Diagnosing running issues...

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Model T Ford Forum: Forum 2017: Diagnosing running issues...
Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Warren- Huntington, VT on Monday, June 19, 2017 - 02:13 pm:

My car was running fine for the first 30 miles that I owned it. I took the fuel line apart to add an on/off valve and a short time after that the car stopped running well. The car doesn't have any power and spits and sputters as it drives. I drove the car yesterday and after it idling in my driveway (temp of 80 degrees) and driving it for 5 minutes, the radiator was boiling and fluid was coming out the top...

I have diagnosed the fuel line/system and feel very confident that the issue is not a fuel issue. I have checked the fuel flow from the fuel line and it is a full strong stream of fuel. The fuel tank is full. I switched carbs with a carb that runs good. I replaced the intake gaskets with the new gaskets/glans and have checked to make sure it's tight.

I have rebuilt all four coils (which were WAY out of spec). All four coils now fire exactly as they should and have been checked on a strobo spark for double sparking. I have checked the plugs and they have the correct gap. I have cleaned all the contacts in the coil box (however i have not rebuilt the coil box). I have switched the timer with a timer that was working well in a car that was running well.

I have also checked the compression and all four cylinders are within close spec to each other and have just slightly above 40lbs of compression.

I don't want to just start replacing things and buying more parts without trying to diagnose the issue. What are the top things that I could do try to chase down the issue I'm having?

Mike


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dufault on Monday, June 19, 2017 - 02:40 pm:

My car was running fine for the first 30 miles that I owned it. I took the fuel line apart to add an on/off valve and a short time after that the car stopped running well.

Time to stop and think, and think again. What else did you change/adjust/replace since the car ran well. Was the addition of the shut off the ONLY thing that changed the performance, of did you do all those "adjustments" to cause the poor performance?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Verne Shirk on Monday, June 19, 2017 - 03:09 pm:

Coilbox wood. Spark plug wires. Timer wiring. Sticking valves. Vapor lock. Blown head gasket.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rick Goelz-Knoxville,TN on Monday, June 19, 2017 - 04:57 pm:

recheck the intake gaskets, I just installed a manifold and everything looked goo it was tight but would pop and bang I tried adjusting the carb but nothing changed, so I removed the intake and found that the manifold was not sealed on the bottom and was cocked out enough to cause a bad leak.

Rick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, June 19, 2017 - 05:02 pm:

What kind of T did you place the valve on? If it is the 26 in your profile, it should have the valve on the sediment bulb under the hood and wouldn't need any other valve.

There should also be no filter in the line except the screen in the sediment bulb. Anything else will impede the fuel flow.

If you put on an in line valve, are you sure that it is turned on and not off? Most of the after market valves have the handle in line with the line when it is on and perpendicular to the line when it is off.

Is it possible that you might have stirred up some sediment when you had the line off and that it might be plugging a jet?

The trouble could be something else such as an ignition problem, however, usually when a car runs well just before making some change and then runs poorly after the change has been made would indicate something changed during the process.

One more possible cause would be low gas in the tank. That is usually not a problem with the cowl tank on 26-27, but is quite possible on the earlier under seat tanks. And it is compounded by trying to go fast, or by climbing hills.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By paul griesse--Granville,Ohio on Monday, June 19, 2017 - 05:16 pm:

clean or replace your PLUGS !


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jeffrey Bowen on Monday, June 19, 2017 - 05:59 pm:

I would pull each plug and ground it, crank the car and check for spark across the gap of each plug.

If you are getting spark, and you are getting fuel to the top of the piston then it has to be the timing of the spark.

Is your timer actually moving with the lever on the column?

Does it buzz when put to battery and fully retarded the timing?

Have you placed your hand over the intake to the carb and cranked the motor? You should feel the pull of vacuum if you don't then maybe Rick is right and its a leak on the intake. With a updraft carb if you have any intake leak at all fuel will never make it to the cylinder.

You tried a lot of things but, the easy stuff that maybe you tried and didn't tell us about could be the culprit.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Warren- Huntington, VT on Monday, June 19, 2017 - 08:07 pm:

David- I couldn't agree more that it is an awful coincidence that when I changed the fuel issue the problem started. I returned everything to the way it was before I made the changes, I switched carbs with a known good one, I checked and rechecked everything cause it just seemed that I must have screwed something up...But I can't seem to find anything fuel related so now I must try some other things.

