flipstar

iTrader: (14)

OK so, long story short, I've messed around with my car for far longer than I wanted to just to make it run smoothly. Problem is, it still doesnt.

1990 GXL, stock.
http://www.youtube.com/watch?v=dg-vWC-7CRI
http://www.youtube.com/watch?v=1UUlmYCJxyk

Problems/Quirks

Popping noises from the exhaust at all times (idle, revving) except for deceleration. It decelerates perfectly. Woo hoo.

Crappy idle - Watch the videos. With the TPS disconnected, its extremely bouncy, but quite mechanical. However when it is connected, the idle is more erratic and quite rough. It never stalls.

Weird cold start - My car chooses to start up at 2200 rpms for a few seconds, then slowly come down to 1500. Once warm, it bounces between 500 and 1000.

When accelerating up to 6K - 9K RPM, and letting off the gas quickly, an very loud pop (afterburn?) can be heard from both inside and outside the car.

Solutions/Steps taken

misteryx69 (dave) stopped by my place a few weeks back to check it out. He said it was missing, but I didnt think so. I went ahead and bought new plugs anyways and no change. All 4 coils work. TPS was also checked, and works.

One other thing of note is that the 6th port actuator is frozen open. Don't think this would have that much effect on my car tho...

So basically the only other thing I can think of is vaccuum leaks... but I REALLY don't want to tear everything down. So if anyone can tell me anything from this, and those vids, I would greatly appreciate it, this is driving me nuts.

Oh one last thing, if I turn the idle adjust screw all the way to closed, the car doesnt stall, which is why I suspect vacuum leaks.. right?

scrip7

iTrader: (6)

Getting a page error on your vids. Grab an unlit propane torch and with it idling, point the torch at the air intake and crack the valve open enough to make a change in the way it runs and post back the results.

That Rx-7 kid

idk im no expert, but i would assume popping is normal at high rpms, possible back-firing no?

misterstyx69

iTrader: (142)

Ya..I saw the car.it would idle,and lightly pop,every once it awhile..it did it Even when the car was getting revved.I checked the coils,and they were fine..The Bad thing about this,Is trying to Diagnose the car when it is Friggin Freezing outside!..Mike,If We get a couple Good Days weather here,Call me up.I'll go down there and I have spare parts here..we can start off wth the Vaccum leak Scenario,and work our way over to Swapping Coils,TPS etc..let me know.OK?

flipstar

iTrader: (14)

Page error iis because I dont know how to make html posts............
fixed:

tps installed
tps removed

flipstar

iTrader: (14)

I've tried the propane torch set up too.. rammed the damn thing in the MAF and I litterally couldn't even notice a difference, which doesnt make much sense to me unless my propane torch is actually just filled with compressed air......

And ya Dave, I know, cold weather is ***** for working on cars. Maybe some good days will be coming soon, you never know with the whack weather weve been getting these days

NJGreenBudd

iTrader: (1)

I'm gonna have to say that there are some leaks in the intake system, might be a vac hose, might be that stock TID, could be a bad gasket or seal, could be a crappy fuel injector grommet. The torch should make a difference though, unless your leak is that big. What other things have you adjusted whilst trying to fix this?

I had a crappy idle once and was able to resolve it mostly by fixing leaks and setting the fast idle cam. This was my expereicne, might be useful to you:

VIDEO - Still crappy idle, no response to idle adjustment??

'87 TII Ovehaul - from bouncing idle to engine refurbishment

Good luck with this.

flipstar

iTrader: (14)

Is there any way to remove the throttle body without taking off the fuel rail on an s5? I just cant seem to get it off the 4 bolts because the rail is in the way.

Basically im trying to get at the fast idle cam and other goodies back there... so if youve got any better ideas let me know

flipstar

iTrader: (14)

ok. so.

I took off the throttle body and the upper intake manifold to dick around with all the screws in the back that are a pain to get to.

At 25 degrees C my throttle plates were slightly cracked (which makes sense due to the AWS/thermowax) AND the throttle stop tab was SEPERATED from the throttle stop screw.

So to eliminate one possible problematic component I adjusted the fast idle screw such that the tab was against the throttle stop screw, thereby bypassing the entire system with the thermowax, because no matter what position the thermowax piston is at, the plates will be fully closed at idle.

