Too Lean or Too Rich? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Russell · 08-10-2004, 04:15 PM

Hey guys!

I finally got my truck running to the point where I can safely use it in the city, so long as everyone is going fast anyways, lol

Basically, if I get off nice and easy, the truck will die, but if I punch it, the truck will go like a bat outta hell from a red light. Before, it died wether I gave it lots or very little pedal, now it only does it if you go very easy on it. If I get off on it, it'll ping for a split second, then is good the rest of the way up, even when it is at it's peak RPMs just before shifting.

Am I idling too lean or something? My vac gauge tells me that my timing is too late, but if I advance it anymore, the thing runs poorer, and it pings something horrible, and I don't think I have a vac leak anywhere... I'm kinda confused becuase I was getting like 19 inches before, lol -- I'm only getting 15 inches right now...

Man I can't wait till I have a computer bothering with this stuff in a few weeks, lol

Destructo · 08-10-2004, 04:51 PM

I put a bad holley on a 305 once that had a poor intake seal and it would spin the tire when I hit it from a stop but ran way rich, but apprently the richness of the carb was able to compensate for the intake leaking, but I didn't have issues with it dying.

What kind of carb is it? Q-Jet?

Russell · 08-10-2004, 05:46 PM

Yeah, its a q-jet, I set my timing to where it should be at 12 degrees, have the screws at 2.5 out each, and the motor is at full temp. I spent like a can and a half of wd-40 searching for vac leaks, and I can assure you that this truck is NOT leaking vaccum.

Here is video of the truck, first is the poor, choppy idle, then me able to change the rpm of my engine by almost 500 rpm by simply closing the choke plate, then me revving my motor from inside, and the popping that it has when it spins down. Yeah, I know my heads are ticking something nasty, they have 250 000 hard km on them, but the bottom end of the motor has only about 30 000 km on it, I plan to pick up a roller shortblock, stroke it to a 383, and put a set of Vortecs on it, and if I can, sell my truck's shortblock to help pay for stuff.

http://www.zieglerdigital.ca/downloa...ketofbolts.wmv

MylilBowTie · 08-10-2004, 06:12 PM

Looks to me like the distributor isn't in right, looking at the video.

Russell · 08-10-2004, 06:16 PM

Shouldn't matter which way it is in, just so long as the pole lines up with the rotor correctly... I put it in that way last time so I could make my rather short dizzy vac line fit, lol, I have a longer one now, so it could be moved back, but it takes effort to move the dizzy around, lol

I've got about 75% of my fuel injection equipment here, just waiting on a few key components and I can drop this carb crap forever

**swervin ervin** · 08-10-2004, 07:43 PM

Back out on the idle mixture screws some more. You are running lean at idle. The screws are usually around 3 to 4 turns out. This should increase your vacuum. I doubt this will fix your dieing. Sounds like you have more problems besides the idle mixture screws. Might be a bad accelerator pump. With the engine off, look in the carb and open the throttle slowly. There should be two squirts of gas, one in each venturi. You need to fix the distributor also. I've never heard of anyone installing a distributor off on purpose because of a too short vacuum hose.

Russell · 08-10-2004, 08:08 PM

If it isn't the carb causing issues, then it is the intake that is causing me problems. The best vac I can get outta the poor thing is about 16 inches, and thats with the mixture screws pretty much taken straight out, less like one turn. I used to be able to pull 19 - 20 inches out of it easy, well within the green zone, now its almost down to the vac gauge saying I have late valve timing, while I know they arn't in the best of shape, they worked fine beforehand.

76HighSierra · 08-10-2004, 09:40 PM

Russell, in the video, your RPM rises when you close the choke. That is a sure sign of two things:

(1) A vacuum leak.
(2) Lean running condition.

Destructo · 08-10-2004, 10:35 PM

yep, lean at idle for sure.

I have tried hair spray, carb cleaner and all that stuff and haven't ever had it work but when I removed the intake and installed new gaskets it ran better. I'v never heard of wd-40 working but I still bet you have a vacuum leak, I never could get those tricks to work so I just started replacing stuff haha. I don't have this truck anymore, never got the engine running at its best before I sold it. This 350 though my 85 K10 with a holley runs much better than the Q-Jet I had crappily rebuilt.

76HighSierra · 08-10-2004, 10:43 PM

Man, a quadrajet is so simple to rebuild. Take some time and read some articles. Russell, you shouldn't throw away your carburetion setup just for FI. I don't mean to be a downer, but I think you're going to be disappointed with FI. If you think you're having probs with your carb system, wait until you start mapping an un-tried EFI system. Again, I don't want to bring you down. Good luck!!

