maheider

Here is my issue. 66 Toronado, 31k miles, 425 engine, 4 bbl original (I think) carb. Overall in really nice shape. It had been sitting with little run time for the last 5 years or so. The car starts fine, sounds awesome at idle, and accelerates most of the time on the road perfectly fine. Light throttle or heavy, most of the time it is OK.

Occasionally, however, it will really "stumble" when giving it more throttle. When it is acting up, it will generally still accelerate OK, even up to 75 mph or more, as long as you are light on the pedal. When it is acting up, giving it 1/4 pedal, or sometimes even less than that will cause the stumble, where it pops and seems to perhaps even slow down. Back off the throttle, and it goes fine.

This problem comes and goes, and may be present for a few miles, then goes away for 40 miles or more.

I am not an expert in car repair, so I am not sure what to look for exactly or where to start. I have checked as best I can for vacuum leaks and did not find any. The hoses look good, everything is tight at the connections as near as I can tell, and pulling off lines here and there show a pretty good vacuum using the "finger test".

I checked the spark plug and coil wires, and everything looks good and tight. The distributor looks to be in good shape - no cracks, points look fine. I checked the timing and it seems to be real close to on with the vacuum advance off of it, and moves ahead as expected with it on.

Like I said, I am a bit of a novice, so I would appreciate any suggestions you might have. If there is more specific information you may want. please let me know.

Professur

I just dealt with exactly the same issue. It was the fuel filter was clogged.

Octania

I was going to suggest that flexing of the pts wire by the vacuum advance system has led to a nearly separated points wire. The varying vacuum levels at some point provide just the wrong position, which then interferes with the spark production.

elcaminodave

I had the same problem on one of my cars. I replaced plugs and wires and still had the problem. I replaced the fuel filter and all is good now.

maheider

Thanks guys.

Looks like two votes for the fuel filter so far. I was not sure that a fuel filter would cause what seems to be almost backfiring (definite loud pops and rough running) at higher throttle levels. I guess I would have expected perhaps a loss of power but not the other symptoms, but certainly I am not an expert and it seems that this has been the fix for a few of you.

Since it had been sitting a while, I bought a filter and attempted to change it out a week or so ago. I did not have the proper size end wrench - it appears that it takes a 1" end wrench to hold the fitting that goes into the carb itself. Trying to use an adjustable wrench was not successful since it was really too wide to also get a smaller wrench on the line fitting that goes into that one.

Plus, even with the correct size flare wrench for the smaller fitting (5/8 I believe), I was not able to break the smaller one free, and was afraid I was going to break something. Since I was using the car in my daughter's wedding, I decided not to break anything ahead of that day and I just tightened things back up since I could just baby the car if the issue started while using it.

I plan to buy an end wrench of the appropriate size (1 inch?) and see if I can get that filter out now. I am afraid the line fitting is bound up in it though, and I want to be careful so as to not damage the carb itself. I tried dousing it with PB Blaster but that did not seem to free it up last time I tried.

I am also thinking about putting an inline filter in somewhere so that if I get the factory filter changed out, I hopefully won't need to go there again. I assume somewhere underneath the engine there is a rubber section of fuel line that I could tap into, as opposed to cutting into the metal line that runs over the engine to the carb. Anyone know if that rubber section is easy to get to to put a filter in, and if so, where it might be routed under there?

Of course, any other thoughts or suggestions would be welcome.

jaunty75

Think about this for a minute. Your car has only 31,000 miles? That in itself is amazing.

But does this mean that the fuel filter could very well be the same one that was installed at the factory in 1966? Given how much difficulty you're having in loosening the connection so you can get to it suggests this might be true.

The idea of adding another filter in the line is overkill, in my opinion. I'm sure it will work, but why go through all that bother? The engine was designed to run with the fuel delivery system that's currently in there.

Do what it takes to get the connection loose, change the filter, and run the car. My guess is that the others above who have suggested a dirty filter as the source of your problem are right. And I'll bet that, once the filter is changed, you won't have this problem for a long time if you ever do. If you do, changing the filter again should be much easier as you will have more recently loosened the connection.

I've got a 425 in my '67 Delta 88, and changing the fuel filter is a 5-minute job.

maheider

I agree Jaunty, changing the filter should not take much more than 5 minutes or so to do. Pop the air cleaner off, hold the big fitting tight to loosen the line fitting, unscrew the big fitting and replace filter. Then reverse to put it back together. That is what I thought would be the case but no such luck.

I do need to get it out of there one way or another, and replace it. The reason I was thinking about an inline filter is that the threads in other Rochester carbs I have seen are very fine for that fitting, and can easily deteriorate with repeated use. I'd really hate to bung them up and have to deal with fixing that, but perhaps it is overkill?

The car does indeed have only 31000 on it at the moment. If you are interested, I posted a few pictures of it in a thread in the Newbie forum here:

https://classicoldsmobile.com/forums...-toronado.html

jaunty75

They may be fine threads, but the fuel filter is a wear item, and the system is designed for repeated loosening and tightening of that fitting over the years to replace it. But the fuel filter is not something you change every week. So it's not like you're going to be loosening/tightening/loosening/tightening that fitting on a regular basis. But even if you were, it should be able to handle it as it's not that fragile so long as you don't cross the threads.

I think your problem is simply that it hasn't been loosened in 47 years. Keep on it with the PB blaster, get the correct tools as you say, be patient, and it should come loose.

Think of it this way. One or way or the other, whether you put a second filter in the line or not, you've got to get this connection loose. If you decide to put a second filter in the line, you won't want to have the factory filter in place as you would eventually have to replace it anyway, so you want to get the old one out of there. You want one fuel filter, whether it's the one the factory built a place for or one you add earlier in the fuel line.

Well, if you have to get the old one out of there, anyway, whether you decide to add a second fuel filter or not, why not take it one step at a time? Get the old filter out, replace it, and see if the car runs better. If it does, leave well enough alone. Change it again a year later or after so many miles or whatever like you would normally would. If the car does not run better, the problem wasn't the fuel filter, anyway, and the only reason for adding a second one, to have one that would be easier to get at and replace, would be if removing the normal filter really does turn out to be a pain in the neck.

jaunty75

I looked at your photos. Very nice car.

If you don't mind my asking, what are the last six digits of the VIN? Ralph Braun, the fellow who writes the monthly column "Freewheeling with Toronado and Aurora" in Journey with Olds and who is a big fan of Toronados, always talks about the VIN whenever he comes across a '66. He's looking for the earliest-production Toronado still in existence.

Professur

This brings up a more serious possibility to worry about. That low mileage suggest that your tank has spend either a great deal of the time empty, or full of old gas. Neither are good. Empty tanks generate rust. And the '66 carb was before things were toughened up to deal with alcohol. You could have swollen and degrading rubber to deal with too.

The new fuel filter should come with a thin gasket that goes on the end of the housing screw. That's your seal, not wrenching it up water tight. There's shouldn't ever be any real force needed to tighten that housing. The other end, on the other hand, is a single flare which does need to be tight, but not super tight either ... you've probably got twice the pressure on the water lines in your house than you do on that fuel connection.

maheider

Last digits of the VIN are 540809

maheider

I am under the impression that the tank was left mostly full as it sat, though I can't say for certain. When I started driving it, I ran it down to just a few gallons before filling it up, which should have diluted the old gas pretty well. I'm thinking once i get the old filter out, I will run several tanks thru it, which will hopefully clear it out pretty good, then change the filter one more time. Hopefully that will be easy to do then.

As far as the alcohol in gas goes, that does concern me as well. I know it can have an adverse effect on any rubber that was not designed for alcohol contact, and there has to be pretty much any rubber part in this car. It is the same thing as I went though with my 83 Mercedes diesel when the only place in town had a bio-diesel blend only. The rubber parts in that car were not happy with that either, but the good news is there were not very many such parts, and no carb to worry about either. I am not sure what the best approach is for dealing with ethanol, since it is all but unavoidable at this point.

The filter does have a gasket that came with it. Thanks for the advice about about how tight things need to be.

Professur

We old car lovers have to stick together. My olds is a new acquisition only recently out of storage and I'm dealing with the same troubles. I'd grab a couple of extra filters and keep them in the glove box ... just to be on the safe side.

jaunty75

Thanks. The starting VIN for the Toronado that year was 500001, so this car would apparently be the 40,809th. But I'm not sure if that's the correct interpretation as there were actually two Toronado styles that year, each with their own separate VIN starting number. The base "Toronado", which would have a VIN that starts 39487, saw a production of 6,333 units, while the higher-end "Toronado Deluxe", which would have a VIN that starts 39687, saw a much larger production of 34,630. But neither reached 40,000. In any event, I'm guessing that yours is not an early model year build.

By the way, which of the two series is your Toronado? Even though it might have been less desirable back in the day, if yours is the base Toronado, it would much rarer than the Deluxe model. Only about 15% of all '66 Toronados produced were the base (39487) series.

maheider

I assume it is the deluxe, but from my limited research it appears that it is difficult to determine with certainty which it is. Apparently you could take a standard and option it up to have the same or very similar equipment as the deluxe, even though it would technically be a base model.

I have things like the second door handle for the rear passenger, which is generally a good indication that it is a deluxe. I imagine there may be other things that help identify it, but I don't know specifically what.

jaunty75

It should be no problem at all. Just look at the VIN. If the third digit is a 4, it's the base model, and if it's a 6, it's the Deluxe. Given that 85% of all '66 Toronados made were the Deluxe version, odds favor yours being one of those.

As far as your fuel being in the tank for 5 years, I'm not so sure I'd worry greatly about it. First, you say you've already run that fuel out plus another two or three tanks of fresh fuel. That ought to have pretty much cleared all the old fuel out of the system.

