Carb'd car owners, step in!

I have a 78 308 and I experience some of the same "symptoms" of the carb car. I have heard that the volume of exhaust will be different from side to side. I wouldn't worry about that. My car also does the fuel starve thing on hard turns, just punch it, that clears out the bobble. Actually, I have read that is a common problem with our carbed cars. Not sure about the idle problem you are experiencing. Your main jets at 125 seem awefully lean. I wonder if that could be a problem.

 

Does it still have points and condensors?

It sounds a lot like poor spark to me. And that hot side is not getting complete combustion. It reads like you've got undburned gas going into the exhaust.

 

Well, I don't have a Ferrari, but...

My Volkswagen, it's carb'd, and it used to do the EXACT same thing your talking about (except the exhaust thing.)

We changed the fuel pump, that helped a little, but it still wanted to get cranky when slowing down after it got hot. It ended up being the carb choke was getting stuck, sometimes in the off spot, making it act like it was running out of gas, especially when I'd start to take off from a stop, I'd have to floor the clutch, give it plenty of gas and let the clutch out slowly. I checked the accelerator cable to make sure it wasn't catching on anything, it wasn't, and sprayed some WD-40 on the choke, now it works like a dream.

Probably the first time in F-Chat history where someone has tried to diagnose a Ferrari's engine trouble from experience on a 40 year old VW...

Hope it helps,

Cheers,
Joel

EDIT: Just remembered, my 1979 Camaro Z-28 did the same thing with the exhaust, except the reason the right side was flowing so much worse was because there was a rather large rust hole in the pipe right after the header, I think most the exhaust was going out of that... and not the muffler... Probably not the case in your car, but might want to check

 

I'd start with pulling the plugs to see what they look like. Should be a light brown. If they're black and carboned you either have rich mixture or poor spark. If they're whitish then you're running lean. The 125's should, in theory, be fine at sea level where you are.

There are a few basic carb checks you can easily perform such as visually inspecting the butterfly movement to ensure all are closing and opening in sync with eachother. Regarding the chokes, a lot of carb'd 308 owners disconnect the chokes to eliminate any complicating variables here (such as a stuck choke) and start the car cold with some pumps of the throttle (richening mixture via extra gas from the accelerator pump).

The prior owner had the carbs tuned you say? Reputable place? Where were the cats sourced from?

 

Agree on pulling the plugs, the popping you hear is a misfire or dead cylinder that is not firing and eventually the heat from the exhaust ignited the raw unburned fuel in it.

I'd check ignition first then go to a carb cleaning or rebuild and retune in neccessary.

 

Agree with everything everyone has said. My additional spin.

As said - ensure that the starter enrichment levers are all the way closed and seated. You may even want to clean out this system to ensure the plungers are seating. Although others will disagree, I think one should COMPLETELY DISCONNECT the starter enrichment system - again, some will disagree. IF it has had 'tweaking' to pass emissions, that would probably mean someone has more likely putzed with the idle jets than the main jets - would look and ensure they are all the same and correct for your year, or just put in 50s.

In addition to looking at the condition of your plugs, I'd check what plugs you are using. Sounds to me like you need a hotter heat range. Of course, all of this can be caused by a malfunctioning enrichment circuit. The enrichment circuit works by lifting little valves in the carb - if they do not re-seat all the way or correctly, you will run WAY rich - which is what all of this is sounding like, at least to me.

Could be quite normal and compensated for by easing on the gas during a turn; My car does this a little. You should be accerating through the corner anyway. Could also be incorrect float levels re-set when they were trying to give your car.

All of the above applies after you have ensured a good spark from TWO good coils and all of the spark plug wires.

Well, just my experience above and I agree with everone else as well.
Good luck - you have a GREAT car and it will be a hoot.
best
rt

 

Hard starting in an old car when everything else checks out can be your coil. They get weak. If yours is (are?) 25+ years old, change it (them).

The popping sound can be an air leak in your exhaust system/header bolts as well as too lean on one carb. Make sure the bolts are tight. Usually they are corroded in place but I had loose ones once and it made that popping sound until I tracked it down.

20W50 is kind of the standard for old cars; see other threads on synthetics on 308 engines. Opionions vary; I use 20W50 as opposed to a synthetic on my car because I change the oil a lot.

Your spark plugs will likely tell the tale as everyone else has mentioned.

Sometimes carb cars get almost undriveable due to emissions tweaking; a stupid situation. You may need to get the car adjusted back to where it runs best as opposed to running cleanest.

Ken

 

I agree with this last statement. Id also put the cats in a box and run test pipes until I needed the cats for testing. Then tune your ignition until you know its bullet proof and then go after the carbs. Unless YOU know what they are doing, and how they are set, YOU will never know. There are a lot of good people here with the answers you need to get it running right. Carbs if in good shape and set up right should be pretty crisp and not altering the cars running from moment to moment. One thing I would check right away is your distributors to make sure they are advancing and retarding correctly. Timing light will tell you if they are working back and forth and how far. Sticking in the adavanced range could give you some of your symtoms.

 

Good amount of information here.

First of all, it seems that the general consensus is that 125s are way too lean, and will cause all sorts of running problems. Also, you should find out what your idle jets are - you have to really screw the car up and get it to run hot in order to pass smog. I'm struggling with a lean condition now as well, after the car was setup for smog. with 125s, there's almost no way it would be running rich.

The Permatune system may be troublesome - some people have had problems with these units in the past. I recommend the Electromotive systems - NickForza sells a bolt-on kit for $1500, that should be bullet-proof for as long as you own the car.

Burning out of the tailpipe could be one of two things - either running too lean, and getting really hot - which is bad, as you can burn an exhaust valve on your engine. Or, the car is running super-rich, and is dumping excess gas into your exhaust system which is being ignited in the catalytic converter - this is why 308s often catch on fire! Either condition is very bad, and I would avoid driving the car until these issues are figured out.

The Cats themselves shouldn't alter the performance of the car, but taking them off will help guard against a fire...

-Wayne

 

Aaron
I can commiserate with you on your dilemma as I have experenced many of the symptions you refered to and the carb'd cars are notorious for a multitude of glitches. All of the suggestions so far are applicable and s/b checked out....I don't think you are going to find a one easy fix. All of the suggestions together should make the car run better. If the previous owner was trying to pass the smog test he may have tuned/chocked down the fuel too lean and is causing a lot of your problems.

I think you should try one simple thing first before tuning or rebuilding your carbs and that is to get a pressure guage (or have a mechanic do it) and place it inline were the fuel line comes into the left front carb after the pump. It needs to be a "T" connection. With the car running at various RPM's the reading s/b about 3 1/2 to 4 lbs. If it is below this reading it may be the reason you experience starvation. Mine would do this when going up a long hill or hard acceleration. It turns out it was a bad check valve (one way) down by the fuel pump and filter. This is a safety devise. At least this would eliminate the fuel supply system as being the culprit. Good luck and stick with this chatline and I'm sure you'll get it running like a top.

 

Another thing too - if you remove the cats from the rear, you can use one of these to finely tune your carbs - no more guessing...

http://www.pelicanparts.com/catalog/shopcart/MISC/POR_MISC_INNOVT_pg1.htm

-Wayne

 

Wayne
Could you expand on this....how can you fine tune one carb when four of them have input in each bank?? How do you connect this up to adj the carbs?? Can the older exhaust analyzers work too??