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Mingo
Tribal Scout

USA
27 Posts

Posted - 26 Jan 2015 :  9:10:37 PM  Show Profile  Reply with Quote
My 67 GTO 4spd have a sluggish start in 1&2 gear unless I punch it. Accelerates strong 3&4 with no hesitation. Rebuilt carb, new fuel pump, new sending unit and new fuel filter. Timing set at 12 BTDC, Pertronix Ignitor and plugs set at .35.

Any ideas what could be wrong?

Very limited in knowledge...just love old rides!

GTO..AL

GtoGuy32
Cochise

USA
842 Posts

Posted - 26 Jan 2015 :  10:35:19 PM  Show Profile  Reply with Quote
Not that it will make huge difference....wide ratio or close ratio 4 speed? Also, what rear gear?

When does your secondary timing come in?

What type of carburetor?

You sluggish performance is gear dependent and not RPM dependent?

-Dave
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Admin
Ye Olde Webmaster

848 Posts

Posted - 27 Jan 2015 :  10:04:27 AM  Show Profile  Reply with Quote
I'm with Dave on this. It could be one thing or a combination of things.

What happens when you rev it up to 2500 and come out hard? Are you moving or smoking tires? Is there a bog? After winding out 1st and shift hard to second are you getting rubber? A chirp? Anything? A stumble?

A cam with a large duration comes on late and requires more gear to get the car to accelerate. What cam is in this '67? Is this a "stock" 335 hp GTO or something that has been modified? If it's stock it will still perform well and pull hard through all the gears if everything is working correctly. If it's been modified you might have some mismatched parts. What can you tell us?

Do you know the rear gearing? When you cruise at 60 mph what rpm is the tach showing in 4th? Is it 2000, 2500, 2700, higher? Also what diameter tire is on this car? We can ascertain the effective gear ratio with some numbers.

Tell us what you can.





"Dedicated to keeping the classic Pontiac engine alive."

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Mingo
Tribal Scout

USA
27 Posts

Posted - 28 Jan 2015 :  12:44:06 AM  Show Profile  Reply with Quote
4sp m-20 wide ratio trans, 3:55 gears in rear (or stock), 600 (1406) edelbrock carb for cruising only, no tach at the moment , will even backfire at times when starting. Seems to smooth out then bog down for no apparent reason. If I get it the tires will spin. Could I still have a carb problem? Starts quick and idles well.
Never overheats. Comp x274 cam (just barely over stock). Run 93 octane and afraid to advance the timing for fear of detonation. Compression 9.6

GTO..AL
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Mingo
Tribal Scout

USA
27 Posts

Posted - 28 Jan 2015 :  12:50:42 AM  Show Profile  Reply with Quote
Sorry.....backfire when accelerating in 1 or 2nd...not when starting the engine.

GTO..AL
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Bill Boyle
Horse Feathers (Charter Member)

USA
4794 Posts

Posted - 28 Jan 2015 :  09:33:02 AM  Show Profile  Visit Bill Boyle's Homepage  Reply with Quote
Gearing should light 'em up. The cam is a bit large for a stock or nearly stock 400, however, my focus would be on that carburetor. I believe, that's where most of the trouble lies. Check for vacuum leaks. Pull #1 plug. What color is it? Rich is black perhaps sooty in appearance. A decent burn is grayish-tan.

"Dedicated to keeping the classic Pontiac engine alive."

----
400 bored +.030, forged TRW pistons, ported 62 heads, Hedman headers, 2.5 SS dual exhaust X Pypes, Comp 276AH10 cam, Scorpion 1.65 RR, 850 Q-jet, stock intake & tuned HEI; original owner.