Now what it does to my idle:

Putting everything back together, I fired up the car. Runs like poop, of course, popping, very shaky, maybe 400 rpms. This can be adjusted with the idle speed adjust screw on the TB. So i turned it up a bit, got it to 800, but again, shaky.

So i unplugged the TPS - No change.
Then I unplugged the BAC, the idle dropped, and stabilized somewhat. Im guessing this means that my bac is working correctly?

I turned off the car, and started it up again with the BAC disconnected and TPS connected. It wont start. Turns out this floods my engine.

I plugged everything back in, pedal to the floor to unflood it, and got it running again. This time, I unplugged the TPS and left the BAC plugged in, but blocked off its air hose........... an interesting result. I couldnt get the car to idle, it would just stall, but if I gave it enough gas to keep above 1500 RPMs... it sounded.......... flawless. Perfectly smooth, no popping, no searching, just perfect. If i let go of the gas tho.. it would just sputter and die.

Now what?

whorider

Yeah mine must be filled with compressed air also. No effect what so ever. I just wanted to say I experienced the same thing. A smoke machine is much better.
Good luck

flipstar

iTrader: (14)

Updates..

So after much tinkering, I finally figured out I had a frozen actuator on the 6th port. It was frozen open, thereby letting in way to much air, and messing up my idle. I fixed that, and fired the car up, and for the very first time, the AWS would actually run it up to 3000 RPMS for 17seconds!

But then it would sputter and die. boooooooooooo

Anyways I tinkered around some more, and now I cant get the AWS to shut off, The car just stays at 3000 RPM, and im SURE its not my thermowax, or throttle stop screw, or idle adjust screw...... Anyone have this problem?

flipstar

iTrader: (14)

Ok I think I've come a long way, and just about as far as I can go for now.

I can get my idle pretty much perfect at 850.

I removed my thermowax ( you wouldnt believe the gunk i found in there.. the wax leaked out ) and I removed my AWS solenoid valve cause it was acting funny too. I plugged the lines with a grommet and pair of pliers haha. If you've got a better idea let me know (vacuum caps anyone?)







So Like I said I can get my idle just about perfect, however, when I turn on the lights, or heater, for example, it will drop quite a bit, and does not really compensate for the change in load on the engine. I basically have to set my idle based upon how much load i will put on the engine on average, so I set it a little higher (~950) so I can turn on my lights and stereo and itll drop to 750.

I guess I need a new bac?

scrip7

iTrader: (6)

Try cleaning the throttle plates/bores with carb cleaner first. There is normally a gap between the plates and bores that gradually diminishes with varnish buildup, and cleaning all of it off every couple years helps the BAC stabilize the idle like it should. Drop a brick on the gas pedal to hold the throttle blades open while you scrub everything with an old toothbrush and carb cleaner. And don't forget to remove the brick before startup.

You can also get a rough idea of how well the BAC is working by removing the air intake hose at the BAC, pinch it closed with a pair of needlenose vice grips (this prevents unmetered air from entering, causing a stall) and with the engine at idle, put your thumb over the BAC inlet and note any changes in air flow when the a/c or headlights are kicked on, or when the BAC connector is unplugged. You can try to clean your BAC with carb cleaner, sometimes helpful, sometimes not.

flipstar

iTrader: (14)

Wait, what?

There is only one hose on the BAC, and if I remove it, there will be no flow in or out of the BAC, so I don't get what you are saying here...

And oddly enough I did scrub my plates and bores with a toothbrush and carb cleaner

scrip7

iTrader: (6)

The BAC get's it's air from the big intake duct. If you remove it from the BAC (temporarily) you will be able to see if there is air flowing through it, and if the amount changes when things are switched on. If you don't close off the hose that you removed you will have a big vacuum leak (umetered air) and the engine will die. Kapish?

flipstar

iTrader: (14)

No, I get all that but... are you saying my car should run with the bac either open to the atmosphere or blocked off? cause it sure as hell does not.

My car will run for about 10 secs if its open to the atmosphere but if i block the bac off OR unplug it (same effect - prevents air from going thru the bac) the car wont even start.

Is this normal?