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Old 11-27-2004, 10:02 PM   #26
GMCjunkie
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Quote:
Originally Posted by tom hand
Sounds like a vacuum leak....could be the brake booster itself
Tom, how exactly would I check to see if its bad?? Thanks.

Brian, Thanks so much!! I believe you would come help if you could, thanks for that break down, that did help me understand that crazy little carb thingie a little better

LUV2... My love troll can kick your love trolls @ss...

Chris, do you HAVE to have a timming light to check the timming?? Is there any other way??

Thanks so much everyone, I appreciate ALL your comments and suggestions. Hopefully it wont be raining tomorrow and I can get something accomplished.
Take care
junk
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Old 11-28-2004, 02:05 AM   #27
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Hey There,As far as fuel problems go,I would check the filter in the carb where the fuel-line enters the carb.It`s either paper like an air filter,or brass?Take notice of the direction it sits in there as you pull it out.Look in the hole it was sittin`in for crud.If you find lil`chunks of rubber,than your fuel pump diafram is shot:Clean hole where the filter sits,Install new filter,Blow-out fuel line between fuel pump`n`carb,&Install new fuel pump.As far as spark goes,if it`s the GM HEI distributor,check the condition of the little length of wire that goes from the side of the dist.to the coil on top in the cap.See if it`s loose or if there is a break/crack in the insulation(rubber)where you can see copper(shiney if fresh/green if old).You may have to flex it around to see the damage.Simple checks of the choke would be:see that there is current to choke,good connection,&lube linkage/check for free movement.Hope I`ve helped.Never feel dumb as long as yer tryin`.Luck...
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Old 11-28-2004, 09:29 AM   #28
GMCjunkie
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Special-K , Thank you!! I already checked the filter, its good. Will check the rest here shortly. THANKS again!!
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Old 11-28-2004, 10:22 AM   #29
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Quote:
Originally Posted by GMCjunkie
Tom, how exactly would I check to see if its bad?? Thanks.


The easist way to test the booster is to get a small pair of vise grips and crimp the vacuum hose shut....then test to see if your other problems disappear...try to limit your tests to the driveway...it would be VERY hard to stop if you drove it. And since you have several problems that have occured at once...hard starting,rough running,dieing,deseling,backfiring,weak brakes....I would be willing to bet your problem is a large vacuum leak....ie brake booster or the hose from the booster...carb loose or bad gasket....intake manifold gasket leak...Good Luck
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Last edited by tom hand; 11-28-2004 at 10:44 AM.
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Old 11-28-2004, 11:03 AM   #30
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sounds to me like you jumped time
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Old 11-28-2004, 08:26 PM   #31
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I love the trouble shooting posts....hey Junkie, let us know when you get it figured out so we know for future reference. My money is on the vacuum leak in the brake booster or the line to it.
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Old 11-28-2004, 10:03 PM   #32
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Ok, I changed the plugs, dist cap and rotar, (oh and the thermo housing, it was leaking). The plugs looked bad as they havent been changed in a while, and have had several trips to Texas. Also had one burnt end on a plug wire from it being too close to the minifolds. She fired right up, good and strong, went to take my son to work, got about 3 miles down the road and outta no where she died and back fired, but then started herself back up. She ONLY dies and back fires while Im goin down the road, never while idling.

If it was a large vacuum leak of some kind, isnt there a way to check that like a "compression test" or something similar??

I had another person say that it sounds like a plugged filter, but the one up on the carb looks fine, I just changed it not long ago. My tank is an after market one, not sure if it has the "sock" or filter in the tank or not. Is it worth the trouble of dropping the tank to check?? Geeeze, what a mess, thanks everyone!!
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Old 11-28-2004, 10:17 PM   #33
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Accelerator pump in the carbeurator?

Not trying to get expensive, but I have seen these cause problems. Kerry
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Old 11-28-2004, 10:49 PM   #34
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If the tank is a replacement tank, then chances are it is not dirty. however, there may well be a filter somewhere between the tank and pump. Look into that, and if there is one, replace it with a section of fuel line. Some ppl feel it is a good idea to have a filter before the pump, but all it does is cause a restriction for the pump to work against.
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Old 11-28-2004, 11:53 PM   #35
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Well, As long as everyone is putting 2 cents into the pot I guess I'll throw mine in. Take the module out of the distributor (It's the part that is on the aluminum base of the distributor under the cap that has wires plugged to it, with 4 or 5 prongs on it, sometimes 2 prongs on each side, sometimes 3 on one side 2 on the other) and have it checked at your local parts store. Autozone does it for free I think. I've had them do some crazy things. Had an 82 GMC Doolley that backfired going down the road and died, would not start, replaced it and had no more problems. I hope that this helps. Kevin
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Old 11-29-2004, 12:26 AM   #36
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Sounds maybe like a couple of different things maybe. Hard to say without seeing hearing. Sounds like the choke isn't right (carb) and maybe ingnition (timing). Vacum (a leak) will or can cause your timing to be off enough to make it backfire. Is it stitting any black smoke out that u have noticed?

Last edited by Mudder; 11-29-2004 at 12:30 AM.
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Old 11-29-2004, 12:32 AM   #37
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Quote:
Originally Posted by 65StreetCruiser
Well, As long as everyone is putting 2 cents into the pot I guess I'll throw mine in....Kevin
well with all of this money getting thrown in she can probably pay for all of the things she is changing, with no out of pocket expense
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Old 11-29-2004, 05:50 AM   #38
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Just picked up a 81, timing was off enough to cause problems like you describe. And the choke was an issue as well..

You've got a sister? She as good lookin as you?
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Old 11-29-2004, 10:39 PM   #39
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Hmm... as far as I know you will need a timing light to check the timing. Maybe someone else can confirm or correct me?
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Old 11-30-2004, 11:01 AM   #40
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Some people can time by ear, I have mine timed by the ping bk I dont have a timing light, I advanced it till the engine pinged and then backed it off. Not a great method but it worked for me.
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