Joined: Nov 22, 2006 Posts: 36 Location: Van Wych, SC
Posted: Tue Mar 03, 2009 6:41 pm Post subject: M38 Trouble Shgooting 2
Gentlemen;
It looks like I am having the same type problem as LoboMike in his February 2nd posting.
Our Jeep has been running like a champ since we fixed the starter in January of 2008. I have had a few backfires through the tailpipe, so I have been fine tuning the adjustments on the the carburetor.
A week ago it started fine, but cut off several times during warm up. It acted like it was flooded. It started it back up several times and then I put it back into the garage.
This weekend, the engine cranks and tries to turn over, but will not. I have new batteries so I was able to crank it several times. Still no joy. We rebuilt the carburetor two years ago and it seems O.K. I have not touched the distributor since we bought the Jeep five years ago. I am not sure when the distributor was last maintained or repaired. Reading in the TM9-8012 manual and on the tech forums, it sounds like I probably needs a new rotor and capacitor...and/or other parts.
Looking at Figure 55 thru 61, my question is...which suppliers might have these parts? Do you have any other suggestions?
Hello Thomas,
It looks like you are skipping the troubleshooting phase and moving straight into the shotgunning stage. Shotgunning is when you just start throwing parts at a problem without first deciding which system is causing the problem.
The systematic approach to troubleshooting saves you both time and money in the long run.
Let's see if we can clarify some of your symptoms.
Quote:
A week ago it started fine, but cut off several times during warm up. It acted like it was flooded.
When you say cutoff do you mean it quit several times, or that it stumbled several times or that it started to miss? When you say
Quote:
It acted like it was flooded
Do you mean you detected a very strong raw gas smell or that you saw heavy black smoke from the exhaust? Without at least one of these symptoms it is not flooded.
Quote:
the engine cranks and tries to turn over, but will not. I have new batteries so I was able to crank it several times
When we mechanics say it cranks it means it turns over. For us the two phrases mean the same thing. Perhaps you mean it will crank (turn over) but will not run? We need to clarify this point as well.
You should really get into the manual and start with item #1 in the troubleshooting guide and carefully check each item in the correct order and when you are done with the troubleshooting checklist and your problem is resolved let us know what it turned out to be. If you cannot still resolve your problem please let us know the results you had for each step in the troubleshooting checklist so we can better advise you.
After you read the intro paragraph #77 then based on what you have given us it looks like you should start with Para 78b. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Nov 22, 2006 Posts: 36 Location: Van Wych, SC
Posted: Wed Mar 04, 2009 7:41 pm Post subject: M38 Trouble Shooting 2
Wes;
Thanks for the input. Here is some additional clarification:
Quote:
"A week ago it started fine, but cut off several times during warm up. It acted like it was flooded".
Additional Information:
I purchased new batteries from Star Electric at Christmas time and filled them with battery acid, charged them, installed the new battery cable connectors, and installed them around New Years. Since then, on the weekends, I would run the Jeep to keep the batteries charges. If the weather is nice, I would take it on drives to charge the batteries. The last weekend it ran, it started just fine, but as it warmed up and I reset the choke, it would stall out and eventually quit. Then, when I tried to start the engine again, it would not start so. I had to leave it sit for several minutes, then it would start again, stall out, and then quit.
Quote:
"It acted like it was flooded"
Additional Information:
When the engine would stop and I would try to start it immediately, it would crank, but not start. When that happened, you could smell the odor of gas. Then when I would let it sit for a several minutes, it would start up again.
Quote:
"the engine cranks and tries to turn over, but will not. I have new batteries so I was able to crank it several times"
Additional Information:
Last weekend, I tried to start up the Jeep, but all it would do is crank. As I opened the choke and/or pumped the gas pedal, it tried to turn over, but would not start. I tried about a dozen times, but all it did a few times was sputter and not start. Again, there was an odor of gas.
Over the years on the electrical side, I have replaced the batteries and reworked the battery cables, rebuilt the starter, rebuilt and adjusted the carburetor, replace the spark plugs, and installed new spark plug wires. I have not done any work, nor replaced any parts in the distributor. Up until two weeks ago, the Jeep was running great. Knowing this, that is what drew me to paragraph 78, sections c3, c5, and e2, as well as paragraph 81 section b 1-3 as a possible cause of my problem.
