Oh no - stepper motor problems again!!!
Oh no - stepper motor problems again!!!
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Discussion

plipton

Original Poster:

1,302 posts

287 months

Thursday 25th May 2006
quotequote all
Hi all,

I have a minor problem with the M12. It kinda reminds me of my TVR RV8 days when the stepper motor needed cleaning.....

The engine runs great when it's warm but occasionally when warming up or starting hot the idle speed has just started to drop down to 400 - 500 RPM and has actually stalled a couple of times.

As I said, it reminiscent of the old TVR stepper motor problem which needed a good clean every so often.

Is there an equivelent part on the FV6?
what else could cause this?
Could it be a blocked fuel filter?
Maybe it's because I put 95 RON in the tank by mistake the other day (although I'm told it should run on the cheap stuff)?

Any advice greatfully accepted.

Ta

Plipton

worty

2,202 posts

254 months

Thursday 25th May 2006
quotequote all
Shouldn't be the fuel as its mapped for 95 ron. Are all the vacume pipes attached correctly as I had stalling problems when one came adrift
worty

plipton

Original Poster:

1,302 posts

287 months

Thursday 25th May 2006
quotequote all
Ta for the tip. I'll have a look in daylight tomorrow

Cheers

obes

3,298 posts

273 months

Thursday 25th May 2006
quotequote all
Interesting one that mate, if it was a 2.5 that would be a classic sign of ECU failure. But yours must be an MBE so it can't be that !

plipton

Original Poster:

1,302 posts

287 months

Thursday 25th May 2006
quotequote all
It's only just started doing it (and then it's not all the time). Weird!

I suspect it may be the fuel filter is blocked or a vac pipe's come adrift/split. Will check tomorrow.



>> Edited by plipton on Thursday 25th May 21:22

petros

2,441 posts

258 months

Thursday 25th May 2006
quotequote all
Don't know about on Nobles but quite a few TVR owners seem to be ditching their stepper motors completely.

plipton

Original Poster:

1,302 posts

287 months

Thursday 25th May 2006
quotequote all
petros said:
Don't know about on Nobles but quite a few TVR owners seem to be ditching their stepper motors completely.


Yeah I heard something along those lines. The fault i have (intermittantly) is very similar to the stepper problem - just I don't think the FV6 has one.

AMG Merc

11,955 posts

282 months

Friday 26th May 2006
quotequote all
So what does a stepper motor do in a car and where's it located - and why can you do without one?!

plipton

Original Poster:

1,302 posts

287 months

Friday 26th May 2006
quotequote all
Well, it happened again this evening

Luckily I caught it on camera. Sorry guys it's a 26 meg file so if you download it, it'll take up to 5 minutes on ADSL and forever on dial up. Best right click and save as....

As you can see, starting up when warm (stood an hour) it occasionally struggles to keep running. Then when I give it a few revs it clears itself after a few seconds and runs fine.

When the engine's warmed up it's not a problem, just starting up from cold or after standing for a while.

My thoughts so far..

Could it be the throttle position sensor? The fault seems to clear after it's revved. I've checked connections and they seem fine - I've also WD40d every electrical connection I could find.

Is the TPS a standard Ford part?

How does it work? Rheostat? on/off switch? something else?

Can someone try theirs to see how it works please (if a rheostat, what resistancees should it give at idle, just off idle, 1/2 and full throttle positions)?

The vacuum hoses all seem intact. If they weren't it'd be a more consistent problem I would think.

Could the engine be choked up? It's used in traffic mainly and rarely gets to rev much.

It started playing up after I washed it on Tuesday. I don't think I got any electricalbits wet, but the engine bay is semi open the the elements (and I use the car come rain or shine)

Any other thoughts? Anyone else had this problem or seen it and know the cure?

I'm sure it's something simple (and cheap I hope) to fix.

