General engine questions/issues that aren't specific to the other categories
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By jred
#358413 Couple day now my engine (B18c tuned with a Hondata S300) went into limp mode. at least i think it is, It won't cross 3500 rpm (revving at idle or driving)
No check light, no codes.. no rough idle or anything it just wont rev past 35k it just goes up to 35k and dies down then bounces back up to 35k and dies back and so forth, and this is with the throttle at a steady position

Things I've checked/replaced so far; ECU is working properly (I checked it by unplugging a sensor to see if it throws a code "it did" ) not 100% sure if that means its working, can't seem to find any wires in the harness that's broken, replaced the O2 sensor, new spark plugs, new fuel filter, check the injectors all is functional, fuses look good (not sure if i missed any), FPR works...

Things i suspect but don't know how to check if they're faulty ; TPS, MAP sensor and Distributor

Has anyone ever experience this before?? I googled a lot of stuff and tried everything that I found and could possibly my issue. but nothing worked..

(A bit of history before this happened: I replaced my clutch a few weeks back and since then every morning at start up the car threw a code 21( Vtec solenoid ) but during the day the code didn't seem to come back when restarting the car (weird) when i finally got time to properly inspect the solenoid i noticed the engine temp sensor wire was almost broken off the plug so i replaced that and the vtec solenoid, the code still was there every morning though....

Then this limp mode issue started (car work fine the day before), so while trying to figure the limp mode issue I check the ECU and saw some poorly connect wires and i re-did the connections and since then no CEL for the Vtec solenoid but i'm still left with this limp mode problem that i can't seem to figure out
Can someone please help?!
User avatar
By jred
#358439 Thanks for the reply almost gave up hope..lol
Oil level is good, as for the Vtec oil pressure sensor, I dont have one. Its a JDM motor so i dont know if its located any where else but its not on the Vtec assembly.

Also I've noticed a slight hard start sometimes when i start the engine, it sounds like when you pull the engine choke on some cars and then it tumbles and start... will that be distributor related or ??
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By Driv-it-hard
#358441 OK, your motor is like mine. I have a b18c1 with no vtec oressure switch and it is ground to the signal coming from the ECU.
When was the last time you pulled off the Dizzy and did a tune up. It might not help , but you'll know that everything is okay there.
If you put the jumper wire on the pig tail on the pass side, does the CEL even come on ? Does it work ?
Check that first and let us know.
User avatar
By jred
#358458 Yeah i did the jumper wire test the light just came on and stayed on indicating no codes, so i disconnected a solenoid to see if it would of even throw a code and it did so guess the CEL and ECU works fine.

Did some more online google ing and was told it might be the igniter module in the distributor, so i went by a buddy who had some spare distributors to try another one to see if that could be it, when we changed the module and started up the engine CEL 9 came on (No1 cylinder position sensor), so we thought this used module caused the CEL so we placed back the original module, and started the engine again and the CEL 9 came on again...

So Im assuming the (CYP) is the culprit that's causing the Limp Mode but never triggered the CEL until we ventured into the distributor :?
Only problem is we don't have a spare CYP to test it out, Hopefully I'll be getting one this evening so will give an update if it works and rid me of limp mode..... fingers crossed.
User avatar
By jred
#358479 Problem fixed :woot:

So last time I posted I suspected the CYP, got a CYP off a used distributor that i had to buy at a foreign used parts dealer, when we replaced the CYP the CEL came off but the Limp Mode was still there.....
My friend suggested that we try another ECU just for the sake of it, when we did the car Rev'ed fine but while driving Limp Mode was still there,. Still can't cross 2500 RPM..... so we checked the TPS again but the sensor was good, so we decided to check the wiring.. end up scrapping the old wiring and rewired the TPS to the ECU and behold the problem was solved.
No CEL no Limp Mode everything worked like it should :woot:

This was by far the worst experience I had with my car because it was so hard to pin point the problem....
I guess a car this age the wires are getting old and need replacing.... since we saw this we ended up taking out the harness and re-doing some of the wiring just to eliminate any future problems like this.
Alot of money was spent on parts that did not need replacing but I guess that was what had to be done to figure out this.....
Honestly im just glad my car works like it should again :D

Thanks for the help and interest Driv-it-hard :thumb: