Matt1821

My buddy bought an 87 trans am not too long ago and it was having hesitation problems. He told me that when he hit the gas it would bog down and then as it got up to speed it "shi t n gits". So he took the carb off and messed with different things and couldn't figure it out, he also doesn't make much so he couldn't afford to fix it. We recently swapped cars. I traded my 89 firebird 305 TBI for his 87 TRANS AM 350 carb'd. I put the carb back on but its spurting fuel everywhere when I start it. I don't know much about carbs but I know a little. I have another carb I got for free with the car and I put that one on but then it just ran horribly. Also accidently started on fire. I don't know where to start, any and all advice would be appreciated, thanks. -Tank

Matt1821

Fuel sprays out of this hole on the bottom of the carb. Looks broken so I think il have to use the other carb. But its different than this one, and has less electrical connections on it.

Matt1821

First two are pics of the carb that was on it when he got it. Last one is the other carb I got for free.

Matt1821

More pics of the other carb and one of the motor... This set up doesn't seem stock at all, there are hoses and clamps everywhere. Many Vacuum lines and diverter valves, just doesn't seem right to me.

KrisW

iTrader: (5)

Just out of curiosity, what is the VIN of your car, for the engine? 87 was available with a carb, but I am wondering if it got swapped on there.

A 350 car would have been VIN code 8, and it would have been TPI. The VIN code F would have been 305 TPI and VIN code G, I think, is for the carb 305.

Regardless, you start with the Quadrajet book. Go to the auto parts store, its there with all the repair manuals. Its for GM carburetors, and usually has a Quadrajet on the front. Also, your 82-92 Firebird manual has a carb section too. Pick up a rebuild kit, and rebuild it the way the book says. I'm talking about the CC Quadrajet, not the mechanical one.

KrisW

iTrader: (5)

Its vin code H for the 305 carb car. Sorry about that!

Depending what the number is off of the carb, to buy the right one outright it will be over 400 bucks. You can send it to a carb shop and get it professionally done, or do it yourself. Around here we are all about do it yourself.

Go through the stickies in the carb section here and follow the book. You'll be fine and it will run great!

naf

iTrader: (7)

It's leaking where the idle mixture screw is. The screw is either super loose or missing. Get a double d driver and check it. Set it (and the other one) at 4 turns out from seated and see how it does. If it's missing, let me know and I can send you one.

Peruse:

https://www.thirdgen.org/forums/carb...-ccc-qjet.html

Swapping to the mechanical will require swapping the dist as well.

Let us know what you find and we can help from there.

Matt1821

Where can I find a double d driver? It looks like there's something on there just can't see it very well. Thanks for the help and support guys.

Matt1821

VIN gf2fw21h9hn241423

travis401

iTrader: (1)

thats a vin code of h, meaning it was a 305 with the cc quad. the cc carb setup was probably the stock on and they just swapped the 305 for a 350 (if its a 350 at all that is) the stock CCquad will work fine on top of the 350, with a little tunnibg, it looks like its not a bad setup, but just needs a little reworking. fuel squirting on a hot engine is just asking for a fire as youre found out first had. id get that taken care of before attempting to dirve this thing again.

Matt1821

Would I just check the block to see if its a legit 350 or what?

89rs454

Check the block numbers and get back. Who would trade a 350 for a 305tbi?

travis401

iTrader: (1)

the block casting numbers that are important on behind the drivers side head on the flange where the trans bolts to. that will tell you if its a 305 or 350 block. wont tell you much else of importance though (like whats in it).

it might be hard to get to the casting numbers, but not impossible. a mirror and light work wonders in hard to reach areas.

KrisW

iTrader: (5)

It doesn't matter what size the engine is. Right now, you need to fix your carburetor. A burnt engine of any size is junk.

Take your computer Quadrajet back off the engine, tear it apart, and fix it. Start at the place where it was leaking fuel.