I will take your advice and double check the other items in Paragraphs 77 and 78. If at the end of this work I still need distributor parts, which suppliers might have these parts?
Thanks again for all your help. I will post again when we get it up and running.
A strong smell of gas is not abnormal on any aborted ir unsuccessful start attempt.
If you have the correct YS series carb pumping of the gas pedal does nothing for starting the jeep. The acclerator pump is vacuum operated.
Quote:
"the engine cranks and tries to turn over, but will not.
This is quite confusing. Cranks and turns over are one in the same. If it cranks then it is turning over.
To secure help and advice we all need to be on the same page.
Cranks = engine rotates via the the starter,
Turns over = engine rotates via the the starter,
Runs = engine rotates continuously without the help of the starter or it is operating.
Quits = Engine stops rotating.
Stall = Engine stops rotating.
Misses = Engine runs roughly or appears to not always fire on each cylinder.
Load up = engines starts to labor and run very rich emitting blackish smoke.
Flood = Engine gets more fuel then it can use and stumbles and emits blackish smoke and often times will quit.
You continue to describe what I assume is poor running and stumbling as a flooding issue yet you haven't acknowledged the blackish exhaust smoke. As I mentioned above a fuel smell is common when an attempt to start is not successful and does not in itself indicate a flooded condition.
The behavior you describe can often be traced to fuel starvation caused by trash in the plumbing and the tank or can also occur when the vent line in the tank is plugged.
To eliminate the vent system clogging issue try running it with the gas cap removed from the tank.
If still the same disconnect the fuel line from the pump at the carb and get a clear plastic bottle and catch a sample of fuel in the bottle from the line while cranking the engine. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
Joined: Nov 22, 2006 Posts: 36 Location: Van Wych, SC
Posted: Thu Mar 05, 2009 7:23 pm Post subject:
Wes;
Thanks for taking the time on this one. Yes, I have the original YS carburetor.
The last time I tried to start the Jeep it did the following:
Cranked = engine rotates via the the starter and tried to start
Turns over = engine rotates via the the starter
Quit = Engine stops rotating when the starter disengaged
Stalled = Engine stops rotating when the starter disengaged
It did not:
Runs = engine rotates continuously without the help of the starter or it is operating
Misses = Engine runs roughly or appears to not always fire on each cylinder.
Load up = engines starts to labor and run very rich emitting blackish smoke.
Flood = Engine gets more fuel then it can use and stumbles and emits blackish smoke and often times will quit.
There was a smell of gas, but I cannot say it was overwhelming. I did notice that the gasket between the intake manifold and the carburetor looked wet with fuel. So, I snugged up the two nuts that hold the carburetor down.
The last time the Jeep was running, the choke was out. As the engine warmed up, and I tried to move it in, the engine would stall and quit.
I will try the set of test you describe, and post when I get some results.
Thanks again for this advice and your time.
The last time the Jeep was running, the choke was out. As the engine warmed up, and I tried to move it in, the engine would stall and quit.
This means the air/fuel ratio is inadequate. You are either getting too much air or not enough fuel.
Too much air can be caused by:
Carb base gasket leaking.
Intake manifold leaking.
Vacuum plumbing leaking.
Those areas can be checked for leakage by using the propane enrichments system. With the engine running you direct an unlit propane torch nozzle at the suspect areas. If you come across a leak (sucking air in) the propane will improve the engines idle.
Not enough fuel can be caused by:
1-Carb float stuck up.
2-Carb float needle valve stuck closed.
3-Fuel pump pressure low or flow rate inadequate,
4-Vapor locking.
5-Trash in gas tank, carb bowl or pump.
6-Gas tank vent plugged.
Those issues can be checked by:
1&2-Tapping on side of carb with small hammer. If no improvement remove top of carb and if bowl is less than half full the float sticks up or the needle seat sticks closed.
3-Connect gage to pump output line to carb and read pressure which should be 4 1/2 to 5 PSI at 1800 RPM.
4-Make sure the fuel line from the pump to the carb is at least 5 or 6" away from the exhaust manifold.
5-Fabricating a temporary gas tank using a one gallon can or an old boat tank and connecting it directly to your fuel pump.
6-Remove the gas tank cap to see if the vent system is plugged.
Also take a close look at the troubleshooting guide on using the Vacuum test gage and give it a shot as well. _________________ Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100
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