Warm engine misses

[Vettehead Mikey]

Go to this webpage to find gas stations that have ethanol free gasoline. There are several in your area of Cortland, New York.
Ethanol-free gas stations in the U.S. and Canada

Let's not start the silly ethanol debate. This is not a factor in the OP's engine issue.

 

[Vettehead Mikey]

Along with this inquiry, I must say that I am not at all convinced that fuel is the problem. I just tried the K100 in an effort to eliminate "water in the fuel" as a cause of misses (and then Vettehead tells me that the stuff doesn't work!!). Since nothing much changed with the K100, I assume that either it didn't work or that was not the problem.

These snake oil products don't work because it's chemically impossible to destroy or eliminate water in fuel. It's still there. The only thing the product can do is cause the water to suspend and combine with the alcohol content and hope that the engine will burn it off. An 8 oz bottle of snake juice might be able to absorb maybe 1-2 oz. of water at best, but if that's all that is contaminating the gas, there would be nothing to worry about in the first place. If you've somehow gotten a larger dose of water, then several gallon of snake juice would be required. There again, your fuel is probably E10, so if you've got 9 gallons of fuel in the tank, that's almost 1 gallon of water-absorbing alcohol.

This presumes that the contamination is water. If it's something else, then (again) bad gas cannot be fixed.

 

[RestoCreations]

Re: 1967 Corvette Coupe Restomod Build Thread

Let's not start the silly ethanol debate. This is not a factor in the OP's engine issue.

Who is starting a debate? Im not saying that is his issue or that it has anything to do with what he is experiencing, because I don't believe it is. If you read my post i clearly stated that I don't think gas is his issue, but if he is going to waste his time draining his tank, why not get some ethanol free gas since it is summer. Ethanol has a lower boiling temperature than gasoline and if you don't think it causes issues in carburetors where i live, think again. However, those issues are pretty much confined to percolation after shut down on hot days.

 

[Bo Dillingham]

To All,

Since this topic has had over a thousand "Views", and more than 60 "Replies", I want to give the best information that I can, as well as act on the suggestions that I receive; so here's today's report.

I just installed a brand new set of plug wires and went for a ride. Nothing changed. To be clear, and for the benefit of those who do not read every one of the more than 60 posts, the '65 Vette 327 starts instantly and idles smoothly. It also accelerates quickly and is very well performed throughout acceleration. Since I am not going too far from home, my "Open road" speed is around 50 MPH, but I think that is enough for observation. Once I get up to speed and level out around 40 or 50, I get a tangible miss. It feels like a slight jerking motion, and it continues all the way down to almost a full stop, like at a stoplight. Once stopped, it goes back to a nice idle, and the cycle starts again.

Since I have replaced points, plugs, coil, condenser, and plug wires (with a couple of different kinds of point sets), and the rotor and cap look like new, I'm starting to think that the carburetor may be at fault. I seems to me, from my old gearhead days, that a carb can be somewhat out of tune and still function pretty well, but I'm running out of ideas.

Considering the simplest of facts; it idles well, it accelerates well, and it misses at cruising speeds, do you have any more suggestions? Remember; 1000 "views" and 60 posts, so I am not the only one interested.

As always, thank you very much for your advice, and especially your patience,

BoDill

 

[Bo Dillingham]

To All,

In reading a lot of "Internet information" regarding engine misses, I ran across an article that said, "A hesitation, stumble or misfire that occurs when the engine is under load can be caused by a faulty power valve inside the carburetor.".

As a starting point for turning this discussion towards carbs, does anyone agree with this? Could a contaminant get past a fuel filter in the fuel line to cause a clog? Are there other places in a Holley to look for something that may cause such a miss (When I got the Vette, I got the paperwork, and the receipt for my Holley says only "03310 Carb" under "Part Description", but I think it's a 650 double pumper/spreadbore).

A friend of mine suggested letting him rebuild the carb, and I'm very likely to let him, but I thought I should ask a few questions first.....

BoDill
<style type="text/css">p { margin-bottom: 0.1in; line-height: 120%; }a:link { }A hesitation, stumble or misfire that occurs when the engine is under load can be caused by a faulty power valve inside the carburetor.</style>

 

[Bo Dillingham]

<style type="text/css">p { margin-bottom: 0.1in; line-height: 120%; }a:link { }</style> [FONT=DejaVu Sans Mono, monospace]To All,[/FONT]


[FONT=DejaVu Sans Mono, monospace]Since I am working for the next couple of days, and you have been so helpful, I thought I'd let you know what's up.[/FONT]


[FONT=DejaVu Sans Mono, monospace]Late last night I got to thinking that I had replaced all the “ignition stuff” except for the rotor and distributor cap, as they looked like brand new, even under close examination. I had a spare cap and rotor in inventory, so I figured it couldn't hurt to put them on. So at 11:30 PM, I put them on and went to bed.[/FONT]


