After having a cruddy day at I work I went out for some much needed 914 therapy. Car was running beautifully (I just changed oil on saturday - castrol 20w50), temps came up to normal, oil pressure normal. I'm heading back to my house (after about 45 minutes of driving) and come to a stoplight. The car slows down but the RPMs go up to 4.5k and hold. It was dark so I couldn't see if the carpet had jammed up under the accel pedal. I fiddle w/ the carpet, try to blip the throttle to see if it is stuck. Something must have worked because just as the light turned green, RPMs came back down to normal idle, but now the engine was running really rough. I'm about 1/4 mile from home, so I ease it into gear and slowly head home. In my driveway, I leave the car running and check to see that the throttle return is working (it is). Idle RPM is normal, but very rough. Engine is 2.0L w/weber 44s & Petronix.

As it was dark and late, I couldn't see very much. A quick search of the forum took me to some posts about problems w/aftermarket accel pedals and cables getting bound up. I'm inclined to think it isn't a problem in the center tunnel (it was running perfectly), but maybe the carpet, or something in the engine bay? I'm not sure where to start or what to look for. Pedals are all stock. Clutch still works fine as far as I could tell. Any advice? Suggestions? I am at the mercy of the Gurus

Look for vacuum leaks. That's where I'd start. Check over the ignition system, too.

--DD

I had a look at the engine and carbs this afternoon. I did notice that on the passenger side carb, there appears to be an adjustment screw missing near where the crossbar links to the carb. I was nervous about starting, but did try a couple times with no success.

Regarding that adjustment screw -- on the driver's side carb, it seems to just go through a little piece and acts as a stopper for the throttle linkage. I couldn't tell if it did anything else.... how do you check for vacuum leaks?

Again, it is a 2.0 w/dual Weber 44 IDF

Thanks again

QUOTE (mudfoot76 @ Jun 30 2005, 11:13 PM)

Regarding that adjustment screw -- on the driver's side carb, it seems to just go through a little piece and acts as a stopper for the throttle linkage. I couldn't tell if it did anything else....

seriously out-of-synch carb linkage will feel like misfire, especially on a flat 4.

Understandable...hopefully this is just a synch problem. I would have thought that the carbs going out of synch would something that gets progressively worse. I'll look through my boxes of Weber stuff and see if I have another one of these little screws.

Thanks!

QUOTE (mudfoot76 @ Jul 1 2005, 11:09 AM)

...I would have thought that the carbs going out of synch would something that gets progressively worse....

depends how long it takes for the screw to fall out :-) ...

i'm not saying it *is* a synch issue, but it's easy enough to check (get a SynchroMeter if you don't have one...) and if it's bad, nothing else you do will make it run right (although a few things can tend to mask the symptoms).

QUOTE (mudfoot76 @ Jun 30 2005, 07:13 PM)

.... how do you check for vacuum leaks?

A classic way to check for vacuum leaks is spraying carb cleaner on suspect areas while idling and check for RPM changes (RPM increase).

A cleaner method is to use a propane bottle with a flexible hose and a push-button valve. Spray the propane around the suspect areas and look for RPM changes.

Two words of advice.
1) Propane is extremely explosive (duh) and therefore you should be very careful using this technique (or carb cleaner - same concern). I always keep a fire extinguisher very handy when working with fuel or welding, etc.

2) Propane is heavier than air so if the air around your intakes is fairly still (not likely), best practice would be to start spraying on the lowest portions of your intake and work your way upwards.

QUOTE

maybe the carpet, or something in the engine bay?

I just did some work to a members '73 2.0 with dual Webers....while looking around the engine bay I notice that the carb linkage would brush the torsion springs for the rear lid. Someone had put a hose clamp aroung the springs so the linkage would open past halfway...if the clamp were to slip while you had the pedal down the throttle would stay open

best fix..rear lid struts...thanks CCLINYOURKITSHIPSFREE

QUOTE (mudfoot76 @ Jun 30 2005, 07:13 PM)

I had a look at the engine and carbs this afternoon. I did notice that on the passenger side carb, there appears to be an adjustment screw missing near where the crossbar links to the carb. I was nervous about starting, but did try a couple times with no success. Regarding that adjustment screw -- on the driver's side carb, it seems to just go through a little piece and acts as a stopper for the throttle linkage. I couldn't tell if it did anything else.... how do you check for vacuum leaks? Again, it is a 2.0 w/dual Weber 44 IDF Thanks again

As soon as I read the first post I thought, "the allen-screw has backed out that holds the linkage to the crossbar". You have the classic symptoms. If you are lucky there is a nice spot where the screw used to be and you may not have to re-adjust much of anything.

QUOTE (Jakester @ Jul 1 2005, 12:28 PM)

Two words of advice. 1) Propane is extremely explosive (duh) and therefore you should be very careful using this technique (or carb cleaner - same concern). I always keep a fire extinguisher very handy when working with fuel or welding, etc. 2) Propane is heavier than air so if the air around your intakes is fairly still (not likely), best practice would be to start spraying on the lowest portions of your intake and work your way upwards.

check for sparks BEFORE doing that...

Starry, starry night..


M

Life being what it is, I haven't had time to mess with the car at all lately. Until this evening that is....

I'm still suspecting the throttle cable, so I take out the carpets and check the attachment to the loud pedal. It giggles, but everything is connected. The attachment to the crossbar is solid, but the acutal cable has a bit of play. I can't look underneath very well, so I put the car up on jackstands and have a look. I can't see any pinches, or worn sheathing, nothing that would suggest a problem. Especially considering that just last summer the whole thing was apart for rebuild...

I take the carpet out and look in the center tunnel and under the console. Again, everything looks to be in good shape.

Isn't that a lovely pedal board?? (Thanks Engman!! )

QUOTE (Hi_Fi_Guy @ Jul 1 2005, 07:11 PM)

As soon as I read the first post I thought, "the allen-screw has backed out that holds the linkage to the crossbar". You have the classic symptoms. If you are lucky there is a nice spot where the screw used to be and you may not have to re-adjust much of anything.

I had lost track of this thread, and didn't see this particular response to my original question. That would have saved me some time this evening, but I'll chalk it up as a learning experience.

Before I was going to start disconnecting things, I wanted to be sure that it was the cable and not something on the carbs or linkage. I noticed that a little pressure on the passenger side of the x-bar would actuate that carb, but the same pressure would not actuate the driver's side. Ah ha! something is preventing this side from opening. As it turns out, the little allen head screw had come loose (see picture), allowing the linkage to slide outwards (towards the carb) and created such an angle on the linkage that it would not actuate the butterfly. Yes, there was a little mark where it had been screwed in before, so slide it back as best as I could guess, tighten, and voila! The engine starts!!!

While it now runs, I can tell that things are unbalanced. Maybe this weekend I'll work up the ambition to once again try to synch up the carbs