Diagnostic help: #3 cyl. acting funny

[Cave Man]

Scott I fought this with my 36 dells. Found out that the problem was that the throttle shaft was just so slightly tweeked. Take a reading of all 4 cyl with your air flow guage and see if #3 is lower than the rest. If it is the the shaft is a little tweeked and not letting the air in that it needs at idle. I couldnt see a difference but the guage picked up on it right away. Then you may need to open the air bypass screw on 3 or close the one on 4 just a little.

Hope this helps  because it is so frustrating to deal with.

[Clinton DdK]

3 to 4 pounds

[scott s]

 Long time since I posted or even messed with this car. Keeping busy with old motorcycles and, frankly, bummed out that I can't fix this thing....

 Anyway, the last time I tried to drive the car, I was getting indications that it was running out of gas. I know those Mr. Gasket fuel pressure regulators are crap, but since removing the leaky one I had was the ONLY change before the car started running poorly, I decided to try re-installing one and seeing if the problem went away. If it did, I'd spring for a quality fuel pressure regulator.

 Got under the car this morning and installed the regulator set at 3#. Tried to crank the car and....nothing. Checked the carbs and they're dry as a bone. Nothing from the squirters when I move the linkage. Tried lowering pressure to 2# and .....nothing. I'm not getting fuel to the carbs at all now. This all leads me to think there's a fuel delivery/pressure problem that could be causing all this.

 I have a CB rotary pump and filter up front. If one of those is going bad, and removing the regulator started all this, think low fuel pressure could be having an effect on the floats/needles/seats, etc and causing the poor running?

 I've just about ruled out everything else in the engine bay (read back through this post). It makes me sick that this car just sits here and I can't fix it.

[Ohio Tom (DdK)]

If the throttle shaft is starting to wear out, it will have the same symptoms as a twisted throttle shaft. (one cyl leading the other).
Short of re-bushing the carb body (ACE can do this) there may not be much you can do to solve that problem.
I have on occasion, given the throttle shafts an intentional twist to balance out a barrel that didn't want to hit at idle. (carbs were tweaked before I got them). I used 2 crescent wrenches. One on each end of the shaft. You must be careful not to wreck the whole thing thou. Go easy with this proceedure if you try it. 
Smooth as silk after that.

As far as giving up at higher rpms. Check your ignition wires and coil. I have had similar issues with bad wires and/or coil before.

Fiat.. Not sure why you hate webers so much. (maybe thier lack of toughness when it comes to hammers). They are great carbs that have actual ball bearings on the throttle shafts so they last.
Unlike Holley's that wear out after the get dirty.
Holley's suck to change jets on too.
The whole "power valve" thing is mind boggling. More of a bandaid for poor metering in my eyes...

Weber is far superior in my book....

If you were over-flowing your carbs, you would see gas running out everywhere. It's obvious.


3.5psi is good for IDA's. Get a fuel pressure gage to check it. Whatever you buy, don't get "liquid filled". They are horrible. Just get the cheap normal kind and only use it to setup your system, the store it in your tool box for later use.

[fiatdude]

OK -- step by step

1.  Easiest first -- remove the fuel line from the exit of the pump -- have someone turn on the key and the fuel should be really flowing out.
Yes it is, go to step 3        No it's not, next step

2.  remove the line from the tank --- there is a screen (sometimes) at the pickup in the tank -- eastiest way to clean without removing the tank is to put a high pressure air line to it and blow. go back to step 1. If this fixed or did not fix the problem I recommend pulling the tank and doing a complete flush of it.

3.   Pull the line off the fuel filter and make sure the gas is coming out of it at about the same rate as out of the pump. If not change the filter, come to think of it change the filter any way.

4.   Pull the line right before it gets to the regulator, it should be at coming out at the same rate as it was from the filter. If not, run a new line. If OK, pull a line just at the exit of the regulator, the fuel should be coming out at a rate that is less than the entry point, but still at a good rate. If not rebuild/replace the regulator.

