Car stumbles on acceleration

buick83-T

83' T-type
Joined
Jun 4, 2001
I have a problem with my car stumbling on acceleration constantly. Carb has just had a new needle&seat put in and accelerator pump. New fuel filter and fuel pump also replaced at the same time. When on incline it will really starts to stumble alot. Can someone tell me whats the problem. THANKS
 
T-type83,
I have took the heatriser off. I have a K&N with heat shield running aluminum hose behind the headlights. Taking off the heatriser hose didnt change it that much only on the right cold start ups (below 40).
 
When my was off my car would bog off the line,heavy foot or not(bad) sitting at a light it would stumble and try to die. At normal driving this car like the heat (116deg) At WOT it wants cold air.
Try add some heat in and see want happens, It'll smooth out
 
The stumbling that is happening is constant it isnt stopping even when warm. I have had the heathose off for a while now. It idles ok but when going down the road it has a light stumble constantly jerking and it is constant not just off the line. When going up hill it gets worse and really stumbles as if out of gas.
 
Even when warm the car needs heat to run right, when at speed mine would surge(with the riser off) like my fuel pump was weak or like you said running out of gas. If I gave it some gas it would bog then start to accel. This problem drove me nuts untill I reconnect the riser. At 80deg out my car run fine, but anything below that I would have problems.
Try it, want do you have to lose?
 
Heated carb gasket.

Mine did this very bad when I removed the heated carb gasket. I figured "screw the dealer" when they told me that it was $179.00 ( :eek: ). So I just put in a regular 4bbl carb gasket. Well after that severly sucked for awhile I figured what the hell and got the part # from the dealer and found somebody that could cross it into a delco part # (21615) and I got it for $89.00 plus tax. Also another thing that could be doing it is the MAP sensor. This tells the computer when there is a load placed on the engine. Just some ideas. If that don't work, let me know. I will run through more thought process. Brain not working. Worked last 12 hours.
 
I switch between a cone and the stock air box. It will bog as Jim describes with the cone. The bog is from the cold incoming air and not the engine temperatures. (Hot engine, cold air will still bog). The SFI cars have a MAT sensor which monitors the incoming air temp, and then the ECM compensate for the colder air. Our CCC ECM can't do this.


Peter also found out that removeing the plenum's heat will cause a bog as well. Since we are talking about '83 TR's, maybe the EGR isn't opening, and therefore not heating the plenum.


The electric EFE (heated gasket) should only operate when the coolant is below a certain temp. This would effect cold start up, but not otherwise.
 
bog

Did the prob. start before or after you replaced the parts in the carb?if it started afterward then recheck what you did and make sure you installed it corectly.If it was bogging before then forget what i just said.YOU say it does it even warm,all the other stuff that was mentioned is more for cold starts nethier the heated carb gasket or heat riser will matter when the motor is warmed up(unless it's below zero outside).I had removed both on mine and it had zero effect when the car was warm.I would check to make sure the plenium under the carb is getting warm once the car has ran,this would cause a bog or hesitation.then make sure vac.lines are hooked up correctly.I would check the EGR valve and make sure it's not sticking open(pull vac line going to it and plug it)and then drive car to see if it runs any differnt.is the turbo working?you may have a frozen turbo and not know it.or the seals in the turbo can be bad and causing a internal vac.leak(but if this happens there's usally oil burning smell or black smoke)Is the M/C siloniod working in the carb?it may be stuck or not adjusted prop.Just by turning on you ign.key you should hear a clicking sound at the carb,if you don't then it's not working or stuck.this would effect crusing speeds or loads.let us know what you tryied and what happened.
 
Re: bog

Originally posted by 83build-up
all the other stuff that was mentioned is more for cold starts nethier the heated carb gasket or heat riser will matter when the motor is warmed up(unless it's below zero outside).


Are we talking about the same thing? I always knew a "heatriser" to be the butterfly EFE valve in the exhaust maniofld which redirects exhaust gases thru the intake manifold. This EFE valve was replaced by the electric EFE (heated gasket). The "heatriser tube" Jim was referring to is for THERMAC air cleaner.

The THERMAC tries to maintain the incoming air at 115°F. Without it, I notice bogging when the ambient air is below 50°F, even when the engine is at operating temp. It seems the EFE and THERMAC do the same job, heating the incoming air. The EFE heats up quickly for cold-start conditions and then turns off. The THERMAC doesn't work immediately, but continues after the EFE has turned off.

