Jump to content

RPM falls under 400 when braking

Almoalla6997

By Almoalla6997
in Troubleshooting & Recalls

Recommended Posts

Almoalla6997 Enthusiast

Almoalla6997

Posted
Posted

HI there,

The other day I was driving my car around, I came to a road bump and had to brake hard from a speed of almost 60KM/H and let go of the brake at a speed of almost 20KM/H. the engine simply went off.

it happens regularly overtime I brake but the RPM falls to around 300RPM causing the car to jerk, however everything returns to normal once I apply throttle.

Dealer said this might be because of a dirty throttle body the cleaned it but the problem persists.

A couple of tuned sierras don't have the issue because the RPM is raised to 800RPM while idling and when the gear is set to D.

 

please help with your feedback.

 

thank you

iCryWheniGoPoop Enthusiast

iCryWheniGoPoop

Posted
Posted

Sounds like you may need a top side or dry side valve cleaner. Either find a BG service center or use something like this (see link below) and report back with your results.

 

http://www.gm-trucks.com/forums/index.php?/topic/170994-Intake-clean%2E--WOW%21/page__view__findpost__p__1598328

 

 

 

 

 

Sent from Off Driller Side

iCryWheniGoPoop Enthusiast

iCryWheniGoPoop

Posted
Posted

Could it be that you've braked too fast for the tranny to downshift and the torque converter is still locked?

That's possible but would just be another issue.

 

Once you completely let off throttle it is programmed to let go of the torque converter at any speed under 14mph for any gear other than 1st, and if in 1st the converter shouldn't be applied at any speed.

 

d13ab7770fb5a681074e49787074c7f1.jpg

 

 

Sent from Off Driller Side

Almoalla6997 Enthusiast

Almoalla6997

Posted
  • Author
Posted

Could it be that you've braked too fast for the tranny to downshift and the torque converter is still locked?

Almoalla6997 Enthusiast

Almoalla6997

Posted
  • Author
Posted

Doesnt really matter if I brake so fast or so hard it could even happen if i apply the brakes slightly.

MAF sensor is cleaned

Throttle is cleaned

 

Tuned vehicles with raised RPM dont have this issue

 

If you fill up the car with gas while the engine is running rpm will fall and the car would also cut off.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,840
    Total Members
    8,960
    Most Online
    appletrav
    Newest Member
    appletrav
    Joined

  • Who's Online   1 Member, 0 Anonymous, 418 Guests (See full list)

  • Latest Articles

  • Posts

    • newdude
      2 speed transfer case optional now?

      By newdude · Posted

      This is a 1/2 ton thing ONLY.  All HDs 2020-2026 have the two speed transfer case, with Autotrac as an option.     1/2 tons 2019-2026, regular 4x4s come with a single speed case (no 4LO!), and trucks with Z71 ordered, or all Trail Boss trucks come with the 2 speed case.  2 speed case is also an option on WT, and is also standard on High Country.  
    • newdude
      Different requirements for oil filters?

      By newdude · Posted

      2013 5.3 still to this day calls for the PF48 filter.  Which as a 15psi bypass pressure.     There is a TSB, 17-NA-157 that talks about the PF-63 and PF-64 filters which have a higher bypass rating of 22psi.    TSB HERE - temp.xml   "Beginning in 2012, the oil pumps began to regulate main gallery feedback instead of pump out pressure. This means that the oil pump now does not begin to regulate until pressure is built up to the main gallery. This change reduces the amount of time it takes to provide oil to the engine bearing and lifters during extreme cold start conditions.  Main gallery feedback oil pump control systems are present on the following engine families which use Spin-on oil filters: Small Gas Engine (SGE), Large Gas Engine (LGE), High Feature (HFV6) Gen2 and Small Block Gen5 gasoline engines. These engines with the main gallery feedback oil pump control systems are factory built with an ACDelco® oil filters"   It also calls out what engines use those filters.  The gen 4 small blocks were not on that list (LMG, LC9, L9H, L92, L94, L20, L96).  Gen 5 small blocks use the higher pressure filter.          That all said...   Your 7045 Napa filter is the PF63 equivalent, with 22psi bypass.  You are already using the higher bypass pressure filter.  You CAN keep using it, you don't technically have to use it though.  
    • Grumpy Bear
      Different requirements for oil filters?

      By Grumpy Bear · Posted

      Do you know WHY the filter relief setting was increased to 22 psig?    When the new system goes into the second stage the pump volume ramps up considerably. It was found that the 15 psi filter bypass setting put the filter in bypass on a warm engine when the second stage was activated. Raising the filter bypass setting forced the filter to do what it designed to do. Filter. Preventing debris from circulating during high load, high rpm operation.    So next question is how did GM find this out? VLOM/lifter failures and a deep dive by Melling Corp.    Last question. Is it required? Look at it like this; a motor may be equipped with a rev limiter. But it only works if the set point in reached. That 22 psig setting only matters if the pressure differential across the filter media exceeds 15 psig during normal warm operation. Second stage kicks in around 3000-3500 rpm.    I can't answer your question because I don't know you and how you use the truck. But I think there is enough information here to let you decide for yourself. 😉
    • Coastie05
      give me some tips to make my truck look better

      By Coastie05 · Posted

      Go back to OEM wheels. 
    • newdude
      2020 Trailboss 6.2 replacement

      By newdude · Posted

      Probably not their first rodeo, so it should go as planned most likely.  Typically the service manager or tech doing the swap will put some seat time to shake it down after they get it all put back together.  We usually put 50-100mi before we hand them back so if something happens, its not after you get it.  A coolant leaks, oil leaks, a ground left off or loose, vibration, etc.     The new engines so far have been good?  There's been a couple that have popped out there again (the replacement engine) but most have been okay.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...