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Step on pedal - No power?

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3.8 V6 checked fuel supply, filter, pcv, choke, and carb.

Runs well at idle but as soon as I give it some gas in gear it seems to bog down. Stock engine.

Any thoughts? confused.gif

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Check timing, points (if it has points).

How many miles are on the engine? Did this problem come on suddenly? or was it a slow progression to what it is now? Will the engine eventually come back out of the bog if you keep the gas pedal down?

Adam

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Ignition is HEI.

Only 66,000 miles.

Does not come out of bog with pedal to floor.

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Have you tried rebuilding the carb? The accelerator pump could be acting up. Float might be sticking also. (you did say this is carbureted, right?) Does it backfire at all when you give it gas? If it does, make sure timing is right. It may need to be advanced.

Adam

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Guest

Carb is OK.

Timing is OK.

No popping thru the carb.

Maybe the coil on the HEI is going bad?

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I don't know much about HEI, but that sounds like a possibility...make sure the plugs are clean and check the wires...maybe replace them if they are more than 30000 miles old. It's possible that the plugs have some oil buildup which causes hesitation at throttle.

Adam

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Could be a sticking power piston in the carb. If it is stuck in the "down" or "economy" position and does not move upward to give a richer mixture under load, it'll do just as you mention. Went through that with dad's pickup with a QJet on it. Your carb is probably the front half of a QJet if it has a carb or even a full QJet depending on the year. If it acts reasonably normal when out of gear, but bogs when you load the engine against the foot brake, that's the first thing I'd see about. Everything else can be new or working fine, but if the carb doesn't put any power mixture into the motor, it just doesn't respond. Once the accel pump shot is gone, so is the power.

Some of those carbs also had dual stage accelerator pumps which were controlled by the ECM via a temp sensor. Not to mention the Throttle Position Sensor on the vehicles with computer controlled carbs.

A friend had a Chevy pickup that acted the same way. The first shop that rebuilt the carb left the spring out (or lost it) from under the power piston so manifold vacuum kept it in full economy mode all of the time. Adding a spring again fixed everything.

Otherwise, check for a clogged catalytic converter or a muffler with a bad baffle that's shutting down the exhaust flow. Slim possibility it could be a transmission torque converter issue, but very slim.

Hope this helps . . .

NTX5467

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you didnt mention what year your regal is. does it "kick down" when you step on it? when the transmission is in gear and you are rolling down the road to about 25-30 mph-if you can get that fast-if you step on the gas does it kick down into passing mode? does it also behave this way if you shift it manually? that could be the shifting modulator.i believe some models were engine vacuum controlled and some were ecm [computer] controlled, just like the carb.

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Guest

Thanks for the input guys.

Will let you know the outcome.

Dan laugh.gif

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Guest

OK. Checked exhaust and cat - no problems there.

Pulled coil from cap and tested - checks out OK.

No codes from the ECM.

EGR - OK.

Now a new development. Start the engine - have to keep tapping lightly on the pedal to keep it running.

Checked fuel pump and filter again - both OK.

Carb problem I'm assuming?

What should be the next step?

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rebuild the carb, unless you've already done that.

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here is someplace you havent looked. you stated your fuel supply was 'ok'. does that mean you have fuel coming out of the fuel line when you crank the motor with the line disconnected from the carb? are you sure of the quality of the gas? do you have any enemies [sugar or water in the gas tank]? if you have GOOD fuel pressure, you are sure it is nothing but good gas, it wont hurt to get a $20 carb kit and just restuff it. while in there, check the carb vs the diagram the kit comes with to see if anything is missing or not quite right. have you checked your compression lately, a steady loss of compression could also cause these symptoms. but i would guess the carb first as it is the easiest to fix. try spraying W-D40 on the outside of the carb body to see if you have any unseen vacuum leaks. carb cleaner will work also but evaporates too fast. use it to clean up after. have you looked at your spark plugs? they will tell you if they arn't living in a healthy enviroment. it started running really bad after you checked your egr? go back a few steps and retry what you checked. now you got me wondering!

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Rebuilding the carb tonight, will let you know the results.

Have a Happy New Year!!

Keep it safe. cool.gif

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Well,

If carb doesn't work, and you did complete tune up including compression check,no vacuum leaks and exhaust is clear....

Start to suspect the timing chain, cam gear is nylon for silent running and deteriorates naturally over the years, you may have skipped a tooth, yes it will still run with out popping but suffers severe power loss.

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Rebuilt Carb. didn't solve problem.

Can't find any vac leaks.

Now what?

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Rebuilt Carb. didn't solve problem.

Can't find any vac leaks.

Now what?

Car runs for 15-20 sec. and stalls. Can keep running if I tap pedal lightly.

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check compression. if you find one cylinder that is low, you have a leaking valve, which can cause hesitation on acceleration.

check timing. (I might have said that already, I don't remember)

Adam

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Timing is right on. All six cylinders have good compression.

This is really a mystery!

If I start it and hold at 1000 rpm it'll keep running. Soon as I take foot off pedal - 15 seconds to stall.

Put in gear - can get to 40 mph by tapping on pedal. Try to give it some gas - nadda! No response.

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glavin!

um...Have you made sure the exhaust system is clear? something is not letting the engine breathe like it should I suspect.

This is odd...just pull it out and throw in a 455. grin.gif

Adam

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Have a '70 455 on my stand as we speak. Doin' the oil mods now.

TA 488/488 cam, dbl groove bearings, super bearings mains and rods, forged 11:1 pistons, cryoed rods, SP1 intake, and stage one heads. No carb choice yet.

WON'T BE THE ONE OFF THE REGAL THOUGH!!!

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HAHA! Grab an 800cfm quadrajet and go to town...make surethe QJ is in working order though wink.gif

Adam

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800 QJ maybe - might have to go larger.

As far as the Regal goes, its back to the beginning.

Will start checking everything again.

This has got me stumped.

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I had an occurence that when I had a large amplifier for my stereo system hooked up it drew a lot of current from the battery and created a pretty bad hesitation for a long time. I finally ripped it out and figured out the problem.

Adam

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