DIY: Stepper Motor & Input Sensor

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DIY: Stepper Motor & Input Sensor

Post by tompocz »

GDay All,

I couldnt post this into the DIY area, as it would not allow, hence posting it here.

I am fortunate enough to have a wife who owns an FTO 1995 GPX car

I am recently experiencing "Flashing N" and idle probs, and thought Id share with you what I have done so far.

1. Replace Stepper Motor
2. Replace Fuel Filter
3. Working on replacing Input Shaft Sensor
4. Use "Wyns Injector Fluid in Petrol tank to clear injectors.
5. Check all vacuum hoses for "gunk"
6. Check Alternator and wiring
7. Clean Idle Screw

Points 3-7 yet to be done (this weekend)

The following Pic shows where the Stepper Motor is, Fule filter and also the "Output" Shaft Sensor. I initiall thought this was where the Input Sensor was located, but it pays to double check and read the manual.



Image

The following picture is the pinout for the "Output Sensor"

Image

This pic highlights the Output Sensor - had some probs in getting it out from the top, but by going underneatht the car, I was able to gingerly leverage it out with a screwdriver.

Image


This pic shows the location of the Input Sensor. it pays to remove the air filter and pipe so as to get to it easily. The pinouts of the sensor are also very important, given that there are two types, as the pins determine which type you require. They also idenitfy whether your car is a pre 09/95 or a post 10/95 model.

Image

The following can help in determining this

http://www.camskill.co.uk/products.php? ... 76&i=11632 - up to 09/95
http://www.camskill.co.uk/products.php? ... 035&i=9265 - from 10/95 onwards

Close detail show it to be a pre 09/95 model.

Image

As to my above probs, I have spent numerous days here scouring the posts for some insigh to my prob, and believe that the above bullet points (1-6) are as far with what I know.

One of the symptoms is that when it idles when initially started in the morning, the idle is fine but as soon as the fan kicks in, the revs drop right down to almost stalling.

Also I can hear it sputter and the smell of fuel exists - have spent days tweaking the idle screw but to no avail. The issue with the Input Sensor I believe is the correct action, as I just recently also replaced the trans fluid and oil. The renown "Flashing N" is a bitch, and hope my above proposed work will resolve it.

Hope the above helps you guys anyway - once I find the prob, Ill update this post. I must also thanks dstocks for his insight and help.

Cheers
Tom
Last edited by tompocz on Tue May 27, 2008 10:16 pm, edited 1 time in total.
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Post by I8A4RE »

Flashing N problems, what ecu errors were you getting? As for fuel smell and the like, what about o2 sensor?
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Post by tompocz »

I8A4RE wrote:Flashing N problems, what ecu errors were you getting? As for fuel smell and the like, what about o2 sensor?
I spent last sat morn doing the trick with the wire and the ecu computer by earthing pin one to the chassis - recieved no errors what so ever which was perplexing.

The gears when driving suddenly move from 4th then stay at third gear. Once pulled over and car switched off for while, restarted the car and all was well for a short time - so says the report from my wife !!.

The hard part in all this, given that its my with's car and she drives it all the time, is trying to get a condition or sympton out of her that makes sense. Comments like" the flashing thingy and then it goes all over the place" does not help.

I even asked her the frequence of flashing n, whether it was twice a second or once a second - her answer was "I dont know, how long is a second !! " - AaaaaaaaH

and she does not have blonde hair either. I heard a classic comment from my son (18yrs old) a short time ago, he said "I inherented my smartness from Dad, and dumbness from Mum". God it was funny watching him try and get out of the hole he just dug himself with the wife !! LOL

I though about tha o2 sensor - is this the lamda sensor ???

cheers
Tom
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Post by I8A4RE »

I though about tha o2 sensor - is this the lamda sensor ???
Yeah sure is i did a DIY on it in this section, but that still has nothing to do with the flashing N, just maybe the fuel smell and maybe sputtering.

I was undeer the impression that the flashing N meant that the tip box has gone into LIMP mode but im not 100%, also apparnetly i read somewhere you can actually check the auto ecu error codes in a similar way but i have no idea how to do this.

When you checked the error codes you hadnt reset the ecu, had you. Cause if you had of disconnectedthe battery, then checked the codes without taking it for a drive then there would be no codes present.
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Post by tompocz »

Gday I8A4RE

The car does splutter, as if its getting to much fuel. When the fan cuts in, the revs go low then high. AS far as limp mode goes, yes u r right, and all indications point to a faulty input shaft sensor. Eben when I had the lights on, and then the fan cut in, I noticed that the lights dimmed down a bit, hence it could be an alternater issue as well.

I had disconnected the battery, but only AFTER I tried to get the codes. I did this so as for the ECU to re-learn the driving patters again. Ensure that everythin electrical like the radio, fan/heater/lights were switch off as well when reconnected the battery and let the car idle for about 20 minutes.

