1G Idle dilemma

[Cherry]

So I recently rebuilt my engine, though I had this issue before the rebuild. My idle will slowly creep up to 2000rpms when it gets to operating temps. I am thinking that the throttle body was messed with by the previous owner instead of fixing it properly by actually getting the base idle set screw out when the head of it was broken and it became stuck. I think they might of taken the other route of messing with the stop screw messing everything up. The only way I could get it to stop this behavior before the rebuild was a block off plate to the entire fiav housing and screw in the new bid screw all the way to get it to idle at around 1000rpm which was much better though I hated having to be in the car to warm it up.

I do have an s90, new fiav housing, new 2g tps with the connector already wired in and a new idle control sensor or whatever people call it since I have seen it called several things. I have read how to set up a 2g tps several times now and I still don't really understand what to look at when setting it up. I was attempting to do it before but I don't know what I am should be looking for when setting the tsp when looking at the volt meter. I just don't really understand it. Do I stop turning when the volt meter stops reading 0.L and turns to a number value? And can I set it without it being on the car?

Any input is greatly appreciated.

 

[o0GuitarKid0o]

Tbh man I had a similar issue with my throttle cable sticking abit inside the sleeve. (Only when it was hot).
What voltage and percentage is you tps at? 10.1-10.9 is in a acceptable range.

You may need to add some slack and lube it up abit

 

[Vegas Smith]

Doing a full rebuild on a throttle body is pretty easy and is something anyone can do regardless of their level of experience. However, it seems like your throttle cable might be improperly adjusted. Adjust your throttle cable when the car is fully warmed up and report back.

 

[Cherry]

I'l check it. I'l just take the throttle cable off and see if it repeats what I'm getting with the n/a throttle body. If it still happens then I'll just file the throttle cable end some more so it moves freely in the s90 and attempt to set the 2g tps on it. I'l read how to do it again to see if I understand it .

I know when I had the s90 on there it would at least idle at a stable rpm. I swapped it because it whistled on the throttle cable side.

What I'm thinking is happening to my n/a throttle body however is when I got the engine and went to set the idle the biss screw was broken and stuck in the tb. So what I'm thing is the other people adjusted the stop screw to open the throttle body slightly. When it warms up that gap around the throttle plate gets bigger slightly which causes the idle to go up. When it' hot. I mean the block was cracked when I got the engine which I didn' notice at the front motor mount or where it bolts to the block I should say and they welded it back on at an angle which crpt breaking front motor mounts. The bearings had hardly any silver left on them as well and the oil pan had a huge hole in it that I could almost stick my index finger through fixed with a rubber plug.

Right now the idle is the last thing I have to fix. I got a new block, piston, cams, new front case and oil pump, flywheel was resurfaced, new clutch, all new gaskets and new seals. If I can get this idle sorted then I'll have a nice little car that I can turbo in the future.

 

[Cherry]

So an update. Just took the cable out of the throttle body and when it warms up it stalls so I'll readjust the cable, set the 1g tps which sounds much easier, but since I have a jmfab intake manifold I had to turn it around so I'll have to set it and then set the idle.

Let' hope that does it.

 

[mitsuowner1991]

This may have just answered my question even though you have a 2g.. so my gasket went bad between the bottom of the TB And where the FIAV and coolant lines connect. So eventually my TB was sticking.. to find out it was leaking in amd gumming up.. anyway when i took it apart i found a little piece of metal as a blockoff plate. So i removed it thinking it would be a good idea to have the fast idle till it warmed up.. but with my cams it stuff.. it revs up at down..up and down.. up and down now... and before when the plate was in it, it idled fine. So i guess i should put the metal back in..?? And block it off again..

 

[mitsuowner1991]

Or just get the block of plate.

 

[Vegas Smith]

This may have just answered my question even though you have a 2g.. so my gasket went bad between the bottom of the TB And where the FIAV and coolant lines connect. So eventually my TB was sticking.. to find out it was leaking in amd gumming up.. anyway when i took it apart i found a little piece of metal as a blockoff plate. So i removed it thinking it would be a good idea to have the fast idle till it warmed up.. but with my cams it stuff.. it revs up at down..up and down.. up and down now... and before when the plate was in it, it idled fine. So i guess i should put the metal back in..?? And block it off again..

You're referring to a fiav blockoff/bypass plate. If you removed that and have your coolant lines disconnected or didn't seal those surfaces then you may have a big vacuum leak there causing that idle surge. Look into how the fiav bypass mod works and you'll understand what just happened. I'd just put the plate back in with the sealant to get rid of any boost leaks.

