If the ECU sees a sensor out of expected range it will disregard the sensor and default to a less then optimal set of data maps to regulate the engine

The moment this accurse has a time dampening component to it

Since the MAF is never in range it may already be in default

An example would be a open spot on your TPS sweep

Not saying you have one

 

To do list

1 check the MAF voltage, clean it

2 check the gap on the butterfly throttle not release the TPS.

 

Check the part #s of the MAF and ECU to be sure you are working with the correct parts

Clean the O2 sensor connectors and grounds

Inspect the Papa Indy 1 and 61 connectors

Did you remove and clean the transmission casting body connector underneath ?

 

All MAF and ECU connectors are okay

O2 sensors are okay but one of them has a lower reading at idle. I will change the positions to inspect an injector issue...

Papa Andy was okay too.

I release the gear box cover on the radio side... It was clean too. The main conector on the lower part from the gear box, could be on the my to do list, cause I cannot access easily to clean it. I will try it today.

thanks

 

Since you have the GM transmission the transmission connector is different

The connector on the normal transmission can be gotten to without jacking the car

ECU and MAF part #s ?

I found green corrosion on my rear O2 sensor connectors

One way to measure the final performance of the full throttled supercharged engine is to run a wire into the cabin from the middle wire on the MAF

The voltage reading can be compared to someone in New Zealand that had restricted and limiting throttle movement until he resolved it

His results were in the 5 volt DC range

 

Middle to line cable

The both sides cables

The MAF is clean



Is there something wrong?

 

The MAF is powered not by a reference voltage of 5.0 DC ( like the other sensors ) but I think without looking 12 volts or B + whatever that may be

The connector has to be hooked up to power the MAF and you are looking for the return signal back to the ECU

Researching

 

Green / Pink wire with the engine running and everything installed including ducting . 1.2 volts DC at idle

The MAF is powered by B + voltage on the Black / Light Green wire

 

so my MAF sensor, it's okay (12 battery)

 

I have notice a poor wiring on the knock sensor but I release the cable and try to start the engine and there was no issues or fouls codes at the OBD readings...
The power wiring is because there was a 150 ohms resistor...



Also it was only one orange-grey cable as showed on the picture.



That is the knock sensor B

Aj16 MY1994 November

thanks all

 

It is the return voltage of one point two that is important that the ECU uses and not the twelve the MAF is powered by

middle wire

The one point two will increase with increasing throttle

 

The knock sensor if the ECU sees it as triggered will retard the ignition timing and reduce performance

The first generation ECU may not show a fault code because this ECU didn't have all the bugs worked out yet

You might be able to see that your timing is at 25 degree advanced and I think this is correct

 

My timing is about 17-18°


Fist engine revs Third timing... 17°

And what about the resistor? Is it usual or have I to deleted it?
thanks

 

At higher RPMs the timing will be more advanced and you may see 25

The timing also relates to the throttle position compared to a mass air flow and RPM if it is behind

 

Today I have checked the spring butterfly and it is okay. It can close the throttle butterfly easily (I contó close it more than the spring...) it estoy at the idle screw.



This is how it looks like. The spring is okay and also the idle screw...

Next step IAC release and check...

 

Unless the throttle pedal has a return spring something has to drag the cable through the cable sleeve to return to the idle stop

Hard to tell if the updated stronger spiral spring is installed but a 2nd external straight spring can be add as a test to see if it give you the idle results

but you did say by twisting your hand you are already at the idle stop

Yes the IAC valve , but is recommended to put some heat on the inside of the TB in the IAC bolt tread area least they break off

Remember to leave the TPS alone for now

Electrically you can test the windings on the IAC step motor

This would be before risking bolt breakage

You may not see a open winding until it is warmed up or hit with a screwdriver handle on the side

You have 4 to the square power combinations or 16

but green to red is electrically equivalent in looking for a open regardless of polarity as red to green and so on

So you have 9 different combinations


ECU black connector

 

There is no problem with unscrewing the IAC I had removed easily a few moths ago.
I will compare the connectors with an other IAC that I bought and the patterns screw was different . May be I will adapt it to the throttle body in other to see what happens... let's see...
thanks

 

The IAC has around 50 ohms resistor between their pins so it's okay.
the thing is that the cone rail is out as you could see on the pictures below



The IAC I think it's okay but may this could be not okay and the dual rail are required to stop the cone spinning.

 

Ignition coils ?

 

I will check the sparks quality with specifics tool to see the coil conditions.

so is the IAC ok taking in account that the cone scree could be screw and unscrew freely be itself?