Edited by - Bill Boyle on 28 Jan 2015 09:51:20 AM
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tjs44
Cochise

USA
412 Posts

Posted - 28 Jan 2015 :  10:49:36 AM  Show Profile  Reply with Quote
make sure you have 12 V to the pertronix.If you still have the resistor wire that is a huge problem.Also open up your plugs to 45 with the pertronix.If that is all OK then look at the carb.I hate out of the box E carbs,have been able to get them to run but takes work.Tom
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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 28 Jan 2015 :  12:36:32 PM  Show Profile  Reply with Quote
Just to add to Tom's comment, Edelbrock could easily do a MUCH better job of helping their customers tune those E-carbs, especially the one dimensional secondaries. For pure entertainment (I was bored in a doctors office waiting room) I watched the various videos Edelbrock has on their carbs relating to installation, tuning etc. They are so useless they remind me of those lame so called "car" shows that give us useful tips on proper tire pressure or how to clean floormats.

It just reinforces to me how out of touch they are regarding the vast issues customers are having with their carbs, namely the secondary tuning or lack thereof.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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cortcomp
Coyote

USA
5335 Posts

Posted - 28 Jan 2015 :  2:32:12 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I've seen a dozen run well out of the box...on chevy engines. One exception was the AVS on my father in laws mildly upgraded 468. It was 2 steps too rich on rods (some kind of spring or rod) and jets. We were at goodguys columbus and we talked to the reps there and they said bring it over, the guy swapped them on the spot to match the non-avs e-carb settings we had on before (he wanted the AVS simply because it was available in the chrome like finish like the rest of his engine bay, the other carb was not.) They didn't even charge him, just handed us the parts he took out and said thanks for being a customer.

The thing is, they are only out of touch with us, as pontiac, and likely other BOP engine families. That combined with the fact that most guys bolt them on, set the idle, and they're happy, well, only 1% of us feel there is even an issue.

That's why i was happy when the street demon carb that fit both spread and square and had the huge adjustable goggle secondary came out...finally might be a bolt on carb that works well on our setups that isn't too pricey, maybe i'll see more of those bolted on vs e-carbs. Guys just fear q-jets and a good one costs more than a $275 carb, so hopefully they start picking a cheap carb that matches their setup a little more.
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Mingo
Tribal Scout

USA
27 Posts

Posted - 28 Jan 2015 :  4:11:06 PM  Show Profile  Reply with Quote
I can't thank you guys enough. It's tuff when you are not an ace mechanic but just love cars, especially a GTO. Since high school I've always wanted a 66/67 GTO. Finally just before I retired I purchased one.

The carb was bad and now the car runs like new with more power than I will ever need. It's nice knowing it's there however...

What a great website and great people! AGAIN THANKS!

GTO..AL

Edited by - Mingo on 28 Jan 2015 4:31:23 PM
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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 28 Jan 2015 :  4:51:45 PM  Show Profile  Reply with Quote
Mingo, that's great news. Congratulations for getting it sorted.

Cort, I no longer buy into that theory that we are a tiny faction having issues with these carbs. While I do agree the majority are going on small block Chevies I do not subscribe (completely) to the notion that the carb is perfect for them. They vary in cid and have a huge range of combinations from mild to wild. Yet I see these E-carbs on a lot of them including dual quads.

I also see them on BBC's and given the aforementioned variations I find it impossible to believe that many of the Chevy guys aren't having issues as well. Sure there may be that "GM Targetmaster" (or whatever they call that pile of remolded manhole covers these days) market that the generic E-carb 600 shiny monkey carb. works great on but there has to be a larger number of engines from all makes and years that don't fit in that specific category.

There can be no way the number of folks having issues amount to a 1% category. But we'll never know the true extent because Edelbrock seems to be living in denial. The shame of it is I believe if they put a bit more R&D into these carbs, they could have the best street carb on the market (after the Qjet of course).

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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GtoGuy32
Cochise

USA
842 Posts

Posted - 28 Jan 2015 :  10:36:01 PM  Show Profile  Reply with Quote
Mingo,

What is your total timing set at now and when does it come full in?

Does your engine rune cool?

Overall, based on what I have read, it does sound like you have some tuning to do on the carb, but it would be good to get a full picture of what your timing and carb situation is.

Good luck!
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Admin
Ye Olde Webmaster

848 Posts

Posted - 29 Jan 2015 :  07:04:17 AM  Show Profile  Reply with Quote
What was the situation with this carb? How did you correct it? Was there a vacuum leak?