Just found the price for a lamda sensor - 270 pounds - ouch !! Found a website that deals with generic lamda sensor parts - http://www.lambdasensor.com/main/mcolours1.htm as I read about it in another forum, hence have bookmarked it just in case. Wont go down this path yet unless I have to - need to do some more checks.

When the missus drove off this morn, the car sounded as if it was getting too much fuel as well. Now given that I have replaced the stepper motor and fuel filter, and all test okay, we also tested the TPS as well and the readings were normal. Hence the only thin left is the idle screw - try to find some docs on how to adjust this as well, but will also tkae this screw out and check/clean it. Read somewhere its made of fibreglass and that u have to be carefull with it.

I know how to adjust this screw - i.e. turning counter clockwise increases the revs and the other way reduces them.

I did make the mistake of adjusting the screw/nut where the acclerator cable goes behind the throttle body and the mechanic said this was wrong and not to touch it - too late. he did adjust it back but fear that it is still wrong. Anyone have any clues on how to properly adjust this screw/nut - it sits underneath a big round spring and the nut is used to lock the screw in so that it doesnt move .

Anyway, your posts are more food for thought - thanks

Tom
Last edited by tompocz on Wed May 07, 2008 12:13 pm, edited 1 time in total.
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Post by Bennoz »

Universal 4 wire 02 sensors are cheap on ebay, $56 bucks :) Just need to cut & shut the Mitsubishi plug on it:

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Post by tompocz »

Bennoz wrote:Universal 4 wire 02 sensors are cheap on ebay, $56 bucks :) Just need to cut & shut the Mitsubishi plug on it:

eBay Link
Thanks Bennoz - will keep this in mind.

As to my above post, do u have any thoughts to my comment and I quote
I did make the mistake of adjusting the screw/nut where the acclerator cable goes behind the throttle body and the mechanic said this was wrong and not to touch it - too late. he did adjust it back but fear that it is still wrong. Anyone have any clues on how to properly adjust this screw/nut - it sits underneath a big round spring and the nut is used to lock the screw in so that it doesnt move .
Cheers
Tom
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Post by Bennoz »

Hi Tom, is the car perchance a GR? Ie does it have a large air flow sensor near the air filter? Have you recently put an after market air filter on? Is the idle stutter less pronounced with the bonnet open?
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Post by tompocz »

Good questions Bennoz

The car when bought had an aftermarket "cone" air filter, but it was never ever connected propely as the jubilee clip kept on slipping as the connection was rubber again rubber.

I decided to do the right thing as "muck and gunk" was getting in abd bought a new cone filter, jury rigged a 76mm (2mm thick) pipe and attached jubille clips to it. (will post photo when the wife comes home tonight).

When started the car/filter does make a nice whistling noise - I can see where u are getting at, whether its getting enough air. The filter sits on the base of the original filter chamber.

As to the stutter being less pronounced when the bonnet is open, I cannot 100% say but will check tonight.

With the above in mind, is it normal for people to take the original air filter base off so that airflow also goes into the cone filter from "all around". ??

cheers
Tom
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Post by Bennoz »

Many people do put the after market filters on without enclosing them in at least some sort of box. While they do collect more gunk, most of them can be cleaned & re-used.
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Post by tompocz »

Thanks Bennoz - I have all the right tools to clean then oil the filter.

just two issues .......... to anyone .....any thoughts on the following ..........

I did make the mistake of adjusting the screw/nut where the acclerator cable goes behind the throttle body and the mechanic said this was wrong and not to touch it - too late. he did adjust it back but fear that it is still wrong. Anyone have any clues on how to properly adjust this screw/nut - it sits underneath a big round spring and the nut is used to lock the screw in so that it doesnt move .
With the above in mind, is it normal for people to take the original air filter base off so that airflow also goes into the cone filter from "all around". ??
Cheers
Tom
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Post by Bennoz »

Well the reason I ask about the air filter, is that I've seen problem as you describe 'when the fans come on' they force hot air around in the engine bay. When that happens, an exposed air filter can pickup all that hot air - when that hot air passes the air flow meter, it will cause the ECU to adjust the fuel mixture accordingly.

I dont think there is anything wrong with your throttle setup (apart from the idle nut.) If the revs are fluctuating when the fans come on, my guess is that hot air is being sucked into the intake, the air flow meter is going nuts, and the ECU is then cutting the fuel supply to compensate for the less dense hot air - hence the drop in revs. The ECU would then also be adjusting the stepper motor to try & correct the idle due to the fuel cut. It also tells me that perhaps the air flow meter is dirty and needs a good clean - as a lot of FTO's are running around with after market filters & not having this problem... yet I've experienced it first hand.

As a matter of course, to get your idle screw right, I'd unbolt the throttle body from the intake, yet leave the cooling lines on it (that way you get get under neath it & reset the idle screw nut. Then with the throttle body off, you can get in & clean the air flow meter in the intake body.

