7 replies to this topic

[Avl_Paul]

Hey folks,

I recently purchased a Crypton ACT I on ebay to use with my 1995 Mini Cooper SPI. As some of you may recall, I had issues earlier this year with the car that turned out to be caused by a bad ECU. During that time, I replaced my CTS and Lambda sensors as well as the ECU. Now that I have the Crypton, I reset the ECU and was going to use it to setp through all of the "Tune" options to make sure that things are configured correctly. First, I set my lost motion gap to make sure it was correct. While doing this, I noted that the values for the stepper motor seem to be off.

Stepper motor positions (steps):
Key-On: 47 Steps
Cycle the throttle manually to set lost-motion: 17 Steps (Supposed to be 25?)

When I try and run the Tune Stepper, the ACT unit reads the engine, then runs the tune where it slowly increases engine speed to a higher speed, then the engine speed drops, and the ACT reports that the Stepper is not operating properly.

Any ideas what is going on? What can I do? Is there a way to reset the stepper motor default positions either manually (taking the stepper apart or electronically). Should I set the idle air setting first? When I was diagnosing my issues earlier this year, I did take apart the stepper and check it out on the bench.


I did have the engine "HOT" when doing the tune with the coolant temp at 92°C. I did note the following additional things:

1) When idling for a prolonged time, the engine does seem to have a very subtle misfiring sound.

2) While Idling, I stepped through the sensors on the Crypton and noted that Engine Speed is varying from about 950 RPM - 1000 RPM (max variance).

3) The O2 Sensor reading was varying from 278 to 600 (that seems a wide range)).

4) The Advance was changing between 5 and 9 degrees.

Are these varying output normal? Is this indicative of a misfire condition?

thanks for any help with the diagnosis.

Paul

[BoyracerAU]

Hi Paul,

Sorry, no valuable input from me except to say this should be a good thread.

I look forward to seeing what the responses are and learning something.

[Sprocket]

Hey folks,

I recently purchased a Crypton ACT I on ebay to use with my 1995 Mini Cooper SPI. As some of you may recall, I had issues earlier this year with the car that turned out to be caused by a bad ECU. During that time, I replaced my CTS and Lambda sensors as well as the ECU. Now that I have the Crypton, I reset the ECU and was going to use it to setp through all of the "Tune" options to make sure that things are configured correctly. First, I set my lost motion gap to make sure it was correct. While doing this, I noted that the values for the stepper motor seem to be off.

Stepper motor positions (steps):
Key-On: 47 Steps
Cycle the throttle manually to set lost-motion: 17 Steps (Supposed to be 25?)

When I try and run the Tune Stepper, the ACT unit reads the engine, then runs the tune where it slowly increases engine speed to a higher speed, then the engine speed drops, and the ACT reports that the Stepper is not operating properly.

Any ideas what is going on? What can I do? Is there a way to reset the stepper motor default positions either manually (taking the stepper apart or electronically). Should I set the idle air setting first? When I was diagnosing my issues earlier this year, I did take apart the stepper and check it out on the bench.


I did have the engine "HOT" when doing the tune with the coolant temp at 92°C. I did note the following additional things:

1) When idling for a prolonged time, the engine does seem to have a very subtle misfiring sound.

2) While Idling, I stepped through the sensors on the Crypton and noted that Engine Speed is varying from about 950 RPM - 1000 RPM (max variance). Clue

3) The O2 Sensor reading was varying from 278 to 600 (that seems a wide range)).

4) The Advance was changing between 5 and 9 degrees. Clue

Are these varying output normal? Is this indicative of a misfire condition?

thanks for any help with the diagnosis.

Paul

The above points are clues to the problem, but, the is other clues missing, the idle steps and manifold pressure with the engine in the conditions above.

The idle speed is high, and with the advance as low as it is, i would suspect the stepper is at 0 steps and manifold vacuum is down. The ECU then trys to control idle speed by retarding the ignition, which will give a rough idle. The ocasional missfire may be down to this combined with the natural fluctuation of the fueling lean/rich. You can normally hear a tone change of the engine with the fueling swing, this is normal, but when ther is a problem some where, it can some times cause a slight missfire.

