Hi, I'm new to the world of Corvettes and even mechanical issues with cars in general. I always dreamed of owning a 58' vette, and about 4 weeks ago I finally got enough money (and credit) to get one (has a 283). Test driving it went great and it sounded/shifted perfectly. After the 10 hour drive home with my new baby on a secure U-Haul flatbed in a non-stop rainstorm I got it home. The next day and ever since, the car starts great, idles great, rev's great, but when I put it in gear and get it out of the driveway, I can go about 200-300 feet before it starts to backfire and loose power (does this in all gears). If I shut it off for a few seconds and then start it back up, I'll get another 200-300 feet before it starts this again. It has new plug wires, plugs, distributor cap, and there is no sign of a bad point. There is new gas in it and the carbuerator has recently been rebuilt. It just ran great and now it doesn't. Could a screw somewhere have come loose during the tow? Could towing it that far in the rain with water spraying on it have caused this somehow? I haven't taken out the plugs yet to examine them, but I'm thinking this would be the next step. Thing is, it sounds so good when idling, so I don't think that's characteristic of a fouled plug or misfire. Admitingly, I'm no expert at this, but I like to think I'm a quick study. I kinda burned through my funds acquiring the car to have to take it in so if anyone has any ideas, I'm all ears. Thanks in advance!

 

pull distributor cap and check for moisture ....what you are describing sounds like it only occours under a load, probably in the secondary ignition...if not then it is in the fuel system, low volume or pressure or float and needle and seat...you may want to seek out some professional help to save some time and part replacing...good luck

 

Is the condensor still hooked up....the screw might have backed out or a cracked cap...

jack

 

It may be a timing issue. It sounds like the distributor is not advancing, or timing too far advanced. I would check the timing, points, dwell, springs, weights and vacumm advance and plate for movement.

 

Blocked fuel filter ?

 

That's what I'd look at first. Make sure you're getting enough fuel to the carb. If you have a blockage which could be in the fuel line or fuel filter, or the fuel pump is not pumping enough fuel, the carburetor float bowls might be running out of fuel once you get up above idle RPM.

Good luck!
Gerry

Edit: By the way, congrats on the new car and welcome to the forum!

 

Wow! Thanks for all the advice (and so fast!--- amazing). This site is the real deal! Okay. Time to get out my Corvette servicing guide and look some of these things up. I have to admit, many of the suggestions, I don't know what the part mentioned looks like or even where it is. Ha, I can picture you all now rolling your eyes! Don't give up on me though, you all had to learn this stuff at some point too! (only you were probably 6 or 7 years old!). What can I say? I didn't grow up around this, so at 32, it's time to learn. Gosh though, I sure was hoping it would be some sort of quick little fix since it ran so great hours before this. Thanks again!

 

find a reputable mechanic to at least diagnose this situation...you can learn later...jmo

 

I have to put on a new condensor about every 4 to 5 months.I
use an excel dual pooint condensor.

 

Check the coil to see if it's going bad.

 

QUOTE=midyearvette;1572125899]pull distributor cap and check for moisture ....what you are describing sounds like it only occours under a load, probably in the secondary ignition...if not then it is in the fuel system, low volume or pressure or float and needle and seat...you may want to seek out some professional help to save some time and part replacing...good luck[/QUOTE]
Last winter my 62 would start & Idle fine, but when I drove it it would backfire both through the exhaust & ocassionally through the carb. It was a moist distributor cap, which causes the spark to fly everywhere inside the cap. I got a heavy duty cap & no problems since here in wet Seattle.

 

Since this seemed to have happened as a result of the ride home in the pouring rain on the back of a flatbed, I would think that had something to do with it and would take the other advice given on the possibel moisture in distributor cap. That is something you can do and if it is moisture, you've just solved your first mechanical problem and will feel great. If that is not it and you are currently not that mechanical, I would take Midyears's advice and turn it over to a mechanic so you can get it back and enjoy it. BYW welcome to the forum. Great bunch of helpful knowledgable guys here.
Don

 

Backfire is usually an ignition problem and with the rain situation you had, like others said first get it dried out.

 

I'll go out on a limb here with an entirely different direction.

How long will the car sit and idle? Can you start it and it idle for 15 minutes or more?

Now while it is sitting, can you bring the engine up to around 2500 rpm for 3 or 4 minutes without this happening?

If you can't to either of these, then maybe it is fuel related. The ride on the trailer may have dislodged something that has stuck under the needle in the carb, such that fuel is being blocked. If it idles, it would use fuel slowly enough to run fine, but running faster, fuel is used faster than it can be replenished in the carb blow.

A WCFB is really a simple carb to work on, but it is probably beyond you right now. You can decide if you want to open it or not. The biggest point of failure for you working on one is getting the accelerator pump in correctly. The originals had leather cups that can turn over (unfold like an umbrella in a strong wind) but I think most have been replaced with rubber by now.

If it will idle for long periods and will run while revving the engine, and only quits and backfires when driving it, then it is probably electrical in the ignition, although I would have thought it had dried out by now.


I think it is more likely the condenser breaking down or the coil failing than water. To check if the condenser is breaking down, simply disconnect the condenser wire from the coil. If it runs fine, then get a new condenser.


Oh yes, missed this post. I think it is more likely fuel related, since you do run some.

 

Just wanted to follow up the result from all the great feedback I was getting. It was the points. The guy I bought the car from said they were just installed too. So either he lied, or they burnt out fast from either moisture or timing. I decided to install the Pertronix Ignitor III with a Flamethrower III coil. I did it myself, with the help of youtube videos and a very detailed picture-by-picture installation on an AMC site. After that (and setting the timing) she runs better than I've ever seen and will never have to worry about points again. Thanks again for all the help!

 

Glad you got your car fixed. If the points burn up quickly, it's caused by a bad condenser which for some reason people fail to replace when they do the points.
Some people love their Pertronix, others hate them. The trouble is that they either work 100% or the fail completely like several that have posted here. I would keep all the parts to convert it back to points in my glove box just in case so you aren't left walking.

Jim

 

You will thank yourself...I run the Ignitor III and the II for years before that and even the I for many years...never a failure or hiccup. Do remember the III has a built in rev limiter set to 5,500RPM from the factory. You could bump up against that and think you have a problem when its just the system working as designed...

 

Frank, what about this thread? http://forums.corvetteforum.com/c1-a...from-idle.html

Jim

 

Think I should raise the limit on Ignitor? I'm just a cruiser with the car.