GN feels like its hitting rev limiter

[TrAb]

Hey guys, i had all the issues on this car worked out. But after working on a few unrelated parts the car is now acting funny. When i go say 70% throttle the car spools and pulls just fine. If i go WOT the car starts to pull hard until it reaches the max boost, i have it set on around 17lbs. When it gets up to around 17lbs it drops to around 15lbs and my boost gauge jumps around in that area a little, the car feels VERY sluggish and acts almost like its hitting a rev limiter. My scanmaster doesnt show any timing retard so im not sure whats up.

 

[turboc87gn]

Whats your spark plug gap set at? I just read a thread where this dudes plug gap was to big and the boost was blowing the spark out...his plugs were at .032 apparently ideal is .027-.028 and his o2 sensor was also on its death bed

 

[ryan george]

at 17 lbs? doubt it...

 

[buickruss]

Its been awhile but I think mine did this with worn out valve springs.

 

[TrAb]

I almost forgot to mention the main thing here. The car did this EXACT same thing once before when i accidently left my wastegate solenoid unplugged. So i jumped out and looked and one of the wires was ripped out of its plug in (must have done it while cleaning) this time. So i stuck it back in the connector and used a pair of needle nose to clamp it back in. Tried it but it did the same thing. Im pretty sure its making a connection but im not 100%. So if my wastegate solenoid goes bad would it cause this feeling? Im gonna check the wiring tonight to be sure its not it.

 

[djj624]

I had a very similar problem after getting alky and turning the boost up, and after talking to Eric, and Julio they suggested i play with the tune(timing and fuel) and after some trial and error i got it smoothed out.

 

[TrAb]

Well the thing is, i slapped on my stock turbo. Took it out for a drive and it did great. Was acually overboosting to like 20psi, so i went and turned it down to 17. I did proabbly 6 pulls that night. Took it out the next week and cleaned the engine up a little, and now its doing this and i noticed the wire coming out of the wastegate solenoid.

 

[Just a Six??]

Plug the hose to solenoid to eliminate from the mix.

 

[TurboSpeed]

your scanmaster should be throwing a trouble code if your wastgate is unplugged or bad.

 

[TrAb]

well i know that it didnt throw a code when it was unplugged that one time, what exactly does the wastegate solenoid do?

 

[aminga]

your scanmaster should be throwing a trouble code if your wastgate is unplugged or bad.

Depends on the chip. TT chips won't

 

[TrAb]

Depends on the chip. TT chips won't

Yeah i have a turbo tweak chip.

 

[TurboBuRick]

What spark plugs?

I would change them first.

 

[Jerryl]

Hey guys, i had all the issues on this car worked out. But after working on a few unrelated parts the car is now acting funny. When i go say 70% throttle the car spools and pulls just fine. If i go WOT the car starts to pull hard until it reaches the max boost, i have it set on around 17lbs. When it gets up to around 17lbs it drops to around 15lbs and my boost gauge jumps around in that area a little, the car feels VERY sluggish and acts almost like its hitting a rev limiter. My scanmaster doesnt show any timing retard so im not sure whats up.

I would suspect that the motor is being flooded with alky.
There are 3 conditions I can see to make this happen in this case;
If you are not running the boost that chip is programmed for, AND, have the alky too high, AND, max out the MAF, you will be flooding the motor.
Bet if you turn the alky down a bit at the lower boost level, it will clean right up.

Technically, there should not be an issue since the alky si progressive and TT is op top of his game.
The reality is that these things do happen.
What is the PAC knob set at?
What if the FP?
What is the MAF reading at the boost/rpm?

I am surprised no one asked that your O2's are at when this happens, or if you have a WB and what the readings are.
A WB and PL file would help a lot.

Of course, I am 1000 miles away and am only speculating since no data was provided . . . . . :tongue:

. . . .The car did this EXACT same thing once before when i accidently left my wastegate solenoid unplugged. So i jumped out and looked and one of the wires was ripped out of its plug in (must have done it while cleaning) this time. So i stuck it back in the connector and used a pair of needle nose to clamp it back in. Tried it but it did the same thing. . . . . .

That is more than likely a complete coincidence. :wink:

 

[TrAb]

I dont have alky or a wideband. The turbo tweak chip is set to 18lbs or so. So it shoudlent be that far off.

 

[TrAb]

What spark plugs?

I would change them first.

They are the AC delco ones that are recommended in the spring cleaning section.

 

[ijames]

I bet the O2's look rich. There is a transition region as the MAF numbers get over maybe 240 but haven't quite pegged at 255 yet that you hit when trying to turn the boost down too far or trying to run part throttle, where the ecm is just starting to add in all the extra fuel the chip is programmed for at wot at full boost. Mash on gas, boost rises up but not far enough, extra fuel dumps in, engine goes rich and egt's plummet and boost drops off, extra fuel gets turned back off, boost comes back up, and around you go. I'll say this since you aren't seeing any knock retard - turn the boost up a couple of psi and I bet is smooths out.

 

[TrAb]

Could i also cut down the FPR a few lbs? I dont wanna run to much boost on this old engine

 

[Jerryl]

I dont have alky or a wideband. The turbo tweak chip is set to 18lbs or so. So it shoudlent be that far off.

OK, my bad on the alky.
I agree with IJames and bet you are still rich.
Good luck!

I bet the O2's look rich. There is a transition region as the MAF numbers get over maybe 240 but haven't quite pegged at 255 yet that you hit when trying to turn the boost down too far or trying to run part throttle, where the ecm is just starting to add in all the extra fuel the chip is programmed for at wot at full boost. Mash on gas, boost rises up but not far enough, extra fuel dumps in, engine goes rich and egt's plummet and boost drops off, extra fuel gets turned back off, boost comes back up, and around you go. I'll say this since you aren't seeing any knock retard - turn the boost up a couple of psi and I bet is smooths out.

 

[TrAb]

Yeah its possible its running rich, the 02's start showing weird numbers when its happened. I believe they go into like 1.2 or somethign weird around that area. Does that mean there going over 1k?