2G Throttle plate position

[MasterMatt209]

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For a while now I have been chasing why my car starts up and goes straight to 2k rpm. Long story short I was inspecting my throttle body and the pictures I am attaching is with a light behind the plate. To me it looks like a lot of light showing through, this is the plate as far as it will go without the stop screw. Any input is helpful I did rebuild the throttle body before because I was getting a lot of air thought the seals.

 

[BLACK'98DSM]

That's definitely a problem. and needs to be replaced. But I'm not 100% sure that it would cause you to run at 2k rpm. But that's a good place to start.

 

[MasterMatt209]

That's definitely a problem. and needs to be replaced. But I'm not 100% sure that it would cause you to run at 2k rpm. But that's a good place to start.

New plate? Whole new TB?

 

[BLACK'98DSM]

New plate? Whole new TB?

New PLATE
I can't think of a way to fix that one...

 

[MasterMatt209]

New PLATE
I can't think of a way to fix that one...

Okay thank you, I believe before it was so dirty that it didn’t matter until I cleaned it.

 

[BLACK'98DSM]

Just another thought, does it stay steady at 2k? Or does it fluctuate?

 

[MasterMatt209]

Just another thought, does it stay steady at 2k? Or does it fluctuate?

Been a minute since I let it run but I know it doesn’t surge. Maybe idle drops a little bit after warming up but not much

 

[MasterMatt209]

Also I’d anyone knows where I can get just the throttle plate let me know cause I can’t find it

 

[BLACK'98DSM]

That's what happened when my throttle cable was too tight. Have you checked that?

Just want to save you any extra work if I can, and that is literally the easiest fix.

 

[MasterMatt209]

That's what happened when my throttle cable was too tight. Have you checked that?

Just want to save you any extra work if I can, and that is literally the easiest fix.

Yes I have checked that, the throttle plate is fully closed when off the pedal and wide open at WOT. Just put a fresh intake manifold gasket too hoping that was my problem. I did a BLT and there is a leak I’m trying to source out under the TB but hard to find where the air is coming from since it’s underneath. I noticed the plate at the time too and how it seems like it could be letting too much air in

 

[BLACK'98DSM]

Yes I have checked that, the throttle plate is fully closed when off the pedal and wide open at WOT. Just put a fresh intake manifold gasket too hoping that was my problem. I did a BLT and there is a leak I’m trying to source out under the TB but hard to find where the air is coming from since it’s underneath. I noticed the plate at the time too and how it seems like it could be letting too much air in

Gotcha. Do the plate, then let us know what happens.
You may have to buy from local junkyard or from a retired dsm'er

 

[DSMPT]

The plate is not centered. The plate has a tiny bit of play, so loosen the two screws and slide the plate a little bit and see if it fully closes. If it fully closes then tighten the screws with the plate being fully closed. If you can not find a position that the plate fully closes then something is wrong.
But looks like who rebuilt this throttle body stripped the stock screws since it doesn't have them, so maybe he damaged the holes on the plate/shaft when removing the stripped screws. You should remove the plate and inspect it. If the holes for screws on the plate are enlarged or damaged, then should replace it. And if the shaft is modified for different thread pitch or screw diameter, you also should replace it, too. Or just find a complete throttle body would be easier.

 

[ThunderChild]

Agree with @DSMPT the plate is misaligned, upside down or backwards.

I'd bet it's fixable relatively easy, but if not a whole new TB may be necessary. Recommend disassembling and attempting to fix first.

 

[luv2rallye]

Agree with DSMPT and Thunderchild. People strip those screws easily. Try loosening them, align plate while holding plate completely closed with fingers (no gaps around it), tighten screws. If it won't do it or stay there, get a new plate.

