HAILERS

Oversteer
While I'm screwing off the morning, I thought I'd put a thought in your head about turboii acv's. As you can tell, yours is getting old (baked switching diaphram). Well there is another malady that old turbo acv's aquire. There is a thing called a AAV inside the air control valve. Its a diaphram that should only open during deceleration. When it opens it puts fresh air into the INTAKE part of the intake manifold. To prevent backfiring.

Now what happens when it gets old and baked, it that it leaks. When it leaks, it put unwanted air into the intake, and makes for some strange idle problem. Its like a air leak in a hose, except worse because you don't think of this as a place for a air leak. Plus its a air leak with some pressure behind it (air pump).

One way to see if its leaking, is to spray some starter fluid into the inlet hose of the airpump. You can figure what happens from there. If its leaking, the starter fluid will get in the intake and change the idle tone/speed. Just another bad thought out of my head this morning. Thats one reason I'm going to have to buy another before next inspection..

HAILERS

Oversteer
You know something. I've been turning one of these truboii acv around in my hands and have come to the conclusion, that if you can successfully swap out that diaphram, your going to be in hog heaven.

I'm talking about the one that four screws and faces outboard. NOT the mushroom at the bottom. I realize that this turboii acv works a bit different than what I had been believing. When you pull a vacuum on that diaphram in you let the air go to the Port Air which is sent to the exaust ports. That will mix fresh air into the exaust ports and have an after effect of making the o2 sensors reading fall at idle.

adamlewis

I found this link helpful

http://www.interro.com/techgas.html

Rob500

Ok. Here is the latest. I passed California smog with flying colors.

I installed a new O2 Sensor.
Fixed my Neutral Switch.
Put New plugs in it (again).
Put 87 octane gas in it.
Asked the Tech to run the tests at the highest rpms allowed.

Rob

Oversteer

I replaced the diaphram on the side of the ACV...got the car good and hot, and it still failed the emissions test. When I got back home I put the meter on the O2 sensor. On a fully warmed up car it read .7 - .8V. It's still way too high. I'm not sure what to do next....besides light the thing on fire and break open a bag of marshmallows!

HAILERS

Oversteer........I was wondering what happened. I don't have any answers. I do know, that if that diaphram is working, a trait of proving it is doing its job is to see a 02 reading of something around .1volts and if the vacuum hose is pulled off the acv (the one that has the vacuum) then the 02 reading should go up to .7 or .8volts.

So what you wrote tells me that for whatever reason, no air is getting to the exaust ports. If it was, the o2 reading would be around .1volt.

I know that you had the acv off the car to replace the diaphram, and fixed that.

The big question: Does the air still dump overboard at the relief port on the acv??? The port the large hose goes to? If it does, then I can see why no air is going into the exaust ports.

I had to take two turbo acv plus one diaphram off a 82 to get one working acv. And it still leaks a bit more than I like at the overboard relief port.

The emissions station. Does it do a test at say 15mph and then 25mph? Or does it do the test at idle?

A very extreme idea I had, and have seen once on this forum, is that a engine was rebuilt, and they put the front rotor housing in the rear and the rear rotor housing in the front. That will screw things up big time as far the emissions go. Car will run great, but the emissions won't work for diddly.

The only way to tell if that is the problem, is to look at the top of the rotor housing. Just to the left of center line there should be a R or a F, indicating you know what. If you see a F in the rear and a R in the front, the airpump air from the acv WILL NOT make its way to the exaust ports.

When you tried the emissions test, did you try to remove the poppet from the Split Air solenoid on the acv???? And reinstall the solenoid without the poppet and spring?

Oversteer

My engine hasn't been rebuilt. I'll try removing the poppet from the Split Air solenoid. In Missouri, they do a 4 minute test on a dyno at speeds up to 58mph. The car is clean at idle....but as soon as it starts moving, all emissions hell breaks loose. I found something interesting last night. I checked the boost sensor using the method prescribed in the manual (add 3.9" of vacuum and check the "D" connector). It read 5V no matter what...even without vacuum. I have a couple spares and they tested the same too. I'm not sure if that could make a difference. I was also thinking about the EGR valve. I tested it and it works fine. However, I don't know if it's getting vacuum when it should so that it works correctly. When you rev up the car, it doesn't move at all???