Second, 5 years, while not just a couple of moments, is not 30 years. When I bought my '73 Custom Cruiser in January 2010, it had sat in the garage of the prior owner partly disassembled (because he had started a restoration on it and then died in the middle of it) since March of 2005. During that time, which was just two months less than 5 years, the family started it up maybe once every couple of months or so just to start it, but the car never left the garage, and no new gas was ever put into it. But it started fine and ran fine, and, when I got the car on the road a month or so later, I just went to the station, filled it up, and drove it. That's all I've done ever since, and the car has had about 6,000 miles put on it since then. (All I did was change the fuel filter!)

So, in short, I doubt the fuel was in your car long enough to be a problem, and your experience since then would seem to bear this out.

MDchanic

Here's another 2¢:

Certainly the fuel filter is a possibility, but I will ask you this:
Does the stumbling occur immediately upon depressing the gas pedal, or does it accelerate smoothly for a few seconds, and then begin to stumble?
And once it stumbles, does it regain its composure immediately when you let off the pedal, or does it take several second (or more) before it smooths out?

If the change is not immediate, I would consider the fuel filter, but I would also consider the fuel pickup sock in the gas tank - if the sock disintegrates, and there is some solid gunk in the tank, then enough fuel flow can suck the gunk against the pickup tube, blocking fuel flow, and then release it again when the suction is reduced. Depending on where the gunk is floating in the tank, you may or may not pick it up at any given time.

If the change is immediate, I would also consider an ignition problem related to high voltage, such as a weakly insulated coil winding or bad wires.

These kinds of intermittent problems can take a long time to sort out.
Generally, it's good to start with cheap and simple (like the fuel filter) and work from there.

Please keep us posted.

- Eric

maheider

When it is acting up, the misfiring starts almost immediately upon giving it throttle, and it stops just as quickly when letting off. If I baby the throttle I can still accelerate, though at a slow rate, but if I give it too much pedal it will once again start popping.

I took it out the last two days for a cruise, not really getting on it a whole lot, and no issues whatsoever for a total of 75 miles. The times I put my foot into it the engine responded as expected. I can almost count on it misbehaving again soon however.

The truly intermittent aspect of this makes me think maybe it is related to wiring somewhere. It seems like a worn wire somewhere could work fine most of the time, but occasionally would get to where it was not passing spark properly and thus cause an issue. I could certainly be mistaken but it seems like a restricted fuel supply issue related to a fuel filter would be more predictable.

I'm going to get that filter changed one way or another soon and see what that does for me. I probably won't get to it until after the holiday weekend since I will be out of town, but I will definitely update this thread with the results.

Mark

maheider

Indeed the third digit is a 6, so put me down for a deluxe along with most others it seems.

Octania

I have '66 Toro #1000 or something like that- crusty car.
I remember the body number is very low, like first week of production.

This wrench may seem expensive but they are incredibly effective and you only need one for the rest of your life:
http://www.grainger.com/Grainger/wwg...rue&sst=subset

Use the 1" wrench to hold the filter housing.
Apply equal amounts of torque to each, so the net torque on the carb is zero
Increase torque until line fitting frees
lube the heck out of it
work it back and forth until it comes off- heavy 5/8 open/flare wrench is ideal:
http://www.grainger.com/Grainger/PRO...t-Wrench-1ANT7


Crowfoot flare sometimes required on the fuel pump end
http://www.grainger.com/Grainger/SK-...rowfoot-12A309

USE GREASE or silvery anti-sieze on the line ends when re-assembling. Between nut ID and line OD, and on the nut threads. The seal is effected at the flare, so DO NOT use Teflon tape or similar on these joints. I use a.s. on the filter housing to carb as well, to thwart corrosion and galvanic decay. FINGER assemble everything and do not tighten anything until everything is started and almost seated.

jaunty75

Cool! You may very well have one of the earliest-produced Toronados still in existence.

MDchanic

I don't believe it.

Proper use of the verb "effect" on an internet forum.

Only on ClassicOlds.

- Eric

maheider

Thanks for the detailed procedure advice Octania. If I still have issues with my 5/8" flare wrench I may spring for that one you linked to. Looks like it should do the job.

maheider

Well, I have not yet been able to break the 5/8 fitting loose. I may go ahead and order the tool suggested to give me more grip on it. The good news is that in the meantime, I have not had any instances of the issue in the last few hundred miles, so maybe it is working itself out on its own?

Octania

The self repairing car- Christine?

I left the Saturn in the driveway for like TWO MONTHS now and it absolutely did not fix its crank or put a new engine in for me.

MDchanic

I HATE when that happens.

- Eric

maheider

Yeah, I think it took itself out to the local Olds dealer and had itself fixed ;-)

Seriously, maybe it was simply some bad gas that I had to burn through. Or, perhaps something in the carb was sticking and finally loosened itself up. I did use some gum out early onto see if that would help. Or, perhaps most likely as anything, this is just an intermittent thing due to some blockage in the fuel delivery system that comes and goes, and it will return at some point.

I can't wait to get that stinking filter out of there. I am curious to see if it has any gunk in it.

deaddds

Try spraying some Kroil on the connection. This stuff will dissolve any crusty rusty crap holding up the show. Give it a few minutes to soak in and it should free up.

oldcutlass

I'm glad to see the shop fairy's are alive and well.