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I am hoping someone can point me in the right direction about how to address two mechanical issues with my VW-based FiberFab.
Drove the car to the upholsterer today (finally). The car has electronic ignition and a Weber Progressive and as usual, it started, ran, and drove fine. Pretty zippy, actually. The problem comes when not actually driving. The throttle stays stuck partly open when stopped at stoplights. After running through the gears, I come to a stoplight and the throttle will simply stick at a high level. If I rev it up, it will back down … some. According to my tach, it’s at 2500 for the sticking position and it drops down to “only” 1700 after I rev it up (it is possible that my tach may be set wrong and the actual figures may be exactly half that). I could deal with the 1700 idle speed but having to rev it up at every light to get it slowed down even to 1700 is unacceptable. Warming up the engine makes no difference, as I drove it nearly 20 miles this morning and it had the same problem the whole way. And it’s not smoking, either. If not for the idle speed issue at stoplights, the engine would be 10/10. I have no idea where to look to solve this problem.Another annoyance has been the squeaky brakes. I had one jackleg mechanic install disc brakes in front and replace the pads in the rear. The car stops pretty well (although it likes to skid if I push too hard) but darn it, it sounds like a haunted house as I pull up to a light. Any ideas how to deal with that one?So far, I’ve found one mechanic I kinda sorta trust, but he’s expensive, he’s not really a VW mechanic, and he’s all the way on the other side of town. Or, if anyone knows a good VW mechanic here in Vegas, let me know.Hey Brother
I saw an add from a company called Stephens Buggy Repair in the March issue of Hot VWs. Their number is 702-642-7897 or 651-9560 and located in Las Vegas. I hope they are helpful.
Im in SoCal and I started with a regular mechanic and he could never fix my car correctly. I started having my car repaired at a VW shop and my car runs like a top. Ill never take my kit to a regular mechanic again.Stephens Buggy repair has been around for a long, long time unless I’m mistaken. Longevity says a lot about their business practices… Suggest you find a shop that really knows aircooled VWs and their quirks.
The squeaky brakes, if from the front is likely caused by the calipers sticking slightly on the pins. If so, there’s a lubricant that can be carefully applied, after cleaning. It MAY be the composition of pads themselves, but not likely.
The sticking accelerator is likely a combination of issues. There’s a roller and a weak spring on the accelerator pedal itself. Over time, this area tends to accumulate dirt/sand and wear enough to where things don’t operate smoothly. A rebuild kit costs less than $10, but doing a rebuild cand be be a bit of a PITA due to where it’s located. The accelerator cable runs through a nylon tube inside the metal tube housing. These can also get dust/dirt in them, especially at the rear of the frame where it exits the frame tunnel – if the rubber seal is missing. Sometimes, spraying a cable lubricant into the tube from the rear will help. Finally there’s the throttle return spring on the carb itself. Using a stiffer spring may solve the symptom, masking other causes – but has the downside of requiring more pressure from your foot to work the accelerator.
Early FF TDr on 69 VW pan
Slowly coming back from the ashes...Well if your tach is reading incorrectly, and the actual engine speed is 850 (or half of the 1700 you are seeing), then your idle speed is fine.
Quick check…What does your tach read at about 60 mph? With a stock trans, it should be about 3,000.
On to the “sticking” throttle….
Is the tube in place that carries your throttle cable through the fan shroud? If it is missing or misaligned, the cable might be sticking.
Is there anything hanging up the gas pedal and preventing it from fully releasing? Carpet? Anything? Not likely given what you described, but it is possible that something is catching when you just lift as you coast in, and you push it out of the way when you rev and quickly release the throttle.
Back at the other end, are the carb linkage and the barrel clamp that holds the cable all moving freely?
How about the throttle valve? You can’t see it. But it’s inside the
carb, where throttle lever is on the outside of the carb (where the
cable attaches). Move the throttle lever back and forth. Does it feel like the throttle valve is sticking
open? Lots of little moving parts here, all interrelated. If it’s sticking, it could be the lever, the bushing where the lever passes through the carb, the valve itself and more.Is the cable snug when the throttle valve is completely closed? It should not be guitar string taut, but there should not be much play either. With the barrel nut loose, pull the cable with your fingers only, no pliers. That’s the amount of tension you want.
Is the cable sticking? There could be old gummed up grease in the cable housing. Easiest way to check, disconnect from gas pedal and from carb linkage and move it back and forth by hand. It should move with minimal resistance.
Check the return spring on the gas pedal and on the carb.
Check the pedal cluster itself (while you have the cable disconnected). Is the pedal moving freely?
Inside the carb throat, is the butterfly valve moving freely?
To dig further into a carb, I suggest you start by reading this:
http://www.vw-resource.com/carb.html
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
Hey John, you may want to do a google search for “Robs and Dave’s VW Repair”. They are a good web resource on all things VW. A lot of my VW Samba friends use their online advice for questions, and problems. I only use a local VW Dune Buggy shop here in Florida, as they rebuilt my engine for $1600, (just a long block rebuild) It sounds like after you check all suggested things of accelerator cable issues, and possible carpet interference, it probably is your carbueator accelator pump or auto choke sticking. I cleaned my fast idle with carbueator spray on the butter fly valve in the carbs throat and the spring in the auto choke. I also squirted some spray on the accelator pump guts. Here in Florida, our “Auto Zone parts store” will also gladly check a customers RPMs so you can compare readings on your car’s Tachometer. Just a quick thought.
