Engine miss firing

[Bowtie67]

Another little thing I used to do is if the engine has a mis and it hasnt been run that long you can find out which cylinder is missing by touching the exhaust manifold as it comes out of the head, the engine that is missing will be cooler to the touch. Also note my hands are pretty callased so unless a manifold is real hot I usually wont get burned.

The other option is to pull the plugs and check them all to see of they are firing, also make sure there are no vacuum leaks as this will also cause a skip. While the plugs are out since you have a skip it would save some time by doing a compression check on all your cylinders to make sure you dont have dead one and as well for the sake that you know that you have good compression in each cylinder.

[R@nger]

Ok well I determined that its getting both spark and fuel...the problem I believe is that its getting to much fuel.

So the carb is now in many pieces. I'm going tomorrow to get some stuff to soak the parts in and possibly even some new gaskets and metering rods. The carb is a Quadrajet that I rebuilt last summer.

The other night when I took out all the plugs and cleaned them I noticed the back two plugs had gas in them, plus the carb looked like it had way to much gas sitting around when I opened the choke plate to have a look see. That would explain why it wouldn't start...to much fuel. I'm thinking that some dirt could have gotten in the carb and is blockin some stuff up, with the carb being a Quadjet I figured theres plenty of places for dirt to do that . I'm also going to replace the in carb fuel filter and epoxy the plugs as seen here(I got this site from someone here)http://www.carcraft.com/howto/57178/

I'll tell ya one thing though...as soon as I have the money I'm getting a Holley carb...this Quadjet is to "scientific" for me.

Hopefully after I've done this the truck will start right back up. If not I'm getting out the big hammer!

[Bowtie67]

If your plugs are extremely fouled with fuel I would replace them with some new AC's, Unless you have a good sparkplug cleaner they will probally give you more issues than not.. also pickup a compression checker since you have the plugs out & do a compression test. You probally flooded the engine with all the pumpings of fuel every time you tried starting it.

[R@nger]

UPDATE: Today I completely cleaned and pretty much rebuilt my carb(I also epoxied those plugs that leak ). I also bought all new spark plugs. Stuck all the new stuff on and tried crankin up the truck...nothing. So I decided I would test every plug for spark. I took the wire off the plug held it with an insulated tool and then put it 1/4 in. away from a good ground. NOTHING, no spark at all. I then tested some other plugs...nothing. I then decided to take the distributor cap off and test the coil. The coil is dead...I will repeat that..*clears throat* the coil is DEAD. I called Summit and talked to a guy there and he said well...it can happen. He confermed that it was dead so he told me just to send this one back and they would send me a new one.

Now if any of you ever say to yourself..."man, I'm one unlucky dude." and maybe your feeling down about it,maybe you even say to yourself, "Boy o boy I'm the most unlucky person on the earth", mearly think of me, Kevin(R@nger). Think of me and realize that compared to me you are the luckiest of lucky . And my speech is done .

[chickenwing]

Kinda expensive for as little as you will use it. http://buy1.snapon.com/catalog/item....re&dir=catalog

[R@nger]

HOOOOOOOO...mmk I'll go with getting shocked .

Thats a little more than I want to spend..very cool little tool though.

[R@nger]

Well today I put my distributor cap and rotor back on. Thing is now it won't even start-up. All the plug wires are on right, the distributor and rotor went back on very easy. Could the coil be bad?...is it not grounded properly? I checked and rechecked the ground for the incap coil and its connected like it should be. I gave the rotor spring that connects to the cap a little more of a bend just incase it wasn't connecting. I also pulled a plug and reconnected the wire..cranked it and there was no spark.

Anything else I should look for?

Oh by the by the starter is doing its job, its getting gas, it just doesnt seem to be firing.

[R@nger]

So check this out...I took off the cap again and broke out my ohm meter. I tested center connector to the ground..nothing. Anything I tested to the ground wasn't doing anything. I then decided to take out the coil. I did so and check out what I found

UHHH OOOOO


After seeing that I got on summit and ordered a new coil, as well as a new distibutor cap and rotor just to be safe. Cool thing was I had a 15 dollar certificate from my last order so I got this coil, only the red/yellow wires instead.
http://go.mrgasket.com/ProductDetail...inselection=16
And this cap and rotor set
http://go.mrgasket.com/ProductDetail...minselection=9
All for only 75 bucks.

Something I noticed about the coil was that there was no secondary ground installed. The wire going to the bottom of the distributor was setup for it but there was no secondary ground strap at the coil.

[67ChevyRedneck]

Originally Posted by R@nger

Something I noticed about the coil was that there was no secondary ground installed. The wire going to the bottom of the distributor was setup for it but there was no secondary ground strap at the coil.

That's the ground wire I was talkin about. My truck had the same problem. Except mine got so bad it killed the HEI AND coil. Noone sells the damn thing either (that I know of), I had to go to a yard just to get that little metal strap.

[R@nger]

Ok well thankfully my new coil does come with one so thats good.

It will be interesting to see if the engine still misses after replacing the coil, distributor cap and rotor.

