Three random shut offs while slowing to a red light.

[olliec420]

So on my 09 Yukon I just had my 3rd random shut down while driving this year. Two times while I was slowing down to a red light. Pop in neutral and turn key and fires right back up like nothing is wrong. I read a while back that could be due to the battery cables (negative?) going bad and that's a known problem on this gen. Can any one confirm that? Mine voltage fluctuates a bit too (new OEM alternator last summer) but that might just be the charging going on and off and its been a bit lower sometimes since summer and the fans might be running hard. Battery is 3 years old this year and seems to be great. Im hoping battery cables.

 

[Doubeleive]

So on my 09 Yukon I just had my 3rd random shut down while driving this year. Two times while I was slowing down to a red light. Pop in neutral and turn key and fires right back up like nothing is wrong. I read a while back that could be due to the battery cables (negative?) going bad and that's a known problem on this gen. Can any one confirm that? Mine voltage fluctuates a bit too (new OEM alternator last summer) but that might just be the charging going on and off and its been a bit lower sometimes since summer and the fans might be running hard. Battery is 3 years old this year and seems to be great. Im hoping battery cables.

I would be checking fuel pressure, should have 50-65 pre-start and 44-50 running.
basic pressure tester is about $30-35 and most auto parts stores have loaners you just pay for it and then get a refund when taking it back, if you don't take it back it's yours

 

[olliec420]

I would be checking fuel pressure, should have 50-65 pre-start and 44-50 running.
basic pressure tester is about $30-35 and most auto parts stores have loaners you just pay for it and then get a refund when taking it back, if you don't take it back it's yours

You think? While slowing down and not on the gas?

 

[Doubeleive]

You think? While slowing down and not on the gas?

yes, classic symptom of low fuel pressure
other signs would be surging while driving, idle up/down, hard to start

 

[olliec420]

yes, classic symptom of low fuel pressure
other signs would be surging while driving, idle up/down, hard to start

Well it seems a little tired under ~2000 rpm but then really goes. No surging while driving or hard to start. A bit of rough idle but that got a lot better when I cleaned MAF and throttle body. I have a scanner so I'll put it on and watch fuel pressure.

 

[Doubeleive]

Well it seems a little tired under ~2000 rpm but then really goes. No surging while driving or hard to start. A bit of rough idle but that got a lot better when I cleaned MAF and throttle body. I have a scanner so I'll put it on and watch fuel pressure.

it's always a good idea to check grounds/battery anyway
but the scanner on fuel pressure may or may not reflect actual pressure, best to put a gauge on it and then prop it up under the hood by the window so you can see what it is doing when it dies or just while driving around.

 

[olliec420]

it's always a good idea to check grounds/battery anyway
but the scanner on fuel pressure may or may not reflect actual pressure, best to put a gauge on it and then prop it up under the hood by the window so you can see what it is doing when it dies or just while driving around.

Oh ok, good call I'll check it out.

Is it correct in my understanding there is no fuel filter to change in the 07-14 gen?

 

[Doubeleive]

Oh ok, good call I'll check it out.

Is it correct in my understanding there is no fuel filter to change in the 07-14 gen?

correct the filter is built into the pump assembly in the gas tank

 

[Fless]

Might need to clean the throttle body and the Idle Air Control.

 

[olliec420]

Might need to clean the throttle body and the Idle Air Control.

Cleaned MAF and throttle body. Couldn't find anything about idle air control on a 07-14 gen.