tougeFB

Vehicle, 88 Turbo II 10AE

I used the writeup on 1300cc.com for the BAC valve cleaning. I did the whole procedure, removed the 2 coolant lines, unplugged the sensor, and took out the two 10mm bolts which hold on the BAC to the manifold. Also took off the lower hose going to the BAC. The only problem I found was that the lower hose seemed a bit weak and deteriorated on one side. The other side was normal. There were no clamps on that line, BTW. I then proceeded to scrape the old gasket off, which is where some of my problems happened. Some of the gasket came off, some didn't.

I then took the cleaner to the BAC, which was fine, it didn't even seem that dirty. But before the idle would fluctuate like crazy, and after doing my research I found others with the same problem, thus I figured this may fix the problem. I didn't have another gasket to use, so I used Mazda factory silicone. (I work at a Mazda dealer). Then after getting all the remaining old gasket off that I could, (since it all didn't want to come off) I proceeded to reinstall the BAC. All was fine and good, until I started up my car and it wouldn't hold an idle. With or without the A/C running it would not stay constant. So I figured maybe I put too much gasket or didn't do a good job putting the silicone on, so I removed the BAC and cleaned it. There was a little bit of silicone inside the air port of the BAC.

So I removed all the silicone, and then just for test purposes I installed the BAC with no gasket or silicone. The car idled, but poorly and still did the fluctuation. Then I think I made my biggest mistake and tried to adjust the screw on the BAC. That seemed to have poor results, because before the car would barely idle and it would change a lot, and now it no longer idles. I ran out of time, and the shop was closed so I couldn't look at a factory manual as to what the specs were, and also used an ohmeter to check the resistance of the BAC, and got a number I believe it was around 21 ohms. I dont know what the factory specs are though, so I can't compare.
I didn't try the click test with the BAC (applying power and ground and seeing if it clicks), but I probably should. Now I am driving with no idle, and it's horribly annoying.
It seems like a vacuum leak to me, only because it seems to be leaking pressure. I even asked a coworker of mine to spray the vacuum lines with carb cleaner to see if the idle raised (when I did get it to idle) and I guess they didn't check the lower hose, which very well may be my problem.

Has anyone else experienced this? Also I didn't search this yet, but how do I raise the idle on an 88 TII. A friend of mine told me the idle was set by the screw on the BAC, but that just hindered me. I don't know, only because I don't have the manual and because I'm used to first gens! haha Thanks in advance, sorry for the novel....

AUGieDogie

iTrader: (4)

I searched for a vacuume leak for two weeks before i found out it was my BAC. Its interesting because all of the vacuum syptoms are the same for a bad BAC. In my case the BAC shorted out the transistor in my ECU.

First go here

http://www.teamfc3s.org/info/articles/idle.html

21 ohms seems a little out of spec but might still be ok. Test it again.

do the click test.

Go to radioshack and spend 99Cents on the resistor to test the wires to the BAC

Get some gaseket making paper to make a new gasket, or just buy a new one. Use your discount

The adjustment screw on the BAC IS where you adjust the idle. BUT you need to jumper the green conector near the bat/coils. otherwise you just mess it all up. As you probably figured out by now.

Can you hear the BAC vibrating with the Ign switch on? I can hear mine clicking if its quiet outside.

Good luck

Augie

HAILERS

Remove the bac but leave the electrical plug on.

Turn the key to ON. The bac should vibrate. Touch it with your finger LIGHTLY to see that it does. If it does not vibrate, the transistor is shot or the electrical plug contacts are not making.

Buy a roll of thin gasket paper and a razor blade. Make a proper gasket.

Stop worrying about that resistance. Pay attention to whether or not it vibrates. Do NOT force the valve inside with a screwdriver etc.

IF the bac is vibrating, do this. Idle the car fully HOT. Pull the bac plug off. The engine rpm should drop a touch. IF the engine dies when you do this, then your idle is NOT set right and you need to get with the program and set your idle first thing. You should be able to set the idle of the engine to approx 750rpm with the bac plug off.

IF you do the above, then when the bac plug is reinstalled, the bac will not have to work its butt off trying to maintain a seven fifty idle speed.

tougeFB

Thanks for everyone's help. I'm working on the fix right now.
I wouldn't have known how to adjust the idle without a manual, and didn't have access to a computer. I didn't know you have to use a jumper wire also. I am going to try this and let you all know my results

tougeFB

Okay so here's the latest.

The car won't hold an idle by itself. The culprit sounds like a vacuum leak to me. It just starts up and dies.

I also (for ***** and giggles) tested the resistance of both the variable resistor and the BAC again.

the BAC: 13.2 ohms, so it seems in spec.
variable resistor: from terminal A to terminal C: 0.5ohms, from terminal B to C: 5.0 ohms
specs are 0.5 to 4.5 ohms.

SO I have yet to do the click test, and also I'll be spraying some fluids around the vacuum line to see it raises while I have someone hold the gas steadily.

Other than that, I'm stumped. How can I tell if my idle screw is messed up completely?
Also where is the variable resistor supposed to be set at? (the L-R screw by the air box)?

Thanks again everyone

AUGieDogie

iTrader: (4)

Follow hailers advice and pull it to see if it vibrates. It takes like 5 mins tops.

The variable resistor doesn't have a specific seting for ALL cars. Its different. Plus its another one of those things that need to be adjusted with the initial set coupler connected.

tougeFB

Thanks guys.
As of Saturday I tried the click test, and everything worked as it was supposed to. I took off the BAC again, sprayed it one more time and reasealed it with silicone. The car idled after this, but VERY weak. almost dying. So because I got it idling, I could now set the idle (for the most part). So that's all taken care of. It still was acting a bit weird, so I sprayed more carb cleaner by the air hose to the BAC and the RPMs rose. I had found two of my leaks!!

So my next trip was to NAPA. I got a new air hose for the BAC, (1/2'' hose) I think was the size. It measured a little less than 2mm. The car was blazing hot at this point, and removing and installing that new hose was a b*tch! I kept having to shorten the length of the hose because the guy cut it too big. I actually cut it a little short, but it still slid on. I want that hose to be the exact size, and then I'm going to throw 2 screw clamps on there. I also picked up a pair of new spark plug wires to help my misfire, but actually the NAPA ones made it worse. The boots didn't fit on right, and I could hear them arcing all over the place. Strangely enough, the car never idled better.. haha

I wasn't about to pay 150 for a set of stock NGK 7mm wires. My roommate actually took the boots from my old NGKs and threw them on MSD wires. 20 bucks, not bad. I will throw those on today. Then I can hopefully return and get a credit, or my money back for the crappy NAPA ones.
I also ordered a new gasket for the BAC, $2.10 my price through Mazda OEM. I have a feeling that my car should be running beautifully soon. (i hope) Thanks again everyone for your help. It was more than appreciated!