To set the idle nut, you just need to wind it in so that when idling properly, its sitting on about 750 - 800rpm. Might be a little difficult when it wont idle properly to start with thou...
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Post by I8A4RE »

If you set it when its cold to around the 2000rpm mark, then as it wams it should drop. Just make sure it drops to around the 700-900 mark if not adjust accordingly.

Totally agree with ben on the filter being unshielded. The air flow meter could be rooted aswell if a clean doesnt fix it. If you live any where near me you could borrow mine to see if that helps
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Post by tompocz »

Thanks I8A4RE for that - I think though that GPX's dont have an airflow meter, but researched this and believe thay have a MAP.

Given that some owkr will be required around the throttle assembly and I dont wish to stuff it up, Ill need to do research on what to do, how it looks like, how to test it , is a gasket required if I remove anything, etc.

The following applies to the photos

A - The screw that I accidently turned/adjusted instead of the Idle Screw (D)
B - Throttle Position Sensor
C - Stepper Motor (Idle Speed Control Sensor I think) - nice and new from Nardel :-)
D - Idle Screw

As to the TPS, I really dont like adjusting this as its easy to screw up in my view - plus the mechanic tested it and it fell within the norm ohms readings.

As to "A", how do I adjust this if its wrong ?? My udnerstanding is that it needs to be adjusted so that the valve sits just open - is this so ?

Image
Image

Will post other photos as to how the air filter looks

cheers and thanks
Tom
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Post by I8A4RE »

Ok sorry mate i didnt realise you got mivec i was just going off what ben had said. So if you got mivec then NO you dont have a MAF (air flow meter), you have a MAP, good researching :D .

That screw that your playing around with will control your idel speed but it is really designed for adjusting the FREE PLAY of the accelerator pedal eg

The more you wind it in the more PULL it will on the throttle
The more you wind it out the less PULL it will put on the throttle

Sorry i am having difficulty explaining what i mean. But basically think of it like this. Your sitting in your car and as you apply the accelerator nothing happens till you have depressed your foot, to lets say half way, then it starts to accelerate. That means you have to much FREE PLAY in the cable so you would adjust the cable to remove that free play.

Sorry if im talking to like a child but i have no idea about your level of knowledge and i do find it hard explaining stuff at times.

Anyway long story short you havent done any damage with what you have done. Youi may just have add a little more FREE PLAY to the pedal or made the vehicle idle higher than its suppose to because you have removed all the FREE PLAY and more.

Hope that helps :oops:
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Post by tompocz »

I8A4RE

Thanks for that, and your comments are NOT stupid but well explained. I have read in the manual that there should be some give, not much though om the butterfly, as well as adjustment made to the accelerator.

Below are some photos of the air filter I have

Image
Image
Image

Below is a further pic for those that wish to know where the output sensor is - phot in previous post showed a cavity as I unbolted and pulled the sensor out.

Image


I will be taking the bottom of the original air filter and let you know if there is a sound difference in the car stuttering when the bonnet is open.

Will let you all know how I go soon.

Cheers and thanks
Tom
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Post by I8A4RE »

Well that filter will definitly be sucking a whole lot of a hot air. Now whether thats has anything to do with your problem i cannot say.
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Post by tompocz »

Well, work done tonight was the following

1. Removed original base plate to air filter so that more airflow reaches the cone filter.
2. tested the voltage across the battery terminals and they range from 13v to 14.5 volts, No problems with power when the fan cut in.
3. Tried to take out compltely the idle screw but unabe to do so - when unscrewing, it would just sit there and turn.
4. With the heater on in the car, I spent time adjusting the idle screw and eventually found a sweet spot where it would idle at 1200rpm when the fan in the engine was rgoing, and would go down to about 800 when fan stopped. At one stage there was a kncking sound coming from the engine - hard to identify exactly where from but it sounded like "someone tapping the engine with a screwdriver - about 3-5 taps in about 3 seconds)
5. No hunting or sputtering was evident from the exhaust or the engine once I committed to a final idle screw adjustment..
6. WIll continue to asses the prob - next step is to put injector cleaner into the petrol tank. Was reassured to find out that the missus puts in 98octane (BPUltimate I think) as opposed to the cheaper fuels - she did take my advice many moons ago !!
7. will wait and see how the car starts tomorrow - have recommended to the missues to warm it up for 15 minutes prior to driving it just in case.

cheers
Tom
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Post by tompocz »

GDay,

Just had a thought - one thing I have not done is to check wire continuity. ie for any potential breaks.

Now, I know that with some sensors, you can test the voltage e.g. stepper motor and TPS. Infact from my understanding, you adjust the TPS by loosenning it and rotating it, and at the same time looking at the voltage between specific pins.

So my question is, is there any "easy" way short of undoing the wire looms, tracing the back and testing for such continuity ??

PS - I have to invest in small alligator clips for my multimeter !! :D

cheers
Tom
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Post by mr-charisma »

Hey mate,

Thought this might interest you;

http://www.fto-ireland.com/forum/phpBB2 ... hp?p=25629
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