Quickin

Maybe this will help someone else. Several pain in the *** issues...GONE. And I see people here with idling and surging issues all the time. I say "HOLY CRAP" because I had no warnings, no SES lights, nothing on scan tools.

#1)
In the past few months I've had surging issues on start-up. I would have to start my engine and not drive it for about 2 minutes while the surging stopped and idled smooth. Then I could get in and drive and everything was perfect. But if I drove somewhere about 15 minutes away and turned the car off, did my business and came out and started it again, same ****, it would do the same thing but only for about 1 minute, then I could drive normally. Also, sometimes I would come to a traffic light to stop and it would start surging while stopped for a little bit. Also, if I turned the A/C on while idling, stopped, it also went nuts for a little bit.

#2)
Shifting from "PARK" to 'REVERSE" was violent, a big bang into gear. Also, from "PARK" or "REVERSE" or "NUETRAL"...into "DRIVE". Big bangs. It sucked.

#3)
I had a scan a few months ago and it showed my Throttle position sensor (TPS) was bad. ***NOTE*** Thats all the scan showed, nothing else. AND never ever an SES light, I just had my friend scan it to see if something showed up
I could unplug it and the engine would run the same. So I replaced it and the problems were still there. Oh well.

#4)
My fuel consumption went though the roof too, starting about 3-4 months ago too. This problem may be solved to, I haven't had a chance to check yet as I just put the new MAF on.


So, a couple days ago I went by Advance Auto for a scan because my SES came on while driving. It showed P1133, "Fuel Air Metering". I bought a new stock OEM MAF.

Came home and before I put it on, for ***** and giggles, while the car was still running, unplugged my MAF. Nothing happened at all, the car just sat idling normal. I left it unplugged and pulled out of my parking lot and went for a short drive....The engine ran NORMAL.

I learned yesterday that a bad MAF causes the PCM to go to a SD tune. Also, when the TPS fails the PCM will go to a SD tune. So you may never know if they fail, I didn't, no SES light. I also had a Z06 MAF on my car for 5 years. The stock one from Advance works perfectly. Engine runs great. Went for a 20 minute drive just now and its all back to normal. Cars is still a nasty bitch and runs perfect.

No surging.
No banging into gear.
I can start it, tuen it off, let it sit for a few minutes and it starts up perferctly and idles right where it always has, immediately, A/C blasting or A/C off.
I'm pretty sure the gas mileage will be better now too. We'll see.

Now before anyone says it, I've had the dealership scan my car about 5 times looking for these problems and my friend who has an OBDII scan it at least 5 times, all over the past 3-4 months. NEVER has anyone showed a bad MAF. NEVER did I get an SES light for the TPS. I changed the TPS back then because I unplugged it and the car still ran perfectly.

So for whats its worth, and since now we know for a fact that an SES light will not come on if a MAF fails (at least in my 1998 WS6), and we also now know that a car with a failed MAF can run perfectly fine when the PCM goes to SD tune.............if you have surging or idling problems, just unplug the MAF and/or TPS at different times to see if this is your gremlin. If the engine keeps idling the same and you can drive it and its the same, there ya go.

What an easy fix to a highly aggravating problems. Too bad my SES light didn't come on earlier and have it show up on a scan, this would have been fixed months ago.





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Reject

iTrader: (24)

hmmmmm wonder if this is my problem, i'm having the exact same problems on mine except that my rpm's go down REALLY low and then surge WAY up

ZL1Killa

iTrader: (17)

if you unplug your MAF...your gonna want to get that VE table tuned.... your fuel trims are gonna go wacky

5_02ls1

iTrader: (20)

all your maf needed was cleaned its actually a common problem talked to death ....and if your meter went bad there would be a code

shaun

well my cars rpm's will drop to about 400-500-rpms some times when i put it in gear[reverse or drive]then the rpm's come back up and its fine so could that be the problem?
im going to the track tomorrow and when i get up tomorrow ill try cleaning the maf to see if it helps.
it hasent been doing it for that long so maybe thats the problem. i also have had a small surge at idle that i can get rid of no mater what i try[seafomed the car tryed different plugs at diff gaps and no luck]

Billiumss

iTrader: (11)

Good right up but if you would have scanned for the MAF freq you would have found the issue much earlier. If the MAF doesn't output a frequency, then it's junk.

Glad you got it fixed though!

DynoDR

iTrader: (1)

Like Billiumss said, The problem is that so many people just dont know how to properly use a scan tool. It is UNREAL how many use a scanner just for a code reader, they see no codes and they dont know how to interpret scan data.

And like he also said, a bad maf, or a dirty maf is usually very easy to spot with scan data and if not a scope check will most likely show it.

Quickin

Tried cleaning it about 1 week ago. Q-tips and alcohol. Whiped all the sensors real good. Didn't help.

What code is for the failed meter?


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Quickin

But if I unplug the MAF with the car running and the car is still drivable and drives normal, isn't that a 100% sure thing that the MAF is doing nothing?


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Quickin

The 5 times the dealer scanned my car, I would have thought they could read it correctly to know whats up.



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Billiumss

iTrader: (11)

LS1 based cars can run with or with out a MAF. Thats why we have a lot of VE resolution. Most boosted guys and hardcore big cam drag racers don't use the MAF and go Speed Density mode.

You go to a dealer, first thing he does is connect the scan tool, if no codes pop up, he stops. If he would have checked the MAF freq on the Tech 2, he would have found the problem.

06MonteSS

what should the MAF frequency be, or how do you know if it's not right??

MeentSS02

iTrader: (11)

Unplugging the MAF sensor should not let your car run normal at all...you'll be falling into speed density mode, and your transmission will shift harder than **** as you have already found. It might appear to run okay, but when I put mine into speed density for the first time, it was running pretty damn rich.

Billiumss

iTrader: (11)

Depends on the car and mods.

On average it should be around 2,500-3,000 Hz at idle and should go up smoothly as rpm increases. Using the awesome scan tool that HPT has, it's real easy to look at the MAF out put in either freq or lb/min, in table form or graph form

Depending on what year LS1 it is, unplugging the MAF doesn't automatically make it shift hard, it did/does on 98 cars but on the 2001-2002 cars it doesn't, I've done it many times when I tune the VE table, A4 cars drives fine.

06MonteSS

is that for any engine/car, or your guys particular ones?? Should it be about the same for my 5.3L LS4 ??

Quickin

Where is our MAP sensor located? I see the big piece that the brake booster line attaches to, but what is the other sensor that is attached to that, the one with the white colored square on it. Thanks.




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Billiumss

iTrader: (11)

It's the one where the 3 pin connector module plugs onto the back of the intake. In that pic it has a white sticker on it.

Quickin

OK, so do I just pull up on it to get it out, or is there a a locking pressure clip on it?

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Quickin

After driving for two days with the new MAF on. My converter is locking up much more crisp and solid. Very much a noticable difference. I've posted in the "Tranny" section a few times asking whats up with my lock-up not being "crisp".

Its kind of ridiculous how many things one single part can change about our cars, but whatever.


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Black02SS

iTrader: (36)

FYI P1133 is normally a bad oxygen sensor.