm as well (might swap them for an old set i have in the garage as well). I'm ***uming the coil is OK but how do i check it, don't have a spare just to swap over! The control box is OK (***umed again).....I hate electrical probs..can't you tell! Anyone got any ideas before I pack it all in, torch the fooking thing and take up golf???
dump the whole system you've got and get a self contained high energy HEI they're cheap and pretty reliable
If it's a stock ZZ why run all the MSD junk. The GM HEI that comes with the ZZ crate is great for a driver car. If don't think so hold a plug wire.................
#1 most likely, the control box. Not sure about holley, but the MSD equivalent has a tool you can plug in to verify function. Being across the pond, you need self-diagnostic capability cause those items are notoriously unreliable. It's probably time to reinstall the HEI's stock module and see what happens. #2 most likely, the coil. Intermittent almost certainly points to the box, but I've also had 3 MSD coil failures on the only 3 MSD coils I've ever owned. Three different types over a 5 year period, three different cars, not a one of em lasted a year. also agree the HEI is plenty of distributor on it's own (up to 6500) good luck
If it's intermittent, check your grounds (earth I believe you folks over there call it). Sounds like coil to me too, but checking the grounds is free (so do that first). I haven't had any problems with MSD stuff, never had Holley Ignition stuff though so . I have had several vehicles with the stock HEI and it works great (even if it is FUGLY ). I even spluged for one to fit the 302 I put in my Model A (it had a MSD module in it and dust cover / wire retainer). It worked great, with no hood, in the driving rain, at freeway speeds and above (I gotta figure it doesn't get much better than that as the Ford lump puts the dizzy up front). Best part about an HEI is the ability to have enough parts to rebuild all but the housing, trigger and advance mechanism on hand for cheap (coil, cap, rotor & module) Kinda like (but not the same as) a points setup and carrying a spare coil, condenser, points and at least one wire. One thing though, on an HEI (or for your MSD for that matter) you want a fairly large power lead (I prefer #10 AWG) and no balast resistor. Not saying I'm an expert or anything, so take all this for whatever it's worth. Hope something there helps.
If it was me I'd go back to step one and put a simple HEI in it and byp*** all the other stuff and see if it runs good.
Hey Paul,poking a stocko ign. in it to eliminate the Holley controls is a pretty good idea.1 wire and you're cured or not.LOL Sounds like a fresh set of sparkers is in order too. Good luck.
OK have worked through the progamming on the quickshot....seems OK have checked the lifters to make sure all the valves are opening and closing....all OK checked the gap on the old plugs....025....open them up to .035 (just to try it...getting desparate now!)...car runs worse!!...... poss coil?? poss crack in dizzy/rotor arm?? dont have a stock dizzy and even if I did it won't fit under the cowl on the A anyway....that's the reason I have an MSD!!
All you spark plug replacers are hung up on ancient 6V ignition or something. Any HEI or multi-spark box small block chevy ought to self-clean the first time it warms up. If I had a nickel for every time my chokeless double-pumpers flooded out plugs I'd be a rich man. Remember, plugs live in gasoline, a little bit of gas shouldn't hurt a street car's plugs. We're not talking about a 650 horse race motor here. For the record, not all ZZ4s stateside get treated well. I know of several that have found their way into beaters and work trucks and ac***ulated significant mileage with virtually zero maintenance. Those are tough ole bullets, not high strung at all. 035 is minimum plug gap for transistorized ignition, open it up to 040 or 050 and take advantage of your spark power. Otherwise, what you describe with opening the gap further confirms the ignition system is generating weak spark. Quit touching valves and **** before you back yourself into other problems. If a stock coil is locally available, throw one at it. good luck
tested the coil.....it's giving a spark at the plug but the spark at the dizzy (pulled the ht lead and cranked the motor) is really weak....so it's new coil to start with.....Ill get back with the results as I can't get a coil til mon or tues....the joys of living in the UK and running an engine from over in the colonies!!!
have you PULLED the distributor yet to check the drive gear on it? I've seen the bronze gears on the MSD distributors get beat to hell from the gear on the cam and then the teeth won't mesh with the cam = no spark or weak spark if its barely turning the rotor. I'd check it out
Don't think an MSD probillet dist uses a resistance wire. If there's a european or asian coil on your parts shelf try it out. If you can hook the wires up it should work for troubleshooting purposes. Spark is the international language Worn gears will manifest themselves as unstable timing when you put the light on it. If it's to the point it's barely turning the rotor you got bigger issues cause the dist also drives the oil pump. Electronics failure is far more common, don't back yourself in a corner undoing mechanical stuff til that's ruled out.
I agree...but if the gear has worn to the point that its missing a few teeth or they just are really worn the timing will bounce around (like you said) as well as oil pressure will be down. What I have seen, is they just "go." Meaning you won't be able to get the car to start at that point. It might kind of sputter and want to sporadically start (when it actually meshes and turns) but you won't get the thing to start/run Put a light on it and see if the timing is bouncing around if you can get the car to idle. If you can't get the car to start, remove the cap and have someone turn it over a couple cranks while you watch the rotor. If she ain't spinnin, I'd bet that gear is spent
Per your posts: The control box is OK (***umed again).....I hate electrical probs..can't you tell! Anyone got any ideas before I pack it all in, torch the fooking thing and take up golf??? "***ume" will get you in trouble every time. I would test or have each piece of the ignition system tested. As mentioned above by others I think I would be looking at the coil and control box. You should be able to find simple test procedures for each. I'm with some of the others in that you don't need an ignition system intended for a 10 second drag car in a street car. Yea it impresses the mouthbreathers at the rod trots but usually is what will cause you grief when you want to make miles or klicks down the road. Not to say that they don't work well in a well setup car with someone who knows how to deal with the system driving it. I'd suggest this, put in (borrow if you have to, and that would be my choice) a point type distributor, wires and coil that are known to work well. Get the car running and get every thing else dialed in. Then go back with the MSD and sort it out or sell it and install something that you can make work.
Jeezus why does everyone want to reinvent the wheel and start pulling mechanical parts like the distributor base? Is it really just because electronics don't have visible failure????? Somehow I thought the problem solving bar was set a little higher around here. Starting to think I've bought some hamb'rs cars before. You know, the ones I buy for $30 with a bad engine, tow home, then throw an ignition module in & drive for a year. Grounds are always a good idea to check, but if the car once ran good then they shouldn't need more than wrench snugging to rule out.
try a different module in the Dist,maybe a stock one if you have one laying around..if I remember right the Probillet comes with the type that contains a circuit board. I had a couple of them go bad on race cars. also make sure you have plenty of dielectric grease under the module or it will overheat and do stupid ****. just another option.
that's why I suggested pulling the cap while a "mate" gives her a couple cranks. CHECK TO SEE IF THE ROTOR IS SPINNING! Or is that too much work? Should we save that for "No Spark: Chapter 2?"
i don't wana cause any arguments but cheers for the advice...the dizzy is OK, ran through the programe on the quick shot so the control box is OK....the spark at the ht lead is real weak so I'll start with a new coil...
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