Good Luck with it. FYI Troller and I are restoring our own interior Upholstrey, Top and carpet. If y all have any questions about that……. Ask away!
On the Square
Dave
Lakeland, Fl (near Tampa)davearoy2016-02-09 05:39:38Dave
Lakeland, Florida, where we drive Topless every dayJohn …no need to google Rob and Dave’s. The carb info link I posted is from Rob and Dave’s. Once you are on their site, you can navigate around their site. It is a treasure trove of info.
If you buy John Muir’s VW book and bookmark Rob and Dave’s web site, you will have just about everything you need to maintain the VW portions of your TDr.
After all the purely mechanical bits are sorted, I agree a sticking choke could be the culprit.
Just my two cents…but your symptoms do not sound like an accelerator pump problem. The accelerator pump delivers an extra shot of gas when you hit the accelerator. But it does not “keep squirting.” Symptoms of a bad accelerator pump include bogging, stumbling or hesitation when you accelerate.
I googled “carburetor car does not return to idle.” Regardless of vehicle or carburetor, almost everything I found pointed at some problem in the gas pedal to carburetor linkage.
PMOSSBERG2016-02-09 10:30:01
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
Paul offers some great advice on troubleshooting a sticky accelerator. My bet is on the cable binding somewhere – at the fan shroud, in the cable housing itself, or at the accelerator pedal. I’d only add one thing to my and Paul’s previous input.
Operate the throttle manually at the carb, from the rear. Use your fingers to move the linkage lever on the side of the carb. Do this with the air cleaner off, and the engine running, so you can see and hear things. See if you can get it to stick – if so, it is likely the carb since you’re bypassing the cable linkage system. Then have someone operate the gas pedal while you again watch from the rear. Pay close attention to the metal tube that runs through the fan shroud. Does it move at all when they press and release the accelerator pedal? Over time, the accelerator cable can wear a groove in that tube and start to catch/bind. If you see that metal tube move, that’s an indication of binding. If it moves, note that you can spin the tube 180 degrees or so, so the cable is rubbing an a fresh part of the tube. Then, put a zip tie around it on the backside, up snug against the back of the fan shroud to help hold it in place. Note also that if this tube is missing entirely (for some reason) the cable will quickly wear a groove in the fan shroud, then catch/bind inside that groove.
As Paul states, the next step would be to disconnect the cable from the barrel connector at the carb, and check for binding/sticking either inside the tubing or at the accelerator pedal. Should you find that it is a problem at the pedal, you may want to consider replacing the flat accelerator pedal with an aftermarket roller pedal(based on a factory VW design of the late 40s/early 50s). Doing this is often far easier than trying to do a total rebuild of the factory flat pedal, requiring that you simply use shim/washers to take out the slop where it goes onto the shaft. The roller pedal also has the benefit of being able to provide more cable travel, ensuring you get a fully open throttle at the carb. Many people run them on high performance VWs for just that reason.
VW Roller Pedal Install VideoKentT2016-02-09 13:26:45
Early FF TDr on 69 VW pan
Slowly coming back from the ashes...With that topic pretty much covered….
Here is a good tech article on noisy disc brakes:
http://www.popularmechanics.com/cars/how-to/a3092/4317748/
Paul Mossberg
Former Owner of a 1981 Classic Roadsters Ltd. Duchess (VW)
2005 Intermeccanica RoadsterIf you own a TDr and are not in the Registry, please go to https://tdreplica.com/forums/topic/mg-td-replica-registry/ and register (you need to copy and paste the link)
KentT wrote:cable binding somewhere – at the fan shroudProbably not of any help here but the tube in the fan shroud of mine has the cable carving a notch out of the end because of a sudden downward angle to the carburetor linkage as it exits there.All this time I’ve had the car (not quite a year yet) I’ve been thinking it’s going to fray the cable and get stuck eventually, but a little oil and it hasn’t changed any. Of course it only has an additional 1500 miles put on it too, for a total of 2700.No idea what it’s doing elsewhere along the cable path but that one place looks like trouble. I’ve got to try and bend that (aluminum??) tube end so it doesn’t keep cutting into the end edge like that.So that makes me wonder what’s going on inside that tube and along other places it’s routed I haven’t actually seen.Running lean was my first thought, reading of the problem described by OP, since idle is often slow to drop with air leaks. Maybe that’s been checked into enough already and eliminated as a possibility.Thanks to all for the suggestions. I should get the car back from the upholsterer by Monday and will do some checking into these things. The most likely culprit seems likely the throttle cable housing at the fan shroud. Air leaks seem unlikely since the carb is new. Brakes? Dunno. May try to find the CRC stuff mentioned in the PM article. Some kind of lube issue seems most likely since they are new also.johnsimion2016-02-11 02:49:23
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