As I was going through the stickies in the carb forum, every instruction you possibly need is there. Go slow, follow the instructions, rebuild it, and re-install it. After you are running, then we can get to the rest of the engine!

Good luck, man!

Matt1821

The engine didn't start on fire, I put the other carb on and fuel sprayed on a vacuum line and cought fire, that situation has been resolved. New vacuum lines and I put the stock carb back on. It was just rebuilt, that's why it was off when I got it. But as for the fuel spraying out, its coming out of a hole in the bottom, I believe its the idler screw. But its not a flat head screw its just a square looking metal piece. Nothing I own can turn it, and I have a lot of tools.

KrisW

iTrader: (5)

I think you need to take the carb off and rebuild it again. You may not have to replace anything at all. If it was recently rebuilt, all the gaskets and seals may be just fine.

This problem with the idler screw has a problem in more than one way.

First off, fuel should never come out of there. That screw controls an air bleed, not a fuel passage. By adjusting those air bleeds you can lean out or enrich the idle mixture as necessary. Backing it all the way out should still not allow fuel to come out. That carburetor may have been rebuilt improperly.

Second, you need to get a good look at what you're dealing with. Taking the carb off and bringing it into the garage is easy. When you get the messed up screw out, you'll be able to see if the throttle body has been damaged in any way or if it is just the setscrew. Either way, you have a parts carburetor that you can probably use to supply the throttle body or the screws you need.

naf

iTrader: (7)

Those are the idle mixture screws. They control the amount of fuel that is allowed into the idle circuits. The air bleed is the large, flat blade screw on top, in the center.

You probably won't be able to swap them out with the idle mixture screws on the other carb. They should be different thread pitches. I'm not certain ALL are different, but the ones I've looked at were.

You can pick up the tool needed at AZ or one of the others. Listed as a carb tuning tool or some such. Mine has a plastic handle with a cap that contains a few different bits and a flexible shaft. Last I saw one it was like $8.

Matt1821

My number one question is because the hole is broken at the bottom does that present a problem or is it still usable? It looks like theres supposed to be something there as there is a perfect circle around the hole that's worn into the metal.

naf

iTrader: (7)

The factory installs plugs to prevent tampering with the mixture screws. They need to be cut out when doing a rebuild in order to access the screws. This should not be a problem, although it is possible that whoever cut into it, cut too far/too much.

Fix that fuel line too.

Matt1821

Witch fuel line

naf

iTrader: (7)

The one that's cobbled together from several pieces/parts and feeds your carburetor.

Matt1821

Ya, I kinda gotta focus on one problem at a time right now. I'm hoping to get this thing tip top, running, and painted by Dec. For a Vegas run. I have enough money to pull it off just need some help with the carb and a couple things here and there. I liked my 305 TBI, nice and simple... I know its possible to get it done by then, with some help from you guys it should turn out nice. Thanks everyone.

Matt1821

oh and I'm gonna pick up that carb tuning tool tomorrow. hopefully I can fix it tomorrow, the sooner the better, I've got a lot of work to do

Matt1821

Picked up the tool, you said tighten it up all the way and loosen 4 turns? Full turns, 1/2, or 1/4 turns? And what about the screw on the top of the carb, where should that be positioned? Also some of these vacuum lines, I'm not sure where all of them go, a couple are no brainers, but some are more confusing.

naf

iTrader: (7)

4 full turns out on both. Make sure they're the same. The top screw is set with a dwell meter connected to the diagnostic lead near the blower motor. If you don't have one now, see where it's at by counting the number of turns to seat then post back. They're normally around 3-4 turns out on the stock 305.

Matt1821

Sorry I haven't posted back in a while, been working long hours due to the holiday coming up, and haven't had time. I adjusted all the meeting screws to what you said and the carb just spits fuel out of the hole to the left of the driver side adjusting screw and the top. Runs rough and idles low. Still trying to figure it out, I was at autozone last night for a part for my buddys jeep and started looking at the haynes manual for tips. I have the chilton but it isn't much help. Any ideas?