HAILERS

Double answer. Sorry site.

HAILERS

About the boost/pressure sensor.......are you real sure that your on the right wire. The wire should be Brown/Red in color. I suspect your on the Brown/White wire. The Brown/White is reference voltage b/t 4.5 to 5 volts.

I'm rusty on the EGR. I put a LED on its output once but flat forgot how it reacted. Maybe tomorrow I can check that out again (and write it down so I don't forget.)

Have you checked for the air coming out of the split air hose at the back of the acv??? Take the vacuum hose off the acv and feel for flow of air at the split air hose? You might do that, and then remove the split air poppet and see if the air increases.

If it does not increase try stuffing a rag/what ever into the relief/dump port on the acv and see if the air amount increases. Heck, it has to dosn't it? I mean there is nowhere else for it to go.

Good to hear that it is not a rebuild, built wrong.

Oversteer

I checked the Brown\Red wire and it has 12V. Something else that is weird is that my car does not have a variable resistor which I see on the wiring diagram. The car is an '88

HAILERS

I can see there are problems. I know you have looked at the 88 manual at http://www.iluvmyrx7.com and seen page 50-25 of the wiring diagram section and it clearly shows that there should be an output from the Boost/Pressure sensor to the ECU on pin 2B. And that output should not be anywhere close to 12v.

I'm stumped. Maybe it's really a series five....which I have no diagrams for. And the series five uses a different boost/pressure sensor. One that does not use 12(from what I've read.)

Did someone put a turbo in a n/a. Like your car. And you don't know about it???? LIke I said, stumped.

Does your factory boost/pressure gauge work????? When you turn the key to ON, does the needle jump up close to zero????? Most likely not.

Hey. Describe the wires on the boost/pressure sensor. Write down what each wire color is. Like B/W for black/white, BrR for brown red, BrW for brown white and B for black.

Yeah. That boost/pressure sensor has to be wrong/junk whatever. The only wire on a 88 that should have 12v is the black/white wire.

Very last thought......write down the numbers on the boost/pressure sensor. Like N318 or N326 or N370 or N350 and if those are notlegible, write down what ever other numbers are on it.

We are talking about the boost sensor. Located at the right hand strut tower. Has an electrical plug and one vacuum line?? Must be. You see a Brown/Red wire there. Hmmm

HAILERS

Tell us what the number is on your ECU, please. Such as N332 or N333 or N326. Whichever.

Oversteer

I thought I mentioned that the car was a TII convertible. It's an '88 with an '88 motor\harness

Here are the details

N318 Boost sensor, and another N318 spare
N318 AFM

N332 ECU

Here are the details on the Boost sensor plug wires

1 2

3 4

1 - Black w\white stripe
2 - Black
3 - Brownw\red stripe - showing 12V
4 - 2 Brown wires w\white stripes

Oversteer

More interesting details. The black wire should be ground. When I check it with the key turned off, it's grounded. If I turn the key on, it's no longer grounded?? This thing is messed up. I can't believe it runs as good as it does!

Oversteer

More interesting details. The black wire should be ground. When I check it with the key turned off, it's grounded. If I turn the key on, it's no longer grounded?? This thing is messed up. I can't believe it runs as good as it does!

Black and white shows 12V
Brown and red shows 12V
Brown and white shows 5.02V

Oversteer

Forget what I said about the variable resistor. It's there...sorry about that one.

HAILERS

Go a step further for me. Go to the ECU. Leave everything connected up. Get your meters positive lead in the back of the Brown/Red wire at pin 2B. That should be the middle plug, far right on the plug, bottom row. With the key to on, what does it read?? Everything else connected up, especially the boost/pressure sensor when you do that. It should read approx 3.5 v with no engine running.

IF you find the brown/red wire somewhere other than 2B, tell me where. Tell me its not in 2H what ever you do.

HAILERS

Yeah, check grounds only with the key to off.

One thing I noticed. On the beginning page of this thread, I posted a jpg of the pins on the ECU and what they should read at idle and key to off. THAT jpg is for a series five, not a series four like you have. It was meant for Rob500 who has a series five. So don't be using it for a reference. You'll have to look at your series four FSM or the one on line. Series four only.

Oversteer

The Brown\Red wire is connected to pin 2B. With everything connected, I show 12V at the plug on the ECU.