Rick- just double checked them and they are tight and sealed.

Norm- It's a 23 touring. I bought a new sediment bulb to rule out any garbage in the one I had. The tank is clean, the fuel coming out of the line is crystal clear, the carb was cleaned in an ultrasonic tank, and was switched with a good running carb and not a single change... There is no filter on the fuel line other than the screen in the sediment bulb. The fuel is definitely on. The gas tank is completely full with non-ethanol fuel. It can't hold another drop it's that full.

Jeff- I am getting spark to each plug. The timer lever is moving on the column and it does make a difference in how it runs, it just doesn't run great. The carb has very good suction when placing a hand over the intake side and each of the coils do buzz when on battery cranking with the handle.

I'll keep trying and see what else I can figure out. I just wish it would completely die, it would be easier to diagnose that way... The rough running part, intermittent power issue is a bit harder for figure out.

Thanks for the suggestions.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Michelson on Monday, June 19, 2017 - 08:30 pm:

I see you switched the timer. But did you change the rotor/brush in the timer also?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Conger on Monday, June 19, 2017 - 08:33 pm:

the on/off valve: is it a multi-turn needle valve from hardware store or a 1/4 turn valve from one of the suppliers?

The valve that everyone buys from big-box hardware stores will never keep up the fuel flow that you need. Additionally, as it runs lean, this will cause your car to overheat.

You changed one thing, the car ran worse, and then proceeded to change a bunch of other things without returning the car to original configuration (fuel line) to see if that was the cause. You now have coil, timer, intake gaskets and fuel flow to troubleshoot.

Personally, I would purchase the quality intake/exhaust set from Lang's and redo the gaskets. It really sounds like a mixture problem either in the carb or now on the intake manifold. Once you've done a couple of sets, you will be able to do it with confidence but the first time or two is like wrestling a bag of snakes, with high probability of misalignment of one or more ports on exhaust and intake. The gaskets are shot after they are seated, so if you partially installed and then started over, this is a problem. Listen to Rick: Just because they are tight doesn't mean they don't leak like crazy if improperly installed (and you can't tell this by just looking, usually).

Good luck and some advice: next time you do something to the car and it runs worse, don't try a bunch of other stuff for the heck of it. Just remedy what changed.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Monday, June 19, 2017 - 09:39 pm:

When you replaced the sediment bulb, did you reroute the fuel line? The line should cross the exhaust pipe with a good clearance and follow the frame member to the carburetor. There should not be a high place in the middle of the line but each end should go up from the center so that if there is an air bubble in the line it will go either back to the tank or to the carburetor. If the center of the line is higher than the end, the air will rise to the high spot and compress causing "vapor lock" also if the line is too close to the exhaust, it can vaporize the fuel causing vapor lock. I have posted pictures of how the line is routed on my 22 and I haven't had vapor lock problems.
Norm




Top of pagePrevious messageNext messageBottom of page Link to this message  By Michael Warren- Huntington, VT on Monday, June 19, 2017 - 10:49 pm:

Scott, Although I didn't write the things I did in chronological order, the first thing I did was return it to the way it was. It didn't help. It was shortly after that time that I realized my coils were way out of whack so I kinda thought that fixing the coils would fix my issue. I didn't try a bunch of other things for the heck of it, I did it after researching on here similar issues that others have had in hopes that I would stumble on something. I tried one thing at a time to see if it helped or didn't help. I didn't change more than one thing at a time. Since I still had the issue, I had to start trying other things as it seemed that I ruled out the fuel issue with all the things I did (after returning it to original without any success). Each time I tried something new, if it didn't make a difference I put it back to the way it was. I tried a different carb, that didn't help, so I put the original back on.

Norm, I have my fuel line running very similar. The lowest point of the line is in the center, this way an air bubble can work its way in either direction.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Rick Goelz-Knoxville,TN on Tuesday, June 20, 2017 - 11:18 am:

This is what i was talking about on the intake gaskets.

You can see how the ring was cocked by the manifold.

Rick


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