9 replies to this topic

[hungdynasty]

Hi all, my 98 JDM SPI was running fine until last week, when I shifted gears(off throttle clutch down in neutral) rpm rev down very slowly or didn't rev down, idling became high and inconsistent. 

 

I check with Rover MEMS app and see that, the idle position number when idling is down to 0(please see picture), idling is high. Lost motion gap is set good but when I open throttle during setting I didn't hear the usual stepper motor sound, and I've never adjusted the throttle screw. All vacuum hoses are good, MAP is around 30kpa idling. When I rev up the engine the idle position number does go up, release throttle then it goes back to 0. Before the problem the idle position number was around 30 at 850-900 rpm, would this problem be caused by faulty stepper motor? 

 

Thanks in advance.

 

 

 WhatsApp Image 2024-11-06 at 5.11.49 PM.jpeg   31.79K   2 downloads

[genpop]

Sorry but sentence shots don't say anything.Only log filesare good for diagnosis.

[hungdynasty]

Sorry but sentence shots don't say anything.Only log filesare good for diagnosis.

I will try to make a log file, thanks in advance!

[hungdynasty]

Hi I've export a log file, please see attachment. I remove the stepper motor to check and it looks fine, resistance between pin 2 to 1,3,4,6 are about 15 ohms. Thanks in advance!

Attached Files

•  rover_mems_export (2) MConverter.eu.txt   70.74K   4 downloads

[genpop]

can you upload without converting? If it will not be send, just rename it .txt. Do not convert!

[hungdynasty]

can you upload without converting? If it will not be send, just rename it .txt. Do not convert!

Sure I will try again, last time I wasn't allowed to upload, thanks in advance.

[hungdynasty]

can you upload without converting? If it will not be send, just rename it .txt. Do not convert!

I wasn't allowed to upload by renaming to TXT, but seems ok to zip it, please see attachment, thanks a lot genpop

 rover_mems_export241109 - Copy.zip   20.46K   4 downloads

[genpop]

Hi

i have no right idea what would cause the problem.But your idle error is constanly too high,possibly thats why the ecu wants to regulate rpm down and iac is down to zero.

Check the lost motion gap or if the engine sucks additional air somewhere ( but map seems to be ok).

Good luck!

[hungdynasty]

Hi

i have no right idea what would cause the problem.But your idle error is constanly too high,possibly thats why the ecu wants to regulate rpm down and iac is down to zero.

Check the lost motion gap or if the engine sucks additional air somewhere ( but map seems to be ok).

Good luck!

Update on my high idle problem. 

From my previous log I found a problem on the Map reading, although it seemed good when idling above 1200rpm but when the rpm fluctuated under 1200rpm the map reading went up to 40+kpa (see attached picture). I remove the throttle body and see that the two gasket between throttle body, spacer and manifold are pretty worn, I suspect there is air sucking in. Replace the two gaskets, re-adjust the throttle screw and everything is fine now. Thanks genpop for all the advice.(attached my new log if you are interested to look at) 

 log 250122.JPG   84.54K   1 downloads

Attached Files

•  rover_mems_export 250212.zip   76.56K   2 downloads

[genpop]

congratulation!

 

if you want to analyse your logfile download newest mems-rosco from github.com/leopoldG, it will read your logfile now too.(readlog)

There is one spike in the rpm but this is in your logfile too.Why have you stopped the engine for a few seconds?

A lot of the parameters will not be shown as graphs but this depends on the logfile.