Engine sputters when turning on high beams

[Ryanoceros]

Hey guys,
I occasionally have an engine sputter. It happens seemingly randomly and lasts for a fraction of a second. My RPMs will drop, engine light flashes, and it goes right back to normal as if nothing happened. I changed my CPS and now it doesn't seem to happen as often but it still does. Just the other night I found I can duplicate the effect on demand. When I flip my high beams on it sputters and the engine light flashes and it goes right back to normal. I do have the headlight mod folks recommend, Hella housings with the %130 (whatever the number may be I forget off hand) Phillips bulbs, and the accompanying harness. Everything works fine but I'm wondering if it may be a battery draw issue. I'm running a good yellow top Optima.

Now I'm feeling like it may have always been a battery issue, maybe an accessory like AC was kicking on and pulling too much current for a sec causing the intermittent issue. Am I thinking clearly here?
I appreciate it fellers!

 

[WallyWest]

Battery or alternator.

 

[Bbrayden85]

Hey guys,
I occasionally have an engine sputter. It happens seemingly randomly and lasts for a fraction of a second. My RPMs will drop, engine light flashes, and it goes right back to normal as if nothing happened. I changed my CPS and now it doesn't seem to happen as often but it still does. Just the other night I found I can duplicate the effect on demand. When I flip my high beams on it sputters and the engine light flashes and it goes right back to normal. I do have the headlight mod folks recommend, Hella housings with the %130 (whatever the number may be I forget off hand) Phillips bulbs, and the accompanying harness. Everything works fine but I'm wondering if it may be a battery draw issue. I'm running a good yellow top Optima.

Now I'm feeling like it may have always been a battery issue, maybe an accessory like AC was kicking on and pulling too much current for a sec causing the intermittent issue. Am I thinking clearly here?
I appreciate it fellers!

You might have a failing alternator, or a low amp alternator. Unless you’ve ever had battery trouble. I have the same problem on my xj when i turn on rear defrost. Is your battery gauge holding at 14?

 

[Ryanoceros]

You might have a failing alternator, or a low amp alternator. Unless you’ve ever had battery trouble. I have the same problem on my xj when i turn on rear defrost. Is your battery gauge holding at 14?

I'll take a look here in a minute when I head back to work. I run a winch also and haven't seemed to have battery issues. As far as I know the alternator is stock and after 130k it probably couldnt hurt to replace anyways but I'll report back.

 

[Gollywomper]

Could be a ground issue. Check your battery to chassis, engine and body grounds.

 

[Ryanoceros]

Could be a ground issue. Check your battery to chassis, engine and body grounds.

I wondered that too, I saw the block grounds were pretty grungy when I did my clutch a few weeks back.

 

[Gollywomper]

Quick easy way to eliminate them is by using a pair of jumper cables as the ground only. Attach to the battery negative only then to frame and body.

 

[Ryanoceros]

You might have a failing alternator, or a low amp alternator. Unless you’ve ever had battery trouble. I have the same problem on my xj when i turn on rear defrost. Is your battery gauge holding at 14?

She is at 14, idle and cruising. I can rip a known good battery out of another vehicle and see if the issue continues and I may get my alternator tested in the meantime. As mentioned above also I may clean up my grounds, I noticed they were pretty gross a few weeks back.

 

[Bbrayden85]

Normally from what ive seen, is the high beam pulls A LOT of aperage, especially if you have stock headlights, and its harder for the alternator to keep up. Therefore it puts a heavier load on the engine. Cleaning your grounds, isnt a bad thing anyways and its easy and free, but i think your problem lies wih the stock alternator

 

[Bbrayden85]

The choppiness should go away and your volt meter on the cluster should rise if you rev the engine a bit. At least while its reved up.

 

[Rubicon88]

You have a MM?
Get helper.
Put mm on battery.
Command starting of Jeep.
Watch the MM
Then turn on ever accessory one by one allowing a few seconds between.
Radio
defrost,
fan on hi,
Lights,
Beams,
Fog lights if factory equipped

Watch your mm.

What are the readings? There should be no huge dip in the alternator with each accessory turning on. A quick drop of a half a voltage is ok. Like 14.18 to 13.78 then right back up.

Next thing...

Let run for 10 Mins with all accessories on. Re-check.
If alternator has now dropped to 13.18 (or something like that) odds are in another 10 mins you'll be in the 12's.

Alternator is shot!

The next thing...or first thing to do...

Date of mfg of battery? It needs tested by a real battery tester too. You need to see the actual cranking amps of said battery...not just 12 volts.

Batteries don't last for shit these days. That's why they all have a warranty threshold date of 1,2 or 3 years free replace or nothing. Pro rated warranties of batteries are a thing of the past.

 

[Ryanoceros]

Waiting on the weather to break so I can get some stuff done but I have a video of the issue in the meantime. Thanks a lot for the suggestions I appreciate you guys.

https://imgur.com/a/PhwCGdN

 

[Jerry Bransford]

Your video shows everything but what the voltmeter does when the problem happens.

 

[CharlesHS]

Remember.... the ECU is what regulates the alternator output voltage....
I would check the connectors on the back of the alternator that read field voltage and then check the (3) 32 pin ECU harness connector terminals for oxidation. IF the ECU is not reading the field voltage properly then it wont regulate the voltage properly.

 

[Ryanoceros]

Your video shows everything but what the voltmeter does when the problem happens.

Sorry Jerry, good point. The volt meter doesn't so much as wince.

 

[Jerry Bransford]

Have any electrical grounds been moved/fiddled with and maybe not have been thoroughly/tightly been reconnected?

 

[Ryanoceros]

Breathing some life into this post. The issue has finally gotten worse. Rather than being intermittent it's happening every time I run the vehicle and it's completely undriveable. The alternator did seems to test fine a couple years back when I was messing with it still.

Things that stand out:

- Only happens at operating temp
- I've done the big 7 mod
- Pressing the throttle makes the engine sputter and cel flash like turning the high beams on does
- Sometimes it'll sit and sputter on it's own with no input from me, to the point it'll kill the engine
- No codes stored

I'll attach a video. At this point I'm thinking coil rail or pcm. Honorable mention to the ignition switch but I have doubts.
https://photos.app.goo.gl/R2WJ5Psp7HHHNvsf6

I appreciate you fellas!

 

[Link]

2006 Jeep?

If so, I’d be talking to @Wranglerfix

Not saying that IS the problem but I’m suspicious of your PCM.

 

[Ryanoceros]

Yea '06. I've been curious myself for a while, thought about cracking it open and taking a look at the board. No way there aren't swollen or leaky caps after 20 years. That would partially explain the operating temp variable too. I wanted to try and verify before taking a $1k leap of faith haha. Regardless, I guess it's a good investment and peace of mind.

 

[Link]

Yea '06. I've been curious myself for a while, thought about cracking it open and taking a look at the board. No way there aren't swollen or leaky caps after 20 years. That would partially explain the operating temp variable too. I wanted to try and verify before taking a $1k leap of faith haha. Regardless, I guess it's a good investment and peace of mind.

WranglerFix can test yours if you want him to. He should see this soon and chime in