calibrating body throttle and air flow ?

[Eduardo Castrejón Elbjorn]

At last, today I saw my engine bay fully assemblied ( nice sensation) after 2 years of saw only parts.

My engine starts but not at first crank, and the idle is high.


AIRFLOW METER

Today I change my airflow meter was very difficult to take out one bolt from the air filter housing ( I bought this rebuilded maf about 2 years ago ), I try to test with a multimeter the 2 maf (old and refurbished) like say in the haynes manual but both gave me the same reading and is not near of the specs in the book. but if both maf gave me the same then I believe both are correct.

I replaced because the refurbished blocks cover is already removed then I can adjust.
Tomorrow I will do this job, I´m planning to folow the instruction of early944.tripod.com to adjust the co level with the oxygen sensor, do somebody already did it ?, waht capacitor range I will need ?

THROTTLE SWITCH- is perfect

BODY THROTTLE

what is the correct setting (rpm,etc)

Let me know

regards

[Scott R]

Sounds like an idle CO issue, you may have a rotten o-ring on the idle speed set screw. It's a brass screw in the throttle body, but you need to bypass the idle speed control motor in order to adjust it.

Near the brake resevior you will see a plastic cap about the size of a pocket watch. Open the cover, you will see one pin that is away from the others, this is the ground. Run a jumper wire from the ground pin to the second pin from the top looking at the battery side of the car as the top. to bypass the idle speed control valve.

Again I wish I could dig up the pucture of the diag port to show you the pins, but I can't find it as usual.

Also after sitting for two years I would remove the throttle body and clean it up.

[todwic]

it's an '84, he doesn't have an idle speed control motor.

[todwic]

I think about 800 rpms is good, mine has an auto tranny, so I have the idle @ about 925 rpms so it doesn't lug too much with the torque converter. Yes, that bolt is a &#^@#%$&^% to get to, so I took it out and left it out. Duct taped the holes in the air box and put some silicone on the part of the AFM that doesn't have a bolt (if you unadvisedly do what I have done, make sure the silicone is fully cured before you start your car, silicone is the lambda sensors natural preditor.

[Scott R]

DOH! Sorry forgot about that.

[Eduardo Castrejón Elbjorn]

Like always thanks to both of you:

Scott:

sorry, I always forgot to mention that mine is 84 auto like todwic

I will check the o ring in the brass screw of the body throttle

I don´t know the correct way to clean the body throttle but I clean a little with a brush and gasoline.

Todwic:

I will follow your 925 rpm idles advice


ok, then what I need to do ?

1.-check the o ring
2.- set idle to 925 rpm
3.- adjust the screw of the afm

that´s everything ?

what about the bolt (not brass) in the body throttle that can accelerate, do I need to unscrew completely to set the 925 rpm with the brass bolt and then screw the other until tops ?

[todwic]

Are you talking about the throttle stop screw? If so DO NOT use it to adjust your throttle in any way. Just to make sure we're on the same page: Throttle stop screw (sounds like a track side cat house) is a piece of allthread with a slot on the back and a nut that when adjust right, touches a plate at the same time your throttle closes. The idle speed screw is a largish screw in the side of your throttle body that sinks into the body. That is the only thing you use to adjust your throttle.

[Eduardo Castrejón Elbjorn]

thanks todwic

[todwic]

Here ya go, Ed, just so I know there's no language SNAFU:

Idle adj. screw out of throttle body

Started in hole, can change the o ring like that should you want to.

How you'll see it in your car.

Throttle stop screw, not to be used to adjust idle, just keeps the butterfly from over closing.

[Eduardo Castrejón Elbjorn]

todwic, thanks for your time, yesterday I already ask to pelican about this o ring.
regards

[Eduardo Castrejón Elbjorn]

the problem was that I can´t had less than 1000 rpm, the problem was throttle stop bolt, then I took out, I calibrate the rpm to 925 and then I took inside the throttle stop until stop with out accelerate the engine, only to stops like your advice.

Then I tried to set the maf and this time when I move the bolt the engine accelerate and desacelerate a little. But I never had the 0.5 v reading. I tried several times but I had between 1 to 2 volts,then change the range but in minivolts change a lot.
I don´t know about the near setup ?
if I push in the bolt until top then how many screws (aproximately) do I need to take out ?

All this tests was with engine at normal temperatures when the fan turn on.

this moment feel better but don´t start inmediatly in cold starting
what happened ?
I already replace the auxiliary air valve and I cheack all the vaacum hoses.

please let my know your opinions

[todwic]

Did you re adjust your Throttle position sensor? It should click at 1° turn of the throttle cam. To adjust, just loosen the two screws that hold it on and twist it untill it clicks as soon as you move the cam. audible click. Then check the values: Three posts middle is the ground. Left on is the WOT value, the other is the Closed Throttle value. One is infinate ohms untill you close it, the other is infinate untill you open all the way, I think, consult the haynes manual.

Also, That little do-hicky that has two hoses at the top, two spad connectors at the bottom and is attached to the same bracket that holds your AFM up on the firewall, it's job is to allow extra air when you turn on the A/C to turn both fans on. That may be messing with you, a bit. Try adjusting it with the ac off.

hen I tried to set the maf and this time when I move the bolt the engine accelerate and desacelerate a little. But I never had the 0.5 v reading. I tried several times but I had between 1 to 2 volts,then change the range but in minivolts change a lot.
I don´t know about the near setup ?
if I push in the bolt until top then how many screws (aproximately) do I need to take out ?

