97 850 T5 starter and/or battery/charging system?

[dcarlson12]

My wife's 97 850-T5 has approx. 232,000 km on it.
Recently, intermittently, the starter doesn't want to engage fully and just spins. It will usually start after two or three additional tries.
First thought is that the starter or at least it's solenoid is starting to go bad/fail.
After reading a few posts on this site, I am wondering if it is the battery or charging system which might be at fault.
I cleaned the battery posts and clamps this morning after previously having measured the voltage at the battery posts. Previously, with the engine off, the voltage read 12.34 volts. Then after starting and running at idle for a few minutes, the voltage read in the range of 13.29 to 13.47. Only load was the driving lights which I have not found a way to shut off.
This morning after cleaning the battery posts and cable clamps, the battery measured 12.34 volts with engine off.
Then started and ran the engine for a few minutes. While running and even when I increased the engine speed to 2000+ rpm, the voltage read in the range of 13.5 to 13.6
Then shut off the engine and the voltage read 12.55 volts.

When starting the engine, it engaged completely and turned over the engine just fine.

I have already purchased a new starter but am reluctant to go the all the work of changing it if the problem is something else.

Comments?

Thks,
Dwight

[misha]

You have a bad bendix....the part of starter.
About charging system...you will need at least 13.5v with all consumers ON.
14-14.2v with all consumers OFF.
My advice is to replace b+ cable,it's usual culprit for voltage drop...but first perform a voltage drop test.

[dcarlson12]

Did a voltage drop test.
On negative side of charging system 0.03/0.04 volt which I understand to be acceptable.

On positive side of charging system measured 0.58/0.63 volts which I understand to be a bit higher that what is normally considered acceptable. I believe normal limit is considered to be 0.5 volts.

From what I can see, there are three 'runs' of wire running from the positive post of the battery as follows:

-a single wire relatively light gauge wire beneath a nut (don't know where it goes to)
-a bundle of approx. 4 relatively light gauge wire sandwiched between the connector of the above wire and the nut and appear to run off in direction of the fuse/breaker box
-a large gauge wire which is part of the cable assembly to which the above wires are fastened with the nut and which runs down to the starter motor

From what I can see, the output from the alternator is connected to and joins up with the large gauge wire from above and both are attached to the starter with a nut/bolt.

I am assuming it is one of the larger gauge wires to the starter from the alternator and from the battery to the starter which is causing the voltage drop.
Which one is 'normally' found to have gone bad?
i.e. the alternator to the starter or the starter to the battery clamp/post?
All the connections appear to be secure/tight.
Does the wire entering the clamp connection to the +ve battery post go bad?

Thks,
Dwight

[tryingbe]

Change the starter, and upgrade all the battery cable/negative cables while you're at it.

I upgraded my alternator to starter, starter to battery, battery to ground, and battery to chassis cables with thick 1/0 gauge welding cable. It's at least 70% thicker than stock.

Here are what you want to buy.

http://www.ebay.com/itm/181074818504?ss ... 1497.l2649

http://www.ebay.com/itm/261298170208?ss ... 1497.l2649

http://www.harborfreight.com/hydraulic- ... 66150.html

And two battery terminal that you can get at your auto part store.

With everything on, the voltage drop between the pos of the alternator and the pos end of the battery is now .07 V vs .7 V before.

[misha]

Dcarlson 12....you have a major voltage drop at positive side of 0.6v.When you add that to 13.5v you will get desireable 14.1v.

Acceptable voltage drop should be 0.2v MAX.

[erikv11]

... Which one is 'normally' found to have gone bad? ...

The main positive from the battery to the starter is super problematic, the original cables are almost all failed or failing now on the 850s, somewhere inside the cable end at the battery. After the car has been running for a short time, like 5 minutes, touch the +ive cable end. If the cable end is hot, that is due to a poor connection inside it and increased resistance: there is your (main) problem.

On some S/V70s the other cable, the B+ (4 smaller wires) is a bad one, but not on 850s.

I usually just replace the batter to starter cable and clean up the grounds, for starters. If the readings are good at that point then let it ride. There are many satisfactory ways to replace that cable, do some searching. There are several good DIY posts in the last year or so, in addition to tryingbe's I recall some from jreed and E_Showell. Or you can buy a cable from Volvo or the other vendors but it is relatively expensive.

[dcarlson12]

To tryingbe,
I have looked up electrical cable size and see 2 AWG, 1 AWG, 0 AWG, 2/0 AWG, 3/0 AWG, 4/0 AWG
I don't see 1/0 AWG
??????
Edit: I found that 1/0 is the same a 0 similarly 2/0 is the same as 00 and 4/0 is the same as 0000
(ref: http://inspectapedia.com/electric/Elect ... s_Amps.php)

And thanks for all the very helpful replies to everyone.
Dwight

[misha]

2awg(25mm2) is ok.
Don't go with thinner than original.It will melt and make a fire.

[erikv11]

I agree with Misha, 2 AWG or thicker.

[tryingbe]

Red is the original alternator to starter wire. Black is the new 1/0 wire.