Removing the cruise control speed limit.

[GTOJOE]

Jimvr4 step inside

so the USDM cruise control limit is 90mph while the Australian and JDM cars are limited to only 110km/h. I would like to work out how to change that. I have looked at the part numbers for the cruise control module and it is the same between USDM and JDM. So the thing limiting the speed has to be either the cluster/speedo or the ECU. Has anyone tested this before?

Cheers,

Joe

[stealthee]

I know this has been discussed before. I can't seem to find the thread. I thought it was as simple as snipping one wire to the ECU? I could be remembering something else from another platform though. LOL

[Jimvr4]

Did a search and found several threads on 3si. According to those threads snipping pin 66 removes the speed governor but it seems the only thing that removed the cruise limit was an HKS module.

In the US ASA there are 4 part numbers for the cruise ECU, all interchangeable:
MB802322
MB852999
MB903862
MR400408

The speed sensor wire goes to the cruise ECU. It is a pulse train that comes directly from the speedo gear mounted in the transaxle.

I *suspect* the issue is the different gear ratios between US and JDM. I think that the pulse train from the speedo gear has to be interpreted differently for the JDM cars due to the different gearing and that the gauge cluster and ECU do this but the cruise ECU doesn't make an adjustment. At least I don't think it can if the cruise ECU is the same between US and JDM cars.

I think the cruise ECU is just counting pulses and deciding to limit the set point when too many pulses arrive.

So I think the options are to put in a translator that changes the pulse counts, not sure if this is what the HKS box did, or reprogram the cruise ECU which is a 68HC11 microcontroller. I doubt anyone would take the time to disassemble the code and try to change it but it is theoretically possible.

[stealthee]

Jim the 5 speeds have identical gear ratios. It is only the 6 speed that differs.

[Jimvr4]

Can someone with JDM ASA search for Speed Control and post all the cruise ECU part numbers?

[GTOJOE]

I have already. All JDM cars use the same part numbers as USDM. Same speed sensor also. So there has to be a device somewhere that trlls it when to set the limit. It can't be gearing because the 1st gens all have the same gearing. I thought about cutting pin 66. If the ecu is controlling it then perhaps when it can't see the VSS then it won't know when to send the stop/max speed instruction. I will have to dissect the wiring diagrams I think. There must be another signal to the CC ecu. All devices see the vss independently from what I can tell. It breaks off to the ecu, speedo, ecs, aa and cruise all under the dash at some point.

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[KeithMac]

Buy a kph to mph speedo convertor (designed for JDM cars) , fit that between the cruise control ecu and speedo signal wire and you have a 1/3rd more mph to play with (if it was 90mph before it will be around 120 after).

[GTOJOE]

Buy a kph to mph speedo convertor (designed for JDM cars) , fit that between the cruise control ecu and speedo signal wire and you have a 1/3rd more mph to play with (if it was 90mph before it will be around 120 after).

This is the reason I started this thread. I have one of these devices that I no longer need so I thought I could use it in exactly the same way as you stated. However after finding out that the jdm part numbers are the same as the usdm ones it was determined that an external device must be sending a signal at 110km/h to tell the CC to limit it. If the main ecu does not communicate with thr CC ecu then it could be the speedo? There are many jumper settings on the speedo pcb. It's possible the configuration has something to do with the CC limit.

I can't log anything as my car now has a vipec ecu and an evo momo wheel and deleted the CC buttons. I'm trying to help out another guy here in Melbourne.

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[KeithMac]

Emanage Ultimate also has a speed signal modifier that could be used.. Wouldn't fit one just for that on it's own though!.

[Toni]

You can also get the split second fc2-100. Have the speedo signal be fixed after a certain MPH or change it throughout the range.