**swervin ervin** · 08-10-2004, 11:02 PM

Quote:

Originally Posted by 76HighSierra

If you think you're having probs with your carb system, wait until you start mapping an un-tried EFI system. Again, I don't want to bring you down. Good luck!!

This is what I was thinking but didn't want to sound like a party pooper. If the Q-jet is giving you fits, you'll beat your brains out trying to get all the bugs out of FI. When you are having problems with this stuff, it costs a ton to replace parts until it's fixed.

Russell · 08-11-2004, 12:23 AM

My #1 problem with this setup is that I am NOT willing to put money into my carb, if I was willing to, I'd change my intake gaskets, and buy a new Edelbrock / Holley / reman Q-Jet or something. I'm already waist deep into the EFI, and I ain't stopping now... With the EFI, I am putting new parts into it, such as new injectors, new computer, new relays, new sensors where required etc. I'm very confident with wiring, so I'm not worried about it in the slighest bit. Unless one of my injectors is defective or something, I can test all of my sensors relays etc. But yeah, if I were to go and spend some money on a carb, I'd be just fine tuning it up, but I have been trying to build one good carb out of half a dozen old peices of crap. I'm not quite as incompetant as it may look, lol

76HighSierra · 08-11-2004, 12:26 AM

Quote:

Originally Posted by Russell

My #1 problem with this setup is that I am NOT willing to put money into my carb, if I was willing to, I'd change my intake gaskets, and buy a new Edelbrock / Holley / reman Q-Jet or something. I'm already waist deep into the EFI, and I ain't stopping now...

Gotta respect a man who sticks to his convictions.

Russell · 08-11-2004, 12:33 AM

Edited my above message :P

I guess that what I am very quickly finding trying to red neck this carb stuff is exactly what Swerve's thinger say "you get what you pay for" and I'm definitly paying for this EFI :P

I did some more fiddling with it tonight, and I've got it running nice in the high range now, just idles real rough, sounds like a rediculously large cam, lol

I got revved at like 8 times tonight...

08-10-2004, 04:51 PM	#2
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	I put a bad holley on a 305 once that had a poor intake seal and it would spin the tire when I hit it from a stop but ran way rich, but apprently the richness of the carb was able to compensate for the intake leaking, but I didn't have issues with it dying. What kind of carb is it? Q-Jet? __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

08-10-2004, 05:46 PM	#3
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Yeah, its a q-jet, I set my timing to where it should be at 12 degrees, have the screws at 2.5 out each, and the motor is at full temp. I spent like a can and a half of wd-40 searching for vac leaks, and I can assure you that this truck is NOT leaking vaccum. Here is video of the truck, first is the poor, choppy idle, then me able to change the rpm of my engine by almost 500 rpm by simply closing the choke plate, then me revving my motor from inside, and the popping that it has when it spins down. Yeah, I know my heads are ticking something nasty, they have 250 000 hard km on them, but the bottom end of the motor has only about 30 000 km on it, I plan to pick up a roller shortblock, stroke it to a 383, and put a set of Vortecs on it, and if I can, sell my truck's shortblock to help pay for stuff. http://www.zieglerdigital.ca/downloa...ketofbolts.wmv __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

08-10-2004, 06:12 PM	#4
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Looks to me like the distributor isn't in right, looking at the video. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

08-10-2004, 06:16 PM	#5
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Shouldn't matter which way it is in, just so long as the pole lines up with the rotor correctly... I put it in that way last time so I could make my rather short dizzy vac line fit, lol, I have a longer one now, so it could be moved back, but it takes effort to move the dizzy around, lol I've got about 75% of my fuel injection equipment here, just waiting on a few key components and I can drop this carb crap forever __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap) Last edited by Russell; 08-10-2004 at 06:18 PM.

08-10-2004, 07:43 PM	#6
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	Back out on the idle mixture screws some more. You are running lean at idle. The screws are usually around 3 to 4 turns out. This should increase your vacuum. I doubt this will fix your dieing. Sounds like you have more problems besides the idle mixture screws. Might be a bad accelerator pump. With the engine off, look in the carb and open the throttle slowly. There should be two squirts of gas, one in each venturi. You need to fix the distributor also. I've never heard of anyone installing a distributor off on purpose because of a too short vacuum hose. __________________ Mike 1985 Chevy C-10

08-10-2004, 04:15 PM	#1
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Too Lean or Too Rich? Hey guys! I finally got my truck running to the point where I can safely use it in the city, so long as everyone is going fast anyways, lol Basically, if I get off nice and easy, the truck will die, but if I punch it, the truck will go like a bat outta hell from a red light. Before, it died wether I gave it lots or very little pedal, now it only does it if you go very easy on it. If I get off on it, it'll ping for a split second, then is good the rest of the way up, even when it is at it's peak RPMs just before shifting. Am I idling too lean or something? My vac gauge tells me that my timing is too late, but if I advance it anymore, the thing runs poorer, and it pings something horrible, and I don't think I have a vac leak anywhere... I'm kinda confused becuase I was getting like 19 inches before, lol -- I'm only getting 15 inches right now... Man I can't wait till I have a computer bothering with this stuff in a few weeks, lol __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap) Last edited by Russell; 08-10-2004 at 04:25 PM.

