Think I screwed something up

[OPELFIEND]

My 73 GT has been running great for some time, but I have had an intermittent problem with something sticking in the carb, making the engine rpm to go as high as 4000. No rhyme or reason to it as far as when it occurs. Car may be fine for when first started and after driving for a while, or it may do it when it first fires up. I punch the gas pedal and it goes back to 1000 rpm.

It started when the accelerator linkage came out because the grommet at the firewall had disintegrated. I replaced the grommet, but it continued to do this. Anyway, I got under the hood to tighten the fan belt, which I did, and then decided to look at the carb. I adjusted the idle and was messing around with the screw behind the choke. Now the car backfires and will barely start. It didn't do this before I messed with it.

I may have done something while tightening the fan belt, but I dont see anything. The tach goes ballistic, no power, flame shoots out the carb, etc. The alternator is less than two years old and came from OGTS. There is a black wire not connected to anything on the back, I really don't know if I pulled it out of a connection or not. Dont know if I screwed up the carb or pulled a wire loose to be honest. Any help would be appreciated.

[traytodd]

First thing we need to know is what kind of carb is it? Weber or Solex? If it is a Weber, there are tuning instructions on REDLINE - Serving the U.S., Canada, Central and South America for over 30 years
If it is a Solex, you need to see the GT factory service manual for adjustments. Is it a water choke or an electric? If electric, is the wire attached?

Is the carb tightly screwed down to the manifold (no vacuum leaks around the gaskets)? Are all the hoses hooked up? Does the choke set properly (close) with a cold engine and a actuated linkage? If you open the choke by hand, is the throttle plate closed?

Tightening the fan belt would have nothing to do with this problem unless the distributor was loose and you moved it. Is it tight? If not it will need to be retimed.

Can you photograph the alternator connector and show us what wires are there?

It is impossible to diagnose problems without more information.

[OPELFIEND]

It is a weber carb. About 3 years old. The choke is electric, and the wire is attached. The reason I mention tightening the fan belt is that I may have pulled something loose. The wire is on the back of alternator and is attached to the terminal closest to the engine. It is a short black wire, if anything it would have to be attached to something very close. The other connection back there is fine. The distributor is tight; I didn't move it. Choke was open. Drove the damn thing home 1 hour before, no problem other than a loose fan belt.

[George]

The black wire could be the one that went to the capacitor that keeps the engine noise out of the radio.If it is the capacitor wire it should have nothing to do with the problems you are having unless it is shorting out.

[Opelmn70]

Did you move the distributor by accident while tighting the alternator? Sounds like timing more than carb linkage or adjustment. Where is the vacuum advance bell positioned(back of the distributor) How about the vacuum hose connections? You could have moved the bell when you tightened the nut on the back end of the distrib. Check the bolt tighten down the distrib for looseness.
Gerry

[ungermm]

My 73 GT has been running great for some time, but I have had an intermitant problem with something sticking in the carb, making the engine rpm to go as high as 4000.

Look at the linkage behind the carb. Make sure nothing is limiting or binding its movement.

The alternator is less than two years old and came from OGTS. There is a black wire not connected to anything on the back, I really don't know if I pulled it out of a connection or not. Dont know if I screwed up the carb or pulled a wire loose to be honest.

Where on the back of the Alternator? Maybe a ground from the Alternator to the engine or the capacitor [resistor] wire. Maybe you just bumped the distributor out of timing.
Jerry

[OPELFIEND]

The distributor is tight, no way I could have moved it. I have looked around several times, do not see any lines pulled loose. The car will start, but runs rough and eventlually dies. I swear, it was running like a top before I got in there trying to see why the carb was sticking open like that. I did take off the electric choke wire, but put it back on. Could I have blown a fuse or something? I'm lost.

