Ashyukun

iTrader: (3)

After the euphoria of finally getting my vert's 'new' engine running, I noticed that after it had warmed up (still has the thermowax) it was idling around 1300-1500 rpm (literally- it bounces noticeably between those speeds very rhythmically). But I can't for the life of me get it to go down to the 750 it should be at.

I've:
Adjusted the TPS
Tested the resistance of the BAC & air control valve (the one right behind the BAC)
idle adjust screw does nothing (no surprise since it's not under 1000 rpm)

I tried using starting fluid to check for vac leaks, but after spraying all around the spider didn't notice any change. As a test, I pulled the pressure sensor vac line (which caused the idle to jump) and sprayed the starter fluid directly into it- which caused the engine to actually bog slightly or at least run at a bit lower speed for a few seconds, which surprised me since I would have expected it to increase.

This is to the best of my knowledge (the shortblock was swapped in from my parts car) a stock S4 block with only the sub-zero assist & EGR removed and blocked off. I also have the port air solenoid left unconnected (since in my research it seemed that it was not really used and if it went bad stood a good chance of toasting the ECU), but I did hook it back up for a short while in my tests. Also, I removed the A/C and P/S when I did the block swap.

Is the engine bogging/slowing after spraying starter fluid into a vac line normal? Is there anything I need to do other than simply pulling the A/C and P/S stuff (jumpering connectors, etc.)? One thought I had was that the high idle could be caused by the BAC thinking the A/C was there and running, but I would think it would default to the case of it not being on if it didn't see the hardware.

Ashyukun

iTrader: (3)

Finally got back to revisiting this yesterday. The first thing I tried was unhooking the BAC- which immediately solved the 'bouncing' and the engine ran at a nice steady speed. Would this be indicative of the BAC being bad, or something else in the electrical system causing it to think it's seeing a varying load?

With the BAC removed, the car idled around 1200 rpm steadily. I was able to bring it down slightly (to a bit over 1000 rpm) using the idle adjust screw on the top of the dynamic chamber- but that was the extent that I could bring it down. Any ideas as to what would be keeping the idle up that high and what to do to bring it down to the 750 that it's supposed to be at?

RotaMan99

How smooth does the engine run?

Starter fluid can bog the motor since its a flammable liquid and to much will replace some amount of air entering the motor.

The BACV is used to keep idle around 750-800rpm. Above 1000rpm im sure its not sure what to do If the BACV checks out from resistance tests, then it should be fine.

Your problem sounds like the thermowax on the back of the TB is incorrectly adjusted or bad.

FSM tells you exactly how to adjust and check the thermowax.

Ashyukun

iTrader: (3)

With the BAC connector pulled it seems to run pretty smoothly- though I can hear some really low bass thumps from the exhaust and uneven intervals, but you've really got to be listening close to hear them- for a while I thought I was just imagining it. There isn't any change in the engine speed associated with them though.

I'm about 90% certain that the thermowax isn't bad- it does seem to keep the engine running a bit faster and then drop it back down once I can feel the coolant warming up. The adjustment on it though I will have to check- I took the TB apart completely and cleaned everything thoroughly and then put it back together, and while I didn't change any screw settings it's possible things aren't quite aligning properly.

RotaMan99

Those thumps are normal. I have never heard a rotary without them.

HAILERS

The thermowax is keeping the throttle plate open. Adjust the thermowax/fast idle cam etc. See the FSM, Fuel section.

In other words the cam isn't coming off the roll pin.

You might try idling the engine for a half hour and close the hood so it gets fully hot. Maybe the water isn't passing thru the thermowax as it should. Clogged pasages? Hose blocked off? Who knows.

TweakGames

iTrader: (3)

Im doing the thermowax thing right now. I had to go down to a craft store and get some .5mm crafting wire to test agaist my throttle plate and the throttle housing. I hope it works out well.

HAILERS

In that picture, if you turn the screw near the words FAST IDLE CAM all the way IN (clockwise), then the cam will come off the roll pin for sure. It won't be set right, but almost a guarantee that the plates will now close all the way after the water gets warm/hot.

