Carb or distributor?

[Irishman999]

I just put the carter Afb on my pickup and it seems to be performing way way better than my quadrajet was. Yesterday I took the truck out to help a buddy move on the other side of town, I went from freeway speeds to side streets and stop signs. It started hesitating off the line like the power pump in the carb was junk. I also noticed when it was starting like the timing was way advanced.

I am wondering if the advance **** inside my distributor is all ****** and getting stuck throwing off the timing....

If the timing was stuck way advanced would it cause my pickup to hesitate while taking off from the line?

 

[crazy4offroad]

Make sure you have your distributor advance on the right port. Mine takes full vacuum. You may want to check the distributor advance, the rubber diaphragm inside it can dry rot and leak, and throw your timing off pretty bad.

 

[crazy4offroad]

Another thing, those carbs are bad about needing fine tuned as far as metering rods, springs and jets go. If it isnt black smoking (running rich) it may be running really lean which can screw up your motor pretty bad. Was it getting hot? If not I would look at the distributor advance first.

 

[Irishman999]

I am wondering if this is the entire reason my truck has been running like **** the whole time. Just like the qjet once the truck was run for a while it ran worse, like the timing was getting stuck. The truck sat for 15 years so its very possible the diaphragm inside the vacuum advance is dry rotted.

I thought the vacuum advance was supposed to be plugged into a special vacuum port on the qjet that was just for vacuum advance. Yours just runs off the normal vacuum port?

 

[Swims350]

yea all of ours with holleyus q jets or edelbrocks all run off a reg. vacuum port. one side is timed, or doesn't pull vac. at idle, but right off idle it does, the other pulls vac. at idle. I see no difference in either other then as you said hard starts. That would be pulling vac. at idle and cranking i'd guess advancing the timing so I usually run ported.

You can test the diaprham with a vac. gauge/hand pump to see if it holds vac. I was thinking maybe the springs or weights or the arms were sticking in the dist. I seen on tv they said you can put a dab of grease on them.

I would yank a plug, maybe it's lean or maybe it's rich so I'd check it.

 

[crazy4offroad]

Yes, the Q-Jet requires timed vacuum, but the Edelbrock AKA Carter requires full vacuum. You'll have to reset your timing too. Stock is 8* but with my cam I run 12*.

 

[crazy4offroad]

Looks like I told you wrong. Full vac has more to do with my cam. From here:
http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf

Long Duration Camshaft
If the engine has a fairly radical camshaft it may require an excessive amount of throttle opening for idle and/or have low idle vacuum levels. Either condition can lead to poor levels of
adjustability and erratic idles.

Another fix for the above condition is to run as much spark advance as possible at idle. If the distributor is fitted with a vacuum advance unit, connect it directly to manifold
vacuum. If you are not able to employ vacuum advance for some reason, then the mechanical curve should have a low limit, which will allow you to use plenty of initial spark advance.

 

[89Suburban]

++++++++++

 

[Irishman999]

That all makes alot of sense. I think I will look into a new vacuum pod for my distributor and spray the living hell out of my mechanical advance with pb blaster, I will bet that fixes it.

 

[nxtlevl]

That all makes alot of sense. I think I will look into a new vacuum pod for my distributor and spray the living hell out of my mechanical advance with pb blaster, I will bet that fixes it.

PB blaster fixes everything...........