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Any Newbie to GTP tuning tips, as far as what NOT to do??

dsmuts said:
Vacuum leak
Click to expand...

98ctd said:
Check all the vacuum "t's" around the LIM and base of the blower I had to replace them on my 99
Click to expand...

Thanks for the quick replies guys!
I will be doing some vacuum leak checking today.

Newbie to these cars, so forgive me...
What is "LIM"? Is that Lower Intake Manifold??

The blower had been replaced prior to us buying the car, so that's a definite possibility.
 


PeezDaddy said:
Thanks for the quick replies guys!
I will be doing some vacuum leak checking today.

Newbie to these cars, so forgive me...
What is "LIM"? Is that Lower Intake Manifold??

The blower had been replaced prior to us buying the car, so that's a definite possibility.
Click to expand...

A nice trick to find leaks, is to hook up the tuner, and scan your O2's and watch the STFT PID, use some non flammable brake cleaner, and start going around all the gasket areas after the MAF sensor, ie: Throttle body gasket, supercharger gasket, all the vacuum lines & T's. When you hit the leak with the cleaner, you'll see the STFT fluctuate, and might even see O2 activity.
 
I am convinced that there are some deeper issues here. I spent about 15 minutes spraying anything and anywhere there could/would/should be vacuum at. Found two very very minor leaks and replaced one hose, and clamped another. Again, both were very minor leaks.

Fired the car up and after a few minutes of warmup started scanning FT's and both O2's.

Had normal rapid movement of front and rear O2's, and movement/fluctuation of STFT's. I thought all was good.

Drove home but stopped at 2 places on the way, both for maybe 15 minutes each. After first stop all still seemed fine but after second stop when car started it was "loping" and idling rough, actually shaking the car.
Hooked scanner back up and O2's were both equal, and less than .100 volts, actually hanging near .070v and STFT's were both pegged out at 20.3%.....
If I held idle up slightly manually, they would both (O2's & STFT's) move but not at a normal curb idle speed....

So now I have no idea what is happening.

BTW this happened on a regular diagnostic scanner not my HPTuners scanner so I have no log unfortunately....

Any ideas???
 
Any type of leak, no matter how small will make the car show lean. That looks like it's still thinking that it's lean, did you try to reset your fuel trims with the HPTuners?
This thing doesn't have any type of valve cover breather on it does it?
 
Still sounds lean. When I had a vacuum leak I used starting fluid and sprayed it around all the hoses and where the Supercharger meets the lower intake manifold (especially under the throttle body). If you spray the starting fluid into a leak the idle will change so it's pretty easy to hear.
 


Reptile said:
Any type of leak, no matter how small will make the car show lean. That looks like it's still thinking that it's lean, did you try to reset your fuel trims with the HPTuners?
This thing doesn't have any type of valve cover breather on it does it?
Click to expand...

Yeah, that is sure what it seems like, but I do not understand why when FIRST STARTED and warmed up, that it was acting "normal", with both the O2's and STFT's moving/fluctuating at idle like they should? The O2's were going between .100 and .900v (with rear one always being a little lower), which is correct and functioning, and the STFT's were also changing at idle and when raised slightly above idle....then they seemed to stop moving and sort of "lockup" for no reason whatsoever??? Is that when it is/was doing that stupid CAT TEST maybe? :th_scratchhead:

No, to both questions.
Was using my scanner here at work, so no way to reset trims, but as I have always understood it, the STFT's will and should change whenever the car is running, regardless of any "memory" saved by the LTFT's? I wasn't even watching LTFT's because I have not seen them change yet, no matter whether I am using scanner here at work, or HPTuners. I have always disabled LTFT's in the past, but have not touched anything in this tune, aside from a mild fan setting and disabling SES light on the P0171 and P0420.

JoRoW99 said:
Still sounds lean. When I had a vacuum leak I used starting fluid and sprayed it around all the hoses and where the Supercharger meets the lower intake manifold (especially under the throttle body). If you spray the starting fluid into a leak the idle will change so it's pretty easy to hear.
Click to expand...

I am going to try that this weekend. All I had here was Brakleen and MAF sensor cleaner, and neither really made a noticeable difference in idle speed or sound.

I am also going to get an HPTuner scan and post it here if I am able to. Maybe if one of you guys looks at it, you'll see whatever it is that I am missing...

