View Full Version : Bad Bad stumble
blue ss Nov 1st, 06, 06:11 AM I have a new 350 mild cam with 10k miles, Q-jet, pertronics plug n play dist.
I went from (after a lot of adjustments the past year) a perfect in everyway running car, I pull up to a light and try to drive away it couldnt stumble more. I could hardly get to 40 mph. Idles great starts great, choke came on and went of as it should this mornin, I did richin it up with the Idle screws last night 1 1/2 to 2 1/4 it seamed better but still undrivable, That tells me a fuel problem. Parked you can jab the throttle is mint- Try to get going forward it just sputter. What could have gone twang all of a suden? My thoughts now are Im getting enough fuel because the bowl is full (I can watch the pump kick many times), enough fuel to get moving 10 feet before it sputters to a stop if it were a fuel pump from just the bowl fuel, ( I cant, it sputters as soon as I want power from it, anything off idle circut) , I torked it up against the parking brake it seems to have power, Mabe the coil? Cap rotor look good. The plugs I thought were going to be black from flooding out were clean as the day I put them in 2-3 k ago, I did not smell any big fuel as I putterd home. Its like I jumped time with the chain but I dought it (Miles). I want to think coil Its a lean mix or I should say a good mix hard to fire lots of coil needed .045 gap. I run 16 initial 17 advance vacume to manifold. Its been a strong strong no hesitation power with this set up. It was mint!
madmax87 Nov 1st, 06, 09:09 AM When you installed your Pertronix dist, did you bypass the resister wire or ballast resister (whichever you have) to a direct 12V switched line from the fuse box.
blue ss Nov 1st, 06, 09:17 AM When you installed your Pertronix dist, did you bypass the resister wire or ballast resister (whichever you have) to a direct 12V switched line from the fuse box.
ya max it was in the instalation book to do it that way. Its been running for 1.5 years this way about 10k miles.
Thanks for your reply
madmax87 Nov 1st, 06, 09:58 AM I'm sure you probably checked, but I'll throw it out there. Sounds like you may have a vac leak. Fine while sitting but fails under a load. Also like you said, maybe coil took a crap. .045 is a pretty good gap. I'm not real familiar with Q-jets so I can't help there.
blue ss Nov 1st, 06, 10:47 AM I'm sure you probably checked, but I'll throw it out there. Sounds like you may have a vac leak. Fine while sitting but fails under a load. Also like you said, maybe coil took a crap. .045 is a pretty good gap. I'm not real familiar with Q-jets so I can't help there.
Well Im thinking because it idles so good and just anything from there is no go under load. a vac leak would leave me with a bad idle. I can get all the rpms I want just not when I let off the clutch and try to go. It has to be fuel or coil. I think anyway. Probably carb somehow. It seems like I got home last nite on just the idle circut. Thanks Max
ace's68 Nov 1st, 06, 06:24 PM i have an edelbrock which is based off of the Q-jet and many people said when i asked why mine hesitated under a load or taking off it was a lean condition. try adjusting your accelerator pump maybe??
Sporter Nov 1st, 06, 06:28 PM This happened all of a sudden? Causes of similar symptoms in engines I've encountered are:
debris in the carb inlet or jets,
water in the carb,
fuel filter so full of debris it will barely flow,
water or oil inside the distributor cap,
timing chain jumped,
vacuum leak in the carb body,
intake valve stuck open,
really bad spark plug wires
Best thing to do is swap the carb for a known good one and test it. If that's not it then swap the distributor, etc. Also, pop your hood in a totally dark area, rev the engine and watch for a light show from your coil, wires or distributor cap. Some light around the plug porcelain is normal.
ace's68 Nov 1st, 06, 06:35 PM how can you get oil inside the cap? is it from a warn distributor? because i know on an old hei i pulled once there was quite a bit of oil and debris in there. my friends had gas in the vacume part of the distributor once... that was a suprise.
blue ss Nov 2nd, 06, 05:52 AM This happened all of a sudden? Causes of similar symptoms in engines I've encountered are:
debris in the carb inlet or jets,
water in the carb,
fuel filter so full of debris it will barely flow,
water or oil inside the distributor cap,
timing chain jumped,
vacuum leak in the carb body,
intake valve stuck open,
really bad spark plug wires
Best thing to do is swap the carb for a known good one and test it. If that's not it then swap the distributor, etc. Also, pop your hood in a totally dark area, rev the engine and watch for a light show from your coil, wires or distributor cap. Some light around the plug porcelain is normal.
