# 67 gto hesitation



## javamon (Oct 2, 2008)

hi all

the short: 67 gto is hesitating a bit off idle...and anything above ~3000 revs with much throttle (i'm thinking when the other barrels kick in?) sends the thing into a really weird low power situation, which is hard to explain. it's like massive hesitation, almost. also need to cure a sticking front drum. thoughts? probably need to read the long section...


the long: by way of introduction, i'm not new to wrenching, but i learned by working on my e36 m3 (1996, if you don't speak bmw-chassis language). as odd as it sounds, working on an older car is actually a bit harder for me, intuitively. i (as of yet) know little about carburetors. so, i'm going to need a bit of assistance, if possible. anyway, this is my father's 67 that he bought new. he passed away last winter, and i'm only now getting the car out and about. for about the last 8 or so years he's been showing it on the POCI circuit in the survivor class - it's in absurdly good shape to be 99% original and 40 years old (every showing has gotten gold in points judged). car was stored in a garage for about 30 years, last few years he kept it in the enclosed trailer - but that trailer sat outside, so the goat did get pretty extreme heat/cold exposure (west virginia). everything else seems to work well, aside from a bit of a high idle at startup that is preventing me from getting reverse. once the idle slows, reverse is available. the front passenger drum is sticking a bit, but i found a new drum in the trailer, which i'm guessing he bought to solve that, but didn't get to install it. i'm guessing this is like any brake drum - pop the wheel off, pop the drum off, spin the little adjuster between the shoes for the new drum diameter, and pop the new drum on?

given that previous 8 years of being trailered everywhere, the car hadn't had any fluids changed since about 2001, and the gas, as near as i can tell by receipts, is from about 2003. stabil was used, but 5 year old gas seems a bit old to me. i've changed the oil (went with rotella-t 10w30 after some searching), not sure if i need to change the coolant or not. i noticed some rust on the lower radiator hoses that appeared to be a very slow drip. but the gas is where i'm thinking of starting for the hesitation issue - draining the tank (if i can figure out where to put the 15-20 gallons i'm estimating that remain in the tank) and seeing if fresh gas cures the problem.

any other ideas? thanks in advance. 

here's a link to some pictures, although that's more for showing off than troubleshooting  Picasa Web Albums - Brian - GTO


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## Pontiac Tempest Cstm (Jun 18, 2008)

hey.i like the e36 my friends got one also .well your hesitation problem might be the accelerator pump, being dried up from sitting for so long.that was my problem and a carb rebuild fixed it.i dont think the old gas helps any either.im notsure where you can dump it legally.you should probably change all the fluids since it was sitting.IMO.i would deffinatly either buy anew carb or get it rebuilt since the cars original.well thats all i can help with im sure some one on here with more experience can be better help.GOOOD LUCK!!!!:cheers




that goat is AMAZING!!!so clean!your father took amazing care of it, its beautiful!arty:


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## Rukee (Feb 8, 2007)

Welcome to the forums!
I'd remove the top of the air cleaner and verify gas is squirting into the the throat of the carb when you ratchet the accelerator back and forth. You may have to hold the choke plate open to look down inside while you pump the throttle. If it is, then get that old gas out of there and drive a tank of premium through. If there is no gas squirting in, then the carb needs a rebuild kit at least.


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## javamon (Oct 2, 2008)

Rukee said:


> Welcome to the forums!
> I'd remove the top of the air cleaner and verify gas is squirting into the the throat of the carb when you ratchet the accelerator back and forth. You may have to hold the choke plate open to look down inside while you pump the throttle. If it is, then get that old gas out of there and drive a tank of premium through. If there is no gas squirting in, then the carb needs a rebuild kit at least.


Thanks, I'll have a look tomorrow in the daylight. I would assume some gas is getting in, because I can drive it. What kind of spray pattern am I looking for?


