Hello everybody,

I just pretty much diagnosed a rough run condition/ lack of power/ occasional surge/and random miss, and it's noticeable if you listen for a while..

The condition is slight but definitely enough to notice and sometimes definitely more noticeable.

So I left my manual that I was borrowing back at the school, but we tested everything, hooked up the scan tool, everything looked beautiful, the block learn was 138 at closed loop, the manual said 110 lean, 150 rich, and the sensor was toggling between lean and rich, so that was pretty nice, and took it for a drive, computer saw no misses or anything shady, egr activated and de-activated properly, and all sensors were working as they should, (at least that's what the readings were) then it got warmed up and the symptoms become more noticeable, but everything visual passed, and a fresh full tune up, we were getting ready to clean the injectors by tapping into the feed line, and putting some gm top end cleaner through the injectors, then while we were waiting for some tools, we decided to hook up the smoke machine and check for vacuum leaks, gasket leaks, etc.

The only place smoke came out feeding it through the back of the intake was the drivers side of the throttle body, and through what i'm pretty sure was the "supposed to be one way check valve on the air pump" and while i'm sure the check valve doesn't cause a driveability issue because it's after the exhaust

But i'm sure the side of the throttle body must be causing a hell of a vacuum leak and here's my question, is it serviceable? or do I have to find a new one?

I couldn't find any new ones or remans at autozone, napa, or anywhere, not even online

What do You Guys Think??

Any help would be greatly appreciated

 

Ok so I emailed hawks and they said they'd sell me one for 75 plus shipping

So should I try to service it? Or just order the good used one???

What do you guys think?

 

Well, if the leak was around the throttle shaft, that would mean either the shaft bushing or whatever else seals the shaft to the main body of the TB is shot, in which case it's probably more cost productive to replace it. However, if the leak was up high, there is a gasket at the top of the TB that can be replaced. Wiggle the throttle shaft on the end where the cables connect to and feel for play.

 

Thanks Mav nice to hear from ya,

Yeah like literally the smoke was comin straight out the side where the cable assembly connects to the throttle body and theres like a little plastic scrunching type of thingy that just kinda loose, between where the tb cable connects to the main throttle body, crazy lol

gonna go out and wiggle it brb

 

Wish I could have helped more, but I got rid of all of my stock top end parts months ago .

 

sorry for the late reply

just got home, car acting like it has an even bigger vacuum leak then ever, givin me hell all night, so yeah...probably gonna park it for a while till I get these parts

I'll probably just get the one from hawks for 75 plus shipping if no one replies to my wtb ad for it for any cheaper.

get a new air pump and I had a small leak coming from the vacuum brake booster hose at the booster end as well, maybe new hose for that?

 

There was no play, everything was solid except for the plastic scrunchy piece, no wiggle, sucks

 

oh man, it's all good, that would have worked out

so should I order the good used tb from hawks? would that be the best way to do it?

is the air pump serviceable?

Thanks for the help maverick appreciate it

 

Yes, I would get a used TB, either from Hawks or wherever or there are a couple guys parting 3.1s on here (FLYNLOW92RS is a guy I just bought a replacement power steering pump bracket from and he's got a whole RS he's parting... look in the Classifieds).

As for the AIR pump, if you don't have smog checks, just can it. You can make a plug for the defective check valve (I doubt you can replace it cheap).

Oh, and yes, the booster hose can be replaced, but the closest size hose there is would be a coolant hose and that would require hose clamps to hold it in place. And then there is the problem that the check valve at the booster could be crap or the o-ring. Also, the coolant hose WILL get sucked flat by the engine vacuum.

 

For sure that will be probably be the best way, as I don't imagine it's that common of a problem with these throttle bodies?

Also RockAuto.com has a repair kit for tb's would this be what I needed to repair it? http://www.rockauto.com/catalog/moreinfo.php?pk=88803

Maybe not, lol

So that was probably why my engine ran so crappy with the shorter belt and the air pump deleted, because I didn't plug those lines up?? as soon as I took it off it threw a code, I had took the belt back, could always get another one,
915k6 correct?

Just Passed Emissions two months ago, so got about two years for the emissions, then I guess one could just hook it back up when time?

