Having some trouble with Orange Crush.

[scitzz]

So, it is over here right now. It is a 1988 carby car. Motoxpress popped in a new engine out of a late, 91 or 93 a few weeks ago, then it came over here for a while with his son.

It developed a problem. It won't rev over 4500 RPM, and trying to climb a hill, it bucks and almost stalls. Pretty much not in any shape to drive.

First, we compared vacuum routings to another known good carby, and replaced all broken parts, and routed all the vacuum lines. One cylinder, number 2, appeared to be a little dead. Soaked it in PB blaster overnight, and now it seems to be firing again. Compression test looks pretty much 190-200 PSI across the board. Vacuum test shows it about 18 inches, with a slight fluctuation to 19 in a slow pattern. Appears OK in all other situations. New plugs, wires, and known good disty swapped in. Spark is bright blue/white at number one wire. Swapped in another known good coil for S&G's, same problem. Exhaust smells heavy of fuel, according to Zachary, I have to trust his nose, mine is clogged due to allergies. Holds idle at 650, and doesn't appear to be fouling plugs.

Thoughts?

[rmoltis]

By the title of the thread I thought this was going to be about orange crush the soda.

[TominMO]

By the title of the thread I thought this was going to be about orange crush the soda.

Yes, he might be addicted to it....

Let's see, fuel, spark, timing, air.
Air is never an issue really, so
Spark: sounds like you have a healthy ignition system, from what you described.
Timing: possibly the timing belt jumped a tooth? That could account both for unburned fuel and poor revving, since both valve and ignition timing would be affected.
Fuel: still could be a carb issue, but I'd check cam timing first.

[scitzz]

Kartracer called today, so I hit him up about it, he thinks diaphragm.

[FestYboy]

diaphram is only good for initial throttle tip in....

look at your secondary circuit and make sure that cat isn;t clogged (if its still there).

pull the air can lid, with the engine running, manualy open the secondary, you should see the venturi get wet with fuel, if you don't, you have a clog.

easy to fix: remove 14mm bolt from bowl (one closest to the head). with a #3 flat tip screw driver, remove the jet and clean it out. blow air into the venturi to clean out the feed tube.

[scitzz]

Will check in the AM! Thanks for the textual reminder

[scitzz]

It has been a very long time since I worked on anything that had a carb. Last time, it took me ten minutes to remember how to adjust the fuel air mix on a chevy small block CA 1982

[WmWatt]

Try spraying in some carb cleaner. Instructions printed on label on can.
Since you have a vacuum guage you can use it to check for clogged exhaust. See "vaccum diagnosing' thread at top of this repair forum home page.

[scitzz]

Try spraying in some carb cleaner. Instructions printed on label on can.
Since you have a vacuum guage you can use it to check for clogged exhaust. See "vaccum diagnosing' thread at top of this repair forum home page.

Vacuum test shows it about 18 inches, with a slight fluctuation to 19 in a slow pattern. Appears OK in all other situations.

Exhaust Back Pressure

Starting with the engine at idle, slowly increase engine speed to 3,000 RPM, engine vacuum should be equal to or higher than idle vacuum at 3,000 RPM. If vacuum decreases at higher engine RPM's, an excessive exhaust back pressure is probably present.

Passes that test. Also, today, for S&G's, I had him loosen the cat itself, and the O2 sensor, sort of relieve pressure there, still did the same thing.

I can get the secondary circuit to actuate by opening the throttle body in the secondary. Gushed gas pretty well. However, no matter how high it is revved, it does not kick in the secondary on it's own. Is that an issue?

[Pu241]

I can get the secondary circuit to actuate by opening the throttle body in the secondary. Gushed gas pretty well. However, no matter how high it is revved, it does not kick in the secondary on it's own. Is that an issue?

Wondering about the accelerator pump.
Or as Graywolf200's carbie was diagnosed by Karteacer46, worn seals around the butterfly valve rods, leaking air into the engine.

[nitrofarm]

It has been a very long time since I worked on anything that had a carb. Last time, it took me ten minutes to remember how to adjust the fuel air mix on a chevy small block CA 1982

These aren't a Carbs,they are over engineered abortions. Carbs are fun these things are crazy stupid with vacuum hose's.Thank God they only came on one year of the Festy.
Scitzz, you are telling us the fella smells raw fuel. Rule of thumb with anything carb if its rich. Check needle and seat,sticking float,and make sure your idle air bleed passages are clear. Where these are on these carbs is anyone's guess. I couldn't find a rebuild manual for mine.So I never even bothered with it.

[nitrofarm]

Wondering about the accelerator pump.
Or as Graywolf200's carbie was diagnosed by Karteacer46, worn seals around the butterfly valve rods, leaking air into the engine.

Air Leaks = Lean, sounds like its running so fat that it cant even make power.

[Pu241]

.....Thank John they only came on one year of the Festy.

Actually two years, all '88's and '89 manuals ('89 EFI were ATX).

[FestYboy]

I can get the secondary circuit to actuate by opening the throttle body in the secondary. Gushed gas pretty well. However, no matter how high it is revved, it does not kick in the secondary on it's own. Is that an issue?

the secondary is actuated via a vaccum diaphram (located on the left front of the carb). it is a load based system and usually comes in after 3000 rpm (Scrappy wakes up just before 4k). if there is a loss of signal to the actuator, the secondary won't move (there is no mechanical means to make the secondary to move, and i wouldn't recomend making a linkage to do so, i tried it, it gets wonky.

[zoe60]

A feedback carb needs a good o2 sensor to operate properly. Mine was real bad when I got it. May be a different symptom but my '89 would buck especially bad when first hitting the gas in 2nd gear. Would also stumble while driving at a steady speed. Exhaust smelled awful too.