🔧 BUILD Upside-down M90 GTP build thread

[Turbocharged400sbc]

I bet it's on jack stands

 

[sktchy]

I bet it's on jack stands

Mines spent most of its life there. No shame as long as a guy is still working at it. And I think if I've got half a clue about this one if it is on the stands it's gonna come off of em alot better than it was before.

I'm still waiting for you to put some boost to yours

 

[GTPpower]

Lol. It is on stands. I need to fix my axle yet though. That's the only reason why.

I got the 3 bar map hooked up right out of the blower and tied it into the egr circuit. I did some scanning with the car running in the garage and a few revs. It's doing some weird stuff, and the two maps aren't really agreeing with each other. So, we may be on to something here, but I really need to get it on the street and make some pulls to see for sure.

 

[v6buicks]

I forget. Where are the two maps? You have one in the intake and one on the blower outlet?

 

[GTPpower]

Yes. One right before the air goes into the engine and one right on the blower outlet.

 

[Turbocharged400sbc]

Don't forget in tiny you need to zero out the EGR timing and mixture adjustments

 

[sktchy]

Don't forget in tiny you need to zero out the EGR timing and mixture adjustments

Things like this and idle timing make me wish I'd have kept my dhp

 

[Turbocharged400sbc]

You don't need the dhp module as long as you have your OS ID in a .bin you just make the edit changes and Tiny tuner open that file up in HP tuners and then import all of your current .hpt changes

 

[GTPpower]

You don't need the dhp module as long as you have your OS ID in a .bin you just make the edit changes and Tiny tuner open that file up in HP tuners and then import all of your current .hpt changes

You have to have an old version of hpt to do that. I think anything after like 2.2 won't let you open .bin files.

 

[Turbocharged400sbc]

Okay so you're stuck doing the Rube Goldberg method of tuning but you still don't need the dhpp Box

 

[Turbocharged400sbc]

So you have to edit it in tiny then open it with early HP tuners save it as a. Each PT open it in the new HP tuners and then import all of your current maf table etcetera

 

[sktchy]

I'll have to look and see what version I have but it might be worth the hassle to try and find an older version just to be able to play with those tables a bit. Or maybe even just digging up another dhp

 

[SaturdaysGS]

You have to have an old version of hpt to do that. I think anything after like 2.2 won't let you open .bin files.

If I can find it there’s a link to ALL the old versions of HPT..

 

[Turbocharged400sbc]

That s*** probably is going to get threatened with some sort of take down action with the new E PA Crackdown

 

[sktchy]

The other thing is older versions of hpt don't like to play nice with files from newer versions sometimes so that could also end up causing issues

 

[sktchy]

At any rate I don't think the stuff I wanted to play with is super necessary but would indeed be nice to have

 

[GTPpower]

The link was on gpf's before it got the site delete function.

 

[GTPpower]

I attempted to hook up my fuel level sensor. Looks like the stock sender shows full at about 2.5 volts and empty at .70. The sender I have is showing full at 5v. So with a half tank, the gauge is still showing full. Basically I need to cut the voltage in half. Any suggestions on how to do that?

 

[1quick]

I attempted to hook up my fuel level sensor. Looks like the stock sender shows full at about 2.5 volts and empty at .70. The sender I have is showing full at 5v. So with a half tank, the gauge is still showing full. Basically I need to cut the voltage in half. Any suggestions on how to do that?

You would use a resistor but that’s as far as my knowledge goes

 

[GTPpower]

You would use a resistor but that’s as far as my knowledge goes

That was my thoughts too, but I'm not sure how to pick the size.

 

[GTPpower]

Went and finally did some testing with the 3 bar. It varies wildly at idle and cruise, but at wot, it's very close. 182kpa on the 2 bar and 186kpa on the 3 bar.

 

[Mr_Roboto]

I attempted to hook up my fuel level sensor. Looks like the stock sender shows full at about 2.5 volts and empty at .70. The sender I have is showing full at 5v. So with a half tank, the gauge is still showing full. Basically I need to cut the voltage in half. Any suggestions on how to do that?

Do you know the resistance when your tanks is full from the sender?

Theoretically I would believe that your gauge reads off what amounts to a voltage divider. There's a built in fixed resistor in the gauge that's connected to +. The sender "pulls down" the voltage of Rgauge so that you see empty. That's why if you short a GM gauge to ground it should pull your gauge from full to E.

My guess is the minimum resistance is too high on the new sender. Either that or you have a poor ground or your sender is open or perhaps even your sender is "reverse" of a GM one and the resistance goes up when the sender is full and goes down when it's empty.

 

[GTPpower]

I will get back to you on that. Just had something interesting happen on the car. Story incoming.

 

[GTPpower]

So a while back I had a thought that maybe my intercooler piping was acting like a restriction. My bov was being boost referenced at the lim, and I should have probably referenced it right off the blower just to make sure it wasn't releasing and limiting my boost.



So I switched the vacuum lines around from the 3 bar and the bov, so the bov was now getting boost reference right out of the blower. Immediately on the startup, the blower was way way louder. It was crazy loud before, but now.....



The bov looks to be staying shut, so I probably need to adjust the shims in it so it stays open at idle.



I drove about a mile through town like this, and boost would build super easy. Hardly any throttle input and it would show 2-3 psi...again blower stupid loud.



All of a sudden, I noticed rpm was increasing and I was having to hold it back with the brakes. I pulled over and rpms were about 2k with my foot on the brake and in gear, but at a dead stop. I shut the car off, and a pretty nice sized plume of smoke came out under the hood. I opened the hood and smoke was rolling out of the blower inlet.



The blower and hot side pipe were both very very hot. I let it sit for a few minutes and switched the vacuum lines back around so I could get back home.



So did I figure something out? I guess I will try to change the shims on the bov and try it again. I'm sad I didn't get a wot crack, but this sounds promising.

 

[sktchy]

Anything I'm finding the correct readings should be 240-33 ohms so I would imagine check the sending unit for resistance and see where your at as opposed to reading voltage off hpt. Might clue you in as to if you have a wiring issue or at least put you where you need to be as far as a resistor goes ?