If the carbs have dried out all the fuel from setting -- here is an old trick --- fill the bowls with WD-40, let them sit for about 1/2 to 1 hour. Then start the car -- Now this will be like running the car on diesel, it will idle and run (barely) and smoke like hell (DO NOT DO THIS IN A CLOSED GARAGE -- I proven this to be a VERY bad idea -- the responding fire engine didn't think it was to funny either). It will take a while for the engine to "clean" up -- remember if you have done all the above, it should be getting gas -- and the new gas will be thinning out the WD-40 and slowly the smoking will stop. You can blip the throttle occassionally during the process to help speed it up, in the beginning it will fall completely on it's face and as the gas replaces the WD it will start runnning better and better. AFTER all this and IF #3 still is acting like chit, go to step #69.

FOR THE FUTURE -- -- If you are parking the car and don't know when you'll be driving the car again, I highly recommend putting a switch on the fuel pump so you can shut it off and then let the car run until it runs itself out of fuel. This is a lot easier on everything than letting the gas evaporate/dry inside. And if the car still has the same gas in it for over 6 months throw the gas away. That stabilizer chit will only last for so long. 

That's all I've got to say about that. EXCEPT -- drive the damn car more often and you won't be having this problem. Take for a trip to the six-pack store every weekend damn it . The car and you will enjoy life more.

69.   Your carb and now your wallet are screwed.  Whip them both out and throw one away, and use the plastic in the other to replace the one you just threw away.


Tom -- new technology for the Holley -- adjust-a-jet -- never have to open the bowls again.  Besides now with modifications to the power valve it will act as a fuel enrichment for turbo applications.       

And the reason I hate Webers is chasing problems just like this one -- one cylinder not responding to anything you do -- now imagine having 4 of them on top of a V-8 and chasing those things until you've pulled all your hair out. When they are running great they are great -- but one small spec of fly crap inside the carb and your chasing you tail.

And yes, there has been a few Holleys that have received that special Hammer-time treatment too. When it has failed to respond to the loving touch in the correct manner, no piece of equipment is beyond that feel good treatment LOL

[scott s]

 As soon as my work schedule allows I will start testing/eliminating stuff in the fuel system. I don't have a lift and will need an extra set of hands to work on it from the garage floor.
 I'll go from the tank forward or the regulator back and check everything. If I have to, I'll send the carb(s) to Art and have him check them out.

 I'd love to drive the car more. I've been having trouble with it for a while now and don't have the skills, experience or professional help in my area to fix it....so far.
 Now that I've sold the '70, this will be my primary "Hot VW" as soon as I can get it sorted. It might be a week before I have time/help to work on it. Stay tuned.

[scott s]

 Old post. Long time no updates, but in case any of you care.....


 After letting the car sit from May until early December, I got a call from my mechanic (who is now retired...but he was the guy helping me earlier this year, trying to get it running). He told me to bring it to his house and he would keep it until it was fixed. Period.

 Turns out I was right about the fuel system. He traced it back to the fuel pump. But, there's more.

  * TANK: He cleaned the tank and got rid of the old fuel. Said there was a small amount of sediment but not enough to cause a problem. He changed the internal filter while he was in there.

  * FILTER: Checked the filter that comes with the Cb Perf. electric fuel pump. Could feel a small amount of restriction but, again, not enough to cause a problem. Changed it anyway.

 *PUMP: The pump would whir and pump, but just didn't sound right and certainly wasn't moving enough fuel to the back of the car to run a 2,276 with 48 IDA's. Changed the pump.

 After all this, he still though there should be more fuel at the rear of the car. He checked the short piece of solid fuel line; the one that wraps around the fan shroud. That line was nearly completely plugged. He said he could barely run a mechanics wire through it. He got over a 1/4" of rust out of that short piece of line.
  Replaced that line and the car runs GREAT! As good as ever, if not better.

 Some of the best news I could have gotten right at Christmas!
 

[martin]

Splendid news! My engine builder gave me a nice Christmas present saying that no more money is needed to finish my engine project.

[Esky]

Good to hear Scott, now enjoy driving that car and have fun with it. Merry Christmas