HOLDING REVS AT 2500 RPM FOR 3-4 MINS TRICK....NC

Noticed this mentioned on a few posts when people changed their batteries to sort out lumpy idle…

I sorted my battery without doing this procedure, but always wondered what this does to your car if you do do it.

I know following the procedure does react like below because I tried before removing battery the first time around.

Does it reset anything else??  should I do it again?? or just stop tinkering

 

If the battery has been disconnected you need to re set the ecu.

Start engine.  Use a peice of wood to hold the throttle down so that it holds 2500rpm.  Then leave it running at 2500rpm.  Don’t try doing it with your foot as small movements in your leg muscles will spoil the process.  After about three minutes the engine revs will suddenly drop down to normal idle event hough the throttle pedal is held in place.  At this point the ECU should be reset.  

 

I’ve tried the above, it didn’t work. The one that did was leaving the car to idle for around 20 mins.

Yeah the 20 minute idle worked for me.just curious what the other procedure does if anything, seems weird that the procedure can be followed and reacts like it’s been posted yet seems to have no effect.Maybe ECU reset like quoted but surprised if that’s the case why when I Google it it’s not talked about a lot.

I changed my battery last week, just drove it and after about 20 mins it settled down to a nice steady idle.

I’ve no battery/idle issues just wondered what holding at revs actually did and why it would drop drown to normal idle after the 3-4 minutes by the fact it does gives me the impression it does some thing,does it reset the throttle etc…??  

Someone on the Miata Forum found it in the fitting guide for the attached.  Page 13 It is ECU reset procedure.

 

 

https://www.mx5parts.co.uk/skuzzle-motorsport-torqintake-induction-mk3-35-p-3451.html 

 

 

The procedure is nothing that I’ve seen in the workshop manual before.

There is a caution in the Owner’s Manual (Fuel and Engine Exhaust Precautions) that advises against “operating the engine at high idle for more than 2 minutes” due to possible catalyst convertor overheating (No airflow across it?). I suspect that the reason that the engine revs drop off after a period of time is the PCM preventing said overheating.

I fitted the torqintake to my car last year. I followed the install guide but bottled out with pg 13  I started to follow it but didn’t like the idea of thrashing the engine at 4-5k revs while stationary. The car started perfectly and settled to a smooth tick over immediately after fitting. Went for a drive and have not had an issue in the 2.5k mikes covered since. (not sure if it’s had much effect on performance either ) I’ve had smooth running issues previously after battery disconnect but ended up just mixed driving until it settled down again. Covered this before but check tightness of battery connections  after reconnection.

Barrie

 

It is my understanding that the ECU just looses some of the fuel trimming that it learns in operation and they have to be relearned. It just needs driving for a bit, that is all. The race cars use a battery isolator, so power is lost every time the car is turned off. There are no problems with these car.

No problems with the car Barrie just wondered if it was another trick that might make things even better 

Makes sense read some posts where it took 2 minutes some 5 maybe that’s the temperature thing kicking in.