Ya all of a sudden, Like a light switch. Pull up to a stop and tried to go- it then started, no power, studer off of idle. So far I tried a new coil (same thing) , I checked for chain slack (thinking I lost time mabe) it was tight mabe 1 deg. of slop. # 1 was at #1 like it should too. Did a test down my street- turned it of when it was stuttering , found plugs fouled brown on one side of the plug (a couple pretty good) I figured one side was washed by incoming fuel and the other side had unburned fuel. That realy didnt mean any thing to me though because if it was distributer control side missing its triger but still fireing some signal to the coil it would be unbured fuel the same as a carb with too lean or rich cant burn correct. I did ohm the wires and found around 500 ohms per foot (should be good) did the rotor 25 ohms cap center 2 ohms. So hear I am thinking I will be a parts changer and pull the carb rebuild it (hoping to find a blocked something or out of place some thing) . That would only cost 30 $ or so. If that doesnt work. I supose a spare dist. would be nice for the long trips anywhay. (Dont want to use HEI dist. too tight of a fit if I needed to change in the midle of noplace) I hate guessing! Dont know how to look down the venturi under load ( mabe I can get my neibor I dont like to sit on the fender and look down the carb with a lighter to see whats happenin when I hit the gas) Thanks for any ideas guys! I will try the nite light show tonite good idea Brian
blue ss Nov 2nd, 06, 06:26 AM I realy am having a bad time of things, when I was loading up the Impala parked next to the camaro with books for carbs and stuff I actuly gave myself a chip in my new paint. Auhhhhhh did that suck! All the way to metal.
blue ss Nov 2nd, 06, 07:19 AM Cast your vote: Carb or Distributer
JimM Nov 2nd, 06, 09:23 AM Brian, I sent a pm to Jason, copied you too. He's not far away and has a garage full of junk, should be able to find some spares for some testing. I vote carb.
blue ss Nov 2nd, 06, 09:58 AM Thanks Jim got your copy, I will sit tight and see if Jason garage full of spare toys has it. We will make some arangemnt. Thanks Jason , If you would intergalactic mesage me.
136679ss Nov 2nd, 06, 11:40 AM Thanks Jim got your copy, I will sit tight and see if Jason garage full of spare toys has it. We will make some arangemnt. Thanks Jason , If you would intergalactic mesage me.
lol. Intergalactic encrypted secret message sent.
blue ss Nov 3rd, 06, 06:02 AM Brian, I sent a pm to Jason, copied you too. He's not far away and has a garage full of junk, should be able to find some spares for some testing. I vote carb.
Well as it turns out ,I did talk with Jason last nite Thanks for a great contact Jim! He does have a great stock of things. I had bought a carb kit just in case. When I got home I couldnt just look at the carb and wonder so---- DRUM ROLL PLEASE ---- Jim is got the right vote! The carb did it. The primary jet power pistion has a bycicle handle style conection at the top that is removable it removed it self and lodged in the air horn. It was slightly bent I unbent it to fit the air horn concave area and bent it level (one rod sat higher than the other) That did it! I HAVE THE POWER! I bet it has a more of a even mix from one side of the carb being lean or rich, they are the same now. Mabe I will have a smoother accel now. One question I still have is how to keep the top of the power piston from comming lose? I want to take a pair of pliers and crip it tight to the bycicle handle where the rods attatch. The hole that the bycicle handle fits into the top of the piston. Thanks guys Brian ,--- Jason I will see ya on the trails this winter!
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