[chickenwing]

Man! I got a killer ground strap from somewhere.... It's all metal, pre-formed to the correct shape, not a wire that will get caught in the cap when you screw the coil cover down. Wish I had a pic... Anyone know where to get these things?

[pjmoreland]

This recent thread talks about this very issue:

http://67-72chevytrucks.com/vboard/s....php3?t=154435

Says they are available at Napa.

[R@nger]

Yeah thankfully mine comes with one of those all metal ones...which seems like a great idea.

Thanks pj for posting that link. I was looking at that post recently but didn't check back to see where you can buy those grounds sepperately.

[pjmoreland]

Hope your truck fires right up after replacing the fried coil! This kind of stuff can be pretty frustrating.

For anybody else who is interested, here's a link to the Napa page for the grounding strap:

http://www.napaonline.com/cgi-bin/nc...grpid=86597630

[R@nger]

Ok...well I got my parts today and installed them. I tried starting up the truck but it still doesn't want to. I took out a spark plug and reattached it to the wire and let it lay on my headers. I then had my sister crank the truck up...there was spark. My question is how big a spark should there be? The spark I was getting was just a little guy but it did keep producing spark as my sister tried crankin it up. I thought well maybe its just flooded...so I'd crank for 10 secs let it sit, crank another 10 let it sit, and so on and so on, it just wouldn't start. I got out my multimeter and tested the battery as well as the battery connection for the distributor, both had the juice they should. Could the blown coil have toasted some other things in the distributor...module, condencer?

I'm at a loss.

Any ideas would be greatly appreciated!

[R@nger]

Here something I noticed...see the burned paint on the module.



As you can see theres no burn marks but the paint has definately been curled up and roasted pretty good. Possibly from the inside.

Would a burned up module not allow my truck to start?

Right now I'm just at the point where I'm looking for any little thing that wouldn't allow my truck to start...sorry for all the overload of questions.

[R@nger]

Ok yet another update.

I took out the module and took it to autozone to have it tested. It was bad so I bought a new one. Put it in the truck and now its at least attempting to start. It will go chug chug chug chug like its firing but it still won't start up.

I'm pretty sure its flooded(strong gas smell) but as much as I cranked it I would think it would have started up by now.

ARG I'll be happy when I have put this problem far behind me.

[Brainchild]

Pulling the wires is the quickest way to narrow down a miss.They sell pliers at autozone/wherever that are insulated for pulling wires.Not a shocking experiance that way
Once you find the miss,start checking all associate firing componets to that clyinder.

If all else fails a compression test is a good way to find a burnt/bent valve,or a weak cylinder.akk of these will make a dead miss.Also a lobe off the cam will do this.Easy things first though,pull the wires one at a time,and narrow it down to which cylinder,and go from there.

Any smoke,popping,or anything like that coming from it?

[R@nger]

Well Brainchild now I can't even check those things because I can't get it to startup.

[pjmoreland]

If your carburetor is flooded, press and hold the gas pedal to the floor while you crank it over. It helps lean out the mixture.

You might want to try checking your timing again while your sister cranks the engine over for you. You've changed quite a few things. Maybe your timing is off.

[chickenwing]

Dang Ranger, if it werent fer bad luck you'd have none at all! (There's a country song in there somewhere) PJ is correct on the flooded issue. My old datsun pick-up used to flood at the drop of the hat. Hold to floor and crank till she fires up.

On the module you installed. You did put a light coat of dielectric grease on the back of it? You did clean the mounting surface? Read somewhere what that is for is to help dissapate (sp) the heat the module generates.

[67ChevyRedneck]

I have purchased bad coils and modules before...especially if you got them from advanced/autozone... Recheck your timing, I believe your supposed to pull the vac. advance off the dist. to get it right. Been a long time since I've had to do it.

[john]

If it has been flooded for numerous attempts the cyls could have been washed clean. I have had to pull the plugs and shoot a little oil in and turn over then put plugs back in. Worth a try. John

[R@nger]

Well I'll try the holdin the gas pedal down while cranking it.

As for the grease yes I gave it a good coating and I cleaned both surfaces before I did.

I can't believe how bad my luck is...freakin ridiculous. I'm not joking when I say I'll fix one thing and several more will break. By the time I get this truck runnin I'm sure I will have had to replace ever part on it .

[D.PASSMORE]

You got to have fuel and spark to make it run, so you have to figure it out which one is causing the problem. Try spraying a little starting fluid down the carb with the throttle wide open. If it wants to start, uaually the carb/fuel flow. if its the same or close to as it was before ---- fire...

Also, look in the carb and see if your jets are squirting when accelerator is pushed. if so, with good spark, it should fire and run somewhat. Weak spark will flood easely. Use starting fluid, but be careful. its a little rough on the engine.

Another, power to the HEI. Check and see if it is correct voltage. Not sure what it should be.

And if you pulled the distributer, recheck timing and firing order of spark plug wires.

And by the way, I seen a guy mannually set the timing on a 350ci. He sat on top of the rad support and had a friend turn the motor over. He point the distributer towards #1 cylinder and kept lifting and dropping the distributer (while it was turning over)back into the hole until it fired. I was amazed it worked and I watch him drive it down the road.

You never know, but I bet its something simple.