I don't quite understand what you mean here.

[Eduardo Castrejón Elbjorn]

Todwic

fast answer, do you live here ?
thanks

Yes, I test the body throttle values only like says in the haynes manual but was correct and I don´t opened.
I will check about the position.
But my car start fast when is normal temperature but in the morning when the egine is cold, delays more like a carburator engine.

what is afm ?

Then I tried to set the maf and this time when I move the bolt the engine accelerate and desacelerate a little. But I never had the 0.5 v reading. I tried several times but I had between 1 to 2 volts,then change the range but in minivolts change a lot.

I only tried to explain that when the body throttle stop screw was accelerating the engine a little, I can´t down the rpm of 1000 and if I screw or unsrew the maf bolt (more or less air, air mixture) I can´t ear a diference, now with this problem solved I can feel a little diference (accelerate and desacelerate) the engine a little.

I told that I wanted to set the maf air mixture (co2 level) following the instructions in the early944tripod home page, supose that I need to use the O2 sensor the set the level of co2 if you don´t have acces like me to a co2 diagnostic machine.
Supose that I need to set the maf screw until I have a reading of .5 volts but I can´t.
I know that the readings will change but I never be near.

Then I´m asking if somebody can tell me an aproximately set up for this maf mixture screw ?
If I screw the bolt all the way inside the maf, then how many screws I need to take out this bolt ? or something like that, instructions to set tha maf screw because in my rebuilded maf cames without the plug and needs to be set properly

Let me know
thanks

[todwic]

AFM=Air Fow Meter/Air Flow Sensor.
Did you unplug your Lambda sensor before you started messing with the CO₂ mixture control? That screw is how a lot of shops make the '44's pass smog. They torque down to where it will barely run, and then test the car. When the test is over, the set the values back to the way they are supposed to be. I guess you can set it by ear, but I haven't messed with mine since I don't have access to the CO₂ mixture tester.
Yes, Ed, I do live here. I got a tent over on the regional forum, by the california arizona area. Lots of lizards, but nobody bugs me over there.

[Eduardo Castrejón Elbjorn]

Todwic

I don´t know Arizona but hope one day

Thanks for your answer

Yes, the 02 sensor is unplugged, ( I don´t have the connections, first I planning to weld the 02 sensor cable to the motronic o2 sensor cable, but yesterday I read in the early 944 ( no sold this wire ! ), I try to understand why ? but I can´t or I completely confuse because I understood that the 02 sensor breaths clean air by the wire !, i completely sure that I don´t understood this.
But to make tests in the future will be better to have coonections to unplug if is necesary.

I also read in other page of early944 that at idle the readings from the 02 sensor always are jumping from lean to rich and yes that is the problem that I had with the mutimeter then I can´t did it.

When the test is over, the set the values back to the way they are supposed to be

Yes, but I don´t know the supposed values

I believe that is not a big problem because when I will connect the 02 sensor the motronic will be adjust the air fuel mixture, but if I set correctly the motronic will have less work to do it in this part.

My posible solutions:

1.- reinstall my old maf that have the original setting but I know that is a lot rich (without the o2 sensor, I never tried with the sensor) but I don´t want to battle again with the airbox bolt.

2.- Go with the car to the ford or chevrolet and try to adjust the c02 level, but what reading will need to have to know that my setting is correct, I don´t need to pass smog laws, then I can have all the time the better performance setup.

let me know your opinions

[todwic]

To adj. the CO on Motronic+Lambda engines when CO₂ tester isn't available: Hook neg. lead to engine ground, pos. lead to Lambda output. Run engine @ 3000RPMs for 30 sec to make sure sensor is hot enough. Turn AFM screw towards lean untill voltage is at lowest point. Turn it the other way untill voltage is at the highest point.Turn it both ways untill you reach the mid point. GENERALY, it's 500mv, but it varies with age of sensor.

Charles Probst, S.A.E.

[Eduardo Castrejón Elbjorn]

Mr. Wilk:

Until this moment I note that you are the author of
http://frwilk.com/early944
thank you very much, veru useful info.

Yesterday I follow your shudder fix in my 944, I really never feels this shudder but I did it.

I already can set the maf with the 02 sensor, thanks

Idle:

At normal driving temp I set the idle at 975 rpm (you say 1000)
My problem is cold start because start at 600 rpm or little less and shakes then after seconds climb to 900 then after some mins
continue climbing until 1100 then the temp goes to mid gauge and fans start up and after some mins the idle goes to 975

I recently replace the air valve and I don´t have problems of leak vacuum hoses.

Do this is normal ?, how I can avoid this shakes at cold start ?
Do the engine at cold start need to climb the revs inmediatly until the engine is hot ?

Please help me with this
regards

[Eduardo Castrejón Elbjorn]

thanks a lot for your answer

Ok, my auxiliary air valve is new about 2 weeks and about temp sender what is this ?
I change too the temp sensor (motronic), do you refer to the other besides the temp sensor ?

[Eduardo Castrejón Elbjorn]

FR wilk;

Thanks for your answer

I will take out the plenum and I will replace the aav hoses and I will post what happened.