horrible boost surge. Powerlogger tables inside!

[nolanator]

I did a pull with the powerlogger connected since I have been having issues at WOT. I would come into boost and it would pull relatively smoothly, and then all the sudden POP! For a split second it feels like im going nowhere. Target boost is around 23psi, but with that pop, i'm surging for that split moment up to 32psi. Before connecting the powerlogger, I had no idea what was happening since I can't watch all the gauges at once during my pull to see exactly what is happening.

I do not have an EGT or wideband connected at this time so pay no attention to those numbers. What I am looking for are a few opinions of what may be happening. The car is running the OEM 2.5" MAF, 80lb. injectors, a precision 66mm turbo that SHOULD be exhaling out of a Turbonetics Deltagate WG. Something is failing here. any ideas

My speculation after seeing that it blew the vacuum line off of my MAP sensor which is connected to the Alky system and I believe is also connected to the wastegate and that when that line came off, the wastegate slammed shut causing the boost spike. Is it possible that I just need to fasten that vacuum hose a little better and be good to go.

This is the last frame that everything feels relatively normal.


This is the next frame.

 

[nolanator]

here is the next window directly after the spike and most likely the reading for the POP I was describing. MAF signal doesn't look great

 

[Chuck Leeper]

@256 the stock maf is pegged, and could be doing the "dropout" scenario?
Looks like the TPS is never higher than 3.24/26V.
Paul mentioned the wastegate, in your other thread...Hanging up?

 

[nolanator]

@256 the stock maf is pegged, and could be doing the "dropout" scenario?
Looks like the TPS is never higher than 3.24/26V.
Paul mentioned the wastegate, in your other thread...Hanging up?

Hey Chuck,
Thanks for the input. Yeah, the MAF is overworked for sure, and will be getting replaced with an LS1 sensor in the next couple weeks. I brought this up in a previous thread, but didn't have any tables to back up the suspicion. As far as the wastegate goes, I just purchased a Turbonetics Racegate to replace this Deltagate. That was another issue that a member had brought to my attention. The TPS, however, i'm not sure how to go about troubleshooting that issue. I understand I should have a reference voltage of around 5.25v, but I will need to get a reading while the car is idling. Any suggestions with the TPS?

 

[captrob]

Key on, engine off...TPS should be .42ish at idle and 4.5ish at WOT. Check that you're getting full throttle blade opening. If not then check your throttle cable and TV cable linkage.


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[Reggie West]

Get your voltmeter out and set the TPS at .42 with the throttle blade closed. You will then need to adjust for WOT voltage of 4.84 volts or higher in order for the ECM to read the TPS sensor correctly. If you are flooring the gas pedal and all the ECM sees is 3.24 volts that needs to be fixed.

I would highly recommend turning down the boost to 15 psi and get some good solid pulls with no problems before trying to make it all work at 32 psi. You are going to blow up doing that. Get it right at 15 psi and work your way back up in 5 psi increments from there.

And yes you still need that MAF sensor we talked about too.

 

[nolanator]

Get your voltmeter out and set the TPS at .42 with the throttle blade closed. You will then need to adjust for WOT voltage of 4.84 volts or higher in order for the ECM to read the TPS sensor correctly. If you are flooring the gas pedal and all the ECM sees is 3.24 volts that needs to be fixed.

I would highly recommend turning down the boost to 15 psi and get some good solid pulls with no problems before trying to make it all work at 32 psi. You are going to blow up doing that. Get it right at 15 psi and work your way back up in 5 psi increments from there.

And yes you still need that MAF sensor we talked about too.

trust me! 32 psi is not what I want under any of these circumstances. I was shooting for 23 at that moment and it spiked. I do have the MAF sensor ready to go and I'm just looking to set a side some time to do the labor for the turbo, intake, new wastegate, MAF, etc. etc. I will be turning the boost down to very manageable levels I the meantime. Thank you for the tips with the TPS. Hypothetically, if the readings are off, am I looking at purchasing a new sensor or is there something further I would be needing to look into?

 

[Reggie West]

check to see if you can adjust it to those settings first. They do go bad after 30 years so it may need to be replaced but that is only if you can't get it adjusted.

 

[nolanator]

check to see if you can adjust it to those settings first. They do go bad after 30 years so it may need to be replaced but that is only if you can't get it adjusted.

Adjust the TPS? how would I go about that? ...unless it's a mechanical adjustment to the throttle cable.

 

[TurboDave]

If you look at the sensor you'll notice it's held in place with a couple small hex bolts, and it adjustable.
the adjustments are made key on, engine off.
First loosen both screws just enough so that you can move the sensor in it's slots. Push it all the way forward in its slots (this is the WOT adjustment) and tighten both screws just enough so it can't move on its own. Have somene mash the throttle as far as they can and take note of the WOT value (shoot for anything better than 4.5v). If its satesfactory, take note of the throttle closed value (it will likely need adjustment). Loosen one of the screw (I prefer the bottom one), this will allow the front "nose" of the sensor to be adjusted up or down (idle adjustment) I lightly tap the front of the sensor to move it up or down at obtain the best tps idle value.
Shoot for .40-.42v.
Once done, tighten both screws to hold it in place.
It's all really easy once you get the hang of it.

 

[captrob]

Make sure the floor mat is not wadded up underneath the gas pedal too limiting its travel.

 

[aminga]

Post the dat file and not the screen shots.

 

[nolanator]

Post the dat file and not the screen shots.

Can you tell me how to do that please?

 

[Pronto]

In the reply box at the bottom there are 3 boxes. Click "upload a file". Choose a file you want and upload it. You can do the same to add pictures.

 

[nolanator]

In the reply box at the bottom there are 3 boxes. Click "upload a file". Choose a file you want and upload it. You can do the same to add pictures.

Thanky you for the tip. I'll be sure to do that next time around. until then, here is the one I did last night with the spike.

unfortunately for me it says the file is unsupported so I cant view it this way. I hope you have better luck

 

[Pronto]

You can only read a Powerlogger "dat" file through Powerlogger.