Thanks for the replies so far. :th_thumb-up:
 
move the vac lines while spraying them.

the evap hose off the tb top, the fat one, it cracked on my car in the bend the line makes, and if i moved it a bit the engine started to surge like it had a huge ass cam.
 
Scottydoggs said:
move the vac lines while spraying them.

the evap hose off the tb top, the fat one, it cracked on my car in the bend the line makes, and if i moved it a bit the engine started to surge like it had a huge ass cam.
Click to expand...

That's what this thing does...lope, lope, lope like a big lumpy cam but with 2 dead cylinders...lol. My boy left car home but no keys....will try again tomorrow...
 


kids, i tell ya... lol

this is the fat vac line i changed, the closest one you see. used a fat one, then stuffed a thinner one inside the fat one then to the factory line to the evap sensor.

vachose.jpg
 
Scottydoggs said:
kids, i tell ya... lol

this is the fat vac line i changed, the closest one you see. used a fat one, then stuffed a thinner one inside the fat one then to the factory line to the evap sensor.
Click to expand...


The hose I replaced, is shown by the yellow arrows, because it was cracked & dry rotted looking, just like yours looks to be. ;)
The larger one I circled, was missing the clamp.

I will double check the one you replaced tomorrow. Thanks again.

I'll post up what I do or don't find tomorrow.
 
yeah it looks cracked, but its still solid. in time im sure that one will need to be replaced. its the last line that needs to be replaced, i changed all of them, and the T's when i did my lim job.
 
well....my 2001 does NOT have that hose you show in the picture?

I tried to attach a copy of tune and scan here, but it says "INVALID FILE", but I do have a copy of each uploaded at HPTuners site:
2001 Grand Prix Supercharged GTP with recurring P0420 and P0171

I cannot find any vacuum leaks, and with MIL/SES light turned off, but still active, as suggested elsewhere on this site, it comes up as 1 I/M monitor INCONCLUSIVE, which will not pass emissions test.

As the scan shows, it is full rich (STFTs), and O2 sensor is less than .100 volt unless I rev it up off idle, then it works fine...

any ideas or help is greatly appreciated...
 
Do yourself a huge favor. Don't even look at 02 voltage... Get a wideband 02!

You said your running very lean...
What are your ltft's?
 


The O2 voltages are fine for monitoring what I need to see....right now.

Not trying to be a knucklehead, and I appreciate all the replies and people trying to help me, but whatever is going on here, basically stops the O2 sensors (both) from moving at all. A WB isn't going to tell me anything different, except an actual a/f ratio which is not what I need to know. I need to figure out what the cause of the O2 stagnation is.

I am not doing any tuning, yet. I'm just trying to figure out what is happening here, and why it is happening. Both the STFTs and LTFTs are pegged full rich when the O2's stop moving. I see +20.3% on the STFTs (which can't go any higher), and I cannot remember what the LTFTs are at the moment. Unfortunately, I cannot view the HPT scan from work PC.
 
Starting to get aggravated at this POS... :(

Our 2001 GTP does NOT have the hose shown above in the picture.

I have the codes (P0171 and P0420) set to "No error reported", just to try and get this this load through the stupid emission test, but now it has one I/M test INCOMPLETE so they won't even test it...:th_scratchhead:

7 READY
1 INCOMPLETE

Says..."EVAP SYSTEM" test INCOMPLETE...

The picture attached... I have circled the hose that this 2001 GTP does NOT have...is that what's going on today with this car? Should that EVAP hose be there somewhere??
 

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    vachose222.jpg
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is there a open tube off tb?

look on the back sc for the evap solenoid, it should have 2 vac hose to it. make sure they are not cracked. maybe just change the sensor? set the code back to normal, and see if that makes it read for the test.


should be set up like this.


0900c15280217d40.gif
 
Scottydoggs said:
is there a open tube off tb?

look on the back sc for the evap solenoid, it should have 2 vac hose to it. make sure they are not cracked. maybe just change the sensor? set the code back to normal, and see if that makes it read for the test.


should be set up like this.


0900c15280217d40.gif
Click to expand...

No, there are no "open" tubes off of the TB, and ours appears to not have that hose above that runs between the TB and EVAP canister purge valve...It definitely does not have the hose I highlighted above, and I believe that is the hose in question.

Someone has recently put a new snout on the supercharger, so I need to see if it even has the purge valve on there or not. This thing's really starting to try my patience. :(
 
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