Weird Problem tonight

[Nuru]

My first showroom new car was a 1962 Austin Healy Sprite and while it was still in warranty, my tachometer developed an odd habit. It showed correctly at idle, then as I accelerated, it came up to about 1500 and just hung there, and when the engine speed got up to about 2500, the tach would suddenly jump to catch up. So I took it the dealer and they pulled the tachometer out of the dash and installed a new one. It did the same thing. Then they tightened the fan belt and that fixed it. Naturally the tach was driven off the back of the alternator.

My first car was a 1967 AH Sprite, yellow with a bad engine, bought it in 1977.
I ran it a while and then I traded it in on a 67 VW bug.

 

[Bird]

My first car was a 1967 AH Sprite, yellow with a bad engine, bought it in 1977.
I ran it a while and then I traded it in on a 67 VW bug.

Did you consider that to be trading up . . . or trading down? In the '60s there were a few times when I thought maybe a VW bug or the VW bus would be a good practical vehicle for me. And each time, I got to thinking that, I stoppd by a VW dealer and drove one around the block, and cured that thought. That was as far as I had to drive a VW to know that I didn't want one. But I guess they actually were good practical vehicles.

 

[Mark3101]

My dealer is coming tomorrow with a new alternator. He thinks that is most likey the problem. I *think* the belt tension is ok and it looks alright to me. I have checked the connections at the battery and alternator and they are tight.

I guess we will see what the dealer finds out. Thanks for the information.

Well, it gets better. The dealer did replace the alternator. They were sure it was bad. The belt was NOT loose, but showed signs of slipping or grabbing on the edges.

They also checked the battery and it was good. Started it up, ran it up and down the driveway several times and all was good.

But, last night, I went out to finish cleaning up and after about 5 minutes it did it again....tach dropped to 650 RPM, lights dimmed, and heater fan slowed down and tractor stopped moving, but engine stayed at same RPM (2500). After about 25 seconds or so, the tach slowly starts to rise and then the lights and fan go back to normal, and the ehydro works normally. I finished up about 45 minutes later and it happened 3 more times. Before the alternator change it would have been about 10 times. So it is better, just not right yet. The dealer is going to submit a case to Deere on this and I am going to check the grounds tonight to see if one may be bad (too much paint etc.). That is about all that we can think of to do until he hears back from Deere.

Anyone have any other ideas? This is really weird...

 

[Mark3101]

Well, it gets better. The dealer did replace the alternator. They were sure it was bad. The belt was NOT loose, but showed signs of slipping or grabbing on the edges.

They also checked the battery and it was good. Started it up, ran it up and down the driveway several times and all was good.

But, last night, I went out to finish cleaning up and after about 5 minutes it did it again....tach dropped to 650 RPM, lights dimmed, and heater fan slowed down and tractor stopped moving, but engine stayed at same RPM (2500). After about 25 seconds or so, the tach slowly starts to rise and then the lights and fan go back to normal, and the ehydro works normally. I finished up about 45 minutes later and it happened 3 more times. Before the alternator change it would have been about 10 times. So it is better, just not right yet. The dealer is going to submit a case to Deere on this and I am going to check the grounds tonight to see if one may be bad (too much paint etc.). That is about all that we can think of to do until he hears back from Deere.

Anyone have any other ideas? This is really weird...

Well, the problem *may* be fixed. I took the ground off the engine and cleaned the surface of the block and the cables. The block looked clean and shiny, but I scraped it down with a razor blade anyway. Cleaned the ring terminals and put it back together. I checked all the other connections on the battery, alt. and starter and the ground strap between the cab and engine. All were tight and clean.

I have put over 3 hours on the tractor since the ground cleaning exercise and have had no failures. I have my fingers crossed that that fixed it. We are in the process of getting a couple of storms now and later in the weekend, so I will give it a good workout to see if the problem comes back. Wish me luck!

 

[dqdave1]

Any other ground straps on this machine? If so, check them ( cab)
I would also look closely at belt while it is running since you stated that the belt "showed signs of slipping and bad edges"; this should not be happening on a new machine.
What happens if you shut heater motor off when it is happening? You may have a blower motor that is bad and drawing high amps.

 

[YesDeere]

If the belt is tight get out when it happens and tap the alternator light to medium with a ball peen. If it starts charging again the bushes in the alternator are hung up. Need new.

 

[irwin]

Well, the problem *may* be fixed. I took the ground off the engine and cleaned the surface of the block and the cables. The block looked clean and shiny, but I scraped it down with a razor blade anyway. Cleaned the ring terminals and put it back together. I checked all the other connections on the battery, alt. and starter and the ground strap between the cab and engine. All were tight and clean.

I have put over 3 hours on the tractor since the ground cleaning exercise and have had no failures. I have my fingers crossed that that fixed it. We are in the process of getting a couple of storms now and later in the weekend, so I will give it a good workout to see if the problem comes back. Wish me luck!

Mark..it had the symptoms of a bad electrical connection or poor alternator operation : loose belt or internal weakness: ...sounds like you've covered the bases, I'd guess you should be okay now.

Well, it gets better. The dealer did replace the alternator. They were sure it was bad. The belt was NOT loose, but showed signs of slipping or grabbing on the edges.

You said the dealer replaced the alternator..did they replace the worn belt also?

 

[turbotime]

New 3320 cab. 59" snowblower on it. 10 hours so far. We had a good snowstorm the past couple of days. Used tractor on Friday no problem. Worked great. Used it again on Sunday a couple of times and also, no problem. Probably ran it about 6 hours over those two days.

Tonight, I took it out to finish cleaning up from the storm. It started and ran fine for about 5 minutes, then suddenly, the tach went to 650-700 RPM and the lights dimmed, the heater fan slowed down...but the engine stayed at 2600 RPM. ehydro came to a stop when this happened. As I sat there for about 30 seconds, engine sounded fine and did not slow down. Then the tach started to climb, the lights got bright and the fan sped up. Then the ehydro also worked fine. Started to work again and it happened within a minute or two just as above.

This went on for the rest of the time I was working...about an hour. I pulled into the garage and checked the battery voltage. It was 12.95 with the tractor off. Battery & Alternator cables are all tight and clean.

If I run without any electrical load (no lights or fan) then it seems to last longer between fits. I can get it to stall almost at will by turning on all the work lights or put the fan on high.

I get no idiot light for the charging system, nor do I get any error codes on the dash display. I am going to call the dealer tomorrow morning. I am thinking alternator, but why no light or code?

Anyone have any ideas?? Thanks!

SAME problem with our 3520...exactly the same thing.
I was snowblowing with it when ehydro stops, fan slowed, all lights dimmed, my RPMs went down to 0 on the tach, but engine RPMs stayed high.
You said you cleaned the ground on the block and it seems good now?
Please keep us updated - if it happens again or not. But either way good luck.

 

[Mark3101]

Any other ground straps on this machine? If so, check them ( cab)
I would also look closely at belt while it is running since you stated that the belt "showed signs of slipping and bad edges"; this should not be happening on a new machine.
What happens if you shut heater motor off when it is happening? You may have a blower motor that is bad and drawing high amps.

Shutting the blower off and also the lights does not make it come back to life. It takes any where from 30 seconds to a minute and it just wakes back up.

I have put over 3 hours on it since i did the ground cleaning and it has been ok since. I will keep my fingers crossed.

 

[Mark3101]

You said the dealer replaced the alternator..did they replace the worn belt also?

They did NOT replace the belt yet. The service man did not have one with him. I am sure they will get me one when this is all figured out.