100 kmph limiter when under ~30*F

[w.tungsten]

This is the only problem I have.

It did not do this a couple days ago when it was 45*F. However today it reared its head again, it's 7*F.

=I know it is a fuel cut, my a/f goes off the chart lean, so I suspected the fuel system (as per zilvia recommendations last winter - fpr, pump, filter) but it never had any trouble with cold/hot starts.
=Has only happened on the freeway.
=Only when it is cold (at or below freezing).
=Happens in 3rd 4th and 5th.
=TP doesn't matter.
=I can cruise at 95kmph all day

SR20DET redtop,
Apexi neo,
Japanese gauge cluster

I would think this is just the SR speed limiter, except 100kmph seems low

thanks for the help
Michael

[Monooxide]

How warm is the engine getting?

The ECU may throwing you into a 'limp' mode.

[w.tungsten]

Hmm, could be. the engine warms up to maybe a notch or two under halfway. I believe it's just slightly lower than normal days.

I thought limp mode was rpm based?

[fliprayzin240sx]

water temp sensor?

[w.tungsten]

Also, thought those effects were rpm based and made it run rich not fuel cut?

Thanks for ideas though please keep them coming.

[fliprayzin240sx]

Only reason I say water temp sensor is you said it only does it when it gets to a certain temp. Water temp sensor tells the engine your engine temps. ECU then decides whether or not to add extra fuel or not. When it dumps extra fuel when its not supposed to, makes the car bog real hard.

[w.tungsten]

Right, but I thought it would do that around 2500rpm and/or it was Throttle position based. Not based on speed. My problem will happen in 3,4,and 5th gear, and it won't matter about throttle position.

I can have my foot to the floor and it will still cut. Plus, it is definitely a fuel cut, not bogging down. If I were to describe it, it feels like first it begins to misfire (maybe it retards timing; soft rev limiter?), then it just cuts fuel and I have to wait until speed drops under 100kmph.

*nonetheless I appreciate the idea

[w.tungsten]

Nobody knows?

Friday I'm putting it on a lift, so I'll be able to unplug the speed sensor, then I'll try it out this weekend see if it fixes the problem.

[fliprayzin240sx]

Try bumming somebodys ECU and see if it does it with a different ECU.

[gunluvS14]

kmph? you meant km/h or mph? b/c 1 kmph is 1,000mph, not a common unit.

if you have 100mph cut with 3rd, 4th, and 5th, (obviously you can't reach 100mph with 2nd gear), I'm thinking it could be a bad 5th gear position sensor. fuel cut happens at 5,500rpm right?

[Monooxide]

kmph? you meant km/h or mph? b/c 1 kmph is 1,000mph, not a common unit.

if you have 100mph cut with 3rd, 4th, and 5th, (obviously you can't reach 100mph with 2nd gear), I'm thinking it could be a bad 5th gear position sensor. fuel cut happens at 5,500rpm right?

Where/when have you seen a 'kilo'-mile per hour(kmph) used? I would LOVE to know that.

[w.tungsten]

Ya I love driving at 1000mph in 3rd gear, since my engine can rev to 65,000 and all....

yeah I'll definitely bum someone's ecu. I'm still going to go for the speed sensor first since finding an ECU may take some time.

Fuel cut happens at 2.5k in 5th and 3.3k in 4th. Higher in 3rd.

so we're all pretty much banking on something electrical?

[fliprayzin240sx]

kmph? you meant km/h or mph? b/c 1 kmph is 1,000mph, not a common unit.

if you have 100mph cut with 3rd, 4th, and 5th, (obviously you can't reach 100mph with 2nd gear), I'm thinking it could be a bad 5th gear position sensor. fuel cut happens at 5,500rpm right?

I guess you missed the part where he says he got a JDM Gauge Cluster right?!?! Read the whole thread will yah...stock Silvia speed cut is at 120kmh ish, thats why he brought it up and said he deesnt think its the speed cut since its kicking in at 100kmh.

[w.tungsten]

If anyone was wondering I could not get it on the lift this weekend, someone decided to do a clutch change on an eclipse took all weekend. Sorry, I know it's pretty lame when people post their problems and don't actually try anything to fix it on their own. I'll be able to use the lift Thursday, so I won't update this until I get it on the lift Thursday.

[w.tungsten]

okay so after trying it out I unplugged the speed sensor and my speedometer stopped working. However the problem still occurred. I did notice that the odometer still worked, so i figure there must be two speed sensors one for the speedometer and one for the odometer.

I'm guessing the odometer plug is the big one that points downwards and to the passenger side at the back of the transmission. It doesn't have a connector until the engine bay. I'm going for it.

I still haven't been able to source a ECU, tomorrow I should be able to use a friend of mines.

[w.tungsten]

problem fixed unplugging the second sensor did it.