swapped in a JDM B20B(97) into a 93 DX hatch...car runs really strong(pulled 14.4@95.9mph) but has an idle problem. Sometimes the idle seems fine and sometimes it idles as high as 1500rpm and the rpms might even slightly fluctuate.

we are using an OBD1 P75 ecu and still using the stock throtle body cable that has been slightly modified. when we disconnect the T/B cable the idle still fluctuates. we tried replacing the idle/air control valve with no luck...

once in a while the engine light comes on, code 43..something about fuel or wiring..

anyone have any input into this? or similar problems?

TIA

 

i have to get this out of the way
when it idles like that is the car fully warm? because when its cold its supposed to idle at 1500.

 

yes the car is warm when this happens

 

also when the car is moving and in neutral the idle always goes up and down

 

Is there enough coolant in the block for the water temp sensor to get an accurate reading?

 

yup, we've flushed the coolent already

 

sounds like a vacume leak then.

 

I just swapped a 96 LS motor into my 95 Civic and am using the OBDI P75 ECU also. When i first finished my swap i did'nt have the Purge control solenoid valve hooked to the charcoal canister and it made my motor do the same thing you are describing. After i hooked it up the idle went back to normal..........

 

hmmm...I'm gonna double check that..

thanks for everyones help and if anyone has any other tips pls let me know

 

a stock B20B? wicked

have you lightened the hatch? no VTEC?

oh yeah - check for vacuum leak AND your TPS...

t..

 

we've checked the TPS and it was fine...we've troubleshooted all vacuum lines....do you guys think that a leak in the intake manifold gasket might cause this to happen?

the 14.4 @ 95.9mph is with JDM GSR tranny, back seat and spare removed, two front GSR seats, 15x6 hammerheads with worn out dunlops, dc 4-1 header, carsound 2.5" cat and custom mandrel bent 2.5" stainless pipeing with 2.5" id universal muffler and some cheap ractive intake...the car runs consistent 14.5-14.6

 

the hatch ran those times @ st-thomas dragway in sparta ontario last saturday...the link below has some pics, it's in the first pic against the CRX.
that CRX has a GSR motor(GSR shortblock with 1st gen B16A head/tranny) and it ran best 14.3 @ 96mph on street tires and 14.003@98mph on slicks...the turbo ZC was not tuned at all and had a best of 14.9 during the day.
the last blue civic is the splitfire civic ran two 9 second passes that day(it was test and tune) and two 10.1s

http://www3.sympatico.ca/richtennis/StThomas.html

 

Don't have a solution for you but i got a few Q's.

Have any traction problems at launch with that gsr tranny and all that tork? You mentioned your tires were worn out even. Other people with that swap claim they can't help squealing into third.

It sounds like you must have the z pistons in there with times like that! Its an ongoing debate over which (if any) jdm b20b's come with the lower comp pistons.

Nice setup, tho, somthing similar is my goal. Imagine a vtec head on that...

d

 

that is my cousins car...I took it for a run that day and wheel spin is a major problem, as well as wheel hop...just gotta take it easy on the launch...in the hatch you finish the 1/4 in almost top of 4th...

I've have taken apart 3 JDM B20Bs thus far(blocks stamped 95-97) and they have all had the dished(lower comp pistons) and not the Zs' flat tops...

I'm currently building a B20B/P72 head as we speak for my DC RS...and the hatch will go frankenstien durring next winter, in the mean time a set of hoosiers should get the hatch in the 13s with a basically stock B20B. We're taking it to the dyno with it's current set-up with the addition of an AEM FPR and I'll post results then.


[Modified by T.O.tegs, 4:51 AM 5/4/2002]

 

YES! a leak in the intake manifold gasket could cause this. start with the torottle body gasket and replace them both.

 

Have you had any trouble prepping the VTEC head for the b20??? And did you use a b16 head or what? I'm saving up for a CR-VTEC swap now, and I'm trying to figure out if i'll be able to do it by myself or if i'll need to take it to a shop...