Cheers

Rick


>> Edited by plipton on Friday 26th May 20:19

brav

131 posts

263 months

Friday 26th May 2006
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Wow plipton - cant really tell, due to audio quality, but sounds like you have a lot of valve/lifter noise. You might want to check your oil level/pressure.

petros

2,441 posts

258 months

Friday 26th May 2006
quotequote all
That sounds like a sick engine

plipton

Original Poster:

1,302 posts

287 months

Friday 26th May 2006
quotequote all
brav said:
Wow plipton - cant really tell, due to audio quality, but sounds like you have a lot of valve/lifter noise. You might want to check your oil level/pressure.


Hi Brav,

It sounds bad on the video as the audio is crap - tinny little microphone on my sony DSC. It seems to amplify the high pitched sounds. While I was recording it all I could hear was the exhaust.

Car was checked out by Vegantune only a few weeks ago. Oil etc are fine. Thanks for the feedback, though.

It's the hunting I'm more bothered by. Strange how it goes away when the engine's warm!

plipton

Original Poster:

1,302 posts

287 months

Friday 26th May 2006
quotequote all
petros said:
That sounds like a sick engine


yeah, see my reply to Brav. The tinny mic on my camera amplifies the high pitch sounds. It really isn't that bad - apart from the hunting on tickover. Needless to say it won't do it now !!!

brav

131 posts

263 months

Friday 26th May 2006
quotequote all
Ah, well thats good news then. I had a similar issue. Is your AC on when you are doing this? You can change the idle with a laptop and the noble software (at least we can in the states). Do you have a 3R? Maybe check air filters, fuel filters, etc.

My 3R never idled well. I had to turn it up to about 1100 or so. And even at that, sometimes its at 900, others at 1300. the TB does not have a separate idle adjustment, all done by computer. Maybe they can adjust the idle mixture.

JLSELAN

405 posts

262 months

Friday 26th May 2006
quotequote all
AFAIK there is no stepper motor in the Noble throttle body assembly. An idle adjustment (increase) might help and can be tried very simply w/o using a laptop--all you have to do is ensure that the ECU is reset to the new setting by turning the ignition switch from off to fully on (no engine start) 10 times in succession. I have found that a 50 rpm change in idle speed can make a big difference in idle speed stability. Another potential fix is an ECU reflash, and Roush should be able to help with that.

plipton

Original Poster:

1,302 posts

287 months

Friday 26th May 2006
quotequote all
No, the AC was switched off. It was fine up to 3 days ago. Very strange.

As you say, I'll change the fuel filter and check the air filters. I don't have the Noble software, but have a laptop if I can get a copy.

plipton

Original Poster:

1,302 posts

287 months

Friday 26th May 2006
quotequote all
JLSELAN said:
AFAIK there is no stepper motor in the Noble throttle body assembly.

I couldn't see one - it's just so similar to that fault i wondered if it could be related

JLSELAN said:
An idle adjustment (increase) might help and can be tried very simply w/o using a laptop--all you have to do is ensure that the ECU is reset to the new setting by turning the ignition switch from off to fully on (no engine start) 10 times in succession. I have found that a 50 rpm change in idle speed can make a big difference in idle speed stability.

I'll try that in the morning. Thanks

JLSELAN said:
Another potential fix is an ECU reflash, and Roush should be able to help with that.

I hope it's not required. Roush is over 200 miles and a 2 1/2 hour ferry crossing from here

Thanks for the ideas so far everyone

robp

2,097 posts

270 months

Saturday 27th May 2006
quotequote all
Rick - I had a similar though slightly more extreme issue when my car was just a few days old. When warm -couldn't hold revs and without throttle being applied. So when coming up to a R/bout, lift-off to change down and revs just dropped like a stone and stalled. Made it quite intresting going round a mini r/b with limited braking and no power-steering! Problem was faulty throttle control valve. Replaced and all was hunk-dory.

yellowshed

587 posts

312 months

Saturday 27th May 2006
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If you get no joy elsewhere and you can live without the car running for a few days, you could post the ECU to us for checking. No guarentees, though, as faults aren't stored on the ECU - they can only be checked on the car. It does sound like a sensor issue, though.

And as others have pointed out, the cars do not have a stepper motor.

YellowShed

plipton

Original Poster:

1,302 posts

287 months

Saturday 27th May 2006
quotequote all
Thanks all

Rick