Oversteer

I just had a thought after re-reading this thread. You mentioned the vacuum line on the ACV that opens up the diaphram I replaced. With the vacuum line on, the ACV should allow air into the exhaust ports. Do these exhaust ports have anything to do with the hole in the rear rotor housing right below the exhaust port? The '87 - '88 exhaust manifold has a 1" hole in it that allows air (from somewhere other than the exhaust ports) enter the exhaust. However, my car has the '89+ turbo and manifold that does not have this hole in it. The hole is blocked by the gasket and the exhaust manifold....so no air could enter the exhaust...Am I making any sense here??

HAILERS

I know what you talk about. If I was talking about a 86-88 N/A, I would say for certainty that that hole is for the EGR only. I've done two turbo engines and I can't at this moment say what that hole is for on a turbo. I think EGR but the EGR is located on the back of the intake manifold on a turbo. I'm going to have to say I don't know for sure. We might as HYPRTNZ or SixRotors or????? My spare turbo is sitting on the floor but its got the lower intake manifold/trubo installed and I don't think I can tell from that. I'll take a look.

I know there is no procedure to do so, but I think I'd stuff a rag in the acv outlet/relief, and look at the 02 sensors reading and see if it varies when you do that. Should go down to .1-.2 or so. Fully warm car when you do so.

I'm also confounded by the 12v on the brown/red wire. Should be 2-4 volts output or what ever the book says.

HAILERS

Well, screwed the pooch on those jpg too. They're for a n/a. Maybe somebody else can use it. But you can see 2B should have low voltage around 3volts.

Damn. I'm going to have to pull the turbo/exaust off my spare to see how thats routed. I've always assumed the Port Air on a turbo was routed like a n/a, but I can see that I've never really looked at the passages on a turbo. Anyone know for sure?

Oh. The way the one inch hole works on a n/a, is that the egr valve, located on the top of the center housing, opens up, and sucks exaust air from that one inch hole thru the egr valve then into the intake ports. The turbo should work similar but the egr is on the aft end of the intake manifold. I'm unsure about the routing on a turbo. I'll take a look tomorrow if I don't come to my senses.

Oversteer

I printed out the ECU pinout for the TII and I've checked every sensor through the harness. I'll plug up the ACV relief this evening and see what happens. Thus far, I haven't been able to change the .8V reading on the O2 sensor.

HAILERS

Yes. Do the plug job. I came to my senses this morning and I'm not going to remove my intake/exaust. I forgot about those to orings for the water passages and it's 28 degrees outside right now.

I looked at the pictures of the intake gaskets for a trubo. It appears the acv air goes into the intake manifold just below the two intake ports for the intermediate housing. Its a rectangular hole just below those two intake ports. I *think* the air goes down a passage inside the intermediate housing and exits thru a hole in the exaust ports. Not the same as on a n/a where the acv air enters the front and rear housings and then makes its way to the exaust ports thru the rotor housings.

I can't get over the 12v at the pin 2B from the boost/pressure sensor. That's just insanity. The ECU determines what the boost level is with this signal and that determines the amount of fuel being delivered plus the timing should be altered as you boost.

I have a 87turbo and all the numbers that you cited for the ECU etc are the same as mine. Except the voltage at pin 2B on my car is closer to the fsm. Much, much closer.

HAILERS

*********I was also thinking about the EGR valve. I tested it and it works fine. However, I don't know if it's getting vacuum when it should so that it works correctly. When you rev up the car, it doesn't move at all???*******

I put a meter on the EGR and went for a ride. Sitting in the driveway and reving the engine, the voltage stayed at 12volts(means the solenoid is pulling a vacuum on the EGR). I drive down the street and the voltage goes to 2.5 volts(meaning the solenoid closed and there is now no vac on the EGR).

Just driving around it seems as I accelerate, the solenoid closes cutting off vac to the EGR. As I cruise along it shows 12v, meaning the solenoid is not energized and is pulling a vac on the EGR while cruising.
Just about anytime I goose the car the EGR closes cutting off vac to the EGR. With the exception of above maybe 3500 or so. Above that it showed 12v all the time meaning it was pulling a vac on the Egr.

That's not very thorough but I lost interest. I've passed emissions with both a turbo and a n/a egr disabled.