Hello everyone,

i dont comment much in the forums because i usually just search and read what i need... but i have a weird problem.


I have civic SiR 2000 canadian (civic SI for USA), swapped b18c Type R 2nd gen with stock SiR (Si) obd2b harness (done by previous owner), the car runs very well except around 7000rpm , the vtec is louder than the crossover around 5500rpm and it starts losing power around 7000rpm (no more pull until car is shifted and rpm goes backk below 7000rpm to gain power)

My car idles rough , the steeering / car / bumper shakes a lot when i use the P72 chipped b18c but when i use the stock ecu P2T (b16a2) , no rough idles but still not vtec ...

Here's what i have done:

• changed the vtec solenoid gaskets (both) , clean the inside with brake cleaner
• vtec solenoid does a click when i apply 12volts
• new spark plugs
• new oil change
• new oil filter
• no oil leak except a bit from the headgasket (between the head and the block , the famous fronter corner where everyone leaks)
• tried 2 different ECU , one its my stock P2T SiR (B16A2) and a chipped for b18c P72 obd1

Could it be timing ? i also read it could be distributor or catalytic ....


Thank you everyone.

 

What in the world makes you think loud vtec means power?

Also, is the B18c modified at all?
What did you do to the harness to get it in this car?
Why not the ECU that comes with the engine?

 

Okay, first of all do you have any codes thrown? and the p72 , is there a correct basemap for it? the p2t isn't the correct ECU so It probably wont run right and all Chipped ecu's should be tuned unless you have a wideband.

 

5$ is betting there is zero reason to have a 'chipped' ECU for this car.

 

I bought the car swapped. The previous owner never gave me a original b18c ecu .... I found it strange though. The obd2b harness (civic sir 2000) was kept in the car so to use the p72 , its using a obd2b to obd1 conversion harness. No check engine because its obd1 right?

I am using a chipped p72 because thats what people said to use, online. To either use a chipped p28 or p72. I bought the chip on ebay (its a mugen basemap for the b18c according to the seller)

I didnt use the p2t because according to some online sources, the b18c will run lean .... I dont even know if the engine is modded.

Could the car just need a simple ecu tune?

Thank you everyone.

 

it could be a number of options , maybe sell the p2t and pick up the oem ECU or borrow it. Also the base map could very well be the issue. There are a lot of options that take play

 

I would find a stock ECU for the B18C, run that and see what CELs you have. The Mugen chip base map crap is probably the issue.

 

No IAB wired up............

EDIT: Need a photo of engine. B18c can mean either GSR or TYPE R.

 

You can't use a OBD2B P72/73 ECU. They have immobilizers. Hence the reason for a chipped or OBD1 ECU.

OP...you shouldn't spray the inside of your vtec solenoid with brake cleaner. Just for future reference.

Which B18C is this? Blacktop (SIR-G) or red top (ITR)?

If this is a GSR/SIR-G swap, they probably have the wrong fuel rail and fuel feed line on there. This will starve the engine at high RPM. You should try a GSR fuel line (fuel filter to rail)

Try a STOCK OBD1 or OBD2A P72 ECU with the correct adapter. Again...I'm assuming blacktop B18C. VTEC is set at 4500RPM and the IAB opens at 5700 RPM. You really don't hear a loud VTEC crossover on blacktop B18C's. But you will hear the IAB open.

 

You will definitely hear the IAB...

 

OBD2A to OBD2B solves the immobilizer issue while running a stock ECU.

 

Sorry guys. Its a B18c type R. Numbers starts with 2xxxxxx below B18C written on the block and PR3-3 is written above the headers.

I just realised that maybe its because the engine is JDM and im using USDM ecus ??

Could that be the problem? both of my ecu are usdm !! and the chip i ordered was usdm , the seller asked me if my ecu was rectangle (usdm) or square(jdm). i told him it was rectang)3.

 

No. That doesn't matter. Check your fuel feed line. Check your ignition components. You can run a OBD2A USDM ITR ECU (HA!!! good luck), or a JDM ITR ECU with an OBD2A conversion harness.

Or if your ECU is chipped correctly, you can use that. USDM and JDM maps are different, but your JDM engine will run just fine with a USDM ITR map.

Using the wrong fuel feed line is a likely issue. IIRC, I re used my B16A2 fuel rail when I did my swap so that my fuel feed line wwould sit correctly. Alternatively, I believe leaving the JDM ITR fuel rail and using a 5G prelude fuel feed line will work.

 

I just noticed something , VTEC DOES work but around 7000rpm , the car will lose power ....! Thank you for your help.

 

No problem. Not sure if this has been covered already. But...you do have enough oil in the engine, yes?

LMK if the fuel line was the issue. I've done a million of these swaps and I remember that the fuel feed lines can be an issue. If you had to force or shoehorn those tabs on the fuel line, then you're probably starving the engine at higher RPM.

Swap your B16A2 rail over and see if that helps.

 

Yes , i did a brand new oil change , 5.1 quarts and new oil filter. new solenoid gaskets (it was leaking oil from there).

I gave the car to a mechanic , i will tel him this , thank you very much for your time.

I told him about fuel filter and clogged catalytic and he does not believe its the case. Either timing. He changed new spark plugs.

Do you think it could be fuel filter?

 

5.1 qts is too much oil

 

oups, sorry , i got mixed up with my s2000 lol. I putted 4.5 quarts.

 

4.5 is still arguably to much oil.

 

I have a JDM p73 ecu pm if interested

 

My mechanic did a compression test and oil pressure test. Oil pump is working good. Unfortunately, compression numbers are as follows : 215 215 215 75

cylinder #4 is super low !!! does it mean my engine is finished? and does this explain the reason for the loss of power at around 6500-7000rpm? Thank you.