AMP gauge - Erratic Readings

jamvan · #1 (**permalink**) 09-19-2003, 09:38 AM

Bob;

I am sure you can help me with this question. Recently my amp gauge (lucas/smith type) on ERA 2017 seems to be a little erratic with its readings when the engine is running. It seems to be most erratic (lots of jumping around) when at idle, but has a tendancy to settle in under accelatation or higher rpms. Note, it is always reading in the +, so it seems that my alternator is charging.

Thinking it was a typical smith gauge problem, I was going to order a new one. I spoke with Woody at Nisonger earlier this week inquiring as to a new gauge availability and looking for a little advise. He told me one of three things could be the problem. In the order of most probable to least probable. They are the following;

1. Bad gauge - Replace the existing gauge with either a new amp gauge or a volt gauge (?) .

2. Alternator/regulator problems.

3. Short or loose wire someplace in the line (least probable problem).

He recommended that before I replace the gauge with either a new amp or volt gauge, I should check with you as to your recommendations, suggestions and advice. Have you seen this problem before. Also should it be the gauge, what is your feelings as to using a amp vs. volt gauge?

Any advice you can give me would be appreciated.

jim v.

Bob Putnam · #2 (**permalink**) 09-20-2003, 05:37 AM

With a VOM, measure the voltage at the alternator's Bat terminal and see whether it corresponds to the ammeter readings.

Also measure the voltage at the alternator's field terminal looking for the same relationship.

I hope that the drive belt is tight.

jamvan · #3 (**permalink**) 09-20-2003, 05:59 AM

Bob:

Thanks for the response. I must admit, I never checked the drive belt. Will let you know the outcome later today.

jim v.

jamvan · #4 (**permalink**) 09-23-2003, 08:39 PM

Bob:

Double checked the drive belt, while it was a little loose and did require a little tightening up, it still did not solve the problem. I then did check the connections as you recommended with a VOM.

While I can't determine that the VOM readings (at both the points you recommended) is the same as the amp gauge since the gauge is jumping around so much. I am getting steady readings on the VOM. Therefore, I guess what you will now tell me is that it is the gauge.

Anything else I should try before changing the amp gauge.

Thanks...jim v.

Bob Putnam · #5 (**permalink**) 09-24-2003, 05:18 AM

Jim,

Have you checked the battery's cable connections and the grounds? Once you confirm that those are OK, I'll send you a new gage to try. I still have some doubts about the bad gage though. It's pretty rare.

jamvan · #6 (**permalink**) 09-25-2003, 03:05 PM

Bob:

I will check them all out this weekend. If I still can't resolve the problem I will let you guys figure the problem out.

If you recall, I had Peter P. price out some work for me earlier this year (which included putting in a drop dash and dash clock). I would like to proceed with this work when you can get me scheduled. If I can't get the gauge issue resolved myself, I will have you look at the amp gauge when you do the work.

I will touch base you you next week and let you know how I made out.

jim v.

jamvan · #7 (**permalink**) 10-27-2003, 06:16 AM

Bob:

Just a little update on my amp gauge. Over the past few weeks as I have been driving the car, I have noticed the following:

1. If the car is cold, the amp gauge reads fine (+ sector). As the car comes up to full operating temperature, the gauge starts jumping around (but always in the + sector).

2. If I turn on the headlights, the gauge stops jumping around and reads prefectly.

Any other ideas? I will be giving you or Peter a call later today to confirm what day you want the car dropped off. Peter told me to give a call towards the end of the month to confirm when you would be ready. Was hoping to bring it up at the end of the week/weekend.

jim

larryar · #8 (**permalink**) 10-27-2003, 06:36 AM

My ammeter acted exactly like yours before the altenator went bad. In fact I lost an alternator and regulator at DVSF III. Since I replaced them, the ammeter is fine.
Larry

petek · #9 (**permalink**) 10-27-2003, 09:09 AM

Altenator or voltage regulator would be my guess (AFTER you've checked all of the ground and positive connections).

jamvan · #10 (**permalink**) 10-27-2003, 11:01 AM

Every connection are tighter than a gnats ass on a lemon wedge. If they were any tighter, I would strip the posts. I would guess it is the either the alternator or the voltage regulator. Wanted your suggestions before I started replacing everything.

Bob, whats your feeling?

Thanks all.

jim