Strange Trans issue

FTEvolution · Post by **FTEvolution** » Fri May 01, 2009 7:53 am

Got me beat mate, if it was Stepper I could have sworn that it would still do it in Neutral

Let us know how you get on aye?

gestalto · Post by **gestalto** » Fri May 01, 2009 8:27 am

Yeah i get what your saying but it cant jump forward if its not in gear if you get what i mean.

I am thinking (hoping) that the stepper motor was making the revs go odd, which in turn was confusing the transmission sensors once the car was warmed up and i put it in D. I'll let you know tomorrow, i am currently in the process of reconditioning the stepper until i can get a new one. So far the reconditioning is going very well suprisingly lol

DaveO · Post by **DaveO** » Fri May 01, 2009 8:43 am

yeah definatly the stepper. the fact that you had to adjust the idle tells me the stepper is stuffed. mine idles at 900rpm cold or hot. the ECU uses the stepper to maintain a constant idle hot or cold. it even compensates for aircon and lights.

gestalto · Post by **gestalto** » Fri May 01, 2009 9:32 am

well ive reconditioned the stepper with some rust treatment and half a can of wd40 and it moves again now lol. However the electrical connections insode have literally disintegrated so it's not going to work as it should still.

BUT i am going to refit it tomorrow as per instructions on http://homepage.ntlworld.com/jaycom/fto ... epper1.htm without the electrical connection and see how it goes until i can get hold of a new one.

Post by **I8A4RE** » Fri May 01, 2009 9:51 am

that stepper is rooted buy a new one case closed

gestalto · Post by **gestalto** » Sat May 02, 2009 7:57 am

right, refitted my partially reconditioned stepper today manually adjusted rather than with the electrics...conclusion, i need a brand new one and wouldnt recommend the advice of having it connected without the electrics to anyone else, revs went either crazy high or crazy low and were very unstable fluctuation up and down by around 1500 revs every 2 seconds.

FTEvolution · Post by **FTEvolution** » Mon May 04, 2009 8:33 am

You can't just install/reinstall a Stepper, they must be calibrated. Anyone who just fits one and goes is plain lucky! Get it calibrated by an auto sparky, don't cut corners or you will end up shelling out far more $$$ than you should!

Post by **Bennoz** » Mon May 04, 2009 8:37 am

Thats not true ^^

I've installed plenty, the ECU does all the calibration it needs.

Post by **vipfto** » Mon May 04, 2009 8:42 am

you can instal its just plug and play no need to be tuned

FTEvolution · Post by **FTEvolution** » Mon May 04, 2009 2:59 pm

I have to disagree Ben, only had it done once and it didn't work "plug and play" styles by a mechanic. Got it towed to a sparky and they sorted it out in under half an hour and told me they see stepper problems all the time. If it has been just cleaned, then fine, plug and play. But if it has been reconditioned (as he said his had) or is new then it needs to be calibrated.

Fair call if you are lucky, but if the ECU "remembers" the stepper in a seized open state then tries to adjust that again, you will end up with a stepper that is outputting data that is out of calibration to what the ECU is expecting to see.

Do it once, do it right.

gestalto · Post by **gestalto** » Tue May 05, 2009 5:01 am

The recon was only the mechanical for a start off, the electrics are knackered in it, totally, so the ecu wasn't doing anything to it anyway.

Secondly the stepper as others have said "is" a plug and play device the only potential "calibration" is done automatically via the ecu after a reset preferably, but realistically not even a reset needs to be done if you leave your car idling long enough. I can't see how else this would be calibrated having dismantled the whole thing the only components are a metal core 2 bearings and 2 electro magnetic coils. You can't calibrate a magnet, and the only thing a sparky could calibrate is a manual adjustment of the ecu or possibly replace wires that had the incorrect resistance.

Also the ecu can't remember if it is in a seized open state because it doesn't get that information from the stepper as the stepper has no sensor on it, the stepper has 2 coils and depending how electricity is passed through them depends which was the core twists, the ecu send pulses to the coils or it doesnt thats the only releationship the ecu/stepper has. The signals the ecu receives to control the stepper are from engine temperature, load and airflow.

EDIT: just to clarify what i mean, my stepper currently has no electrical connection to it but is manually in the fully open position, which means the car starts and idles perfect when cold, however as it warms up the ecu is reading the greater temperature and should technically start to close the stepper resulting in lower revs, but it doesnt so the revs just go higher and higher until the car is at full operating temperature, then the ecu starts to get confused because the temperature readings mean the stepper should now be pretty much closed and the airflow should be at a minimum when idle, beacuase it's not the revs then starts to drastically fluctuate because the ECU is getting different signals from the air flow sensors than it expects when it thinks the stepper is closed and accelerator not depressed.

This is evident from the air flow sensor errors coming out of my ECU after doing this, however if i manually turn the core the opposite way once the car is warm i get no such error and revs are stable. Hope i've explained that in a clear enough way so as not to confuse the hell out of poeple lol

Post by **I8A4RE** » Tue May 05, 2009 8:22 am

Good info

gestalto · Post by **gestalto** » Tue May 05, 2009 10:02 am

lol thanks. I'll post anything i find out about the FTO on here cos everyone else seems to be enthusiastic to help, unlike some other forums.