Engine Misfiring

-
I didnt read every post but when i bought my dart i had a similar problem. If it is when it idles pull the wire off of the plugs one at a time and see which cylinder doesn't change then you know its in that area. maybe you have wires crossed or something If you have 2 that don't change anything then switch them and see if it is better.

just an idea

Good Luck
 
is your electronic ignition blue wire supplied with 12 volts? is the box grounded well? how many turns out are your idle mix screws? were they set to highest vacuum?
 
redfastback said:
is your electronic ignition blue wire supplied with 12 volts? is the box grounded well? how many turns out are your idle mix screws? were they set to highest vacuum?
Click to expand...

Idle screws were set to highest vacuum and were a turn and a half out. Tried going one and stwo steps in both directions, no change.

Box is grounded ok, double checked that.....
 
I quickly read through the post, has anyone mentioned vapor lock? could be clogged fuel filter, shut it down just long enough to get some fuel thru then sucks dry shortly after you fire it up. pressure will read ok just little or no fuel volume to the carb.

Cars need 3 things to run.
1.gas
2.air
3.spark at the correct time.
Write down the things that can hose up 1, and 3, cross of the things you've already done. At least the problem is reproducible.
 
player1up said:
I quickly read through the post, has anyone mentioned vapor lock? could be clogged fuel filter, shut it down just long enough to get some fuel thru then sucks dry shortly after you fire it up. pressure will read ok just little or no fuel volume to the carb.

Cars need 3 things to run.
1.gas
2.air
3.spark at the correct time.
Write down the things that can hose up 1, and 3, cross of the things you've already done. At least the problem is reproducible.
Click to expand...

I think thats my next trick: fue pressure gauge, fuel filter, then the pump if it isnt improved or pressure is low. The pump, however, doesnt look too old though, possibly replaced a while back by previous owner.
 
you can learn alot from parts that the PO replaced, maybe they were trying to track down the same problem. My car had an alternator, 2 ballast resistors and a spare voltage regulator in the trunk. Hmmm charging problems? Good hunting.
 
player1up said:
you can learn alot from parts that the PO replaced, maybe they were trying to track down the same problem. My car had an alternator, 2 ballast resistors and a spare voltage regulator in the trunk. Hmmm charging problems? Good hunting.
Click to expand...

I would tend to discount charging issues, as the volts are at 14-15(read high) when driving and 10-13 at low rpms/idle, especially with all accessories on.

Battery stays charged and turns the motor over with ease.
 
Fuel filter and fuel flow do sound suspect. I had a VW that would shut down completly then start right up again and idle perfect, run a 1/4 mile maybe. Wasn't the only one I've encountered either. Debrie that gets past the filter can stop behind needle/seat restricting flow also.
 
MOPARJ said:
There is plenty of popping in the exhaust though and I did notice the exhaust smells different, definately not rich.
Click to expand...

When was the last time you filled up the tank with fresh fuel? Gas goes bad in time and has a very distinctive smell when it does.
 
ramcharger said:
When was the last time you filled up the tank with fresh fuel? Gas goes bad in time and has a very distinctive smell when it does.
Click to expand...

The gas is fresh and it has plenty in the tank. I drive the car 100-150 miles a week and I actually use Mobil mid grade, so its great fuel. Nothing but the best for my cars.

I am leaning more and more towards fuel related/starvation related the more as I sit hear in my office working, well, taking my lunch anyways.

I can see the issue with volume of fuel reduced from the filter, but still trying to correlate it to heat and rpm. I guess the heat, which can cause vapor lock and fuel perculation, especially in these alluminum Edelbrock carbs could be aggitating the issue, if there is one with the fuel filter, thus causing it to suck more air than fuel, until the I bring the rpms up, then it cleans up some and runs a little better, but still pops and the revs wont stay steady, like its still starving for fuel.

I will know after tonight, hell, it needs replacing anyways.:-D
 
When the engine is doing the popping thing, add propane from a torch (not lit of course!) to the air horn and see if it smooths out. If it runs rougher, it's running rich, if it smooths out, it's running lean, if nothing happens it's most likely an ignition/timing/compression/valve problem. You can also use this technique to find vacuum leaks.
 
J

The reason I mentioned running a hot wire to the coil and resistor is it may help locate the problem if it's in that wiring harness. Replacing a coil and ballast does nothing if a wire is corroded from the inside out.

Wiring is like following a map. You may know where you want to go, but have no idea on the route. Got to check the route to see if it's clear.
 
crackedback said:
J

The reason I mentioned running a hot wire to the coil and resistor is it may help locate the problem if it's in that wiring harness. Replacing a coil and ballast does nothing if a wire is corroded from the inside out.

Wiring is like following a map. You may know where you want to go, but have no idea on the route. Got to check the route to see if it's clear.
Click to expand...



Agreed Rob...

Tried jumping the wiring to the coil...no dice...

There is some cobbled wires that were litterally tied together, rather than using a connector or splice method near the ballast and ecu. Some wise one mickey moused it somehow.

I may try rewiring this portion to see what will happen, regardless of my results from the hot wire test...
 
when it's running decent again, take something and shake the wires around the ecu, and resitior, and see if it starts acting up, i had a dieing problem one time and found it like that it was the blue/yellow wire from the ecu ,
 
mr.318 said:
when it's running decent again, take something and shake the wires around the ecu, and resitior, and see if it starts acting up, i had a dieing problem one time and found it like that it was the blue/yellow wire from the ecu ,
Click to expand...

which hopefully yours is to the ign sw(12 volt) side of the ballast resistor.
 
redfastback said:
which hopefully yours is to the ign sw(12 volt) side of the ballast resistor.
Click to expand...

Just a thought, if somehow, either by me or someone else the two wires on the left side of the ballast resistor got swapped (bottom on top, top on bottom), would it make something like this, or would it be just like a complete failure with engine firing with turn of key, but dying as soon as you let go of the key?

I say this, because I noticed that the two left wires were separated and plug into the ports individually. This was doen by the previous owner for his MSD box. He left all of the wires to the ballast plugged in, with the exception of the top left side wire. Is this the blue/ecu wire? When I switched back to the box, I simply just plugged in the ecu harness to the ecu and reconnected the top left wire to the ballast and it ran perfectly, until now. There is a chance I may have accidentally swapped top with bottom on the left side of the ballast, but I dunno. I can try it, along as it doesnt zap something when I switch the wires.
 
Well, looked into the carb I have a little more this weekend, and sure enough, its the culprit of the problem. For whatever reason, when looking down the carb with a light while running and working the throttle by hand, fuel is flowing into the carb, rather than a gentle spray. It seems to be flooding the motor somewhat over time.

Dammit.


This Edelbrock carb is only a year and a half old. Looks like I am going over to a Holley now.:angry7:
 
no. just pull the airhorn and reset float level and float drop. its common for them. float level set to about 7/16", float drop set to about 15/16".
 
bad valve giudes
pull the v covers, rocker shafts pull one or more plugs
air lock a cylinder remove the spring
put mechanics wire on valve to hold it up
dischange air and check guide for side movement
bad guides bad running
compression test will tell u a lot
if your readings change on a second test or just not consistent possible guide problem
compression test first
 
You must log in or register to reply here.
-

Back
Top