"Dedicated to keeping the classic Pontiac engine alive."

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cortcomp
Coyote

USA
5335 Posts

Posted - 29 Jan 2015 :  10:50:42 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Phil: I do believe that there's more than 1% of them that aren't perfectly setup, i meant that only 1% of us are perfectionist enough to know that it's not right. Most people bolt them on, go "it idles great! running well! so shiny!" and drive off, never noticing the bog at WOT or that their car is running out of steam 400 rpm earlier than it did before they moved to a 600 or 650cfm carb.

People just aren't complaining because they don't know there's an issue. It's the same in my line of work (tech). I can tell a person until i'm blue in the face that there's problems with their system and this and this should be that and that. They get on, do their email, read the news, and think i'm crazy, and when it dies they go to worst buy and get another shiny overpriced one off the shelf and are happy they got 2 years from something they should have gotten 5-6 from for less money.

Ignorance truly is bliss, i'm jealous of the people in the hobby who can sleep at night truly believing their 350cu in 290hp camaro is a 10's car, they sleep better than i do worrying about the details.

Edited by - cortcomp on 29 Jan 2015 10:51:32 AM
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Admin
Ye Olde Webmaster

848 Posts

Posted - 29 Jan 2015 :  7:22:06 PM  Show Profile  Reply with Quote
"Ignorance truly is bliss...." Yes it is. It reminds me of a story.

In 1965 I was into the surfing scene with a friend of mine. We'd go to various beaches with our 10'6" boards and paddle out to wait for a wave to ride. On one occasion we were with several others who were tagging along to be at the beach (girls). My eyesight needed correction but when I went into the water, no glasses. I relied on my friend Gregg for the "details." Well, I decided to paddle out by myself while my friend Gregg and our "friends" were enjoying themselves on the beach. Well, I was out there in a blissful mood unaware that several sharks were close by. My friends on the beach were yelling to me, but because the wind was blowing toward the beach I couldn't hear them I could only see them waving frantically at me. It finally dawned on me to go in and I did. As I got to the shore and grabbed my board the whole gang was shouting at me. What is wrong with you and other choice words. I asked what are you talking about? Then I was informed of the sharks swimming near me.

Now that is ignorance. You can't be afraid of something you don't know about.

Yes, I did go surfing again, but never out by myself. The thrill of going surfing slowly went away and I found a different hobby...a better one.

"Dedicated to keeping the classic Pontiac engine alive."

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Mingo
Tribal Scout

USA
27 Posts

Posted - 29 Jan 2015 :  10:53:48 PM  Show Profile  Reply with Quote
Which carb would you recommend for what I'm engaged in? I just turn a few corners and rarely even turn the tires (my wife won't let me). Some guys tell me I need to blow the carbon out of that car...occasionally I do.

GTO..AL
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cortcomp
Coyote

USA
5335 Posts

Posted - 30 Jan 2015 :  10:02:32 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
The Q-jet is/was a versatile carb that everyone had good luck with when setup properly. There are still holly fans as well. I like the Qjet because of the small front primaries (where i drive 99.9% of the time) and the trademark sound of the secondaries opening. Also, i'm a guy who likes things to look stock and the edelbrocks just never blend in. Never buy a qjet from summit, jegs or the other giant rebuilding houses, i have had bad luck with those. Either get cliff's book and go through the carb yourself, or find a reliable local pro that will do what you want (i use benchwick's in youngstown, he's fast, affordable, and had zero issues with his carbs.)

I do however want to try the street demon as i mentioned, it has small primaries, GIANT secondaries, and fits spread or square bore. It's small enough to use on all dual quad manifolds if that's your thing, and has only gaskets above the fuel line so less chance of leaks or issues. No idea if they're good or not, they just look like a decent shiny alternative to the qjet and edelbrock carbs.
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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 30 Jan 2015 :  10:19:13 PM  Show Profile  Reply with Quote
I think there was a thread somewhere on those and some buyers have had issues. I also have concerns about stock and aftermarket drop base air cleaners fitting on them as they seem to have a large flat deck like an Aircraft Carrier.
caveat emptor.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.