[FONT=DejaVu Sans Mono, monospace]This morning I took the car out for a short spin around the block, and didn't get the misses that these posts are about. Acceleration was good, and there were no severe misses at 40 to 50 MPH.[/FONT]


[FONT=DejaVu Sans Mono, monospace]It seems like there were a couple of misses during the ride, but it might be that I am over-sensitive at this point.[/FONT]


[FONT=DejaVu Sans Mono, monospace]At any rate, over the coming weekend I will likely fine tune the timing and anything else I can think of, and I will post my findings. I'm not done yet, but things are looking up....[/FONT]


[FONT=DejaVu Sans Mono, monospace]BoDill[/FONT]

 

[Tom Bryant]

I thought about carbon tracking a while back but you said that you have inspected the cap and rotor more than once. On a cap it's usually easy to see as it looks like someone drew a line with a pencil down the inside of the cap towards the distributor housing. I have also experienced a carbon track down the underside of a rotor from the rotor tip to the distributor shaft. Do you see anything like this on the old cap or rotor?

Tom

 

[Bo Dillingham]

To Tom,

I'm working, so this will be short.

I couldn't find carbon tracks, or cracks, etc. even on close examination under good light. Also, my "test drive" this morning was short, so I don't want to jump to any conclusions. My last post was more of a courtesy to everyone who has been helpful, and who are following these posts.

As I stated, I'll do more over the weekend, and will post reports; good or bad!!

BoDill

 

[RestoCreations]

Looking into common issues with your carburetor is very simple and something you can do on your own if you follow the article from Lars that I posted. A power valve is very, very simple to replace. However, if the power valve is blown you would have issues at idle...the car would want to stall when you come to a stop.

 

[Bo Dillingham]

To RestoCreations and all,

I have printed the articles by Lars and read them all at least once. Now I intend to read them again slowly and carefully, and pay very close attention to the one on carburetors. Since my car has only logged abound 20 to 30 thousand miles since its rebuild (around the year 2000, and I'm not sure because the speedo wasn't working all the time), I didn't expect any problems yet.

Now that I have at least a glimmer of hope that there is a light at the end of the tunnel, I will continue to drive it, tune it, check things out, drive it, retune it, etc. etc. Since I'm not yet sure how many problems are solved, I don't want to get overly optimistic; I've had ONE SHORT RIDE that didn't show any real problems.

I will, however, post any pertinent info whether it seems to be important or not. Personally, I'm still in awe of the results of replacing the rotor and distributor cap, and I will try to find an explanation for that too!

I'm at work, so that's it for today......

BoDill

 

[Bo Dillingham]

To All,

Again, I'm working today, AND the weather in Upstate New York is supposed to be "rain" for the next few days, so I probably won't do much test driving, so this will be short.

Though I haven't been able to REALLY test my theory about the rotor cap being the problem, I have re-examined it more carefully and I found something that I hadn't noticed before: it has a separate piece at the end of the contact strip (I'm not sure if that's what it's called, but it is the metal strip that maintains contact with the center pole on the distributor cap). At the end of the strip is a piece that could be compared to the head of a pin, but about 20 times the size. As a matter of fact, I found a photo of what I believe is the exact rotor and cap that I had in the car at (file:///home/bodill/Desktop/corvette-distributor-cap-rotor-kit-dual-window-62-62), and you might be able to tell from that photo that there is a separate piece on the tip of the rotor contact.

At any rate, the "nail head" at the end of the contact is rusty. At first glance, it just appears to be dirty, but once you bend up the spring and REALLY look it over, it is rusty, and the stem that goes through the spring is seriously rusty. If I haven't described this properly, let me know and I'll try again. Also, I don't mean to sound critical of the these components, as this car has been running well since at least the year 2004, and it is stored all winter in an UNHEATED garage!!

Now, as I said, this is just a minor theory right now, as I haven't had a chance to really delve into it, and I won't have a nice day for test driving for at least a couple more days. I thought I would put it out there and see if it gets any comments from you.

BoDill

 

[Bo Dillingham]

To All;

It's Monday evening and I just got a chance to take the vette for a short ride. Unfortunately, it still "misses". This trip, I tried to get a "feel" for the car at around 1500 RPM, which was around 30 MPH, on a few straightaways, and the miss was there, but it seemed rather irregular. During the ride of about 20 minutes total, it would seem fine under some conditions, like during acceleration, but misses when speed is reached. Unfortunately, it might be misfiring during acceleration but could be hidden other factors; I simply don't know.

I have looked around on the internet for a comprehensive article about fuel and its relation to misfires, but I haven't found anything convincing yet.

