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Grandpa's 2001 Silver Metalic GTP

Re: Grandpa's 2001 Silver Metalic GTP -Low on boost?!

No misfires. The thing runs great. Just seems to lack boost.

Once I get a scan, that should tell me a little more.
 


Re: Grandpa's 2001 Silver Metalic GTP -Low on boost?!

Haven't tried anything yet. I wanted to the TPS code resolved first. I think we're good on that.

Remind me... You're talking about this guy, right?:
BypassSolenoid_zpsh3nmgfsg.jpg

Right under the bypass actuator.

If so, unplug the electrical connection, or the vac line? Probably either?
 
Re: Grandpa's 2001 Silver Metalic GTP -Low on boost?!

I'd unplug both, just to be safe. I've had mine gone since the second week I had the car. Vacuum line is what matter though, if it's unplugged the solenoid can't do anything.
 
Re: Grandpa's 2001 Silver Metalic GTP -Low on boost?!

Well, here's what I did:
1.) Unplugged the vacuum line from the boost control solenoid to the boost control actuator. - No change
2.) Replaced the vacuum line from the vacuum port on the to of the supercharger to the boost control actuator. It was really dry rotted. - No change
3.) Manually applied vacuum to the boost control actuator. - It held vacuum.

I'm going to put the boost problem on the back burner until I get the negative fuel trim figured out. I suspect a faulty MAF. It appears to be a generic aftermarket unit. Same part number as my car, so I will swap it with my stock delco MAF to see if anything changes.

In the meantime, I did some scan comparisons. First pic is of grandpa's car. Second is of another STOCK grand prix during similar weather conditions. Note the TPS, RPM, and MAF value. If the If the TPS and RPM are the same on both, shouldn't the MAF value be closer than that? That flat MAP value kills me too.

Grandpa's:
SamathaFreezeFrame_zpsspy1qq84.jpg


Other stock Grand Prix:
CompareFreezeFrame_zpst5hwf4rg.jpg
 


Re: Grandpa's 2001 Silver Metalic GTP -Low on boost?!

That map reading is no bueno. You tried a different sensor?
 
Re: Grandpa's 2001 Silver Metalic GTP -Low on boost?!

Are you getting that code? That plus your no boost issue seems to be pointing to a map sensor. If you need one cheap I've got a spare factory one. Dunno how much they run, picked one up last time I was at yard just in case I needed it.
 
Re: Grandpa's 2001 Silver Metalic GTP -Low on boost?!

No code for the MAP sensor, but the TPS code points to a faulty MAP. I want to do an actual diagnosis, because it started to act up shortly after I did the VC gaskets. Part of doing the VC gaskets is removing the MAP bracket and MAP sensor. It wouldn't surprise me if there was a broken or weak wire somewhere.

Part of me want's to do an actual trouble tree diagnosis, but a bigger part of me wants to just swap the MAP from my car for a quick diagnosis. Part of the troubleshooting involves a vacuum pump, and I don't have one of those yet. Looks like it will be musical MAP's tomorrow. I suppose I can wiggle the harness while watching the scan tool. That would show a short/break in a wire.

Meh, That's tomorrows problem.
 


Re: Grandpa's 2001 Silver Metalic GTP -Boost is back!! But Neg. LTFT?

I got my boost back!! Split vacuum boot going to the MAP sensor.
DSC_0032_zpsd0ciiycd.jpg


Replaced with a short section of vacuum line to diagnose. All is well now! Well, except for the P0172 (System rich). I guess that's better than lean. When I go WOT, at least it's pig rich.

P0172 Points to either, leaking injector, faulty O2 sensor, or faulty MAF. Already did a MAF swap, and PO just replaced the injectors, so I'm leaning towards a failing O2 sensor....
 
Re: Grandpa's 2001 Silver Metalic GTP -Boost is back!! But Neg. LTFT?

I also plan on re-running all the vacuum lines after what I saw today. So I grabbed a box of hose and a blister pack of tees. Only available in white. No bueno. So, out comes the Krylon.

Before; (Blah)
DSC_0034_zpsk8aimjhe.jpg


After: (Clean)
DSC_0002_zps5z3vcm7l.jpg
 
Re: Grandpa's 2001 Silver Metalic GTP - Now with P0172!

All new vac lines, including the one from the port on the top of the supercharger to the purge solenoid. Still seeing P0172. Swapped MAF's with a known good unit, and according to the HPtuners scanner, the 02 sensor is retracting as it should. Within the specified appropriate range. Probably swing into O'Reilly tomorrow to "rent" a fuel pressure gauge. At least then I could rule out over fueling.
 
Re: Grandpa's 2001 Silver Metalic GTP - Now with P0172!

Not at all, but I have to check just for posterity. You know... Assuming the fuel pressure is acceptable, the next suspect is the evap purge solenoid. After that... I'm out of ideas.

I guess i could just run an e50 mix and call it a day. Haha!
 


Re: Grandpa's 2001 Silver Metalic GTP - Now with P0172!

I'm starting to wonder if I might have a problem with mine. I need to look up how to trouble shoot it.
 
Re: Grandpa's 2001 Silver Metalic GTP - Now with P0172!

With your trims or the purge solenoid? I've been looking at the trouble tree on gearchatter for my P0172. Pretty helpful.
 
Re: Grandpa's 2001 Silver Metalic GTP - Now with P0172!

My rich fuel trims. Everything checks out so far, I just threw it up to my tune. I know yours is stock and all.
 
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