As for the stepeer motor, remove it from its housing and go over the solder joints again with a soldering iron, make sure all the teeth are on the plastic cam, the pin is straight and not sticking. Re fit it. Dismantle the throttle linkage that sits across the top of the manifold and lubricate the pivot. Adjust the throttle cable correctly.

Steps at idle should be around 30 - 40 and manifold vacuum should be in the 500s when the engine is warm

[Avl_Paul]

The above points are clues to the problem, but, the is other clues missing, the idle steps and manifold pressure with the engine in the conditions above.

The idle speed is high, and with the advance as low as it is, i would suspect the stepper is at 0 steps and manifold vacuum is down. The ECU then trys to control idle speed by retarding the ignition, which will give a rough idle. The ocasional missfire may be down to this combined with the natural fluctuation of the fueling lean/rich. You can normally hear a tone change of the engine with the fueling swing, this is normal, but when ther is a problem some where, it can some times cause a slight missfire.

As for the stepeer motor, remove it from its housing and go over the solder joints again with a soldering iron, make sure all the teeth are on the plastic cam, the pin is straight and not sticking. Re fit it. Dismantle the throttle linkage that sits across the top of the manifold and lubricate the pivot. Adjust the throttle cable correctly.

Steps at idle should be around 30 - 40 and manifold vacuum should be in the 500s when the engine is warm

Sprocket,

You are right. When idling, the stepper IS at 0 steps. I had not recorded the manifold vacuum so I got the engine hot recorded Live Data again tonight. Results:

Stepper Position: 0 steps
Idle Spee: 1100RPM and cycling by about 50-60 rpm.
Manifold Vaccuum: ~588 mmHg (saw as low as 556).
Temp: 94 Deg. C and creeping up
Timing Advance: 15 Deg. (pegged?)

Any idea what it means that the timing advance is now sitting solid at 15 Deg? It was not doing that yesterday.

Is there any way to adjust the # of steps at a given condition? I recall you saying that you set it for a different default position. It sounds like you suspect that the problem is with the stepper motor and not the ECU? Any chance it is ECU?

By the way, while I was idling, the coolant temperature crept up as high as 113°C and the auxiliary electric fan never cut on? What temperature is the temp switch in the radiator supposed to close at?

Thank you for the help here.

-Paul

[Avl_Paul]

Sending this back up to the top. Sprocket or others experienced with the Crypton ACT, any help?

Engine: Hot
Condition: Idle
Stepper Position: 0 steps
Idle Spee: 1100RPM and cycling by about 50-60 rpm.
Manifold Vaccuum: ~588 mmHg (saw as low as 556).
Temp: 94 Deg. C and creeping up
Timing Advance: 15 Deg. (pegged?)

Any idea what it means that the timing advance is now sitting solid at 15 Deg? It was not doing that yesterday.

Is there any way to adjust the # of steps at a given condition? I recall you saying that you set it for a different default position. It sounds like you suspect that the problem is with the stepper motor and not the ECU? Any chance it is ECU?

By the way, while I was idling, the coolant temperature crept up as high as 113°C and the auxiliary electric fan never cut on? What temperature is the temp switch in the radiator supposed to close at?

[Sprocket]

The fixed 15 degrees may be a built in fail safe where if the steps = 0, advance < 5, throttle pot < 0.5v, Temperature >85*C, And RPM < 1200, the advance will be fixed at 15 degrees. Perhaps?? Baisicaly in that situation, the engine should be idling, there is a clear problem so it has decided to fix the advance.

Use the ACT to test the stepper manualy, mottor the stepper using the commands, its a bit funny as it does a different thing to what the ACT tells you, drive the stepper open and it returns itself also might be worth checking that the solder connections on the motor are good As i explained further up in this topic

You may have a reasonably large air leak, doubly doubly check,, but if not, make sure the throttle cable is propperly adjusted, if you need an explanation of that, ask Then make sure the throttle cable/ linkage is not sticking. If the idle is still high and steps bellow 30, you need to adjust the small screw on the throtle linkage that bears on the pin of the stepper motor. Adjust untill you get the steps to 30 - 40 at an idle speed of 850rpm. Adjust in small increments so as to let the system adjust to it

Manifold vacuum is fine, anything less than 500 at idle and you need to start looking for the reason why.