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## brock5ga (Sep 29, 2008)

The squirting Rukee is talking about will be 2 streams from the top of the carb just under the choke flap. With the choke flap open, push the throttle and you should see two straight, steady streams, almost like fangs, coming from the front of the carburetor and shooting towards the back. The vacuum will control your metering jets and let your engine idle and accelerate under light throttle, but your accelerator pump enriches the mixture for faster acceleration. There is also a check ball under a screw in the bottom of the carb bowl which may be stuck from sitting. If the car is all original, most rebuilt carbs are junk. A quadrajet is not hard to build if you have some advanced mechanical ability.


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## javamon (Oct 2, 2008)

brock5ga said:


> The squirting Rukee is talking about will be 2 streams from the top of the carb just under the choke flap. With the choke flap open, push the throttle and you should see two straight, steady streams, almost like fangs, coming from the front of the carburetor and shooting towards the back. The vacuum will control your metering jets and let your engine idle and accelerate under light throttle, but your accelerator pump enriches the mixture for faster acceleration. There is also a check ball under a screw in the bottom of the carb bowl which may be stuck from sitting. If the car is all original, most rebuilt carbs are junk. A quadrajet is not hard to build if you have some advanced mechanical ability.


Gotcha, I'll have a look for that tomorrow. My mechanical ability is pretty good...but I need some literature to get me started. Any recommended guides/books on this carb?


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## Old Indian (Jul 4, 2007)

If you're going to keep your Q-Jet, invest in Doug Roe's book on the subject. Inside, you will find great pics and descriptions similar to what the guys above have recommended. Old gas gets like varnish and causes things to stick together inside the carb. One thing that was not mentioned is the power valve which controls the amount of gas going to the carb. It is prone to sticking in cars that have sat idle for an extended period of time. Doug's book shows where it's located and how to make a tool to free it from outside the carb. If the valve is stuck, it could be leaning out your engine as the RPMs increase. The secondaries provide additional gas, but the primaries still need to be running flat out to keep the mixture at the right level. A lot of people swear at Q-Jets, but they can be maintained and adjusted like anything mechanical to give you great service, excellent drivability and gobs of power when those huge secondaries come in.
Good luck,
Bill


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## geeteeohguy (Feb 2, 2008)

Change the coolant, too. It gets acidic and will eat up yur radiator over time. A brake drum will not cause a sticking brake. It's probably a rusted wheel sylinder or faulty hardware. Remove the drum to inspect. Do NOT overtighten the wheel bearing. All very simple and straight forward. It sounds like the carb is gummed up like the others said. Clean and inspect it per/the manuals. Sorry to hear about your Dad, but it sounds like he left you his legacy! Good luck
Jeff


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## ppurfield001 (Jan 21, 2008)

Sorry to hear of your Dad's passing, but he left you a hell of a going-away present!

Also, Rukee, Old Indian, geeteeohguy and the others on this website have a wealth of knowledge about GTOs and their advice is usually right on the money.

Welcome to the herd!


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## javamon (Oct 2, 2008)

I had a look this morning, and there is fuel coming into the car as one of the previous posters indicated there should be. It seems to be flowing very well, actually - two well defined streams, very fang like. I've found some scanned pdf's of service manuals, but I'll pick up the Roe book as well, because it doesn't look like it'll be a 5 minute fix - although I will drain the tank and try some fresh premium first. 

The longest period it sat without being run was this past year - prior to that, he at least started it every month during the summer (we could debate the wisdom of starting it without driving it, but suffice it to say, that's a moot point now - and not a practice that i'm going to continue).

I'll have a look at the brakes after the football weekend is over...

Thanks for the quick responses all!


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## javamon (Oct 2, 2008)

geeteeohguy said:


> Change the coolant, too. It gets acidic and will eat up yur radiator over time.


That popped up as I was replying - apologies for the multipost. 

I'm assuming there's an engine block coolant drain plug - I'm sure I can find it by looking, but just to double check because I'm overly careful...about where is it located?