Edited by - Phil on 30 Jan 2015 10:21:33 PM
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bluebird
Cochise

USA
292 Posts

Posted - 05 Nov 2015 :  2:14:21 PM  Show Profile  Reply with Quote
I had a edelbrock 750 cfm on a 455 that would hesitate on acceleration. I finally found out that there are three holes for the linkage on the accelerator pump. Mine was set at lowest. I set it to highest and it made a huge difference. No more hesitation.

"Experience is the best teacher, unfortunately, it's the costliest!"
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mike389
Big Trees

USA
568 Posts

Posted - 05 Nov 2015 :  3:36:58 PM  Show Profile  Reply with Quote
Mingo
i had the 1406 on my 389+30 and performance + backfire was crappy, timing was 10 BTDC ! carb not enough CFM sold it to a chebby guy (where it belongs)i went with my 800 CFM Q-Jet by Cliff and upped timing to 12 instant performance gains !! lots better of the line & passing gear @ 65 it gets to 110 + very quick !! with the e-crap it hardly got out of it's own way !! a change of carb would solve a lot of your issues !!
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RayK
Cochise

USA
925 Posts

Posted - 23 Nov 2015 :  6:34:03 PM  Show Profile  Reply with Quote
A guy I know recently asked me to look at his Edeljunk chrome paper weight in the shape of a carburetor. He was complaining that it really drinks fuel badly. Other than that it runs fine. I told him it won't get any better, and he should buy a different carburetor. He doesn't want a Q-Jet because it isn't chromed. I told him buy a Holley single pump vacuum secondary. Vic Edelbrock is making a sh!t ton of money off of people who have the "ignorance is bliss" syndrome going on because just like a transmission, carburetors are generally misunderstood.

1969 Firebird 461, #62 iron heads, Comp roller, Performer RPM, Q-Jet Turbo 400 w/ Continental converter. GM 8.5" 10 bolt with 3:73 gears.11.50's@ 119+ MPH
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Blued and Painted
Chief PONTIAC

USA
3406 Posts

Posted - 23 Nov 2015 :  6:46:37 PM  Show Profile  Reply with Quote


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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tjs44
Cochise

USA
412 Posts

Posted - 23 Nov 2015 :  7:13:54 PM  Show Profile  Reply with Quote
E AFBs race well but IMO,drive like crap on the street on our pontiacs.Tom
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RayK
Cochise

USA
925 Posts

Posted - 23 Nov 2015 :  7:30:17 PM  Show Profile  Reply with Quote
I tested a 650 AFB E-junk and an Avenger series on my Bird. They both were absolute dogs. Couldn't tune the secondaries at all. Cannot compare to the Q-Jet, not even in the same ballpark in my personal experience.

1969 Firebird 461, #62 iron heads, Comp roller, Performer RPM, Q-Jet Turbo 400 w/ Continental converter. GM 8.5" 10 bolt with 3:73 gears.11.50's@ 119+ MPH
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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 23 Nov 2015 :  9:44:40 PM  Show Profile  Reply with Quote
Well stated Tom and Ray!

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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Blued and Painted
Chief PONTIAC

USA
3406 Posts

Posted - 23 Nov 2015 :  10:59:14 PM  Show Profile  Reply with Quote
Lots of e-junk carbs on the restoration shows. All makes and models.

If your going to install E-Heads and intake, it just makes sense to get the matching carb?

- https://www.youtube.com/watch?v=hMk63SOkdms -



Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 23 Nov 2015 11:09:51 PM
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RayK
Cochise

USA
925 Posts

Posted - 24 Nov 2015 :  03:14:24 AM  Show Profile  Reply with Quote
Edelbrock carbs are used because they are cheap. Like anything else, if you want good quality you pay for it. One of those dumb tv shows got to me one day about a month ago. I think it's called "Garage Squad" and their supposed top notch engine guy was talking about the SS Monte they were doing and he made a comment about the "Quadrajunk" (exact word) being replaced with a better carburetor, then they put an Edelbrock on. That was the only time I watched that educational show.