As for the fan, that should cut in at around 102*C, and off at around 97*C. Check that the fan works, short the two wires together that connect to the thermostat on the bottom of the rad. The fan should run. These wires are only the ground to the fan relay. With the ignition on one will show 12v and the other 0v, thats only because the relay has not been grounded and the voltage has saturated the relay coil, as soon as you ground the relay coil the voltage will drop to the ground voltage of 0v that will show if the fan is working or not.

[Avl_Paul]

Thank you Sprocket! Your input has led to some success.

It appears that the throttle stop screw had been mal-adjusted by a previous owner. I reset the throttle stop screw to achieve 30 steps at idle and then the idle speed went to 850 RPM. After that I reset the lost motion position (which had changed significantly) and reran the tune.

It now passes the Idle Speed tune stating that the Idle Speed is set correctly but it still fails the "Stepper Motor" tune saying "Stepper Motor is not functioning correctly."

The good news is when I idle, the ACT live data reads:

Stepper Position: 31 steps
Idle Spee: 850RPM
Manifold Vaccuum: ~550-588 mmHg
Temp: 93 Deg. C and creeping up
Timing Advance: 13 Deg - 17 Deg (varying)

Do these values sound correct? is the varying 13-17 Deg advance correct?

I ran the Test on the stepper motor by actuating it manually and the plunger extends way out and then it retracts automatically (glad you mentioned this behavior b/c it did confuse me the first time I saw it). I have had the stepper motor out fairly recently and all the solder connections were good until I accidentally shorted the board and fried a connection on the board. I have fixed that and confirmed that the stepper works but maybe this is the cause of the error. Perhaps I changed the resistance slightly, etc.

So, is the "Stepper Motor Tune" operation important? Do I really need to sort this out? If the above values sound fine, perhaps nothing is broken now that I have reset the idle speed.

Here is a complicating factor. I misinterpreted the ACT manual to believe that I was supposed to adjust the Air bypass screw on the back of the throttle body to adjust idle speed (instead of the throttle stop screw) - the manual is a bit misleadign since it implies thatthis should be adjusted during Tune/Setup. (Not that it is factory set). I have now reset it to an intermediate position. Is there anything else I can do to reset it properly. Could this be the source of my issues?

[Any advice on how to test for air leaks? I have sprayed carb cleaner around the different pipes with the engine running to see if I could detect an engine speed change and everything seemed good. I've checked the vacuum lines multiple times. ]

Thanks for the input on the temp range for the auxiliary fan. I had previously checked whether the fan operated by shorting the thermoswitch wires and the fan ran fine. Sounds like I need a new thermoswitch. I knew I should have replaced that when I refurbished my radiator recently but it was backordered at the time.

Thanks,
Paul

[Sprocket]

Those values look good!!

The varying advance is correct. This is how the ECU controls the idle speed. idle advance is 15 degrees +-5 when it is outside these limits, it will motor the stepper to change the air entering the engine and return the idle advance to 15 +-5 degrees. As you can see in your original situation the the idle speed was high, steps were at 0 and the advance at 5. Because the ECU had removed all the air it could by closing the throttle, it kept reducing the advance to try and still reduce the engine speed.

The changing idle advance is the primary idle speed control not the stepper

The screw on the back of the throttle body is indeed factory set, but I dont think it is for idle air setting, I have played around with that on the 1400 and very little effect was noticeble. The only thing I can think it is if on over run with the throttle fully closed it ensures there is at least some air still entering the engine to prevent deep vacuum in the engine.

If everything apears fine now, I wouldnt worry about the stepper motor test. I bought a complete new injection manifold and it gave the same error on a brand new stepper. Its just a little tempremental

As for air leaks, from what I have seen in the data, I would't worry about it anymore and go and enjoy your car

Good job well done