If this is a non turbo, that screw is almost hard to access without removing the throttle body. Just four nuts hold the body on and maybe some other small things, but well worth doing.

I'd do this prior to adjusting anything else. Really.

TweakGames

iTrader: (3)

Hailers, I am doing this RIGHT now, what mark should I align the roller cam on? the lower or upper on? I was thinking the same thing, if it gets any hotter the roller cam will fall off. Maybe right in the middle?

Ashyukun

iTrader: (3)

That'll be the first thing I check, then.

Would the best (and relatively easy) way to adjust it right be to warm the car up to running temperature, shut the car down, and pull the TB and adjust the screw until the cam comes off the roll pin?

TweakGames

iTrader: (3)

no, there are two marks there, and from what I have understood so far, is the thermowax piston will push that screw up the hotter it gets (As the thermowax expands) when the screw goes up the plate with the marks on it goes down. If you set it to the top mark the plate will go so far down that the roller will fall off the plate.

Im "GUESSING" that it needs to be set in the middle when its 77 degrees. Dont quote me on that though, im still playing with it right now.

Ashyukun

iTrader: (3)

That sounds true- from what it looks like the FSM is saying (and what makes sense) once the engine reaches operating temp (solidly above 77F) the thermowax extends enough that the roller comes off the fast idle cam entirely and the throttle mechanism can move freely (which is what it sounds like mind isn't doing).

TweakGames

iTrader: (3)

awwwww didnt think about it like thattttttt its supposed to come off the marks.... interesting .... Im going to poor some hot or boiling water in to see what happends. And then cool it down to see if it comes back on.

TweakGames

iTrader: (3)

Ok, so I poured a couple cups of almost boiling water past the thermowax, and it kinda almost got to the edge but it didnt come off. I dont know if its not hot enough, or that it doesnt come off. Maybe my water wasnt as hot as the car. Anyways, im going to set mine like FSM and throw it back on there. I will see what happends.

Ashyukun

iTrader: (3)

I think we're both actually 'right'- according to the FSM at 77F the roller is supposed to be centered on the mark on the cam, and if it's functioning properly then when it's heated up to running temp the roller will come off the cam. I was just trying to come up with a simple way to do it without having to worry about getting the thermowax at exactly (or close to) 77F.

TweakGames

iTrader: (3)

When you force your roller off the cam, does it come back easily or do you have to force it?

HAILERS

It really does not have to be set JUST like the manual. You can always fudge a bit where it'll come off earlier than the manual says. We're talking about something that is fifteen plus years old. \

Make it work in YOUR favor. No sense being dogmatic about setting it exactly like the FSM.

TweakGames

iTrader: (3)

WELLLLLL im an idiot ! its true dont beleive what everyone else tells you! I had my injector plugs messed up. I had my primary inj plug on my trailing and my trailing on my primary. Kinda doesnt like to run right when you do that.

Wow she pulls a lot harder then the NA. Also stops really fast when you hit the fuel cut at 4000 rpm @ WOT. lol I only have down pipe. Not as loud as I was thinking it would be either. Anyways anybody reading any of my posts in the last 3 days, unless you have ur injectors mixed up, dont listen to anything I am saying.

Good luck to you all!!

Ashyukun

iTrader: (3)

Heh. Yeah, I imagine that would mess things up a bit. :P

In my case, turning the fast idle adjust screw in a few turns did the trick- though the BAC still wants to kick the idle up to around 1100 rpm if I leave it plugged in (even when the engine is plenty hot and has been running for a while). I'm back to wondering if in pulling out the A/C & P/S for some reason the BAC is thinking that something is there and running that isn't. But, at least as it is once it's warmed up it settles down to a nice ~750 rpm idle. Can't wait to get to really drive it tomorrow for the first time to go get its license plates.

RotaMan99

Have you tried jumping the initial set connector near the leading coil? If you don't, then the BAC could fight your idle setting.

Ashyukun

iTrader: (3)

I had tried it before, but I haven't gone through the full idle-setting/testing procedure since adjusting the fast idle cam- I'd been dealing with clutch issues and having bought another car as a turbo engine (after a rebuild) & performance part donor...