KA24E Rev Limiter Issues

[Datsunsinc]

I have finished swapping a 1989 KA24E into a 1968 Roadster. I am having a problem with the rev limiter kicking early probably around 4k or so, I do not have a tach hooked up yet. My question is that I do not have any of the transmission sensors hooked to the ecu, no speedo sensor (went cable drive). Do you have to have the 3/4/5 gear senders off the transmission hooked to the ecu or do I have another problem? It does not cut out in 1st or 2nd. Other than that issue it runs great.

Thanks for any help you can give.

Alexi

[Dattebayo]

Yes, you need to have the gear sensors connected to rev the full range.

This is absolutely true.

[SMoKeM240]

no u dont, i never had any hooked up and the only one i have is the reverse... something else is wrong

[Datsunsinc]

I have been told that the ecu has to recognize the speed sensor and has to have the speedo from the car hookup to recognize, I also have been told that the only other option is to have JWT revamp the computer and remove the limiter, which is expensive. I am trying to wire in the stock cluster to see if the stops the issue.

I would welcome anybody's opinion.

Alexi

[SMoKeM240]

u can use a auto ecu or a guy in arizona makes rechiped ecus copys of jwt which i have, and before that i never had a problem going to redline without anywires on my transmission

[Bigvinnie]

Hey guy's why are you fu$kin around with the sensors in the back of the transmission so that every thing doesn't work??????????Go buy this niffty gadget called the HKS SLD. It is only $115........Like Emerald SAYZ ...................... BAM!!!!!!!! Here's the web site fella's, quite fuc$in around with equipment that was programmed to function!!!http://www.hksusa.com/categories/?id=1926

[benemorius]

Hey guy's why are you fu$kin around with the sensors in the back of the transmission so that every thing doesn't work??????????Go buy this niffty gadget called the HKS SLD. It is only $115........Like Emerald SAYZ ...................... BAM!!!!!!!! Here's the web site fella's, quite fuc$in around with equipment that was programmed to function!!!http://www.hksusa.com/categories/?id=1926

Why? Perhaps because it's... well... you know... FREE!

[Bigvinnie]

Why? Perhaps because it's... well... you know... FREE!

Yeah it maybe free but I have an s13 with digital hud without those sensors my rpm and digital cluster wont work, so what is the point?

[deviousKA]

If the ecu senses a malfunction from one of the variety of sensors, and goes into any kind of "fail safe" mode, the rev limiter will be lower. From what i recall this is more around 5000 rpm. You will need to feed the ecu whatever it needs so that it runs in normal operation mode, with the regular limiter of 6475 rpm. I dont think that it is possible to delete any of these inputs to the ecu with ecu retuning.

Here is a shot of the limiters from a 1990 240sx, direct from ecu. It may be possible to change the value on both of the speed limiters to keep the same operation as you are seeing in 1st and 2nd gear.

[neagan]

Do any of you remember the TV coverage of the Chip Foose build up of the Hot-Wheel's El Diablo? full size surfing truck? The donor vehicle was so computer sensitive even these master mechanics couldn't clip or cut ANY sensors for fear it would affect the ECU.

I would think that just because one of us got away with not having a sensor hooked up is no guarantee that it won't screw things up for someone else.

It sure sounds like a fun roadster project though! Got any Snaps/Pic's??? Nitro

[Bigvinnie]

Yeah I also think the people that claim that have done this "so called" rev limiter removal are not as truthfull as they say they are in the forums.... I know what problems there are from disconnecting the sensors.....On another note NOTHING IN LIFE IS FREE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Bigvinnie]

when disconnecting the 5th gear sensor, you are also reducing fuel economy, and this isn't in a performance sense........If you have an 89-90 get an eprom chip........Don't devalue your ride and ghetto rig it, it doesn't make sense.If you can't find a chip buy the sld, no one said performance wouldn't cost money. If your going to do modification's do them RIGHT!!!!!!!!!!!!!!

[vegita1647]

hahaha lets disconnect shyt n see if wee get faster sounds a lil on the shortbus side to me.... hks sld is for the kids driving to school yanking random sensors short bus... hmmm sounds like an easy choice spend the 125bucks and save your self thousands in wiring jobs done by somebody who actually knows what there doing

[Vegascorbin]

Check my response in this thread:

zer...s-out

It explains the 4000rpm cut out with the SOHC.

Also for those of use that run thses cars on a track in a pure stock class, the only option we have is re-wire or disconnect sensors. Re-programing or add-in parts are not allowed. Of course wew never get fast enough on a 1/3 mile dirt track to worry about hitting the 115MPH limiter.