Low revs while idle.

MR2YEN · Post by **MR2YEN** » Wed Apr 29, 2009 9:33 pm

I was driving today and it seem like every time there was a red light, the revs would drop to 500rpm and under. It felt like the car was going to cut out at any moment. I had to move the steering wheel around when stationary to get the rpm around 900. When driving everything is fine.

Don't know if this is related by i tried starting it while the engine was cold and it wouldn't start, the battery level was at 12volts, but i kept turning the ignition and nothing happened until i tried it for the 12th time.

What would i be checking?

martyjer · Post by **martyjer** » Wed Apr 29, 2009 9:50 pm

Stepper motor? Might need a cleaning or refurb. Usually cleaning it helps a good bit.

yano · Post by **yano** » Wed Apr 29, 2009 11:52 pm

Check stepper motor but dont forget to give your throttlebody a good cleaning out..

mz_madz · Post by **mz_madz** » Thu Apr 30, 2009 1:01 am

Mine idles at 500 rpm but doesn't seem like its going to cut out =/ (once the car is completely warmed up).. on start up im usually at 1200 rpm ..

i have no problems so far *touch wood* .. my old baby (Robbie - has her now) idled at 500 as well..

blaykee · Post by **blaykee** » Thu Apr 30, 2009 2:16 am

yea mine idles @ 500 too but doesnt feel like its going 2 stall..when cold between 1000 & 1200

Post by **I8A4RE** » Thu Apr 30, 2009 8:26 am

500 is too low. Should be idling (after warm up) 750 +/- 50.

Yeah sounds like stepper, your charge light isnt coming on is it?

Post by **vipfto** » Thu Apr 30, 2009 10:27 am

mz_madz wrote:Mine idles at 500 rpm but doesn't seem like its going to cut out =/ (once the car is completely warmed up).. on start up im usually at 1200 rpm ..

i have no problems so far *touch wood* .. my old baby (Robbie - has her now) idled at 500 as well..

speaking of which after starting to prep motor for removal last night noticed was dry of water and obviously had leak from filler cap. But i suspect that may have drinking a little bit of water, dont think its head related but do you know any more on this? not a biggie just helps me out if you know.....

gestalto · Post by **gestalto** » Thu Apr 30, 2009 11:40 am

:O something i actually know how to diagnose lol. Ok based on my MGF which had numerous issues throughout its life with me before i traded it in for what is now seemingly another irritating car, the best way to check whats drinking your water is...

Fill er up with coolant, take the car for a quick 10 min drive, then once warmed park it on your drive and constantly keep it revved it whilst in neutral to around 2000 rpm for a few minutes, by this time you will easily be able to check for leaks in hoses because they tend to only leak when hot if its not a crazy leak.

If there is no leaks and all hoses are properly warmed then your looking at your coolant evaporating internally somewhere...which generally would be head gasket. Check dipstick for may and get a pressure AND chemical test done.

My MGF had the same type of issue your talkign about with water dissapearing, sometimes overnight sometimes after a few weeks, but ultimately it was the HG and was only pressure tested which didnt pick it up, 4 months later BAM HG gone totally while i was driving, no warning, nothing

Post by **vipfto** » Thu Apr 30, 2009 11:08 pm

gestalto wrote::O something i actually know how to diagnose lol. Ok based on my MGF which had numerous issues throughout its life with me before i traded it in for what is now seemingly another irritating car, the best way to check whats drinking your water is...

Fill er up with coolant, take the car for a quick 10 min drive, then once warmed park it on your drive and constantly keep it revved it whilst in neutral to around 2000 rpm for a few minutes, by this time you will easily be able to check for leaks in hoses because they tend to only leak when hot if its not a crazy leak.

If there is no leaks and all hoses are properly warmed then your looking at your coolant evaporating internally somewhere...which generally would be head gasket. Check dipstick for may and get a pressure AND chemical test done.

My MGF had the same type of issue your talkign about with water dissapearing, sometimes overnight sometimes after a few weeks, but ultimately it was the HG and was only pressure tested which didnt pick it up, 4 months later BAM HG gone totally while i was driving, no warning, nothing

actually i jave bought the motor and trans (manual) off robbie as a wreck it was originally mz madz. just noticed may of had a leak but not entirely sure as it may of just been drained only noticed radiator cap was shot. So was just trying to get info that may of been any use.... i`m not worried about it as the motor will just sit around for awhile any known issues would just of been a help

but thanks for input

gestalto · Post by **gestalto** » Fri May 01, 2009 12:06 am

damnit...i;m useless

Post by **vipfto** » Fri May 01, 2009 9:30 am

no you had a very valid point you just didnt know the whole details

gestalto · Post by **gestalto** » Fri May 01, 2009 9:33 am

hehe cheers

payaya · Post by **payaya** » Fri May 15, 2009 9:57 pm

when you say it took several attempts to start it do you meant it fires up then dies, or engine does not fire at all?

incoming · Post by **incoming** » Sat May 16, 2009 8:39 am

i had this problem a week ago.

like what everyone said - stepper motor prob has a lot of carbon buildup. check the common fto faults on how to remove and clean/replace.

temp fix is to adjust the idle screw on the front of the throttle body.
u gotta pick of the dust cover to get to the screw.

mz_madz · Post by **mz_madz** » Sat May 16, 2009 1:22 pm

vipfto wrote:
mz_madz wrote:Mine idles at 500 rpm but doesn't seem like its going to cut out =/ (once the car is completely warmed up).. on start up im usually at 1200 rpm ..

i have no problems so far *touch wood* .. my old baby (Robbie - has her now) idled at 500 as well..
speaking of which after starting to prep motor for removal last night noticed was dry of water and obviously had leak from filler cap. But i suspect that may have drinking a little bit of water, dont think its head related but do you know any more on this? not a biggie just helps me out if you know.....

It was due for a new radiator cap. I was meant to be getting one the day I was hit. Noticed it about 2 days before I was hit but other than that no other problems with that engine

Post by **vipfto** » Sat May 16, 2009 8:07 pm

mz_madz wrote:
vipfto wrote:
mz_madz wrote:Mine idles at 500 rpm but doesn't seem like its going to cut out =/ (once the car is completely warmed up).. on start up im usually at 1200 rpm ..

i have no problems so far *touch wood* .. my old baby (Robbie - has her now) idled at 500 as well..
speaking of which after starting to prep motor for removal last night noticed was dry of water and obviously had leak from filler cap. But i suspect that may have drinking a little bit of water, dont think its head related but do you know any more on this? not a biggie just helps me out if you know.....
It was due for a new radiator cap. I was meant to be getting one the day I was hit. Noticed it about 2 days before I was hit but other than that no other problems with that engine

Thanks

have already done major service all new gaskets/timing belt, seals, spark plugs etc (should be like new when i finish with it

)

MR2YEN · Post by **MR2YEN** » Sun May 17, 2009 12:49 am

Noob question, but where is the stepper motor?

Post by **vipfto** » Sun May 17, 2009 10:25 am

MR2YEN wrote:Noob question, but where is the stepper motor?

just below throttle body held in by two bolts will eother black or brown in colour
only a small unit about 2-3inch long (just like I8a4re)