Thanks for the replies

 

and also it looks as if FLYNLOW92RS sold the throttle body already,

but I posted a WTB ad

probably just going to end up getting the one from hawks, they've always sent me good parts

 

That RockAuto link is merely a replacement for a leaking fuel pressure test port on the back of the fuel rail, so that's not going to help...

The GP Sorenson TB repair kit I got a long time ago was merely gaskets. It's not going to help with a bad shaft seal, I don't think (I only used the top housing gasket on my TB).

AIR pump delete should not cause any issues... ECM won't even know it's gone. If you had issues, there were other problems with the engine systems (low vacuum, etc). I've never had one, and the harness/ECM I had installed from a 91 for a while never knew the difference (if it wasn't for the ignition issue, I'd still be using it). Although, I'm not sure what the deal is with the charcoal canister on those cars with respect to the AIR pump line...

Yes, the 915K6 is the A/C, NON-AIR interchange belt...

Let me look up the exploded diagram and stuff for the 3.1 TB tomorrow (FSM is in the garage) and get back to you...

 

Cool, the one I was loaned from school I left at school and cant get it till monday, that would be really cool

Just let me know

 

I didn't get a chance to look at the 91 FSM, but for my 87 (same TB design with few changes), the main body of the TB is apparently not serviceable... The exploded diagram shows everything connected to it (top vacuum cover, lower coolant ports, sensors) but no exploded view similar to a carb... Apparently the main body is serviced as a unit. There may be a guide of some sort on 60degreeV6, but that's as much as I can say at the moment.

Oh, and are you 100% sure the leak is coming around the throttle shaft and not the TB to plenum gasket behind it?

 

Pretty sure..it was a pretty direct out the side shot of the smoke, my teacher had said as well that these were serviced as a unit and I would need to replace, he also said I might have luck with used ones as it wasn't to common of a problem?

 

I should probably just replace the gasket first just to be safe and do the smoke sometime again,

also for the air pump would this check valve work?
http://www.autozone.com/autozone/par...52231_17696_0_

Thanks for all the help bro

 

If you're sure that the AIR check valve is leaking, yes, that would be the replacement valve.

The reason I said to ask the guys on 60*V6 is that there is a guide on there for a newer TB that tells you how to remove the throttle shaft for opening up the throttle bore to put in a bigger plate. I'm not 100% sure if the TB they describe there is a GM or other TB, but they tell you how it's done. As far as I can tell, at the very least, you would need to press off the TPS lever, take the screws out of the throttle plate, and find a way to disconnect the throttle return spring before sliding the shaft out. Probably easier and more cost effective to get a replacement TB as you may not be able to find the seal you would need, if there is one in there somewhere. If I had a spare TB, I could rip it apart and let you know, but I got rid of both the 2.8 TB I had and the FWD TB I had a while ago as well as the 3.1 TB.

 

Appreciate it Mav,

No problem though

Got a new (used) one coming from hawks, just ordered..

Now, as I understand it will be JUSt the throttle body...Do you think she meant, no tps, no iac, but the linkage assembly will still be on there right lol

So I would just take the sensors off mine and put them on the new one then?

I don't know for sure , but the smoke was coming from behind the pulley pretty much directly from the front of the air pump, and teach said the check valves behind there?

BTW bidding on a GM manual on ebay hehe hopefully get it for 20 bucks, that would make me very happy

 

Wish I had seen this earlier, there's a couple V6 cars at my local jy I could have pulled one from.

 

You'll find out if the TB is bare or not when you get it... I'm going to assume all of your add-on parts (TPS, IAC, cables) are still good, so those will probably just swap over if the TB is bare.

Yes, the AIR check valve connects via a hose to the AIR pump somehow (didn't get the pump on my 3.1 and didn't do anything with the one at the J/Y I pulled the harness from) and then to the exhaust manifold with a 90* pipe. Won't hurt to get the valve, but I'd replace the hose on the end of it first or at the same time to make sure there isn't going to be an issue with the hose when you're done.

I did a Buy It Now on both of my FSM's... Got both (87 for chassis and wiring, 92 for engine and such) for less than half of what Helms wants for reprints .

 

Yeah I guess it should still be good right?

