Old Dog Posted June 6, 2023 Share Posted June 6, 2023 Just installed new starting batteries (3 - Interstate Group 31HD lead acid), replaced original starter and cleaned/inspected all cables & connections including: Neg - Both sides of the connector blocks at the battery box. All battery connections including jumpers, jumper from starter to frame and from frame to battery box connector block. Pos - All connections inside battery box including connector block and battery jumpers, connections to/from chassis battery switch, and connection at starter. Couldn't get to the outside of the battery box connector block. None of the connections were corroded or dirty, certainly not bad enough to cause this sluggish turning over. Batteries have 13.5v at pos to ground and 13.4v at starter pos connection to ground. The engine turns over too slow to start for approx 5-7 seconds then stops just like low or dead batteries. Doesn't matter if I use battery boost to interconnect house/chassis or not. I've had the block htr on all day and it's approximately 70 degrees. I'm at a loss and and suggestions or assistance would be appreciated. Link to comment Share on other sites More sharing options...
Dr4Film Posted June 6, 2023 Share Posted June 6, 2023 Remove starter and have it load tested or just remove and replace with the one some members here have done to spin the engine better than the stock starter. Link to comment Share on other sites More sharing options...
Frank McElroy Posted June 6, 2023 Share Posted June 6, 2023 Likely you have a poor battery cable connection. One of the cables going to the battery starter or ground is either loose or corroded. Trace all cables from the batteries to the starter and measure the voltage drop across each one - Positive and Ground cables. Any cable connection showing a voltage drop will be the bad cable. Also, 13.4 volts can't be the battery cranking voltage - that is the battery charging voltage. What is the actual cranking battery voltage. The important number is actual battery voltage at the starter while cranking. 1 Link to comment Share on other sites More sharing options...
Old Dog Posted June 6, 2023 Author Share Posted June 6, 2023 As I wrote in the opening post, I have cleaned and inspected every connection from the battery terminals to the starter. Both pos & neg including the one I couldn't get to the frist time, the pos battery connector block outside the box. Yes, the 13.4v is charging voltage. Have to rig up a jumper to test voltage at the starter when cracking since I'm by myself. Since all the connections look good a bad cable is possible but that doesn't seem like a common failure. This coach has never seen salt or de-icer and has no corrosion to the undercarriage. Link to comment Share on other sites More sharing options...
Frank McElroy Posted June 6, 2023 Share Posted June 6, 2023 Yes, once you test the voltage at the starter you will have a lot more info. On my coach, the battery connectors weren't making full contact at the starter terminals. Once fixed, the starter worked just fine.. Link to comment Share on other sites More sharing options...
MyronTruex Posted June 6, 2023 Share Posted June 6, 2023 Frank is spot on. You need to get a voltage measurement while cranking. Make a long jumper to connect to the starter so you will be out of harms way when someone helps you hit the starter. Corrosion can creep into a wire and be hard to see but I suspect just one connector is loose. Twelve volts has very little (push), and anything that is not very tight can block the flow. Heavy loads like a starter will find a loose connection quickly. Get a voltage measurement at the starter, using a good clean shiny ground for your voltmeter. However you need to test the ground side to and using that shiny clean spot for your voltmeter negative lead, put the positive lead at the center post of the negative terminal of the starting battery. Do this under cranking conditions of course. This negative terminal will show voltage if you have a ground side issue. The voltage on the negative terminal will not show up unless you are cranking the motor. If you find close to zero volts on the negative side and around 10.5 at the starter while cranking, you likely have a bad starter or the wrong one and it is binding. You should also carefully feel your cables after an attempt to turn it over. You might find a warm or even hot connection do to resistance causing a voltage drop at that point. Link to comment Share on other sites More sharing options...
cbr046 Posted June 6, 2023 Share Posted June 6, 2023 Be sure to test (under load) the connection between the battery clamp on the wire and the wire itself. All that jostling around could have loosened a crimp on a cable. Dropping 0.1V between battery and POS sounds suspect. There should be NO drop without a load. Testing while cranking should reveal the problem like Rudolph at Christmas. Let us know what you find. Just my 2c - bob Link to comment Share on other sites More sharing options...
Old Dog Posted June 6, 2023 Author Share Posted June 6, 2023 If it continues after changing overnight I'll just make up cables straight to the starter from the battery and bypass the 6 connections and 3 cable on the pos and neg sides until I have time to check every cable. Link to comment Share on other sites More sharing options...
vito.a Posted June 6, 2023 Share Posted June 6, 2023 Hope you find the bad cable. There may be a connection on the outside of the battery box. Does your Executive have an ISX? If so, you may need to install one of the new gear reduction starters. It will turn over much faster and require fewer amps. Link to comment Share on other sites More sharing options...
Dennis N - 2005 Windsor Posted June 8, 2023 Share Posted June 8, 2023 (edited) You state that you have installed three new batteries; can you confirm the cold cranking amp rating of each battery and just to be sure - these are 12 volt wired in parallel (positive to positive to positive to load)? Just want to make sure the basics are covered. Edited June 8, 2023 by Dennis N - 2005 Windsor Link to comment Share on other sites More sharing options...
Old Dog Posted June 20, 2023 Author Share Posted June 20, 2023 The problem turned out to be a seized AC Compressor. Blown my mind that a tiny compressor auxiliary drive could stall the starting system. Wasn't able to overcome the resistance until I installed 4/0 cable directly to the starter then the belt finely slipped. Shows how undersized the stock wiring is. Now my coach turns over great with just the starting batteries, no need to cross connect the house batteries. Link to comment Share on other sites More sharing options...
Ivan K Posted June 20, 2023 Share Posted June 20, 2023 Good find, so the clutch was engaged while turning the engine over, I suppose. Unless seized also, I would expect that accessories have no power while the key is in start position. That's what I am used to anyway. 1 Link to comment Share on other sites More sharing options...
Ivylog Posted June 20, 2023 Share Posted June 20, 2023 (edited) The Delco geared starter on my ISX got slower and slower, even using the boost. Replaced with a Denso geared starter and as a test, I tried starting using just one battery. All 3 would start it individually. Not sure how a smaller motor will spin it faster, but it does. First time I went to put it on, the fewer teeth stopped me from doing it. Turns out the teeth are off center and what I bought was correct… a Denso R5 428000-4440. Edited June 20, 2023 by Ivylog 1 Link to comment Share on other sites More sharing options...
Old Dog Posted June 20, 2023 Author Share Posted June 20, 2023 Haven't looked at the clutch yet but it must of been locked even though the ac was off. Not sure way that happened. Link to comment Share on other sites More sharing options...
Guest Ray Davis Posted June 21, 2023 Share Posted June 21, 2023 Sounds like you still have a cable issue. The cable you installed bypassed everything and provided full power to the starter. The A/C belt probably slipped because it needed tightening. You could take the belt off as a test & see if it will turn over using the old cables etc. JMHO Good luck & let us know Link to comment Share on other sites More sharing options...
Happycarz Posted June 24, 2023 Share Posted June 24, 2023 It is not necessarily the compressor, but just the pulley bearing. With the belt off and key off try turning the pulley. If locked replace the pulley bearing Link to comment Share on other sites More sharing options...
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