Major FLAW discovery with Electronic throttle control with MAP sensor equipped engines

[gooffeyguy]

Curious, what's the video of it sitting overnight for 14hrs show?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

 

[R3cord303]

Next you're gonna tell everyone that lower control arms are a maintenance item and that autoride equipped vehicles will cause our vehicles to start bouncing up and down like low riders.

 

[Rocket Man]

yea message me

your uses the clip on type correct?


you can see it's fouled with oil there was No oil when the port was probed with a q tip just a bit of dirt

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Yes mine uses the same as the NNBS even though it's an 02. AC Delco 2134434. Oil should be no problem, we all know the intakes on LS engines get oil from the PCV system, thus the popularity of a catch can. You could have had a different problem, maybe intermittent, and it just happened to go away when you swapped that. Have you tried reinstalling it to see if it can be reproduced or did I miss that part? You could have had any number of problems that caused your condition, faulty grounds being one. Unfortunately, my MAP is on the back side of my supercharger and a real ***** to get to so I'm not willing to try this out. If it was in the stock location, I would do it for sure. I'm more than confident the MAP didn't cause a runaway engine though. Maybe try it again on yours or find someone local to try it out on.

 

[BG1988]

Curious, what's the video of it sitting overnight for 14hrs show?

2001 Yukon SLT
2012 Yukon Denali XL
2011 Yukon Denali RIP 5/20/18

lol obviously it was off for 14 hours sitting over night
video of the cold start


Don't whine about the Brake fluid being low That is how it works it lowers on startup and reflows back into the reservoir tank after a few min of shut off

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[Rocket Man]

lol obviously it was off for 14 hours sitting over night
video of the cold start


Don't whine about the Brake fluid being low That is how it works it lowers on startup and reflows back into the reservoir tank after a few min of shut off

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What the hell does that video prove? That your engine starts? WTF? Put that MAP sensor back in and post a video of your engine revving to redline by itself after it’s installed. If that is what caused it, it should do it again as soon as it’s installed.

 

[BG1988]

Yes mine uses the same as the NNBS even though it's an 02. AC Delco 2134434. Oil should be no problem, we all know the intakes on LS engines get oil from the PCV system, thus the popularity of a catch can. You could have had a different problem, maybe intermittent, and it just happened to go away when you swapped that. Have you tried reinstalling it to see if it can be reproduced or did I miss that part? You could have had any number of problems that caused your condition, faulty grounds being one. Unfortunately, my MAP is on the back side of my supercharger and a real ***** to get to so I'm not willing to try this out. If it was in the stock location, I would do it for sure. I'm more than confident the MAP didn't cause a runaway engine though. Maybe try it again on yours or find someone local to try it out on.

The engine runaway was from auto stop startup both times on a slight uphill grade..



one time was without Cruse control and one time was with cruse control on..(was able to get the engine to come off the runaway, the second time by pressing the X button for CC ).. the plug for the connection is clean ..


the sensor was just bad it CEL right away with in a mile even after clearing the codes..

there is a TSB for oil consumption issues that only applies to engines after all Hybrid Models Built July 7, 2009 - October 1, 2010

mine was build date 01/2008..


it's a small investment getting one but i can buy one.. i don't think it will catch anything

but if i buy one it has to be made of metal and not plastic

 

[R3cord303]

It still doesn't prove what you were saying. Plug HPTuners in and see what the datalogging stuff shows. If you MAF reading is all screwy that doesn't mean the MAF is buggared? Could just be that the throttle is opening for some reason? Maybe the throttle itself being bad? The funky ECU proggramming being bad?

 

[Doubeleive]

haha, Brent your a clown, no offense but some of the stuff you come up with.......

 

[Trey R]

if you have a broken MAP sensor or oil fouled map sensor ..
on your GM engine it will OVERRIDE the Electronic Throttle control...

really it will


Your engine will be subject to "RUN AWAY" .. this happened 2 times



2 times Engine Runaway.. Was Able to stop the run away happened from an auto stop..


looks like GM failed at the correct ECM programming, and the MAP sensor overrides the Electronic throttle control (aka gas peddle )
this is the dumbest thing ever!


The stupidest thing MAP sensor has full unrestricted control over the electronic Throttle control very smart



At this point in time it's safe to assume also MAF ECT IAT Braro sensors have full unrestricted control over the electronic Throttle control as well....according to a few websites site the MAP sensor is a backup to the MAF sensor..

I still have the old map sensor just in case... anyone wants to reproduce the issue on their svu..


I KNOW MAP sensors are a normal wear and tear item but there still should be a fail safe mode or ignore if the part has been compromised i.e faulty..

make sure you keep your map sensor clean or replace often like every 30k-40k miles esp the oil burner engines.. or IF you use an oil based air filter. I did find new clean oil on the sensor i suspect the chain shop tampered with it... were i had a oil change done at 84k miles since I had CEL after going there P0069/P0430 there was dirty oil on the engine cover were the map sensor was so the person must have tampered with it. the only person that had dirty oil on them was the person who changed it..

Since this is not a diesel engine ( turning off the engine will STOP the runaway) it means you will lose engine power items.. keep that in mind.


this can be a problem if the map sensor shorts to signal ground




Scenario

Map sensor: *yells at engine* hey i'm getting 4.5 volts to 5, you NEED to wide open the throttle NOW..

ECM: Yes sir

Throttle Pedal Position sensor: tells ECM We have some user input please accelerate ..

ECM: TPPS what?!



ECM: Hey throttle plate Open WIDE NOW you have a full load requested by MAP sensor.


ECM says : Send more fuel and air


ECM continues to send more air and fuel causing the engine to accelerate as requested by the map sensor....




so the point is the ECU ignores the Throttle Pedal Position sensor request ... while the MAP sensor(aka back up system to the MAF) request WIDE open throttle which is agreed upon by the ECU...



the whole point of the TPPS is to be the master switch that controls all throttle response passed set idle speeds.. in gm case a mistake was made in the ECM giving the MAP sensor(possibly other sensors as well) HIGHER priority then the Throttle Pedal Position


what exactly is the point of me requesting 25-35% throttle if i'm going to get 100% throttle from another sensor requests?

I had a similar situation I had replaced my throttle body on my 07 Tahoe and I got the runaway at a red light and almost rear ended someone and I was reading online and apparently my ECU had to "relearn" it's proper idle positions... well about six months later (present day) I'll be cruising at 75 and my rpms will fluctuate about 700 rpms enough that I can feel the truck surgeing I got one CEL and it said throttle position sensor... I cleared and it has never came back butttttttttt the truck is still having the surging at 75

 

[Rocket Man]

I had a similar situation I had replaced my throttle body on my 07 Tahoe and I got the runaway at a red light and almost rear ended someone and I was reading online and apparently my ECU had to "relearn" it's proper idle positions... well about six months later (present day) I'll be cruising at 75 and my rpms will fluctuate about 700 rpms enough that I can feel the truck surgeing I got one CEL and it said throttle position sensor... I cleared and it has never came back butttttttttt the truck is still having the surging at 75

The TPS wiring harnesses have a known issue with corrosion and broken internal wires. No doubt these components can cause a throttle problem since they're directly connected to the throttle. That’s way different than a MAP sensor doing it. You can install a new pigtail on the TPS but be sure to solder and heat shrink the wires, it’s sensitive.