 

[MasterMatt209]

The plate is not centered. The plate has a tiny bit of play, so loosen the two screws and slide the plate a little bit and see if it fully closes. If it fully closes then tighten the screws with the plate being fully closed. If you can not find a position that the plate fully closes then something is wrong.
But looks like who rebuilt this throttle body stripped the stock screws since it doesn't have them, so maybe he damaged the holes on the plate/shaft when removing the stripped screws. You should remove the plate and inspect it. If the holes for screws on the plate are enlarged or damaged, then should replace it. And if the shaft is modified for different thread pitch or screw diameter, you also should replace it, too. Or just find a complete throttle body would be easier.

Agree with @DSMPT the plate is misaligned, upside down or backwards.

I'd bet it's fixable relatively easy, but if not a whole new TB may be necessary. Recommend disassembling and attempting to fix first.

I centered it and the area showing light is much smaller. It shouldn’t block completely right? Just trying to make sure it’s right before I put it back on.

 

[MasterMatt209]

Agree with DSMPT and Thunderchild. People strip those screws easily. Try loosening them, align plate while holding plate completely closed with fingers (no gaps around it), tighten screws. If it won't do it or stay there, get a new plate.

Completely so no light should shine through?

 

[ThunderChild]

It should be almost no light. You might see a tiny bit around the perimeter, but no more than a hairline worth.

 

[MasterMatt209]

Idle is now about 1700. Probably need to play with the plate a little more

 

[luv2rallye]

Completely no light (or at least no space around plate). There's a bypass port in the TB for the idle function (it should not use any space around plate for that).

 

[shinzon]

Anyone else extremely nervous about those hardware store throttle plate screws? Red locktite those at minimum--I'd NEVER put that throttlebody on my car again for fear of those screws backing out and ending up in a cylinder. I'd also assume that whoever did that botched other things with the shaft seal install.

Don't quote me on it, but i think the plate and screws from a junkyard 2.4L spyder can be used in a 2g turbo throttle body, might we worth looking into. You'd likely need a new 2g turbo throttle shaft too since those self tapping screws no doubt buggered the threads.

Edit: unrelated to the current problem, but looking at those paint marks on the spring, whoever was in there didn't get the throttle spring tension correct either.

One last thing: where's the fast idle air valve that's supposed to be on the bottom of the throttle body? I don't see a blockoff plate either... If that's missing, and isn't blocked off, that'd be a massive amount of air bypassing the throttle plate.

 

[luv2rallye]

Yes, have the throttle body shaft seals been replaced? They are another unwanted air source.
https://www.dsmtuners.com/threads/throttle-body-shaft-seal.394103/#post-152484314
http://www.ca.dsm.org/faq/tb-shaftseals.html
https://www.dsmtuners.com/threads/throttle-body-shaft-seal-install-help.495582/#post-153533252

 

[BLACK'98DSM]

Idle is now about 1700

Have you replaced the TPS before?

 

[DSMPT]

@MasterMatt209
Did you take the pic while you were disassembling the throttle body, right? Because in the pic, the throttle body doesn't have the ISC and FIAV is wide open. If you don't have it, that's the issue.
If you have it, then fix all vacuum leak, connect two coolant lines and try to adjust the BISS, throttle cable, stop screw, the TPS and the base ignition timing properly and see if the idle speed gets proper.

 

[Mello]

To me it looks like the throttle plate is in upside down. Others have had this problem after doing a rebuild too. Check out this thread from a little while back it may help. https://www.dsmtuners.com/threads/how-does-this-happen-to-a-throttle-body.519350/#post-153700563
The spring is not tension correctly either. It needs another twist so the added on paint mark makes a straight line.

 

[DSMPT]

To me it looks like the throttle plate is in upside down. Others have had this problem after doing a rebuild too. Check out this thread from a little while back it may help. https://www.dsmtuners.com/threads/how-does-this-happen-to-a-throttle-body.519350/#post-153700563
The spring is not tension correctly either. It needs another twist so the added on paint mark makes a straight line.

The plate's direction is correct.
If the screw heads are in the inlet side like the OP's pic then the stamp "50" should be on the upper side of plate. If the screw heads are in the outlet/intake manifold side then the stamp should be on the lower side of plate. And the screw heads and the stamp should be in the same side.