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## geeteeohguy (Feb 2, 2008)

You won't find a block drain plug. Just drain the radiator at the petcock or lower hose, and refill with 50-50 coolant/distilled water mixture. If the coolant in it now isn't rusty, you'll be ok with the small amount of "old" coolant in the block. It's sort of like doing an automatic transmission service: only SOME of the fluid gets changed, but if done regularly, it remains in good condition. Post some pics of your car when you can: I know everybody here wants to see 'em!!!
Jeff


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## javamon (Oct 2, 2008)

geeteeohguy said:


> You won't find a block drain plug. Just drain the radiator at the petcock or lower hose, and refill with 50-50 coolant/distilled water mixture.


Ahh...overcomplicating things! Will do, then. Any specific kind of coolant these engines like?

And for a few pics...these are the same as from the above album I linked in the first post, because I haven't gotten to taking any pictures myself. Hopefully I'll have some fresh ones in the next few weeks - but the car hasn't changed at all.


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## geeteeohguy (Feb 2, 2008)

Can't open your pics!! Oh well. Use reguar green glycol based coolant like Peak or Prestone, etc. Be sure to use soft or distilled water. These are very simple, low tech cars that will run forever if cared for and maintained. We'll do our best to help you get it up to snuff and going. My prediction is, once you begin to drive the car, you'll be hooked. It's happened to every GTO person I've met, including myself!
Jeff


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## ITSA64 (Aug 21, 2008)

If it's not the accelerator pump, I'd check the distributor vacuum advance.


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## javamon (Oct 2, 2008)

an update. first things first - i drained the tank, and the gas looked like a really dark lager. put some fresh 93 in, and after a bit of idling, the off-idle hesitation seemed to go away. i would road test it, but i want to have a look at the sticking brake, first. best not to unleash that kind of power with some semblance of momentum control, heh.

i took some pictures, and have a couple questions - keeping in mind that i'm still new to old technology 









this is the bottom of the carb where it meets the header, toward the front, driver's side. a little bubble is escaping...which means there's also some fluid. is this a coolant passage? i'm guessing this shouldn't be happening.









top shot of carb. is the reddish fluid in the hole on the right old gas? what i syphoned out didn't look that dark, and it almost has the consistency of oil...i'm guessing this is a big part of the problem here.









and finally, visible in the last picture, this is the top driver's front corner of the carb. seems to be a bit wet again.

i'll start a thread somewhere else with some of the non-diagnostic pictures i just took of the rest of the car.


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## ITSA64 (Aug 21, 2008)

just a guess here - I'd bet the red fluid is either marvel mystery oil or automatic tranny fluid that was poured down the carb (with engine running) when it was being put into storage. this is sometimes done to help protect internal engine parts like valves, pison rings, etc from rusting/corroding during long term storages. 
Paul


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## Rukee (Feb 8, 2007)

The first pic if that's the carb base, then no, there is no coolant there. It is probably gas or condensation. Behind there is manifold vacuum, so there is no pressure to push anything "out" from there.


The third pic is the accelerator pump shaft, it can be difficult to get that to seal up good. A little leaking or a small amount of seeping can almost be considered normal. However, if it's squirting out of there at any time, then that's a problem.


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## javamon (Oct 2, 2008)

well, i fixed the brake - just needed some adjustment - so i took her out on a test run. there's no hesitation now off idle whatsoever. part throttle to wide open is pretty instantaneous. but once you're into the throttle for a second or two - after it sounds like the secondaries have started to open - it almost feels like a hard fuel cut. no more acceleration. WOT at low revs works okay, it's only when it's up past 2k, depending on the gear, that i'm having the problem.

with the advice above, and talking to a mechanic friend of my dad's, it sounds like i'm going to have to open up the carb and have a look because it could be a number of different things. this is assuming the fuel filter i just picked up doesn't solve the problem (but, I wanted to get the potential simple fuel-related issues out of the way), which i doubt it will.

thanks for all the input guys(/girls?). i'll report back here with some progress when there is some, which might take some time. some quick pics are in the show us your car thread over in the general forum.


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