Dusterdude72
IN MOPAR MUSCLE MAGAZINE
Hey guys....been trying to track down an issue for a few years now ( never confronted it head on because I have been in the middle of restoring the car...but the car is about done so now i need to get it taken care of).
Anyhow. I have a mild built 318,mild cam,long tubes,eddy performer intake,summit 750 carb,pro from electronic ignition conversion,high energy coild,mechanical fuel pump,.030 over pistons,,2.5" true dual exhaust,2500 stall,trans go tf2 shift kit,4.56 gears. just to give you an idea of what I am working with.
Already checked for vacuum leaks and all appears to be good.
fuel system is clean
ignition timing is set where it should be.
I have had probably 5 different carburetors on this car over the years and they all have had similar issues and similar symptoms.
The car starts good,idles good,revs up good, has great performance. But runs REALLY rich....will puff smoke and burn your eyes if your around the car and if I rev it up it will spray raw fuel out the tail pipes and leave a wet patch behind each exhaust tip. Also.....every once and awhile in gear with foot on the break if you tap the gas and immediately let of it will stall the engine almost like it cant catch back up.
Like I mentioned.... I have been through multiple carbs...even new ones. (thinking a 750 was to large I have even in the past tried switching to a 600 and still ran just as rich). I have tried tweaking the carbs, I have messed with jetting...still no luck.
oil smells really gassy from getting to much fuel and I have checked my spark plugs and they are pitch black and reak of fuel.
Another issue that i have found is that most of these carbs had really touchy A/F mixtures screws....most made little effect on how the engine ran. (normally you should be able to turn the mixture screw all the way in and cough the engine out.....but my issue is it will still run in most cases with the carbs I have tried).
and being that I have tried multiple carbs,upgraded from points ignition to electronic ignition,messed with plugs,timing...etc...etc.. and still have the problem...it leads me to my next set of questions....being the only things I see left that could be an issue.
I want to say I am getting to much fuel maybe?....and the A/F mixture screws have little to no effect due to fuel pressure being high enough to still blow past them?. And also causing the excessive dump of fuel that is causing the very rich condition?.
do you guys agree?
that leads me to the question of....on my fuel pump (new,mechanical pump, airtex brand,factory replacement). I have no pressure regulator and no fuel return line hooked up in the system.
Should I have one or both of these? and do you think that would be the cause of my issue? (to much pressure build up with no place to go).
I have yet to get my hands on a fuel pressure gauge to test my theory out....but I figured I would run it by you guys first and see what you think and if maybe any of you have had a similar issue.
sorry for the long post and thank you in advance for the help.
Anyhow. I have a mild built 318,mild cam,long tubes,eddy performer intake,summit 750 carb,pro from electronic ignition conversion,high energy coild,mechanical fuel pump,.030 over pistons,,2.5" true dual exhaust,2500 stall,trans go tf2 shift kit,4.56 gears. just to give you an idea of what I am working with.
Already checked for vacuum leaks and all appears to be good.
fuel system is clean
ignition timing is set where it should be.
I have had probably 5 different carburetors on this car over the years and they all have had similar issues and similar symptoms.
The car starts good,idles good,revs up good, has great performance. But runs REALLY rich....will puff smoke and burn your eyes if your around the car and if I rev it up it will spray raw fuel out the tail pipes and leave a wet patch behind each exhaust tip. Also.....every once and awhile in gear with foot on the break if you tap the gas and immediately let of it will stall the engine almost like it cant catch back up.
Like I mentioned.... I have been through multiple carbs...even new ones. (thinking a 750 was to large I have even in the past tried switching to a 600 and still ran just as rich). I have tried tweaking the carbs, I have messed with jetting...still no luck.
oil smells really gassy from getting to much fuel and I have checked my spark plugs and they are pitch black and reak of fuel.
Another issue that i have found is that most of these carbs had really touchy A/F mixtures screws....most made little effect on how the engine ran. (normally you should be able to turn the mixture screw all the way in and cough the engine out.....but my issue is it will still run in most cases with the carbs I have tried).
and being that I have tried multiple carbs,upgraded from points ignition to electronic ignition,messed with plugs,timing...etc...etc.. and still have the problem...it leads me to my next set of questions....being the only things I see left that could be an issue.
I want to say I am getting to much fuel maybe?....and the A/F mixture screws have little to no effect due to fuel pressure being high enough to still blow past them?. And also causing the excessive dump of fuel that is causing the very rich condition?.
do you guys agree?
that leads me to the question of....on my fuel pump (new,mechanical pump, airtex brand,factory replacement). I have no pressure regulator and no fuel return line hooked up in the system.
Should I have one or both of these? and do you think that would be the cause of my issue? (to much pressure build up with no place to go).
I have yet to get my hands on a fuel pressure gauge to test my theory out....but I figured I would run it by you guys first and see what you think and if maybe any of you have had a similar issue.
sorry for the long post and thank you in advance for the help.
