Stumped and Frustrated with a Holley 670 Hesitation

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Hey Ramie, Maybe I could stop by sometime this weekend and we can swap out my 750 onto your car just to try it. Wouldn't want to mess with any settings because I feel I have it dialed in for my car pretty well finally but I'd be happy to let ya try it at least.
 
inertia said:
Yeah,, I'm old school and repair the problem,, not replace the part.. could seldom afford new stuff.. lol
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Totally agree with you, As do I typically but carbs are like French to me. Ive tried all the suggestions from here. The suggestions from a holley tech and I feel I've exhausted all my sources. I mean this carb was sent back to holley for a reason, they claimed to refurbish it but I just wonder if its mechanically bad.

Can't hurt to try a different carb and if it solves all my issues I'm money ahead in my opinion. It would be nice to enjoy the car and have it fun and drive good.

So far I've worked thru all the other problems with my car on my own sometimes you just have to give up and wave the white flag.
 
MobileCustoms said:
Hey Ramie, Maybe I could stop by sometime this weekend and we can swap out my 750 onto your car just to try it. Wouldn't want to mess with any settings because I feel I have it dialed in for my car pretty well finally but I'd be happy to let ya try it at least.
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Doug, awesome gesture. If this guy with the carb doesn't have it ready Friday I'll call you. Thanks buddy
 
Im gonna say it again.I would disable the secondaries and tune the primaries first. I think you will find that the 6.5 PV is opening too late. And it will give you a chance to properly jet the front side.
 
I spoke with the carb shop and they will have the trial carb ready for me Wednesday. They are setting up a QFT slayer 750. I'll update again after the test of that carb. Still crossing my fingers it works.
 
Man... you are soo close to fixing it yourself for free,, 30 posts ago you didn't know how to set up anything..

If you go back thru the "hesitation posts" for a coupla years,, you'll find dozens of posts similar to yours,, in most cases the person disredarded LOOKING at the pumpshot,, even tho mentioned a dozen times,, WHY they won't look is baffling.. When they finally did,, they go "doh" it splutters and isn't a strong shot,, but I rebuilt it,, or replaced the pump,, or some other lame answer.. jmo.. rant over

When you get another carb,, and it does run better,, look at the pump shot compared to yours,,, and you will realize you couldaa done it yourself.. jmo
 
inertia said:
Man... you are soo close to fixing it yourself for free,, 30 posts ago you didn't know how to set up anything..

If you go back thru the "hesitation posts" for a coupla years,, you'll find dozens of posts similar to yours,, in most cases the person disredarded LOOKING at the pumpshot,, even tho mentioned a dozen times,, WHY they won't look is baffling..
When they finally did,, they go "doh" it splutters and isn't a strong shot,, but I rebuilt it,, or replaced the pump,, or some other lame answer.. jmo.. rant over

When you get another carb,, and it does run better,, look at the pump shot compared to yours,,, and you will realize you couldaa had it yourself.. jmo
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Are you speaking of the pump shot nozzle size? I've tried different ones of those and no change. Adjusted the pump cam, and no difference. Just didn't change to the larger cc pump.

You guys may be right and I may be close. Or I may not be lol. I know when I go to pick up this carb he is going to strip mine down and go thru it just to see if there is anything that is a for sure ugh huh, that's the problem. I'm overall curious just to try something and see if there is any improvement.
 
We are refering to actually watching the fluid,, how it discharges,, it must start to discharge from the nozzle the INSTANT you move the throttle,, it must be a strong, continuous shot of fuel for as long as you move the throttle..

Also after moving the throttle about a 1/2 to 1 inch, stop and hold.. wait 5 seconds,, it must instantly deliver fuel when you resume throttle movement,, any delays you SEE,, will be your hesitation.. Do it numerous times,, scrutinizing the flow,, somewhere there's a pause, splutter.. hope it helps.. really do..
 
inertia said:
We are refering to actually watching the fluid,, how it discharges,, it must start to discharge from the nozzle the INSTANT you move the throttle,, it must be a strong, continuous shot of fuel for as long as you move the throttle..

Also after moving the throttle about a 1/2 to 1 inch, stop and hold.. wait 5 seconds,, it must instantly deliver fuel when you resume throttle movement,, any delays you SEE,, will be your hesitation.. Do it numerous times,, scrutinizing the flow,, somewhere there's a pause, splutter.. hope it helps.. really do..
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Ahhh 10-4!

I can play around with that over the next couple days. See if I can see anything out of the ordinary.
 
And don't confuse a shot with it's working. Some guys will move it an 1/8th of an inch for example and then see the pump shot and think it's OK.

If you move that throttle and do not instantly, as in right now, see a shot, that could be your issue. It could be as simple as a minor adjustment if you find this to be the case.
 
If you don't have one, a $150 A/F meter would do wonders to help diagnose the issue.

The issue can be rich or lean...
 
Bad Sport said:
And don't confuse a shot with it's working. Some guys will move it an 1/8th of an inch for example and then see the pump shot and think it's OK.

If you move that throttle and do not instantly, as in right now, see a shot, that could be your issue. It could be as simple as a minor adjustment if you find this to be the case.
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I had the same problim with a 3310 once rack my brain :violent1: for 2 weeks turned out all i had to do was push down the arm that rides on top of the pump cam,it was bent up to much took screw driver and wack it down,it work.Not saying that is your issue but worth a look,i thought the past owner of the carb must of went nuts trying to figure it out lol.
 
