Gas Grade Opinion Help....

[CaliDude76]

Hey Fellas, need your input on this one.. I trust and respect all your knowledge and info....

Seeings that I'm a college student on a serious budget.. I tend to run 87 Octane fuel in my square. Now lately it's been intermittently idling real rough.. chased all the vacuum lines I could.. adjusted timing... idle speed screw.. everything but the air/fuel mixture screws at the base... I don't like messing with those to much... not sure what the right combo for those are.

I'm running a stock q-jet m4me connected to a ecu brain in the dash...

every so often I buy a STP fuel system treatment.... but rarely run 89-92 octane... (a bit costly for me..), and is there something better I could use?
I just bought some LUCAS fuel system stuff, that the parts store guy recommended.. so I'll give that a few days.

In your alls opinion.. should I run a tank or two of the good Chevron (92) stuff, to boost the steadiness and performance in the carb... or does that make a difference... and am I looking at a carb re-build?.. because I know it use to idle real nice... and purdy like... can't seem to shake what the problem is.

Here's a pix of my carb....in all her vacuum glory! LOL

What exactly is the screw adjustment right ot the top facing up in front of my primary ports?

A BIG THANKS IN ADVANCE FELLAS!!!!!!

-CALIDUDE

 

[89Suburban]

It should idle the same on any octane. Something else is going on. Check your plugs, cap and rotor for buildup on the electrodes first buddy.

 

[HotRodPC]

I don't have time to read all this, as I am running out the door, but one thing I can tell you, is you can not get good gas in CA. Its all diluted with ethanol, alcohol, methanol etc etc. This is due to the tough emissions standards. You basically need to get your vehicle flex fuel capable. I have seen some carb kits that are now adveritesed for E85 Safe, Ethanol approved etc. Check into that and I'll be back later.

 

[Irishman999]

You mean this?

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If that is what you are referring too it looks like the linkage that keeps the secondary flaps (I think they are called air valves) from opening when the choke is on. The air mixture screws are actually encased in the base plate. To get to them you have to drill a couple holes and knock the plugs out with a hammer and punch, once exposed there is a special adjusting tool that fits the idle mixture screws. If you feel like giving the rebuild a shot let me know and I will explain the bit I learned from doing mine twice.

 

[HotRodPC]

Lets see if the Lucas does any good for you Calidude. I personally would have tried Sea Foam first, but Lucas is supposedly a good product too.

 

[CaliDude76]

You mean this?

You must be registered for see images attach

If that is what you are referring too it looks like the linkage that keeps the secondary flaps (I think they are called air valves) from opening when the choke is on. The air mixture screws are actually encased in the base plate. To get to them you have to drill a couple holes and knock the plugs out with a hammer and punch, once exposed there is a special adjusting tool that fits the idle mixture screws. If you feel like giving the rebuild a shot let me know and I will explain the bit I learned from doing mine twice.

No.. it's above that..in that picture you can see the choke flap is open, on my primaries... its that little deal right in front of them... if you were standing directly in front of the truck... there's a screw in there...and the screwhead is facing directly upwards.... wish i could do that red circle thing you did.. how do you do that?

 

[Irishman999]

No.. it's above that..in that picture you can see the choke flap is open, on my primaries... its that little deal right in front of them... if you were standing directly in front of the truck... there's a screw in there...and the screwhead is facing directly upwards.... wish i could do that red circle thing you did.. how do you do that?

I use paint for the circles since its a simple program and I can do it quick.

 

[Irishman999]

I see what your talking about, no clue man. My Q-jet did not have one.

 

[CaliDude76]

[QUOTE If you feel like giving the rebuild a shot let me know and I will explain the bit I learned from doing mine twice.[/QUOTE]

I appreciate the offer to help, Hopefully I might not have to, I know this carb was put on when it was new.. like 10 years ago
I'm not sure the lifespan on these bad-boys.. I know accelarator pumps... floats, jets, all those inner workings get worn, and no matter what you do.. they just don't run right... so we'll see

 

[HotRodPC]

Not sure why my mind works like it does, but after going to be last night, I got this thought in my head, Have you cleaned your EGR lately??? I know you have one being in Cali. Sometimes they get carbon nasty build up and they can shut off completely causing a gradually ugly idle that will get worse and worse as you described here. Take that dude off and clean it up and put it back on. Just a thought and sure not a waste of time if its not been off in awhile.

 

[89Suburban]

Not sure why my mind works like it does, but after going to be last night, I got this thought in my head, Have you cleaned your EGR lately??? I know you have one being in Cali. Sometimes they get carbon nasty build up and they can shut off completely causing a gradually ugly idle that will get worse and worse as you described here. Take that dude off and clean it up and put it back on. Just a thought and sure not a waste of time if its not been off in awhile.

Yes, Caliduder, check the simple stupid things first. cap/rotor, plugs, egr, pcv, etc.

 

[HotRodPC]

He may have checked all that already, but the EGR is the most overlooked problem for poor idle condition, and sometimes why I check it it first cuz it can't hurt to take it off and clean it.

 

[CaliDude76]

Yes, Caliduder, check the simple stupid things first. cap/rotor, plugs, egr, pcv, etc.

John.. YOU ROCK!!!!!
Thanks for helping me figure out how to work that program!!

Didn't even realize I hade that in my PC

This is one of the screws i was asking about:

 

[CaliDude76]

He may have checked all that already, but the EGR is the most overlooked problem for poor idle condition, and sometimes why I check it it first cuz it can't hurt to take it off and clean it.

Thats a good idea!! Never thought about that...
funny thing is.. my smog guy told me he had to do what he had to... in order for my truck to pass, just recently
Got my truck back.. and it was still idling real twitchy... he told me it has to be either vacuum, or adjustments to get it all the way right... but h e didn't have the time to go fully into it... said he would do it for 150 bucks plus...

I bet he knows exactly what it is.. and probably an easy 10 minute fix...
I wish I knew more about adjusting on these things.....

 

[89Suburban]