 

[Cherry]

I have a 1g but I have several options I can do for a throttle body setup. I have the stock n/a throttle body that has the 1g tps which I need to find out how to set it since the vfaq link is dead and everything else that is out there is setting it with link. I don't have that and need to do it manually and spent a while looking on how to set it but I have found nothing on it.

I also have an s90 70mm throttle body that has the 2g tps which is 2 things in one basically and with the s90 you have to use a 2g tps, or you have to be able to fabricate your own mounting bracket the sensor that tells the computer that the throttle plate is closed which I have seen called different things. And also that I found, at least with the n/a version of the 4g63 the s90 isn't a direct bolt on since your fuel rail is in the way so you need an aftermarket intake manifold.

You can get a new gasket I think from STM is where I got mine, or extremepsi that goes between the fiav housing and the throttle body. Though if things are gummed up it might of stuck the fiav so it no longer works. I got my new fiav from autozone but it wasn't under the eclipse, I think it was under the 3000gt vr4. It's pretty pricey though.

Also was it an entire block off plate or just for the fiav, the fiav housing has the fiav and the iac, the block off plate being on the idle might of been adjusted and now that the block off plate is off and the idle not set properly you will probably get that idle surge. You have 2 places to ground to be able to set your idle.

At that point it just depends on what you want to do, put the block off plate back on or get a new gasket and possibly a new housing clean everything up real well put it back together and then set the idle. Once I know how to set the 1g tps I can set the idle and hope all that will fix everything. Since I removed my throttle cable from the throttle body it now dies when it's warmed up telling me I might of had my cable just a tad too tight opening the throttle plate driving up the idle.

 

[Cherry]

Well a little update, I set my CAS which for some reason was WAYYY out, about 12 degrees ATDC, need to get my TPS again but it was at .5v like it is supposed to, adjusted the IPS and it was way out of adjustment, new o-ring on the BISS and decided that since none of that being set properly fixed my idle issue to rebuild the throttle body. I did just use o-rings like I have heard other people do and since its actually really easy to rebuild these things when I get a turbo I can get proper seals though people have gotten o-rings to hold 50psi so I figure that they could hold back a vacuum if it is in fact the throttle body seals that are bad.

To me the seals dont look bad though they fell out of the throttle body really easy. The one on the throttle cable side fell out before I even removed the shaft and the TPS side stuck to the shaft when I pulled it out so im guessing the throttle cable side was done. I took some pictures of the seals to get some peoples opinions if they would even show wear. I have it all back together and unlike the turbo throttle body the n/t throttle plate slides out of a groove and was probably the hardest thing on the entire rebuild was getting it back in. I used dielectric grease as suggested by many people when rebuilding it so I guess in the morning I will know if it fixed the issue which is an idle surge issue which was still there if the ISC was blocked off so the block off plate wouldnt of done anything to solve the issue.

I clearly have air entering somewhere else and I think I could hear air on the throttle cable side of the throttle body. I might even reseat the EGR valve block off plate and just not use the gasket but some silicon as a gasket.

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There are the pictures of the throttle body shaft seals. I dont know if it helps or anything, but with them being hard plastic it doesnt seem like they would seal anything that well. Though these things are most likely close to 30 years old it would be easy to assume they are bad and leaking like crazy.

If there is any information about the seals I would appreciate any input. I did notice that there was some sort of gummy stuff towards the inside of the shaft in the throttle body opening around the shafts. Do these have some kind of other seal towards the inner parts of the shaft like some kind of rubberized coating? Or could that just of been junk that got into the air system and since the seals were leaking it accumulated in these areas though it having a vacuum and not an inner pressure like a turbo system you would think if it was gunk it would of been sucked in instead of pushed out. Lets hope these o-rings (14mmODx10mmIDx2w) that I doubled up helps out. Everything works smoothly by hand at least and the gap around the plate looks even. If it doesnt then I might just have to swap out to the JM Fab manifold and s90 though. I dont really like that setup since I think the JM Fab manifold could of been designed better for street use so that the bottom of the throttle body isnt tangled up in the shifter cables. S shaped pipes would of been better between the head and the manifold chamber.

It would be so much easier to work on stuff, it might not have that big of a difference on performance though a straight shot from the chamber to the head flows better. And if I do the change I would have to either get a new slim battery or relocate it again which I dont really feel like doing.