The Wankler

iTrader: (14)

Is there a way to force your ECU into closed loop?



Another question?

After boosting your car, what switch, solenoid, ect, tells the ECU to go back into Closed Loop?

I tore down my top end, my car was going into closed loop durring cruise, as soon as I gave it boost, it stuck in the rich side. That is my reason for the above questions. I have tested most of the solenoinds at the ecu with a volt meter. I am at witts end.

Thank you,
Chris

Tofuball

I have NO clue why you would want to do that, but you have to put a high vac source (more then 7INhg) on your MAP sensor, and smoth out your throttle movements (as not to use the TPS to 'disable' the closed loop'

You should not be in closed loop under boost with the stock ECU.

The Wankler

iTrader: (14)

I am trying to figure out why I am not going back to closed loop. So, I am asking different questions that I had in previous threads. Any idead about question 2? What tells the ECU to go back to closed loop after boosting?

I am failing smog.... that is why I am currious about closed loop. My AFM is not bouncing...

Tofuball

Check your TPS to make sure it is not spiking, and make sure your MAP is good.

Check that first and then we'll go from there.

The Wankler

iTrader: (14)

The Map, being the little black box that you hook the FC off sensor to? How do I check the TPS for spikes?

Tofuball

Yes, thats the MAP.

And to check the TPS: http://fc3spro.com/TECH/HOWTO/TPS/tps.html

edmcguirk

As far as I know there is no single signal that tells the ECU to go into closed loop and no diagnostic signal that will force it into closed loop.

You have to be under 4000rpm and midrange on the manifold pressure (too low and it goes into fuel cut mode and too high and it goes into open loop acceleration mode).

Maybe after boost you are over 4000 rpm. It won't go into closed loop over 4000rpm.


I had the opportunity to watch my AFR gauge during the dyno test for NJ emmisions. It stayed in closed loop the whole time.

An old sensor can get too sluggish to work in closed loop, maybe you need a new one.

ed

HAILERS

Just a hint. Look at the 88fsm online, fuel section. Right at the beginning there is a section called SELF DIAOGNOSTIC CHECKER. Read it and the part about the FEEDBACK SYSTEM.

I know you don't have a Diognostic Checker. It matters NOT.

The green light can be simulated using a LED from radio shack and the green check connector under the hood.

I THINK I described how to do that in your last thread. Maybe, maybe not.

Bottom line: the fsm has you pull the tps connector off. Then disconnecting the neutral switch (putting it in gear does the same thing). Fully warmed up engine also.

The green light (your led under the hood) should blink on/off when your b/t 1500 and 2000rpm.

Personally I suggest putting the LED in the green check connector and running the light to the cabin and going for a drive while monitoring the LED.

WAYNE88N/A

I think he already checked the O2 sensor's input with a meter, Hailers. I think this is his 2nd post on this subject...

Sometimes (even when she's settling down into "cruise" mode) it takes a while for the ECU to kick in the closed loop. 15 seconds, maybe, with no throttle movements whatsoever...

The Wankler

iTrader: (14)

It is stuck in closed loop period.

After the last post Wayne88N/A mentioned, I took apart the top end. Found a small/ well, large leak in my smog pump. Fixed it, put it all back together, and walla! I went into closed loop at 2.5K - 20mph........... cruising. I was happy. But, as soona s I gave it boost, bam, never went back to closed loop.

My car has been quit erratic. Everytime I start it, the idle stays around 1200rpm. I let it warm up, way up, never drops. I then set the timming per the FSM. Adjust my TPS. Then go for a cruise, come back, I have to readjust everything a little bit again. Then next day I get up, I have to do it all over again.

I have done quite a bit of testing as you have all advised, but I am sooo missing something. Probably right in my face!

I have a new comp on the way from RResurrection, and a new smog pump. \

Thanks all for your help!
Chris

WAYNE88N/A

Umm, I think you need to find the OTHER vac leak...