Bad Sport said:
And don't confuse a shot with it's working. Some guys will move it an 1/8th of an inch for example and then see the pump shot and think it's OK. If you move that throttle and do not instantly, as in right now, see a shot, that could be your issue. It could be as simple as a minor adjustment if you find this to be the case.
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Ok so I got home and went right to the garage. First off I did this with the car off, pretty sure I was suppose to. So I slowly opened the throttle and the gas trickled out of the squirters. Then I gave it a quick bump to say half throttle and gas did squirt, and appeared like it was instant. So at half throttle still, I bumped it again to 3/4 throttle, appeared to be about the same. I noticed from about 3/4 throttle to WOT the pump lever didnt move at all. It was riding on the flats of the pump cam and no longer pushing down. I repeated this a few times and it all seems to be about the same each time I did it. So I need to ask a few questions to make sure Im doing it correctly. When you guys say to do this do I do it fast or slow, like if Im going to WOT or just easing into WOT?

crackedback said:
If you don't have one, a $150 A/F meter would do wonders to help diagnose the issue. The issue can be rich or lean...
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Do you have one that you recommend? I've seen these mentioned in other posts and have looked at them but there are so many I wouldnt have a clue on what I would need.
 
Oh and this carb came with a orange pump cam in the #2 hole. Shouldnt this be in the #1 hole like what the video Inertia posted early mentioned. For cars that idle below 1000rpm. I have my idle set to about 900rpm...

Please tell me this wasnt my issue the entire time?? I swear I looked at that a hundred times and it was in the #1 hole...
 
Snake said:
Do you know what arm i am talking about.
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I believe I do... Your talking the arm that is actually riding on the pump cam. If that is the arm it is riding tight to the cam and cant be pushed in any direction.. Although Im sure I can bend it but it doesnt look like it has been moved or bent from the factory, and I dont know if I want to start bending the metal pieces yet.

Can you tell me what color pump cam you have and what hole it is in on your throttle arm.
 
[ame="http://www.amazon.com/AEM-30-4110-UEGO-Ratio-Gauge/dp/B00N3VGPYS#productDetails"]Amazon.com: AEM (30-4110) UEGO Air/Fuel Ratio Gauge: Automotive[/ame]

That one is pretty good. I think it will allow for logging as well. It's good to get the readings along with rpm.

If the check ball from the bowl to the pump diaphram is messed up, that might cause a delay in delivery. Sometimes it's a rubber style plug.
 
straightlinespeed said:
So I slowly opened the throttle and the gas trickled out of the squirters. Then I gave it a quick bump to say half throttle and gas did squirt, and appeared like it was instant. So at half throttle still, I bumped it again to 3/4 throttle, appeared to be about the same. I noticed from about 3/4 throttle to WOT the pump lever didnt move at all. It was riding on the flats of the pump cam and no longer pushing down. I repeated this a few times and it all seems to be about the same each time I did it. So I need to ask a few questions to make sure Im doing it correctly. When you guys say to do this do I do it fast or slow, like if Im going to WOT or just easing into WOT? Do you have one that you recommend? I've seen these mentioned in other posts and have looked at them but there are so many I wouldnt have a clue on what I would need.
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Would you think the very first shot was as strong and immediate as the following strokes?

Try and imagine your foot motions on the gas pedal when it hesitates,, and try to reproduce that motion at the carb,.. You can try this with the car running,, but keep your face to the side,, and not over the carb,, where a backfire may singe your eyebrows, pls br real careful here,, safety glasses a must,., a mirror is helpful here..(if the car never backfires, you're relatively safe..)

I have 2 thoughts,,

As mentioned previously ,, there's a small needle underneath the squirter,, if it's not seating,, the fuel will drain back outta the squirter creating a void/hesitation, that the pump has to fill before it can squirt.. To try and remedy that,, take the squirter out, and you shoud see the needle sitting in the squirter hole,, if you have a small punch, you need to give the needle a light tap a coupla times to re-seat the needle..

Also if the squirter gskt leaks, same deal,, drains squirter..

2nd, and drove me nuts half a day,, is in the accelerator pump cavity, (take the diaphram off) and there's a small shiny ball captured by a metal strap,, make sure that there no crap stuck in there,, and more importantly, is that the strap holds the ball almost snug,, if the ball appears to have quite a bit of motion off the seat,, tighten it up by adjusting/tapping the strap.. That ball,, if left really loose,, will cause a healthy hesitation,,, Readjust the linkages to no slack,, and cross your fingers,, .lol

as always... hope it helps
 
AJ/FormS said:
oh oh,dribbling is not right. I wonder if the check valve under the squirter is missing. Or debris causing it to not seat properly. That could cause most of your symptoms.
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I double checked and also sprayed carb cleaner down the hole. The check was in place and it appeared to be clean. I reassembled and it acts the same way when I open the throttle slowly. If I open the throttle fast it squirts a nice stream out.

crackedback said:
Amazon.com: AEM (30-4110) UEGO Air/Fuel Ratio Gauge: Automotive That one is pretty good. I think it will allow for logging as well. It's good to get the readings along with rpm. If the check ball from the bowl to the pump diaphram is messed up, that might cause a delay in delivery. Sometimes it's a rubber style plug.
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Thank you I will look into this.

Snake said:
Mine is orange and set at the # 2.
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Thank you
 
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