Definitely replace the hose at the same time, that would be the best,

I def. need my own manual though, yeah i'm buyin it now, lol

Thanks for all the help with this, gonna get back to you asap when I get these damn parts!

 

A tip: If the "new" TB does come "loaded", as they say, save your old TPS and IAC. The IAC alone will save you about $40... If it works right. Just don't lose them!

 

got the new throttle body from hawks, not too bad, came with all sensors and old gaskets attached

I was wondering should I just replace the base gasket to the plenum, and use the sensors they sent me?

They also sell a set of gaskets for this tb at autozone, for some reason it's not online though.. I went there and the pic had all the gaskets to the different parts I could see on the one I just got, Im wondering if all I had to do was get that gasket set and swap all the gaskets out??Too late now I guess lol But should I get the gaskets and slap em on the new one?

Got a Master Torx Set for the tb bolts and the water pump bolts as well....

Yeah gotta do the water pump as well...probably should do the timing chain as well while i'm in there....theres a first time for everything

and finally got my distributor wrench to fix that damn oil leak, gonna be busy tomorrow

 

Replace the TB mounting gasket (between it and the plenum), bypass the heater lines, and put it on as is. If the sensors are bad, then you have spares. I've bought sensors from junkyards that were just fine, $10 a pack for a bag with a TPS, CTS, and IAC (about $100 in that bag!), so I'm willing to bet that there is a good chance yours are as well.

Replace the torx bolts on the water pump while you're at it with regular bolts to save headaches in the future.

 

Definitely, will give these a shot, so that works, and also, should I replace the torx bolts??I just spent like 50 bucks on the set lol was hoping that they would work in the future

What do you mean by by-passing the heater lines? Like bypass the coolant lines on the tb?

 

Leave the torx screws on the TB itself alone... But scrap the ones on the water pump.

Bypass the heater lines running to the TB by connecting one hose to both sides of the intake manifold pipe. One less thing to leak. If you want to break in you new torx bits, remove the heater pipe adaptor from the bottom of the TB so it's not sitting there looking ugly with those nasty coolant pipes sticking out. Yes, it does come off, and it has another o-ring on it that can leak.

 

Ok, sorry I didn't get back to you sooner, had a slight internet snafu

However I pulled an all nighter the night before last replacing the water pump, throttle body, coolant flush, oil change, plug wires, just wanted to get it done and had my buddys garage to work in so it was lovely

Had to take the power steering off, coated a thin layer of rtv on each side of gasket, spread it with finger....was that the right thing to do??

Anyways, did that and when I put it back together I unfortunately forgot to ditch the torx bolts, but I wire brushed em up real clean and put rtv on the threads, then the PITA back bracket to the power steering...I just left that off and bolted it with the front thick one, it seemed very sturdy, you think that was cool to leave off?

Didn't read this in time but I put the damn coolant lines back on the tb with hand turn clamps, but yeah I didn't have new hoses and looked inside the old ones from the tb and they were pretty funky inside I felt bad putting em back on there but fatigue starts to get to you after a while...

So your saying I can just take that coolant thingy that the hoses to the tb are on, off? Is that just it, just take it off and youd be good, or is there something you have to plug??

Still gotta get the air pump, still have a slight rough run at idle, and it's not only leaking, but getting a little noisy as well, and for some reason the service manual says if not functioning correctly it will affect driveability and gas mileage??

But other then that, the throttle response is a LOT better, and butter smooth

AND

Merry Christmas by the way

 

The gasket will be fine...

What I learned to do with the power steering pump is to remove the nuts (the ones on the pump studs, not the bolt in the engine block and not on the exhaust) from the rear bracket, remove the nut and bolts from the front bracket, and slide the whole pump and front bracket assembly forward and off of the rear bracket and head. This makes alignment with the water pump bolt easier as the whole mess just slides back in again where it's supposed to be. You may need to loosen one or both of the PS lines to do this.

Take one of the TB coolant hoses completely off (one is longer than the other, remove the short one), and turn the other one on the hose adaptor so that it faces the other nipple, put it on the nipple, and clamp it down. Then take the 4 bolts out of the TB adaptor (the one on the TB itself) and junk the thing... I think there is a pic floating around somewhere of my 3.1 TB with the adaptor removed and my 2.8 TB with it still on there right next to each other.