i recently finished my LS swap into my 99 EX. im using the EX harness. heres what i had to modify

*used the EX distributor plug on the LS motor
*changed the crank sensor to the plug from the EX
*temporarily using the EX ECU and running an open header till i go to get my exhaust fixed........

anyways, the motor will not rev past 3500 rpm. its almost like there is a rev limiter at that rpm. also, my headlight will flicker when it hits that rpm. what could be the issue???

 

I think it's your ECU bro, try using an LS ECU and see if this problem still occurs.

 

have one here, just waiting on a jumper from Boomslang.............anyone else have any input???

 

The EX ECU is likely not communicating correctly with parts of the motor because its expecting radically different input than its getting. My best guess is that it is goign into "limp" mode. LS ECU should fix it...if not then you've got something major goign on. Just my .02.

 

i was thinking limp mode as well...due to no vtec.....

 

good input everyone................thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by iluvboobs &raquo;</TD></TR><TR><TD CLASS="quote">i was thinking limp mode as well...due to no vtec.....</TD></TR></TABLE>

Should get your harness in no time. Ordered mine from Boomslang last wednesday and it got here friday.
I'm using the dx harness and it was having erratic revs and flooding with fuel due to the O2 sensor difference but the ECU fixed it.
Good luck

 

another question i have is if the LS motors have a knock sensor?? someone told me to hook it up cuz i will need it to make my motor run correctly with the LS ECU installed.

 

change out that ecu, run and obd1 ls ecu, i had a 99 si one running mine first, ran like ****

 

ok, soo i received my jumper from Boomslang today and hooked it up with my 98 LS ECU. soo, i start the car up and get an immediate CEL. i kno one of them is for my 2nd o2 not being hooked up. anyways, the car WILL NOT rev past 3500 rpm. anyone else have anything in mind?? im leaning towards problems with the distributor wiring that was done................

 

the car is definatly in limp mode, it'll get horrible gas milage if you try to drive it. are you sure you don't have the tps sensor hooked to the map sensor plug and vise versa? That would cause these issues.

 

i checked those connections and everything is hooked up ok. im leaning towards my distributor being the main issue because i had to switch the plugs from the LS to the EX plug from the dizzy. anyone got some input on that???

 

What about your alternator belt. I know it may not seem like it's the problem, but when mine was loose, it didn't rev past those RPM's either..

 

The sensors in the distributor are picky about polarity, if you wire one backwards it won't send the proper signals. Also double check the wiring to make sure all the sensors are going to the same place. If all these ecus are known to be ok, then that is what I would focus on.

 

i checked my belt and it is nice and snug. also, im leaning towards the wiring on the dizzy being the main problem. i had one leftover wire from the LS dizzy that was a red color that was spliced into a blue wire on the EX harness. could that possibly be the problem???

 

I'd have to sit down and look over the wiring diagrams, I don't remember them off the top of my head, sorry. If you have them handy, just go though them wire by wire and make sure everything goes where it should.

 

Did you find out what the all the CEL are? It seems like an ECU problem. I had suttin like this before and i realized one of my injector plugs poped off.