BUICK83-T, whats your outside air temp like where you live?
 
Re: Re: bog

Originally posted by b4black



Are we talking about the same thing? I always knew a "heatriser" to be the butterfly EFE valve in the exhaust maniofld which redirects exhaust gases thru the intake manifold. This EFE valve was replaced by the electric EFE (heated gasket). The "heatriser tube" Jim was referring to is for THERMAC air cleaner.

The THERMAC tries to maintain the incoming air at 115°F. Without it, I notice bogging when the ambient air is below 50°F, even when the engine is at operating temp. It seems the EFE and THERMAC do the same job, heating the incoming air. The EFE heats up quickly for cold-start conditions and then turns off. The THERMAC doesn't work immediately, but continues after the EFE has turned off.

BUICK83-T, whats your outside air temp like where you live?


Air temp i would say is around 50-60 lately. I agree with 83buildup about the heat souces(efe,thermovac) having no effect when motor is warm(no bog or stumbling) that is how my car does;It does fine when warm on cold mornings. Only when around 30 does my car hesitate or bog (this is without thermovac(i do have the efe)with motor cold.) Problem i am talking about is a constant surge even warm it still does it.
 
Originally posted by buick83-T
When on incline it will really starts to stumble alot. Can someone tell me whats the problem. THANKS

Do you mean like when you're driving up a hill? :confused:
If so, someone misadjusted the float inside the carb. One here at the forum asked if this began to happen after the needle repacement ? Good question......carb problems usaully begin after having someone open up the carb. :rolleyes:
 
Re: Re: Car stumbles on acceleration

Originally posted by Freddie's Buick


Do you mean like when you're driving up a hill? :confused:
If so, someone misadjusted the float inside the carb. One here at the forum asked if this began to happen after the needle repacement ? Good question......carb problems usaully begin after having someone open up the carb. :rolleyes:


Yes when going up hill problem becomes worse. I have been told as you said the float is not adjusted as it should be. And yes the problem did occur after carb was opened. Should find out very soon what problem is.
 
Hey Freddie..

I was going to say the same(float misadjusted) but did not won't to be the only one and be wrong!!:D
 
Yep...It could be many other things but more than likely I'd check the float first.

Another good suggestion:

I've written many times here that having a spare working carb, (Q-jet), is a must with these cars. Now-a-days Q-jets are difficult to find and finding a decent mechanic that know's how to deal with them is evening harder.

1) Get a spare Q-jet.

2) Get Doug Roe's 'Rochester Carburetors' (excellant Book!)

3) Educate thyself on the marvalous Q-jet and its electronic version.

Once you know 'em, (Q-jets),.... after-market carbs will become exotic big expendiatures $$$ (More for the adventurous or the professional racer). That's only my opinion! :D
 
Exotic Big Ependiture

Originally posted by Freddie's Buick
Once you know 'em, (Q-jets),.... after-market carbs will become exotic big expendiatures $$$ (More for the adventurous or the professional racer). That's only my opinion! :D

Have you check the price on thestock rebuilt carbs? Most places want about $550-$700 for the stock rebuilts for the 83 t-types.
 
You're right Pat. Been looking at those prices for new or rebuilts....yikes!:eek:

What I meant was to yank a bone-yard Q-jet. Once in a while one can find a few. Around my way they go for $25.00. (No warrenty).

Still, they are getting harder to find. Just to be on the safe side I got two. What I like about 'em is pretty much the only thing that goes bad from hanging around a junk yard is that the TPS shorts out. :rolleyes:
 
I got a rebuilt carb from National (I think) down by Freddie (FL)
I got the carb for under $300. I will try and find my recipe, but I did get the last one on their shelf.
I first hunted around all the u-pick places and the already pulled places with no luck. OH ya I keeped my old carb.



I not have the EFE, it was removed before I got the car. It's alittle cold blooded when first started, but no worse than other carbed cars I have had.

Hey pat83t did you still have the Thermac hocked up at the time?

And Hey what's so bad abut ng first, Always look for the simple stuff first...think long think wrong :D
 
Problem solved. Found that the mixture control solinoid was adjusted way off. Car runs very good now.:D Thanks guys for help
 
OK found my sales slip.... $299.95 shipped & to keep my core
National Carburetors, Jacksonville, Fl
Toll Free: 1-888-636-9420
I did get the last one, but if you ship them yours they will rebuild it. For the price I could not pass it up & now I have a spare to tweak with the help of Doug Roe's book & Freddie's pages. :D
 
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