I'll probably drain the tank, and likely tune the carb, and anything else that sounds like a reasonable suggestion. I'm also more than willing to take it to a good mechanic, but I hate to give up without trying everything that I can do myself. 'Anybody got any more suggestions?? Please let me know, as I will likely try them before I turn this thing over to a shop.

Thanks for you patience and support,

THIS EDIT as of 8:15 EST; I just drained the tank. I jacked up the right side of the car, and put a stiff drain hose down into the left rear of the tank, and from looking into it with a flash-light, it looks like I did a pretty good job. Now, since I have never done this before, are there things to look for? Is there a way to tell if I had bad gas to begin with? Should I try to clean the tank with something before I refill it? Any information will be appreciated....

Again, thank you,

BoDill

 

[c5vetter]

Again, I have to ask - did you or did you NOT change plug wires as I suggested? I still believe you may have an arc or something going on that you can NOT see

 

[Bo Dillingham]

To c5vetter,

To quote my post of July 27, 12:40 PM, "I just installed a brand new set of plug wires and went for a ride. Nothing changed." Unless I'm missing something, I think I have changed out every ignition component.

Also, as I have said, the car starts with surprising ease!!!! I barely turn the key and it jumps to life!!! The "miss" is difficult to fully describe because it is not consistent, and it is not regular. By that I mean that I would expect a bad wire or a bad plug to miss with a regular "beat". My misses are not regular, and they seem to come and go, and do not seem to be dependent on speed.

To All,

Right now my fuel tank is empty, and I haven't found anything of value on the internet regarding cleaning it, or doing anything after emptying it other than refilling it. Also, after all this screwing around with ignition stuff, I'm not anxious to get into the carburator. Perhaps someone could suggest a couple of easy steps to take to do some preliminary checks on the carb before going after an entire rebuild?

Thanks.....
BoDill

 

[Mac]

Have you checked/changed your inline fuel filters? Many moons ago, I ran into a strange engine miss caused by the fuel filter on a Q-Jet. I was getting ready to rebuild the carb as I'd convinced myself that was the issue. When I disconnected the fuel line, I saw the filter was crudded up... so I replaced it and resolved the issue instantly.

Mac

 

[Bo Dillingham]

To Mac,

Yes, changing the fuel filter is among the first things that I did, and I apologize for not mentioning it back in the beginning of all this.

 

[Bo Dillingham]

To All,

It is around 8 PM my time, and the last thing I did was syphon the gas out of the tank with right side of the car on a jack, to put the last bit of fuel on one side of the tank. I found no water, so I'm not sure what I'm going to try next. I'm leaning toward a carb rebuild, as I don't have any other reasonable ideas, and a carb rebuild probably won't do any damage (its been running since at least 2004 without so much as an adjustment, so maybe its time anyway).

This post is for two main reasons; 1. Is that so many people are following it that I don't want you to think I have just abandoned this when I'm gone for awhile, and 2. Since I won't get a chance to rebuild the carb for at least a few days (maybe weeks), perhaps someone will come up with some other ideas in that time.

Let me know....I really appreciate your comments and support,

I'll be back,

BoDill

 

[RestoCreations]

At this point, i think you are grasping at straws. Aim small, miss small! You have a minor problem with your distributor or carburetor. My money is still on the distributor.

 

[Bo Dillingham]

To RestoCreations,

Thanks for the comment. Since a heavy downpour is looming, I haven't driven the car today, but I just put a few gallons of new gasoline in it. Since I have replaced everything having to do with ignition (points, plugs, wires, Distributor cap, rotor, and coil), and even tried various things like "points with the condenser built in", and I checked the wires in the dark (no sparks), I'm beginning to lean towards the carb. Also, I have had the distributor out of the engine, and it looks like new. I have spent some time on the internet looking at various sites that have discussions about "misses", etc. but haven't found anything earth shaking, and I believe that the people at CAC are the better source of info anyway. ( By the way, it seems like most of the mysterious misses experienced by others are due to modern equipment that is NOT on my 65 Vette. )

To All,

In the next couple of days, weather permitting, I will drive it around again if for no better reason than to see if new gas has helped, and will report any findings, progress, or problems along the way.

A quick phone call to Holley got me some info on my carb, which is a model 4165. I am certainly not going to rush into anything with the carb, but I will likely rebuild it soon out of respect for my car. The poor thing has been driven in the summers and stored in the winters since 2004 with no problems until now.

More as it happens,
BoDill

 

[RestoCreations]

Just because you replaced components in your distributor, does not mean you still do not have an issue. There are so many factors that could be at play. If you are going to screw with the carburetor, i suggest starting with the basics...check your float levels first as per lars instructions.