08-10-2004, 08:08 PM	#7
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	If it isn't the carb causing issues, then it is the intake that is causing me problems. The best vac I can get outta the poor thing is about 16 inches, and thats with the mixture screws pretty much taken straight out, less like one turn. I used to be able to pull 19 - 20 inches out of it easy, well within the green zone, now its almost down to the vac gauge saying I have late valve timing, while I know they arn't in the best of shape, they worked fine beforehand. __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap)

08-10-2004, 09:40 PM	#8
76HighSierra DAMN, I love Big Blocks! Join Date: Aug 2003 Location: New Mexico, USA Posts: 619	Russell, in the video, your RPM rises when you close the choke. That is a sure sign of two things: (1) A vacuum leak. (2) Lean running condition. __________________ Marc Bona Hobbs, New Mexico 1976 1/2 ton GMC High Sierra. 454 c.i.d./ TH400. *Soon to get a mild warming over.* 3.40 rear.

08-10-2004, 10:35 PM	#9
Destructo Registered User Join Date: Sep 2003 Location: Lewisville, NC Posts: 1,836	yep, lean at idle for sure. I have tried hair spray, carb cleaner and all that stuff and haven't ever had it work but when I removed the intake and installed new gaskets it ran better. I'v never heard of wd-40 working but I still bet you have a vacuum leak, I never could get those tricks to work so I just started replacing stuff haha. I don't have this truck anymore, never got the engine running at its best before I sold it. This 350 though my 85 K10 with a holley runs much better than the Q-Jet I had crappily rebuilt. __________________ 1985 Scottsdale Shortbed 4x4 Stout 350 with some "upgrades"-700r4-33x12.5" Mud Tires, Warn 8274-50 winch. 2005 Chevrolet Colorado Regular Cab 2wd 4-banger, 5 speed, Street Pack with 3.73 axle.

08-10-2004, 10:43 PM	#10
76HighSierra DAMN, I love Big Blocks! Join Date: Aug 2003 Location: New Mexico, USA Posts: 619	Man, a quadrajet is so simple to rebuild. Take some time and read some articles. Russell, you shouldn't throw away your carburetion setup just for FI. I don't mean to be a downer, but I think you're going to be disappointed with FI. If you think you're having probs with your carb system, wait until you start mapping an un-tried EFI system. Again, I don't want to bring you down. Good luck!! __________________ Marc Bona Hobbs, New Mexico 1976 1/2 ton GMC High Sierra. 454 c.i.d./ TH400. *Soon to get a mild warming over.* 3.40 rear.

08-11-2004, 12:23 AM	#12
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	My #1 problem with this setup is that I am NOT willing to put money into my carb, if I was willing to, I'd change my intake gaskets, and buy a new Edelbrock / Holley / reman Q-Jet or something. I'm already waist deep into the EFI, and I ain't stopping now... With the EFI, I am putting new parts into it, such as new injectors, new computer, new relays, new sensors where required etc. I'm very confident with wiring, so I'm not worried about it in the slighest bit. Unless one of my injectors is defective or something, I can test all of my sensors relays etc. But yeah, if I were to go and spend some money on a carb, I'd be just fine tuning it up, but I have been trying to build one good carb out of half a dozen old peices of crap. I'm not quite as incompetant as it may look, lol __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap) Last edited by Russell; 08-11-2004 at 12:33 AM.

08-11-2004, 12:33 AM	#14
Russell Professional Grade Join Date: May 2003 Location: Fort McMurray, Alberta Posts: 7,915	Edited my above message :P I guess that what I am very quickly finding trying to red neck this carb stuff is exactly what Swerve's thinger say "you get what you pay for" and I'm definitly paying for this EFI :P I did some more fiddling with it tonight, and I've got it running nice in the high range now, just idles real rough, sounds like a rediculously large cam, lol I got revved at like 8 times tonight... __________________ 1995 Chevrolet 2 Door Tahoe (6.6L LBZ Duramax / ZF6 / NP241 with 1 ton solid axle swap) Last edited by Russell; 08-11-2004 at 12:41 AM.

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