1969 Firebird 461, #62 iron heads, Comp roller, Performer RPM, Q-Jet Turbo 400 w/ Continental converter. GM 8.5" 10 bolt with 3:73 gears.11.50's@ 119+ MPH
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Admin
Ye Olde Webmaster

848 Posts

Posted - 24 Nov 2015 :  07:29:10 AM  Show Profile  Reply with Quote
"educational show" an oxymoron. There are relatively few things that a gear head can pick up watching these shows. Everything is simplified and sponsorship from the aftermarket keeps them alive. Hawking aftermarket stuff, one has to see some of it as gross "puffing." It's up to the gear head to separate nonsense from reality.

My wife watches QVC. She comes to me several times a week talking about some product, or gadget. She'll say, "come watch, it's on right now." I will watch and usually say that's interesting, but I will often add, that won't last long. Some times she will agree and other times she'll say I want to give it a try. With my "negative" input, we've managed to buy products that are pretty good. I fear that if I wasn't consulted, we'd have more widgets and gadgets that we could use or would work. It comes down to the old latin "caveat emptor" that is, "buyer beware."

Bottom line--don't buy something just to skimp by with it.


This ends the lesson for today.

"Dedicated to keeping the classic Pontiac engine alive."

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tjs44
Cochise

USA
412 Posts

Posted - 24 Nov 2015 :  10:48:14 AM  Show Profile  Reply with Quote
Guys,the E carbs out of the box work well on some engines.For some reason their setup does not work well with our pontiacs.They usually have a off idle stumble.I have had holleys do the same thing.Many QJs need work to get them right also.I for one HATE QJs just because I have never taken the time to learn how to tune one and at almost 71 I have NO interest in learning.Im lucky to have SMI a few miles from me and can just drive there and have Sean trouble shoot and fix them.Tom
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RayK
Cochise

USA
925 Posts

Posted - 24 Nov 2015 :  3:28:30 PM  Show Profile  Reply with Quote
Tom, usually we find that E carbs work well on the average small block Chevy, not too many modifications and for cruising around. As far as anything else, we get 10 calls per week with people complaining about their e carbs and can we do anything. No, we don't work on them. If folks need help with their e carbs they need to call Edelbrock's tech support and talk to their tech puppets.
Q-Jets are a very good carburetor, as long as they are set up properly for the application. The factory built them application specific. That is why you can't buy a junkyard Oldsmobile 455 Q-Jet and stick it on a 350 Buick and expect it to run correctly. This is one reason they are given a bad name. A fair number of re-manufactured Q-Jets find their way to the shop because guys buy them from whomever rebuilt them and they have idle issues, stumbles or whatever. 99% of the ones we work on have the bypass plugged, mismatched air horn main castings, wrong base plates, incorrect jets/rods, missing power piston springs, etc. My suggestion is to anyone considering buying a re-manned Q-Jet look into the shop that has rebuilt it, ask questions about them, call them and talk to them, find out how they handle problems when you have them, etc. Just because Summit Racing carries re-manned Q-Jets doesn't mean they are worth a damn. They get A LOT of returns trust me.

1969 Firebird 461, #62 iron heads, Comp roller, Performer RPM, Q-Jet Turbo 400 w/ Continental converter. GM 8.5" 10 bolt with 3:73 gears.11.50's@ 119+ MPH
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tjs44
Cochise

USA
412 Posts

Posted - 24 Nov 2015 :  5:39:02 PM  Show Profile  Reply with Quote
Your so right on the QJs!They like most carbs need work when running big cams.ALL pontiac factory carbs were engine specific and people dont always realize it.Im a big pontiac AFB fan.Have been running them since 1962 including the SD carbs of 61-63.I have 3 carbs in my cabinet that are what I call my dyno carbs.Known carbs to use when putting a new engine on the dyno or breaking in a cam.Also have 2 dist just for the same deal.If I had only one go to carb it is one of my 63 421 SD factory Carter AFBs for a square bore and a 9273 QJ.Tom
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