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Still fighting Fuel vs. Electrical issues

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Jim_Gruber

Jim_Gruber

Yoda
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As I recounted to many of you I'm still fighting the fuel vs. electrical issues on Bugsy my '68 Sprite with 1098.
Problem began as intermittent missing that would continue to get worse and worse and all of a sudden the engine would simply die. A turn off and tuen on and hte engine would immediately restart and pull strong with no miss. It might runb fine for 5-10 minutes and then the problem would start again.

Trouble shooting so far.

1) Replaced fuel filter ahead of electric fuel pump, no change.
2) Discovered loose wire on 12VDC+ side of the coil. Though that was the issue car ran fine for 2 days and then started acting up again.
3) Suspected coil - Replaced coil - no change
4) Pulled tops of float bowl- both carbs have equal levels of fuel. Supect rubber lines, replace lines, smell fuel, discover gas pouring out of front carb over flow.
5) Pull carb float, clean needle valve seay and blow out with air, reset float between 1/8 - 3/16 gap, closer to 1/8" & reinstall
6)Leak stops but engine really feels like it is way off tune. Drivable but way off power, high speed miss. Idle seems real unever.
Mother's Day weekend no time for doing diagnostics.
7) Start Bugsy to run an errand yesterday. Smell gasoline from underhood after going 1 block. Engine really rough, turn around and return. Pop Bonnet and discover gas pouring out of rear carb. WTF- other than popping the top and making sure no crap in the fuel bowl why is this one suddenly pouring gas out the top i.e. stuck float.
8) I will pull apart this evening and reset float gaps and clean the needle valse seat. Other than the crap that was fouling the front carb possibly migrating to the rear carb, I can't figure out why rear carb is all of a sudden messed up when it has not leaked for 8-9 years of ownership. More front carb either

Plan tomorrow night
1) Stop the fuel leak
2) Change out dizzy to known good mechanical dizzy to make sure not condenser or points issue in dizzy, reset timing and rule out electrical
3) If issue still persists replace fuel pump.

Could a going bad fuel pump all of a sudden be putting out Too much pressure? The mystery continues.

Any other ideas from the list?
 
A few years back, although my car was running OK, I figured it was time to get the carbs rebuilt. I sent them off to Joe Curto. When I reinstalled them I could smell gas. To make a long story short, we (Paul A. and I) tried everything we cold think of of stop them from overflowing. We changed needles, seats, needles and seats, floats, tops, even the fuel pump. What worked was to install a Fuel Pressure Regulator. I got a Holley having been warned against those little round ones as being worthless.

If you have changed the float level, you should re-adjust your carbs as they won't be set up properly anymore.

As I recall you have changed the condensor already. While you have the dizzy out, change it again.

I have had low speed miss for way too long. High speed fine, low speed an occasional flutter, NOT related to acceleration, so NOT Dashpot related. That seems to have been cured when --- after I changed the cap and rotor (to BRASS style from Advanced Distributor) and it still missed--- I brought the cap and new wire up to the kitchen table and SHOVED the wires in HARD, using dilectric grease on the connections. ... Could part of your problem be something as simple as that?..

Paul A forwarded me the following letter as well. .. does any of this apply..?
*****************************************************************
---I've been having some annoying little performance issues for some time. Nothing awful, just one little thing after another. Anyway, I had Jeff rebuild my dizzy last year and drop in a Pertronix.

Without going through the history, here's what I learned from Jeff that I didn't know before. The newer carbon spark plug wires don't work well with the BE screw type dizzy cap. You ought to use solid core wires which can be hard to find (took me 5 stores to find them). I found a set of Belden wires at a long-time NAPA store. I had a set of newer wires in and they worked OK for a while, but one eventually (and according to Jeff inevitably) shorted out. The solids work great.

If you're running a Pertronix, it can be susceptible to RF interference which can result in misfires. Along with the solid core wires, you ought to use resistor plugs. I don't have a radio, so figured it didn't matter, but according to Jeff, it does. And when I switched to resistor plugs, the problems disappeared.

