Engine Slower Crank Than Usual

[CaptainXL]

A few days ago I went to start my truck and it cranked about 3/4 as fast what it normally does. I let it sit all day yesterday. I checked the battery last night and this morning and it's rock steady at 12.2 volts. So today I started it up and it did the same slower crank. It's noticeable like when you start in 15 degree F weather. But it's been rather mild the past few days in the 50s so it ain't cold related. So I'd like to know is this a sign my starter is going? The battery is an acdelco replacement changed 2 years ago. I have 130k on the engine and all maintenance is up to date. Ohmmeter shows alternator charging at 14 volts. Kinda scratching my head here.

 

[rcam81]

Have a load test done on the battery. Could be an early sign of internal failure. Our vehicles are hard on batteries.

 

[Hypnotoad]

Look for corrosion and cracks in the battery cables too.

 

[CaptainXL]

Yeah definitely will get this load tested asap. I was thinking about getting this.

http://www.harborfreight.com/automo...ry/500-amp-carbon-pile-load-tester-91129.html

All the cables are good mr. toad. As a matter of fact I just got done cleaning off a bunch of corrosion on the cables and replaced the battery bolts. At that time I also cleaned tightened the alternator connection. Nothing seemed out of the ordinary. Truck started fine after doing this up until a couple days ago.

 

[gmcman]

Do you have access to a clamp meter? If so then I would check the starter draw current. My Grand Am had a slow crank for awhile and with a fresh battery it cranked strong but kinda slow. I replaced the starter and it was like I was trying to start it without the plugs in ...the deterioration was over such a long time I didn't reallly pay too much attention to it.

 

[CaptainXL]

Do you have access to a clamp meter? If so then I would check the starter draw current. My Grand Am had a slow crank for awhile and with a fresh battery it cranked strong but kinda slow. I replaced the starter and it was like I was trying to start it without the plugs in ...the deterioration was over such a long time I didn't reallly pay too much attention to it.

I got this one form Harbor Freight. A bunch of funtions on it. Even though I am good with electronics I have ever used it for testing amp draw. This would be my first time using it on a vehicle. I just set it to a 1000 amp setting and clamp it to the postitive cable and crank right?

7 Function Clamp-On Digital Multimeter

 

[gmcman]

That meter appears to be AC only for current, you will need an DC current meter. When you do the test, some meters won't respond very quickly so you will likely miss the peak draw but still be able to capture the rest of the load.

You may want to pull the fuel pump relay so you can get a solid reading thus allowing longer cranking time.

 

[CaptainXL]

That meter appears to be AC only for current, you will need an DC current meter. When you do the test, some meters won't respond very quickly so you will likely miss the peak draw but still be able to capture the rest of the load.

You may want to pull the fuel pump relay so you can get a solid reading thus allowing longer cranking time.

Correction I have this one. Digital Clamp Meter 266, professional grade

Unfortunately it is only ACA not DCA. It looks like the DCA meters are up around $70 or more. Any particular brand in mind? There is a Fluke for about $90. What about DCA limits? There is a Craftsman that goes up to only 400 DCA. Wouldn't I need at least 600 DCA?

 

[gmcman]

I haven't clamped mine in quite some time and I cannot recall what the starter draw was. I would think 400 would be plenty but may not be able to capture peak. Maybe someone here has documented amp draw fronm the starter, I can clamp mine tomorrow and give you a ballpark.

I would definately check all the connections, especially at the starter.

 

[CaptainXL]

I haven't clamped mine in quite some time and I cannot recall what the starter draw was. I would think 400 would be plenty but may not be able to capture peak. Maybe someone here has documented amp draw fronm the starter, I can clamp mine tomorrow and give you a ballpark.

I would definately check all the connections, especially at the starter.

Ok, I fully understand now. A 400 DCA clamp on meter is more than enough. According to the rule that Duane puts forth in his video a starter that is loaded and turning the engine should only pull 120-150 amps. Anything significantly higher and the starter is toast or like you said a connection issue. Thanks for the help. I will be buying a suitable meter and get back to everyone with the results.

http://www.youtube.com/watch?v=ABdgkHI8qSs

 

[CaptainXL]

Went to Autozone and they hooked up a battery and alternator tester. Test passed for both.

Before I went over there I double checked the battery bolts and they were a little bit loose but nothing major.

Going to check my battery voltage in the morning and see if it has dropped down to 12.2 volts (50% charged) again.

I disconnected the negative battery cable and hooked up my multimeter on 20 Amp scale to see what my vehicles amp draw is with key off. It read 0. So after thinking about it for a while i think the inline fuse inside the multimeter is blown from many years ago. Will take a look inside. Then I can check to see if Ihave any parasitic drain going on.

 

[CaptainXL]

Well I picked up some fuses from the Shack a few days ago. the 20 amp was blown. But before i got a chance to use the multimeter I got some new East Penn battery bolts that were a bit longer than the ones I got before. Also bought a battery wrench as well. Haven't had a problem since.

 

[The_Roadie]

I disconnected the negative battery cable and hooked up my multimeter on 20 Amp scale to see what my vehicles amp draw is with key off. It read 0. So after thinking about it for a while i think the inline fuse inside the multimeter is blown from many years ago. Will take a look inside. Then I can check to see if Ihave any parasitic drain going on.

Disconnecting the negative cable while you insert the meter in series is a slightly misleading test. All the modules with a timer inside are going to reset when their power goes away. They may come up in a properly powered-down state, where the parasitic issue you have might be a failure to properly go to sleep while powered up. Better to pull the cable while holding the meter in a way that will allow the modules to retain power during the cable pull. This isn't easy.