Author Topic: Distributor problem?  (Read 6993 times)

Offline 1979C20

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Distributor problem?
« on: January 28, 2011, 03:21:49 pm »
Well. My truck left me stranded today. I turned a corner and got 2 VERY loud back fires through the exhaust, my truck stalled. I tried to start it again and it just keeps backfiring through the carb. I pulled the number 3 plug wire (easiest one to see) to check for spark and,there was none. There is no oil pressure when im cranking, too. The cap, coil, and plugs are new. The accelerator pump is still working, all the wiring is hooked up. No amount of throttle will start it. It smells flooded. The distributor is old. So I can only assume a spline broke on the gear? Im going to pull the cap off and check the rotor in a few.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline beastie_3

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Re: Distributor problem?
« Reply #1 on: January 28, 2011, 04:12:02 pm »
Id suspect the cam gear/dizzy gear as well. Report back.

Offline 1979C20

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Re: Distributor problem?
« Reply #2 on: January 28, 2011, 04:27:27 pm »


My distributor gear is shot. ): so sad. Probably explains the slight drop in oil pressure, and the fluctuating idle. My dads friends got a distributor for me. I'm going to check the cam gear. hopefully its okay. Its a new comp cams, installed when I rebuilt the motor in May-ish.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline 1979C20

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Re: Distributor problem?
« Reply #3 on: January 28, 2011, 04:28:38 pm »
I can only assume the bushing in the bottom of the distributor is worn out, so the cam gear wore it down funny. I'm checking the cam gear now.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline VileZambonie

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Re: Distributor problem?
« Reply #4 on: January 28, 2011, 04:32:09 pm »
Is it a roller cam? Make sure you change the oil & filter too.
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Offline 1979C20

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Re: Distributor problem?
« Reply #5 on: January 28, 2011, 04:41:52 pm »
Honestly, idk the difference between cams. Its a comp cams 12-206-2.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline 1979C20

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Re: Distributor problem?
« Reply #6 on: March 15, 2011, 03:32:46 am »
Okay, I replaced the distributor with one I got from a family friend. Got about 300 more miles on it and its doin fine. Except, is it possible that the vac advance is ALWAYS on? My idle keeps on getting hogher and higher, and when I unplugged the vac advance and plugged the hose it dropped down to 600ish where I set it. As soon as I hook up the advance it goes up to 900. I hate it! And mythrottle is sticking, when I come to a stop I have to lift up my pedal to lower my idle or it sits at lije 1100.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Irish_Alley

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Re: Distributor problem?
« Reply #7 on: March 15, 2011, 08:48:19 am »
Did you take the throttle spring off.  maybe it needs to be adjusted
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

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Offline Grim 82

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Re: Distributor problem?
« Reply #8 on: March 15, 2011, 09:57:42 am »
If you are running full manifold vacuum to the distributor it can pull in a few more degrees of advance at idle, which would raise your rpm. Since you swapped the distributors, the one that's in it now might allow for more vacuum advance, which could explain why you notice the rpm difference.
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Offline 1979C20

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Re: Distributor problem?
« Reply #9 on: March 15, 2011, 03:51:35 pm »
It is full manifold vac, as I hear from this forum it should be. Irish, adjusted how? I put a new spring on a few weeks ago and it ran fine, then when I adjust the timing/idle the throttle no longer returns to the set screw.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF

Offline Irish_Alley

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Re: Distributor problem?
« Reply #10 on: March 15, 2011, 04:30:25 pm »
I was saying the spring maybe needs to be bent of just spray some wd40 on the linkage see what it does
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline 1979C20

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Re: Distributor problem?
« Reply #11 on: March 15, 2011, 05:23:47 pm »
I put some 3in1 on the linkage and the spring looks like its doing its job. If I lift up on the pedal or turn the throttle backwards, the idle drops down to where it should. I'm wondering if theres a bind? I lubed the throttle cable too.
1979 SCLB C20 Q-jet 350 SM465 14b F.F. 4.10 G80
1989 GMC Suburban V2500 TBI350 TH400 4in lift 35's 14b SF