Help???

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steve7de3

New Member
hello everyone.. i need some help here.. i have a 93 civic dx.. i bought with a down grad swap which is a d15b8.. i swapped the head to a 1.5 vtec.. the problem im having is 2 engine check lights..1 is code 21 and the other is 1.. i know what 1 is for.. but i dont know what 21 is for.. when i run it up the street i can floor it and its like i have no power??.. i swapped the head, timing belt, pulled the oil jet plug off the block and a few other things as well but still no power?? can someone please help me out here??... Thanks
 
What ECU are you using? And I'm pretty sure the D15B8 is what would come stock in the car, so I don't know why you're thinking it's a swap...
 
D15B8 = 8 Valve CX motor 70hp

D15B7 = 16 Valve DX motor 102hp


Do you have a shop manual so you can look up what code 21 is?
 
im using a p28.. the first ecu was a cx??.. this is a 8 valve motor.. but my head is a 1.5 vtec.. are these two not gonna work together??
 
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im using a p28.. the first ecu was a cx??.. this is a 8 valve motor.. but my head is a 1.5 vtec.. are these two not gonna work together??

Its not an 8 valve motor anymore;).

You're using the right ECU, my guess is sounds like theres something wrong with your vtec solenoid, there should be a procedure to check it in your manual.
 
is that the reason its really slow when i test drive it?? it sounds like im hauling ass but im hardly moving

Try changin into 2nd gear:p

on a serious note:

are you saying the engine is reving high, but the car doesn't accelerate and any faster? do you hear the vtec change over, i dont know about the D's, but on my RSX-S I could definitely hear when the VTEC engaged.

Does the engine lack power at all or RPM's or just at the top end?
 
i can go threw all gears and it slowly pickes up speed.. no vtec sound but not im doing 25 to 30 and im at like 4 1/2k on the rpms.. my engine lacks power and i noticed when i rev it, it has a bog in the begining..
 
i can go threw all gears and it slowly pickes up speed.. no vtec sound but not im doing 25 to 30 and im at like 4 1/2k on the rpms.. my engine lacks power and i noticed when i rev it, it has a bog in the begining..

are you sure the timing is correct?
 
The D15b7 doesn't have Vtec, nor does the D15b8, putting the D15b7 head on the D15b8 won't magically give it Vtec...

Yea the D15b7 is a pathetic little motor. I would know, I have it. I did beat my friends ranger (so it isn't the slowest thing out there) the other day when we were messing around on his long ass driveway on his property.
 
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do you hear the vtec change over, i dont know about the D's, but on my RSX-S I could definitely hear when the VTEC engaged.

VTEC is usually more noticeable on more performance-oriented dual-cam engines than with the single-cam ones. I used to have an EX Accord and you couldn't really feel or hear much of anything when it crossed over into VTEC.

The D15b7 doesn't have Vtec, nor does the D15b8, putting the D15b7 head on the D15b8 won't magically give it Vtec...

Yea the D15b7 is a pathetic little motor. I would know, I have it. I did beat my friends ranger (so it isn't the slowest thing out there) the other day when we were messing around on his long ass driveway on his property.

Well he did say that he put a VTEC head on it, so theoretically he should have VTEC now assuming that everything is wired up right and working correctly....
 
yeah lol the D15b8 is a POS.. it revs with a little bog in the beginning?? i have ex wiring in and out so my vtec wires are good i have a p28.. my timing is correct.. when i take off it just puts along and slowly picks up speed lol
 
thats a dx tranny for ya

Oh yeah...good point there AHHVTEC...

So did you keep the stock DX tranny in there? That will definitely put a damper on your VTEC fun.

Also, and sorry if this was already mentioned, but are you throwing any error codes?
 
im using the cx tranny.. i got a ex on the way.. im throwing up 21 and 1 and now 41??
 
im using the cx tranny.. i got a ex on the way.. im throwing up 21 and 1 and now 41??

Well code 1 and code 41 are both for the oxygen sensor, so I'd check to make sure you don't need a new one of those or that it's wired up incorrectly. That could be the cause of your problems honestly. A car will often run shitty if something's wrong with the o2 sensor. Code 21 is for the VTEC solenoid, so I'd definitely check on that too.

Do you have a service manual? That would probably be a helpful thing for you to pick up...
 
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