Alright i have a 99 civic ex with jdm b18c gsr swap. ive been running the p73 ITR ecu since ive gotten it. I recently purchased a p72 ecu because this one is specifically for the motor i have. and from research on here, the p72 is better the the motor i have than the p73.

I got the yesterday and switched them out today! Started the car and the check engine light came on right away. I went ahead and drove just to see how it was running. Well everything seemed to be fine so i got on it a lil bit to see how it was when vtec engages. BUT as i was accelerating it wont go past 5,000 rpm. It just sounds like a rev limiter kicking in.

I got home after testing it. Checked my codes and im throwing the following:

Code 22 - VTEC Oil Pressure Switch defective circuit or unplugged / defective oil pressure switch
Code 54 - CKF Sensor (Crankshaft Speed Fluctuation) defective circuit or unplugged / defective sensor

Now are any of these codes the cause of not going past 5,000 rpm? Any input?

When i had the p73 ITR ecu, I didnt have these problems and only was only throwing code 23 - KS (Knock Sensor) defective circuit or unplugged / defective sensor.

Anyone know whats going on? Why am i throwing different codes with different ecu's? Is it true that the p72 is better for my jdm b18c gsr swap than the ITR ecu?

Any help would be much appreciated. I have this posted on ClubCivic as well, but not getting too many answers yet. Thanks!

 

Throwing those codes likely put your ECU into limp mode, which limits revs and obviously doesn't allow VTEC to engage. My first course of action would be to reset the ECU, either by disconnecting it at the harness, pulling the backup fuse under the hood, or disconnecting the battery(I prefer to disconnect the ECU since I'm lazy and don't like resetting the clock and settings on my deck). Then, see if any of the codes come back. If not, great, have fun with your car. If they return, read on.

Is the P72 ECU USDM? If so, then the USDM ECU is looking for the crank sensor that's built-in to USDM oil pumps and is not found in JDM oil pumps. You would need to switch to a USDM VTEC oil pump if you want the USDM ECU to function properly with your engine. You may also need to splice/rewire your CKP sensor plug if you have a 3-wire plug on your engine harness since the 96+ B series VTEC CKP sensor uses a 2-wire plug. I'm not sure if the 99-00 Civics had a 2 or 3 wire plug, but I had to splice a plug from an Integra harness for my swap(I think I actually cut the plug off of an old D16Y8 oil pump and wired a plug from an Integra engine harness to make a jumper/conversion CKP harness). Otherwise, you could run a JDM ECU or a socketed OBD-I ECU with the appropriate bin loaded, along with an OBD-IIB>OBD-I jumper harness. Is your knock sensor hooked up? If so, and you're throwing the knock sensor code with the JDM ECU and not with the USDM, then I don't really know what to tell you about that. For the time being, if your P73 ECU was able to run without going into limp mode, I would just run that until you decide what to do about your CKP situation. I would assume the VTEC oil pressure switch code is a random occurrence, possibly related to the ECU being in limp mode, so unless it comes up again, I wouldn't worry about it.

 

that seems to be good information to go about. ill definately start by resetting the ECU and go from there. Ill let you know what happens.

Im pretty sure the p72 i bought is USDM..so that seems to be my problem. i think my buddy has a JDM p72 that i might be able to try with my car. But if not ill try the oil pump and mess with the CKP sensor plug. How hard is it to replace an oil pump? could this vtec oil pressure **** be causing me to burn oil? B/c i am burning oil and have been tryin to figure that out for awhile now. I did a compression test and it was like perfect. So i was thinking maybe valve seals. But could this oil pump/pressure effect this?

Yes my knock sensor is hooked up. It was weird because i never had that CEL until i replaced my map sensor it seemed like. because i was throwing a code for that awhile ago, but thats fine now since i replaced it. And the funny thing about the knock sensor CEL with the p73 ITR ecu...vtec would kick in! I thought it was odd.

 

You have to get the crank pulley off to change the oil pump, so if your timing belt/water pump have some mileage on them, you might want to change those while you're changing the oil pump. Do you have an oil pressure gauge? If so, what kind of oil pressures are you seeing at idle/3K RPM warm? Any fluctuations in oil pressure might potentially throw the VTEC pressure switch code, but again, if you haven't had an issue with it before, it might just be a random occurrence and I don't think it would cause you to burn oil. How much oil are you burning between oil changes? Do you actually see any smoke, or does it just consume oil? If you're getting visible smoke, under what conditions do you see it? Is it smoking during start-up, during WOT, or while decelerating?

 

alright...shouldnt be too hard to change the oil pump then, thanks! no i do not have any oil pressure guages. do you recommend getting one?

as far as burning oil...it smokes at idle, but not alot. And if i really stomp on and hit vtec, its like a huge cloud of smoke. It appears to be lighter colored smoke thats blueish. Its kinda hard for me to tell. i know its not white tho. You can also see some smoke pop out, for example if im on the highway driving and let off the gas and then get back on the gas. What did you mean by...during WOT? not really sure what that is. Im still trying to figure out exactly how much im buring between oil changes. After i did any oil change a lil while ago. The oil level was find for awhile. One day i checked and it was like bone dry. I bought a quart to put in it. And drove like 5 minutes awy to my friends...checked it and the oil level was like perfect. It was weird.

 

I vote bad rings. Get a compression tester, pull the ecu, do the normal WOT 3 cranks, compair. The readings should be w/in 5-10 psi of each other. Smoke when you get on it, let off, and at idle indicate that the bad rings are sucking oil through them when the pistons have to pull a high vacuum (zero throttle), leading to blue oil smoke.

Also make sure to check when oil is warm, and on a level surface. A pressure gauge is always a good idea, especially for a used motor that will hit 8k rpm. You should have 10-15psi at idle, and 50psi+ at/over 3k rpm - when warm.

 

hmm. my compression test was..220..216..220..220

yea ill look into an oil pressure gauge

 

WOT is wide open throttle. Your compression numbers seem good, so you might want to do a leak down test as well.

 

Oh alright. What all should a leak down test show me? Is this somethin I can do myself or do I need to get it done at a shop?

Also, I reset the ecu and CEL still comes on. So I guess ill just go about getting a USDM gsr oil pump.

 

It'll tell you if you have any compression leaks past your valves or rings. You need an air compressor and a leak down test kit.