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GTOholic
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Discussion Starter #1
While driving my 2004 Pontiac GTO on the interstate, my body shop guy noticed a significant loss in power and saw the "check engine light" come on. When he got to his shop, he noticed the MAF and Cone Filter from my Speed Inc. High Flow Induction kit had FALLEN OFF. The induction tube was sucking "raw" air into the throttle body.

He re-installed the MAF and filter, but the "check engine light" stayed on. He brought the car back to me. I drove the car about five miles and noticed a significant loss in power, although the car idles very smoothly and the exhaust still sounds awesome. I parked the car (engine off) for about two minutes, came out of the store, re-started the car... still had the "check engine light." After idling at the next red light for about a minute, the "check engine light" went OUT all by itself.

But the car has lost significant power. Punching the throttle when revving 3000 RPM in 2nd gear used to snap my head back. Now it just eases forward. When launching in 1st gear, it takes enormous effort to spin the tires. If I floor it in 1st, the engine bogs, stumbles, then goes.

What do I do now?
 

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DOG
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626 Posts
Pull the negative power cable, reset your radio in the morning and see if that works. If not, off to the dealer, and don't tell them the sensor fell off ;)
 

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GTOholic
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Discussion Starter #4 (Edited)
BTW, the body shop guy said he disconnected the battery for about 10 minutes, hoping the "check engine light" would go out, but it didn't. Do you think 10 minutes was not long enough to reset the PCM?

Ewwwwwwwwwwwwww, "off to the dealer". That's a bad idea. No way are they going to fix it under warranty. I have already had that discussion with them. Their service manager was not "happy" that I put the HFI kit on in the first place. This reeks of big $$$ out of my pocket.

I had already disconnected the negative lead of the battery before I made this post. I'm going to reconnect it in the morning and let the car idle for about 10 minutes, then let it sit until tomorrow afternoon.

P.S. The hood looks great! :slap:
 

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Admin
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9,705 Posts
You only need to disconnect it for a little while, it wont make a difference how long. It will make a difference when it re-learns. It has "learned" this huge amount of air that is not metered.... hook it up now and let it idle for awhile and take a drive. Bet you it'll be much better.
 

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Knight Errant
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1,800 Posts
'Special' clamps

FLORIT said:
...(snip)...
P.S. The hood looks great! :slap:
Use the 'special' clamps at the throttle body to air tube and MAF to Filter joints. Use the normal hose clamps for the MAF to air tube adapter. After I did mine like yours, I wiggled and wobbled things around before driving. The MAF separated right at the adapter joint. The 'special' clamp could not adapt to the 2 different sizes, so I moved it to the filter joint and used the two normal hose clamps on the stepdown adapter....follow me?
Your PTM will re-learn, it's just apt to be doggy and inefficient for a bit. No damage to the MAF wires and thermistors, right? and you have a PM Sam. :thumbs:
 

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2004 GTO IBM/Blue m6
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316 Posts
FLORIT said:
While driving my 2004 Pontiac GTO on the interstate, my body shop guy noticed a significant loss in power and saw the "check engine light" come on. When he got to his shop, he noticed the MAF and Cone Filter from my Speed Inc. High Flow Induction kit had FALLEN OFF. The induction tube was sucking "raw" air into the throttle body.

He re-installed the MAF and filter, but the "check engine light" stayed on. He brought the car back to me. I drove the car about five miles and noticed a significant loss in power, although the car idles very smoothly and the exhaust still sounds awesome. I parked the car (engine off) for about two minutes, came out of the store, re-started the car... still had the "check engine light." After idling at the next red light for about a minute, the "check engine light" went OUT all by itself.

But the car has lost significant power. Punching the throttle when revving 3000 RPM in 2nd gear used to snap my head back. Now it just eases forward. When launching in 1st gear, it takes enormous effort to spin the tires. If I floor it in 1st, the engine bogs, stumbles, then goes.

What do I do now?
Why was your body shop guy driving your GTO on the interstate anyway? :confused: Sounds like a poor excuse to speed up the paint drying process if you ask me. :D :D
 

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13 year owner
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16,379 Posts
You need to disconnect the negative side of the battery WITH the Ignition ON! UNless you have a scan tool and can clear it that way too.

The clamps rubber grommets and fittings that you carry over from your stock unit are a tight fit on the larger Speed Inc unit. As such, you have to make sure it is fully secure once installed. But yes, they do fit together tightly.
 

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DOG
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626 Posts
MI_WS6 said:
Why was your body shop guy driving your GTO on the interstate anyway? :confused: Sounds like a poor excuse to speed up the paint drying process if you ask me. :D :D

Checking the stability of the carbon hood would be my guess.
 