Ju$+iN

 

I'm using a p72(GSR) head...need to relocate the dowel pins and block and re-tap the oil feed...I recommend doing this at a reputable machine shop. and since the head will be getting machined(might need some resurfacing) might as well do a port and polish and upgrade cams/valve springs/retainers and even valves.

save up and do it right the first time


[Modified by T.O.tegs, 5:07 PM 5/4/2002]

 

Interesting, you're the first experienced person who has claimed to me that at least "some" jdm b20b's have the lower comp pistons. One guy even claimed that he had literally dozens apart and they all had the higher comp. pistons in 'em. Did you do a compress. test on any of these engines? I'd estimate that the z pistons would yield close to 200psi...

You have any insight then as to which jdm engines may have the higher cr? Or is it just hit and miss. I was hoping maybe the '98's at least would have them. I had ordered a '98 b20b engine from a shop in T.O. It was a sweet deal for only 1g, but they DROPPED the engine taking it off the shelf and that 1 was all they had. Every other distributor i called wanted $1500+ for them. Guess i'll have to wait til the next shipment.

d

 

all B20Bs (blocks stampted 95-97...heads stampted 96-98) came with the lower compression pistons. I've never seen it otherwise. on a good B20B the compression test should yield between 165-170 all the way accross. The JDM B20Z(98+) has the flat top pistons and so do USDM CRV engines.

the B20B/Z is a very fun engine in a hatch...it just pulls hard from right off idle to 7200rpm. very nice swap!

 

Ive got a question, why do you guys use OBD1 ECU's w/ your OBD2 B20's ??? Is there a reason for this???

 

They went from block stamping to head stamping in '97?

I don't actually have the hatch yet. I'm still running my '90 rs integra which is in need of the swap. the car is bare bones, so it should be about 2500 lbs light, its no civic hatch, but it should be close to the Si hatch weight.

I've got a '90 civic cx hatch, but that car isn't worth the trouble and i'm gonna get rid of it as soon as i can fix up some o the rust.

What do you make of these numbers i pulled off the jap honda site? The consistancy is pretty bonkers, eh?

JDM CRV w/b20b

1996:

cr - 9.6:1
ps - 130@5500
kgm - 19.0@4200

1997:

(2wd?)
cr - 8.8:1
ps - 130@5500
kgm - 18.8@4200

(4wd?)
cr - 9.2:1
ps - 145@6200
kgm - 18.2@5200

1998:

cr - 9.6:1
ps - 150@6300
kgm - 18.8@4500

JDM S-MX w/b20b

1996:

cr - 8.8:1
ps - 130@5500
kgm - 18.7@4200

1999:

cr - 9.6:1
ps - 140@5500
kgm - 19.0@4200

2000:

cr - 9.6:1
ps - 140@5500
kgm - 19.0@4200

JDM Orthia w/b20b

1996:

(2.0GX, 2.0GX-S)
cr - 9.2:1
ps - 145@6200
kgm - 18.2@5200

1998:

2.0GX, 2.0GX-S)
cr - 9.2:1
ps - 145@6200
kgm - 18.2@5200

 

Daver, I dont think the compression has anything to do with the year... there are MANY types of B20's out there and heres what ives picked up so far.

There is a FWD and a 4WD system out there

There is also AUTO tranny and MANUAL tranny

The Orthia is the FWD version, but the CRV also does come in FWD format, and I believe in Japan its on the lowest model CRV (kinda like a civic VX/CX here) which explains the less tuned motor. Theres a little more to it, but it breaks down to being just like why here in the states some cars has VTEC and some dont -- and for those of you knowing what you are looking for its easy to figure out if your motor does ot not :D

 

there are also B20s that come with a huge intake manifold(hence the lower horsepower ratings) and there are B20s that come with an intake manifold similar to the B18B I/M...

BTW, all heads are stamped which year they are made and same with the blocks and it is not an uncommon thing to see a different year stampted on the head then on the block...example: block stampted 95 and head stampted 96.

it is also easier to do an OBD2 to OBD1 conversion on the engine harness then to convert everything to OBD2...besides, OBD1 is the shizznits

 

Hehehe, how hard is the actual wiring if you are too cheap to spend $250 on the Hondata harness? :x

 

I guess its for compatibility with plugging into the obd1 chassis harness, sparq. I think the adaptors are expensive.

Can you use the existing civic engine harness or do you have to get an integra one?