Wassup honda-tech i have a problem with my B20 VTEC that i just put together, and it's hitting VTEC at 4100 and rev limiting at 6500. I tried everything, i have a chipped p28 with a b20v tune and the tune is set hitting VTEC at 4800 and the red line is sopposed to be 8000. I even took the chip to get it checked out and everything is set right. I have a spare P28 virgin that i tried and it hits VTEC at 4500, and the rev limit is 6500...so that's not right. I double checked my wiring, (including TPS, MAP, and IACV), distributor, spark plugs/wires, new fuel filter, oil it right on the level, everything seems right and NO CHECK ENGINE light...the motor runs fine, this is pretty much my only problem. I'm using my stock OBD1 P28 wire harness that came with the EG coupe.

So my question is what would cause it to hit VTEC so early and my rev limit so early even though i try other chips or ECUs...it's never right. Oh and the weird thing is that while in Neutral, i can rev up 7000 RPM so that makes no sense to me but while driving (or load on it?) it stops reving at 6500? Need help, thanks

 

Sounds like a bad chip try the other p28 and get a chip from somewhere else

 

Try taking it to a tuner

 

does it struggle to reach the rev limiter or it does it easily?

 

Well...the thing is i actually have 3 chips, and i tried every single of them with my socketed P28 and my friend's socketed P28 and i had the same result on all.

No it still pulls like my B20 and VTEC kicks in but i can't enjoy that top end because it just starts red line. But it doesn't do it in neutral...

 

Check ground on water coolant neck

 

You're talking about the ground for the thermostat? If so i checked that already because my tach needles were jumping up and down.

 

anybody else?

 

I'm still dealing with this headache. Someone help please.

 

Do these p28 chips your putting in have maps for your engine type/size?
What tuning software are you using again?

 

just saw this part...Put another igniter/ICM in the distributor.

 

^^^^same thing happend to me, but I replaced the whole distro\dizzy and issue was gone.

 

i believe its chrome that was used to tuned the chip, it was tuned to my specs (stock build) with bolt ons so i know its not the chip.

i replaced everything in the distributor and had the same result.

we might've had similar symptoms but its def not the distributor, injectors, fuel pump i can rule those out.

 

I still say its the chips .... Baseman chips are just to get your car running so you can go get it tuned , insome cases the tuner burns the chip that looks or resembles your setup but the rev limits and redlined could be set up totally different happened to my buddy he had no redline on his hip shitwouldjust bang off 9k all day long

 

Still having this problems guys! i need help i'm stumped...i can't believe no ones really had this problem before.

 

How are you reading the RPM? The stock tach? Stock tachs are known to be off by as much as several hundred RPM in the upper rev range. Just another possibility.

 

Id get off crome and use neptune and burn that profile onto your chip and see what happens. thats the only thing that has stayed the same and Crome is known to have bugs. Especially if its an older version from years ago

Another thing to consider is the tach like said ^^

If you had your ride on the rollers when tuning or even a street tune, then you shouldve seen the tach differences. It shows right in the software.

P28 means nothing when it comes to a B20V. P28 tune is tossed in place of a new tune. IDK why people still are on the P28 bandwagon unless your ride needs a P28 tune exclusively.

 

I dont think its a chip problem. Check J1 on the ecu, the jumper that essential tells the ecu to read the aftermarket chip instead of the factory program. I had this same problem. kept making changes to the chip and nothing changed. come to find out I had a bad solder joint at J1.

J1 is top right of the chip itself.
Photo from here:

http://www.theclubindustry.com/hondaecu/chipping/

Check every add on component for good solder joints. a computer shop might be able to fix any soldering problems.

 

^^
OP said he used another ECU and same result..

But good to know!

 

IDK who in their right mind would rev an unloaded engine to 7k. Def not a healthy thing to do.

 

Whoops!

It definately seems like a ecu problem. Find someone with a chip burner and see if the burn is corrupt, Ive seen that also. Do you have the chip in the correct way?

What is the base ecu you are using? If its like a Pxx maybe we can compare the OEM vtec engagement point and rev limit to what you are seeing to know if the add on chip is being read or not.

 

yea i'm using my stock tach but i just don't see how the tach would be off by so much...i mean it's showing i rev limit at 6500 there's no way i hit 8000 so fast and you can tell VTEC is kicking in too early.

well you could be right but i have ruled out ECU and the chips because i used my stock p28 and pretty much had the same results.

thanks for the help bro, but it have ruled the ECU out because i had the same exact symptom when i used my friend's chipped p28 , there's no way his was bad too...also when using the P28 it was pretty much the same result.

i only did it once to see if i have fuel cut off at 6500, apparently it only does it through the gears.

 

Probably lean as hell using a base P28 tune..


Lets not do that again..


Id look to a new tuner and/or software (after you check your soldering of course)

Check your socket solder as well.


Id like to see a dyno sheet on this set up

 

Where do you live?

 

Just curious, why would a chipped p28 ecu be so bad? As long as it has the proper base map made for his set-up and then tune it. I would understand if he threw a virgin p28 on and called it a day.

This does sound like a bad ecu,chip, or base map burned incorrectly.