Gwallegro09 Report post Posted July 18, 2015 Replaced batteries and starter still turns over very slow. At times have to put on charger to get started. Volt meter reads 14.5 before starting and after drops to about 12V. Share this post Link to post Share on other sites
rlbarkleyii Report post Posted July 18, 2015 What engine 12 or 24VDC Diesel? Share this post Link to post Share on other sites
Gwallegro09 Report post Posted July 18, 2015 12V for 09 Allegro Bus Share this post Link to post Share on other sites
wolfe10 Report post Posted July 18, 2015 Gwallegro09, Welcome to the FMCA Forum. You need to fully charge the chassis batteries and then have them load tested. Very high likelihood that they are bad if battery voltage drops from fully charged to 12.0 VDC after a few seconds of trying to start the coach. What happens when you engage the boost switch and then try to start it? Share this post Link to post Share on other sites
Gwallegro09 Report post Posted July 18, 2015 Put in 2 new batteries plus new starter and same problem. Took new batteries out put in 2 more new batteries and same problem. When coach not in use plugged in to 50 amp dedicated circuit. Also, has 2 amp trickle charger on board coach. Share this post Link to post Share on other sites
wolfe10 Report post Posted July 18, 2015 The drop to 12 VDC from a few seconds of indicates weak or discharged batteries. Use of the boost switch should give you an indication of whether the chassis batteries are the problem. If your starter turned over slowly, but battery voltage did not drop that much, then you would want to carefully look for corrosion or loose connections at both batteries and engine-- both positive and ground. Share this post Link to post Share on other sites
Gwallegro09 Report post Posted July 18, 2015 Replaced batteries and starter same problem. Bought 2 more new batteries same problem. Put in all new coach batteries as well. Coach plugged in to dedicated 50 amp circuit when not in use. Also has 2 amp trickle charger in coach for chassis batteries. Share this post Link to post Share on other sites
dickandlois Report post Posted July 18, 2015 Gwallegro09. Most coaches have a large braided ground wire that connects the engine to the chassis frame rail, no longer the 18in. in most cases. So check the cable ends along with the other connections posted by Brett. The one other possibility is the crimped connectors have a high resistance due to battery acid oxidation. One can mix up some baking soda in a large container and place the cable ends into the container one end at a time or the entire cable if they fit. They will bubble as the acid and soda interact-this action will remove the oxidation enough to lower the resistance. You might want to do each cable on the chassis battery(s) and also the coach cables. BE SURE to take a picture or make a drawing before disassemble so the reassemble is much easier. Rich. Share this post Link to post Share on other sites
obedb Report post Posted July 18, 2015 Corrosion and ground cables seem to go together. The volt meter readings seem normal to me. When the starter is engaged readings head south. If the starter was installed by a shop, they should have checked your ground. Cables that are old do occasionally corrode internally (out of sight) and they fool a lot of mechanics, but your unit is way too new for that to be a problem, unless you live in Upstate New York and do a lot of winter driving. Something is right there for you or the shop to see. Let the forum know because it helps others. Share this post Link to post Share on other sites
wolfe10 Report post Posted July 18, 2015 Certainly agree that voltage in the proper size, good and charged chassis batteries will decrease while cranking. But a drop from fully charged (over 14 VDC) to 12.0 VDC after trying to start could indicate a battery issue. If they only "rebounded" to 12.0, they could have been in the 10-11 VDC while cranking and that WOULD give slow cranking. Here, a digital voltmeter IS YOUR FRIEND. Check voltage at the chassis batteries before trying to start, voltage while cranking and voltage after the batteries have had time to "rest". Share this post Link to post Share on other sites
obedb Report post Posted July 18, 2015 I kinda thought he was referring to the voltmeter while starting read at the instrument panel. In that case it would be normal. Of course as you have suggested, Brett, dropping to 12 volts at the battery terminals seems strange, especially since the batteries are new and apparently properly charged. I normally see voltages on a starting battery freshly charged with my voltmeter in the high 13s. 14.5 volts seems like alternator voltage to me. Something is in sight and it is being missed. Unit is too new for this to happen. Share this post Link to post Share on other sites
huffypuff Report post Posted July 18, 2015 An amp gauge clamped around starter positive lead will give good indication of whats going on. High amp draw don't mean the starter is bad but could be problem with the engine. Hopefully it.s not engine that causing problem. May be best to bar over engine by hand to be sure. If OK have the starter bench tested. Share this post Link to post Share on other sites
obedb Report post Posted July 18, 2015 Trying to pull a test for a bad ground connection or cable up out of my mind. Have not used it for many years. Meter positive to negative post or ground post on the starter . Meter negative to a good ground preferably the starting battery negative post. Someone engages the starter while the measurement is being done by another. The measured voltage on a good ground should be in the low tenths of a volt. Probably anything over .4 volts indicates a problem with the ground circuit. A good heavy ground circuit should be a dead short to ground with almost no measured voltage. I read about this test eons ago in Commercial Car Journal I think. Actually helped a good wrench get a truck no start problem fixed. It was a bad cable. Buddy called me for advice. The wrench worked for him. I didn't even get a beer out of it. Oh! Resistance test for starter cables is not reliable. If just a few strands are intact the multimeter will show OK no resistance. The multimeter is powered by double a or triple a batteries. Starters are powered by huge amperage for short periods. Just an afterthought. Share this post Link to post Share on other sites
obedb Report post Posted July 18, 2015 When I install replacement starting cables for big engines or house battery cables I use 00 welding cable. Very flexible and imagine the amps going through the cable when welding. I don't use the crimp terminals. I use copper sweat terminals, separate flux and solid core solder. More expensive than store bought cables but they do not fail. Learned the technique in the late eighties. No internet. Probably read a how to manual when installing golf cart batteries in our gasser. Share this post Link to post Share on other sites
wolfe10 Report post Posted July 22, 2015 Received a PM from Gwallegro09: "Found the issue. Ground wire between starter and battery not connected. Thanks for the chat." Share this post Link to post Share on other sites
wildebill308 Report post Posted July 22, 2015 Glad he found the problem. Bill Share this post Link to post Share on other sites
