Engine spits and misses @ high rpm

[Silverdome]

could you explain this logic for me please...

If you have excess play it can cause the gap to become erratic which effects the amount of spark the ignition points or in his case the pick up can make. And usually the higher the RPM the more noticeable it is.

[Plymouthy Adams]

Silverdome, on 22 Aug 2014 - 4:34 PM, said:

If you have excess play it can cause the gap to become erratic which effects the amount of spark the ignition points or in his case the pick up can make. And usually the higher the RPM the more noticeable it is.

I can see this argument in a distributor but you are saying generator...

[Silverdome]

I can see this argument in a distributor but you are saying generator...

Sorry about that, I corrected it to say distributor shaft.

[soth122003]

The distributor is fine. The play is less than .001. Already pulled it, cleaned it, replaced a wire and did the checks on it.

 

Joe

[soth122003]

Alright, Update time!!

 

Got the genny back and put it in yesterday evening. Started the car and she ran fine at idle. Amp gage reading about -5. Reved  the engine to about 1500, no misses or spits and the amp gage reading +20. Increased the rpm's to about 2500, no misses or spits, amp gage pegged out.

 

Took it for a test drive for about 2 miles today and the engine is doing fine, no misses or spits at high end rpm in any of the gears. The amp gage however, is showing pegged with the higher rpm's. At idle, it is about 0. But as soon as I step on the gas, the amp gage shows an increase until it pegs out. This is at a middle range rpm. The amp gage pegs at about 30-35 mph. And since I don't have an rpm gage, I can't give specific values.  

 

All that being said, the car is running great, but the amp gage is worrying me. Any comments or suggestions would be greatly appreciated.

 

Joe

[greg g]

What happens if you turn your headlamps on? If the gauge shows lesscharge with lights on your voltage regulator probably needs some attention.

[soth122003]

Just played with the VR. Now there is no amp reading on the gage except discharge. Time for a new VR, I guess.

 

Joe

[_shel_ny]

This may be of some help when checking the charging system.

 

http://vrr.dyndns.biz/Docs/Autolite/autolite_gen_and_start.pdf

[soth122003]

Greg G: you were right on the money there with the lights on.

 

Shel_ny: Thanks for the info, While it helps a lot, I don't have the test equipment to do the adjustments.

 

I ordered a new VR from amazon last night, but it wont be here until Friday. I am going to try and set the VR with a simple multi meter, but at best guess it will be mostly trial and error. Between the shop manual and the pdf file  shel_ny posted I might get it close.

 

It must be a law somewhere that states your crap will always break on a week end when all the repair shops are closed. Add to that it's a holiday week end as well.

[_shel_ny]

I would expect that a new voltage regulator should be "plug n play'. You should not need to go into it.

 

 

If you are talking about adjusting the old one, the link I posted should help with the basics of operation, and adjusting that should allow some tweaking without all the fancy equipment.

 

I have not adjusted one, but I know it is important to get it right so that you don't continually over charge your battery.

[soth122003]

shel_ny: You're right. The new one is plug and play, but I won't get it unitl Friday. I'll tinker with the old one and see if I can adjust it to work. It was working after I reinstalled the genny,  but it showed a continuous high charge when the engine was reved. The amp meter was pegged positive. I took it out and adjusted the air gaps and now it shows no charge at all. Methinks I got something wrong and I'll recheck everything to be sure. Besides it can't hurt to have a spare VR and it was only $58.00 w/shipping.

 

Joe

[Niel Hoback]

   You say it was working after you installed the generator,  if it was showing a continuous charge and pegged the needle, it wasn't working right. Overcharging will ruin your battery and unregulated charging will burn up your generator. 

[soth122003]

Hey Niel,

 

You're right it was showing a slight charge maybe 1-2 amps positive, but when you revved the engine it would move up until pegged. I just got done with some minor adjustments and now with the engine revved it shows about 25-30 amps+. I think the current limiter is messed up. The circuit breaker works as advertised, but the current and voltage limiters may be out of whack. Not as bad as before I made the adjustments, but with out a bench test set I can't get it spot on. I think it is usable now if I use the headlights as a buffer, this will bring the amp gage down to about 5+.

 

When I get the new VR on Friday, I will see if one of the local shops can set the old one to the proper specs. That way I can have a spare.

 

Joe

[Jerry Roberts]

Be aware that if you bring your voltage regulator to a shop for testing / adjustment , they probably will want to test it WITH your generator . 

[soth122003]

Thanks for the info Jerry. I drove my car around for a couple miles today and after I got home I let it run above idle with the fast idle cable. Probably about 1000 rpm's, and the amp meter was reading about 20 amps+ when I started and after letting it run for about 20-30 minutes it was reading about 10-15 amps+. 