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Member #804
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5,539 Posts
In alot of cases disconnecting the battery doesn't work, The MIL SES or check engine light is going to stay on weather or not you fixed the problem at that time. The reason why you expirienced that low power is cause the PCM probley went into limp mode. The MAF lost frequency or didn't correlate with the engine rpm so the computer went and determined fuel table based on throttle postition and coolant temp sensor. Why don't you go to autozone act like you dont' know whats up and they will tell you your code no problem. Weather they have a clue to what fixes it doesn't matter you already know the scenario.
 

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Registered
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16 Posts
Just turn your key to the on position and disconnect the negitive cable for about 2 minutes. Turn the key off and reconnect the cable. Start it up and let it idle for about 3 minutes with everything electrical on (radio, AC at full blast, rear defrost) After that, drive it like you stole it for about a half hour. I have done this serveral times to clear the "Lean Condition" code while I was messing with different combos of intakes, MAF ends and filters.
 

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Moderator
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2,432 Posts
CMNTMXR57 said:
You need to disconnect the negative side of the battery WITH the Ignition ON! UNless you have a scan tool and can clear it that way too.

The clamps rubber grommets and fittings that you carry over from your stock unit are a tight fit on the larger Speed Inc unit. As such, you have to make sure it is fully secure once installed. But yes, they do fit together tightly.
CMNTMX is right the key here is to have the ignition on before disconnecting the negative or else you aren't resetting anything.

The other option is to pull the red fuse in the middle top of the fuse block. Just pull it for about a minute.

FLORIT, as many times as you took apart that induction kit you probably just didn't get things back together tightly.
 

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Gone but not forgotten
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4,672 Posts
tiggerfan said:
Checking the stability of the carbon hood would be my guess.

yeah, i bet thats what it is. i was watching the GTO review on the speed channel. they were showing the drifter GTO. i couldn't believe how much that hood oscillated when it was goin around the track. looked like it was gonna fly off any minutes
 

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Moderator
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GTOdriver7 said:
yeah, i bet thats what it is. i was watching the GTO review on the speed channel. they were showing the drifter GTO. i couldn't believe how much that hood oscillated when it was goin around the track. looked like it was gonna fly off any minutes
Yeah that drifting cars hood was crazy. I think they must have trimmed it down to just the skin.
 

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GTOholic
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1,504 Posts
Discussion Starter #17
I pulled the negative lead of the battery (with the ignition on), waited a few minutes, then hooked it up again. I let the car idle for 10 minutes with the AC full blast, rear window "defrogger" on, radio blaring, even the windshield wipers on. Then I took the car for a medium-to-hard 20 minute drive.

What seems to be missing is the low end torque, that "pull" I used to get off the line and when flooring it in a low gear. At high RPM (and throttle position) the car seems fine. It also seems to idle nicely. But it just doesn't have that "oomph" it used to have in lower gears, at lower RPM.

In 3rd gear, 30 MPH, about 2000 RPM, it almost sounds like there is a "miss". The car (and exhaust note) is putt-putt-putt-puttering along.

For all I know the car is fine. There are no trouble codes on the DIC. It still sounds the same, pretty much. It seems to idle nicely. It just feels... different. Until I take it to the dealer for a "check-up", I'm going to have this big, lingering doubt troubling me.
 

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Moderator
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FLORIT said:
I pulled the negative lead of the battery (with the ignition on), waited a few minutes, then hooked it up again. I let the car idle for 10 minutes with the AC full blast, rear window "defrogger" on, radio blaring, even the windshield wipers on. Then I took the car for a medium-to-hard 20 minute drive.
I think you went the wrong direction there. You want to not have a load on the car when at idle. No AC and all that.

I do what the Aussies do:
http://www.mytired.com/cars/index.htm?page=car_rset.htm
 

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GTOholic
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Discussion Starter #19
I tried to follow the GM Driving Cycle as closely as possible.

I just got back from another test drive and I believe that the timing is off, if that is possible. Something about the way it sounds when I romp on it reminds me of that "timing off" sound from my youth. I suppose the spark and knock retard tables could be skewed, and I'm not sure a PCM reset would cure that. Unless, of course, all the tables are overwritten with "default values", which would make sense.

Anyway... long story short... too late, I know... but... I'm going to call the dealer tomorrow for a service appointment. It needs "treatment."
 

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Registered
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Good luck. It sounds like the investment is ls1edit wouldn't be a bad one. Reading this thread and others it sounds like you can really fine tune the computer and get it running better.
 
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