[yellaopelgt]

If you didnt loosen the bolt for the dizzy when tightening the belt, lets assume your timing was OK......this doesnt mean its NOT off though. Many times a poorly tuned carb is compensated with timing. Now, back to what you did with the carb,I think you may have adjusted the air/fuel mix a bit too far......that, and the choke isnt working correctly. I'd pull a spark plug out and check on its condition.(willing to bet its black from running too rich)
The only wires on a stock Opel alt is the 3 wire plug,the large (brown) ground wire, and the short black condenser/capacitor/RFI filter! [resistor]. I am assuming you have the stock configuration here.....So dont worry about the alt or timing at this point, go back to where the problem originated ,the carb. I've honestly never had an electric choke carb so I cant really help you set it,(others will probly chime in here)but thats where I would start after checking the plugs.Sounds like your running WAAAAY too rich and basically flooding out.
HTH
Joe

[newman27]

Just brainstorming here - but do you have one of those anti-dieseling solenoids installed? If so, is it's wire still connected? Maybe it has failed or is affecting the idle somehow.

Here is the link to the post I was thinking of: http://www.opelgt.com/forums/afterma...tml#post153804

[bear's GT]

Do you have points on the car. If you left the ignigtion on the points may be burnt.

[Bill Hoffmann]

The Weber on my GT did this occasionally as a result of the secondary throttle shaft sticking. The way the progressive linkage works, the primary shaft can return to idle position while the secondary is stuck open. One possible cause is some gunk or varnish on the shaft. Another is that the carb base is warped, and when tightened it makes the shaft bind. I would check to see that the secondary shaft moves freely and maybe shoot some WD-40 around it.

Bill

[traytodd]

I would start by checking the throttle linkage again for binding. Then check the throttle plate for binding. If the base of the carb is warped, then the throttle plate may be binding up. Next I would print the tuning instructions from Redline
CARBURETOR SET UP AND LEAN BEST IDLE ADJUSTMENT

and follow them. Setting the screw on the throttle linkage is critical for proper operation.

One other possibility I ran into on my Weber was a loose part in the float bowl that prevented the float from dropping. The car idled but ran the bowl dry above idle.

[tomking]

I believe you mentioned the tach went crazy? That can be an indication of a coil going bad.

[OPELFIEND]

Coil, points, plugs, alternator were replaced less than two years ago. Brand new carb put on 5/06. Weber 32/36 DGEV. It has about 8000 miles on it. It must be something I fiddled with on the carb. I screwed around with two things there: the idle speed screw and a screw directly behind the choke with a spring on it, I think it's the fast idle speed screw. The car did start today, but ran rough and eventually died. The tach appeared to be OK at that point. Don't see any vaccum lines loose. Likely something simple, I'm just to inexperienced to figure it out.

[dallasmanta]

Sounds like you need to re set the idle air mixture screw to full closed and then back it off 2.5 to 3.0 turns. This is a starting point to get the engine to run. Once you have the engine running. Follow the directions on the link in the earlier post that shows how to adjust and set the carb. Check you timing. Now look for any binding or sticking on the primary and secondary linkages to the carb. fix as needed. Use carb cleaner sprayed around any vacuum hose, carb base etc. Engine rpms will change if you have any leaks in any of the areas. Ron

[Anonymous D]

Achieving a correct Opel tune-up, is a deductive process. You need to eliminate possible sources of problems, to identify definite areas for repair.
You can refer to a download available at the link below, for more information:

http://www.opelclub.com/TuneUpPart1bJune2006.pdf

[OPELFIEND]

Thanks to everyone for their help on this. I really appreciate it. I'm learning as I go, and need all the help I can get.

[Tru-Craft]

Remember Murphy's law!
Maybe your problem has nothing to do with what you did.
I would do a routine tuneup also.
Check the points, condensor, cap, wires......
I was struggling with tuning my carb and the distributor cap was cracked causing all my problems.
I would also think about pertronics, it is cheap and it will make the ignition system trouble free.
Use carb cleaner on all the linkage, then WD-40 and some light oil.
Go back to basics and you will find the problem.
Lyle

[OPELFIEND]

Tru-craft, I believe you're right. I did all those thing regarding the carburetor and linkage, but the tach is going balistic. Must be something to do with the points or coil. I can see sparks around the condenser. No loose wires that I can find, so something is F'd up.

[namba209 (R.I.P.)]

Check the mounting screw on the condensor. If it's loose it will cause the ignition system to become erratic.