 

I don't know if it's because the genny brushes are wearing in or the battery is taking a slow charge, but the amp meter reading is coming down. I put a battery tester on it yesterday, and it was reading in the green, hit the toggle to simulate a load on the battery for 10 seconds and it moved just a bit but still stayed in the green, so I assume my battery was fully charged.

 

 I also checked the output of the genny armature it was putting out 7.4 volts. The battery terminal on the VR was also showing about 7.3-4 volts as well. Same with the arm tab on the VR, 7.4. But the battery itself was only showing about 6.5 on the meter. This was at about a 1000 rpm's. With all that said, I think the VR is pretty close to its supposed standard. I'll double check the readings again when I install the new VR on Friday.

 

Joe

[greg g]

OK you have hit upon a good point on VR/battery condition relationship. The VR 's job is to sense the battery charge level, and restore it to a fully charged condition. So typically assuming a fresh and full charge battery, when you start your car, the battery will discharge to spin the starter and power the ignition circuit. The VR will sense this drop and engage the gen by energizing the field coils. This should be reflected on the amp gauge, by showing a 10 amp charge as you begins to drive around. As soon as the VR senses that the battery is at full charge level, it will cut out the field coils. This will show on the amp gauge as a 0 charge state, or a slight positive to account for the power needed for the ignition circuit. Typically all things being in good condition, your Genny and VR aren't really working that hard just driving around. Stop lights and signal lights being the only load other than ign. If you drive at night with the heater fan on, then you will begins to exercise the system, but in typical daytime driving once you put back what the starter draws, there isn't much going on electrically, so the VR and Genny are basically in standby mode.

[soth122003]

Well, took the P-15 out for about 70 miles today. The new VR came while I was out. The car ran good and I got it up to 70 mph today. It still feels like it is running just a little rough, not much though. The VR showed a constant 10-15 amps+ the entire time, but the engine did not miss or spit like before. I ran through some rain and with the lights on, the VR still showed about 5-10 amps+. The engine didn't seem to struggle with the extra load and when I went to idle at a stop the VR would go to zero with the lights off or 20 amps- with the lights on. Step on the gas and the amp gage went back to about 15 amps+. I think the VR is working, just not like it is supposed to. I'll take some voltage readings off it and compare them to the new VR when I install it later on today.

 

That being said, I think the timing might be off just a touch, which make me feel that the car is not quite right at higher speeds. I'll check that this weekend.

 

Joe

[soth122003]

Well I changed out the VR and tried to get some voltage readings off it. The digital multi meter I was using was flipping between 4-18 volts like a speed addict, so I couldn't get a decent reading at all. My amp gage was showing a slight negative draw with the key on and not started. When I started the car the gage went to zero. Revved the engine and the gage didn't move. Turned the lights on and the amp gauge went to -25. Revved the engine and no movement on the gage. I talked with my neighbor and he gave me an analog multi-meter. Using that I got steady readings from the genny, VR and the battery. The genny was putting out about 8v @ 3000 rpm's same as the arm and bat tabs on the VR. So I know that part of the system is working.

 

Quick question for all you guys out there. Do you use a digital or analog meter when checking you electrical systems? And why use one and not the other? I tried looking for an answer on the threads but rally couldn't find one.

 

That being said, I think the wiring to my amp meter may be old and grounding out. I am going to try some jumpers today and see if that makes any difference.

[TodFitch]

It is my understanding that the very noisy electrical system presented by a generator is best measured with an analog meter as it has a needle that is inherently damped as opposed to a digital meter that might be doing instantaneous sampling. I am guessing you could get your digital meter to read better if you put a choke on the test lead to smooth things out.

[soth122003]

Well a final update. I got a hold of a analog multi-meter and the readings on the old VR were pretty much on the money. I also noticed that after the last adjustment I did the VR would read about 15-15 amps+ then slowly go back to about +1 and ride there. It took about 5-10 miles to get there but I am not complaining. The generator is generating, the VR is regulating, and the amp gage is working like a champ. I also set the timing after making a new pointer for the engine, and installed a 160 degree thermostat, and now I am running great and getting 18 MPG at just under 180 degrees on these hot humid Florida days.

 

The last two problems I have are the gas gage not reading right. As far as the gas gage goes, it works but it is not reading right. probably a ground or wiring problem somewhere. And the exhaust manifold that has a hole and a crack at the #1 mount and a crack at the #6 mount. This leads to the Bonnie and Clyde syndrome. It sounds like a machine gun when I am accelerating down the road, and since the sound proofing in these old cars is really low, I can't hear any other problems that might be happening over the TAT, TAT, TATx1000, of the exhaust leak. If any one has an old exhaust manifold laying around, PM me and lets talk. I also posted in the "car parts wanted" section about this. 

 

Joe Lee