HAILERS

If you set the timing with the engine at 1200 rpm.........the timing is OFF. The ECU advances the timing somewhere around 1000-1100 rpm all by itself. I'd suggest getting the idle down to a reasonable 750-800 rpm.

There's no way from here to tell why your idle is that high. Could be a number of things. Long list.

The Air Pump has Nothing to do with open/closed loop at all. None. Zip

The Wankler

iTrader: (14)

Ok, I have a little more info now. The one thing I have not tried is Haillers recomendation to fun the light into the cab and watch it blink for closed loop. I will try that after lunch.

Yesterday, I went for a drive, a hard one. I noticed while driving up a long gradual incline, my AFM would bounce in closed loop, as soon as I panned out the gas peddle, the AFM read rich. Same thing with feathering the peddle downhill, closed loop, until I pan off. When I jump on it, it does go into open loop as needed though.

My question?
Could I have two vacum hoses backwards?
Maybe a couple wires?

Thanks,
Chris

WAYNE88N/A

Why would you have a couple of wires backwards, lol???

Reading your above post, I'm wondering if anything really is wrong, or if you're getting just a bit critical on what you think the ECU and A/F should be doing in closed loop. I can't really tell. What you described is normal operation in my book...

The Wankler

iTrader: (14)

ok, wel, the guys at the smog shop told me ( I know, I know, just repeating what the, "Smog Experts" said) that my car is not going into closed loop while I am in cruising mode. The tests performed on the car is on a Smog Dyno, reving the car to 2500 rpm, at about 25 mph, no load. My cars AFM was not bouncing, and the smell of rotton eggs was appearent. (Brand new cats, timing on the money)Now, you have me wondering about that wayne. Maybe I should just go shove the smog pump hose straight into the cat...... I jsut wanted it to run right first, but like you said, maybe I am being to critical?

Thanks Wayne!
Chris

WAYNE88N/A

Have you checked your split-air system to even see if pump air is getting back to the cats?

A lot of guys rig theirs up so that pump air is continually fed to the cats to pass smog, BTW...

I don't know if our cars are capable of going into closed loop at 25 mph. I had to really work at it just to get closed loop going in 4th gear at about 40 mph once (doing some "testing", lol)

If you were in 5th gear at 25 mph, the rpms might have been too LOW to get a closed loop going, I'm not sure...

If all you're worried about is passing smog, you can rig the ACV to pump air to the cats full time without rerouting any hoses. Pull the little solenoid plunger and spring out of the split-air solenoid (back of the ACV), and route vacuum full time to the relief valve on the ACV (I forget if it's the front or rear nipple above the ACV, but I can check it out for ya on my car if you want)...

The Wankler

iTrader: (14)

Wayne, thank you. THat is what I am going to do. I am probably a bit foolish forlistening to the smog guys, hell, they, like most, dont even kwon where our no.1 plug is. However, I have learned so much listening to you, Hailers, and NZ. Of course, everyone else as well. Thanks, I am going to do that with my smog pump, and disconnect my AFM before I go back there to finalize my smog.

The Wankler

iTrader: (14)

I have added pics because I am not exactly sure what solenoid plunger and spring you are speaking of. Is that the one? If so, do you snip it to get it out?

""and route vacuum full time to the relief valve on the ACV (I forget if it's the front or rear nipple above the ACV""

^^ not sure what you are speaking of.

Thanks,
Chris

WAYNE88N/A

What car do you have? You got '82 listed in your profile, but I thought you were S5???

In any case, that ACV doesn't look exactly like mine, and I don't want to lead you astray...

On the S4, anyway, the back solenoid is the split air solenoid. When you figure out which one it is on yours, pull the solenoid body, pull the little plunger and spring out (don't lose 'em), and reinstall the solenoid body (no wire cutting needed). This will simulate the split air solenoid being energized all the time...BUT...

You need the relief valve opened inside the ACV to route air to the split air solenoid port. Look at the cutaway drawing in the FSM to better understand what I'm trying to say here...