Matt1821

I've been trying to tune this carb all day, I put it back to the way you told me NAF but when I give it gas I get a mean back fire that almost blew my face off as well as blowing my ear drum... It wasn't a good time for me seeing as my girlfriend was outside watching me work on my car. (she thinks I'm dead sexy) Haha

travis401

iTrader: (1)

if youre getting a backfire, its either running way lean, or the timing is off.

Matt1821

Too little air or fuel?

travis401

iTrader: (1)

lean = not enough fuel. rich = too much fuel. id check/reset the timing just to be sure

Matt1821

Set it to 0*? Or Advanced?

travis401

iTrader: (1)

i can remember if the 305 tbi gets set at 0 or 6*, but i think its 0. either way you need to disconnect the esc when setting the timing.

travis401

iTrader: (1)

o wait, this is a cc carb, ill see if i can find the timing setting for it.

travis401

iTrader: (1)

from what i can find, the cc carb is set at 6*

naf

iTrader: (7)

If you're comfortable setting the timing, check to see where it's at now before dickering with it. Check it with the four wire plug to the side of the distributor disconnected and it should be between zero and four. With it re-connected the timing should be around twenty or so and should increase when the engine is revved. It may be hard to get it to idle with the wire disconnected but you need to have it idling below 1000 (and preferably nearer 800) when timing it.

If the carb is leaking out the top and at the idle mixture screw opening, it's time to take it off, open it and see what's wrong.

Matt1821

It no longer leaks fuel from anywhere. But the car idles around 3 or 4 hundred rpms (digital gauges) not so accurate. Still gives me a good back fire occasionally when revved, so I'm still trying to figure that out, I won't be able to get a timing light till possibly tomorrow.

travis401

iTrader: (1)

sounds like the timing is retarded too much, try bumping it up a tad and see if that helps anything.

travis401

iTrader: (1)

turning the distributor clockwise advances and counter clockwise retards, just in case you didnt know

Matt1821

Ha I know, but thanks. I know a lot about cars, I have 5 ase cert's and my associates degree in automotive. I just don't know much about carbs. Just goes to show know matter how much you pay for an education there's always more to learn.

travis401

iTrader: (1)

yea, if the idle speed is low and its back firing, it most likely just not advanced enough. keep advancing it until the idle speed get about 800rpm, then see if its still backfiring.

naf

iTrader: (7)

Make sure the ignition system is up to snuff. If the cap/rotor/plugs/wires have not been replaced I'd do it now. These are routine, tune-up replacement items. A mis-fire can cause your backfiring. It's unlikely the timing is off unless someone's been dickering with it.

Matt1821

Thanks guys, I planned on replacing all that anyway, I guess now is as good a time as any. I was wondering though, the ses light is on but my code reader won't work on this car, why? It worked fine with my 89 firebird, but I tried using it on this one n the light just stayed lit, didn't blink like it should...

naf

iTrader: (7)

Make sure you've got power to the ECM. It receives 12volt directly from the positive cable via a smaller (red?) wire that splits off through a fusible link and runs along the right inner fenderwell into the ECM harness. You should also check the ENG Controls fuse under the dash. This provides power to all of the thingies that the ECM commands (the ECM provides the grounds to complete the circuits).

A quick check is to verify that the Mixture Control Solenoid (MCS) inside the carburetor is clicking (10 times a second) when the key is turned to run. If it is, then everything above is good. If that's the case check the ground at the ALDL. I've heard tales that it can be bad and fail to read although I've never experienced it myself.

Matt1821

Just lettin everyone know, I tuned the carb and fixed the timing. The timing marks were gone so I basically did it by ear, but it runs pretty well considering. thanks for all the help and I'm sure il need more advice in the future so keep in touch. Haha

Thanks,
Tank