Something else I never knew... I had been running non-resistor plugs. One was bad and the parts store only had a resistor plug. So the guy behind the counter said it would work fine. But... Jeff told me that resistor and non-resistor plugs fire at different times. I had a high speed miss at 3000 RPM. The two different types of plugs were causing the problem. Replaced the 3 non-resistors with resistors, and there's peace in the valley. Runs like a champ. Probably until tomorrow, but runs great today. Anyway... I've been futzing with cars for a long time and never ever thought about the composition of wires or the differences between plugs. Never knew they fired differently.----
 
Bill,

Possibly. I only messed with float level on the front carb. Stopped leaking gas out of the overflow but it seems off tune. I've got a known mechanical dizzy on my spare 1275 that I'm going to swap in to see if that resolves and issuer with condenser, or points. Last night gas started pouring out of the rear carb. Going to look at it tonight if I get a chance and set float levels same as the front or go back to level on the front to match the level on the rear.

I've got to get it apart and compare float heights. Will have time to do a full carb adjustment tomorrow night when Mama is in class and I've got the gartage to myself to make all sorts of noise and emit noxious smells. Oh wait a minutem that's me after eating beans, not Bugsy. Got confused for a second there.
 
a comment on the "can a fuel pump going bad suddenly put out too much pressure?" question--
The same exact thing ( suddenly way too much pressure) happened to my carter p4070 last month. I posted about it here. New pump installed and flooding/ extemely rich problem is gone. My pump was 6 mos. old, tops.
 
Jim
I see that you have a filter before the fuel pump but do you also have a very fine filter just before the carbs? I put a coarse filter before the pump and a sintered one before the carbs.
Bill
 
If you're concerned that the fuel pressure might be too high, it's time to buy a pressure gauge. They're not expensive, and if you install a regulator, you'll need a pressure gauge to set it up properly.

I fought a similar problem for some time, and finally decided to put in a pressure regulator (dropped the back-off pressure from 3.5 psi to a little less than 2.0). I also found that the pivot pins for the float were worn and I think that the lever was binding against the side of the float bowl. No trouble since then.

Now--if you fixed a loose coil connection and it ran fine for a while, there are only two possibilities: (1) you have more than one problem, or (2) the problem is somehow related to that connection or to something you inadvertently changed when you reconnected it.
 
Instead of using resistor plugs try using solid core wires + resistor spark plug conectors, like the short brown Bosch ones used on old Beetles. They screw into the wire end, clip securely to the plug (remove the little threaded cap on the end) and are dependable. And get rid of the points & condenser.
 
If you have changed the float level, you should re-adjust your carbs as they won't be set up properly anymore.

Old wives tale. Float level has nothing to do with carb adjustment for running.
 
jlaird said:
If you have changed the float level, you should re-adjust your carbs as they won't be set up properly anymore.

Old wives tale. Float level has nothing to do with carb adjustment for running.
Click to expand...

Well now, this Mother Hubbard don't agree. The higher the float level, the higher the fuel level in the jet.
 
Gota set it to spec, then it should be right on.. Anyway that is idle not running. Running it will set its self.

Your only adjustment really is idle speed and idle fuel unless you change needle sizes.
 
I think you should check your tank for trash.

Years ago I had trouble with the carbs on my Spitfire overflowing. Each time it was a small bit of trash in the needle. I already had a filter before the fuel pump. It hasn't re-occurred in some time, but it could be serious if it happended when the car was hot, as the fuel spills onto the exhuast.
 
Your right, a good clean out would not hurt in any case.
 
Guys I'm working through all of those issues as we speak. Got a buddy coming over tonight to help. I did take the float apart on the back carb last evening. Removed float and needle valve. Blew out with compressed air and did see a small black speck come out on my hand. Extremely small, could have been on my hand prior to running air through the float. Overflow did stop once I reassembled.

Now I've got a conglomeration of parts and pieces on this car I've discovered. Front float is adjustable, and I've adjusted to spec 1/8 to 3/16" gap and it is set closer to 1/8. Back float is non adjustable fixed type and float appears to be less that 1/8" gap. That may be totally irrelevent in this case.

At this point I'm happy if gas isn't pouring out and running all over the hot exhaust manifold. I'm leaning more and more towards fuel pump issues. Connections are tight, I picked up a new set of points this AM and will change out or use my spare mechanical advance dizzy for testing. Kim, I will not add additional variables in by using a condenser with the dreaded orange wire. Coil has been replaced so that is not the issue.

Plan is to go through a methodical step by step tuneup procedure this evening and see if we can find anything wrong that needs to be fixed. I'll take it back to basics and take it one step at a time and see if we can isolate the problem.

I'll provide a complete report.
 
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