she runs for a minute...

barbarian

Junior Member
So i did a swap on my 92 cx... put a d16z6 head on the cx block... she starts and runs when cold, but as the engine warms up the idle just keeps going down and down and down until it sputters and takes a big crap... this takes place over the course of about 3-4 minutes, from start to crap, that is.... we're pretty sure the timing on the belt side is good enough to keep her running... after first getting that problem we thought maybe the distributor was an incorrect match (off the cx) so tried another (6th gen lx, i believe), but that one might have been fried from the start... same issue with both distros..... it seems like, after it warms up, the engine is trying to find slow idle, can't, and just dies.... It isn't throwing any codes which leads us to think the sensors are all fine.... I'm baffled, but then, this is my first swap so go easy on me.
 

barbarian

Junior Member
Originally posted by Calesta@Jan 18 2005, 02:06 PM
What ECU are you using?
[post=447465]Quoted post[/post]​


The cx ecu... and we thought about that, though had heard that they should be compatable since we haven't hooked up the vtec yet.
 

92civicb18b1

The Trisexual
Why do people insist on running there cars when they aren't fully together, you have to expect problems when you aren't completely finished.

I personally can say, yes, I did have to start the car no matter what, I wanted to see it run, I knew there were going to be issues because I was using the incorrect distributor.

You're using the incorrect ECU and wiring incomplete.

Are you throwing any codes, I suggest you get the thing finished up then check timing and compression.
 

xj0hnx

I wanna be sedated
VIP
He said he isn't throwing codes, and the CX ECU runs (idles and drives, not perfect, but it does) a B16A without problems like that.

Sounds like it could be a vacuum problem, as pressure builds it chokes it out, look around for collapsed hoses. This may not be it, but it is another avenue to explore.
 

barbarian

Junior Member
So... We're still hunting down another distro, but we did get new cam gear (before we had the cx camgear on the z6 head) just to be sure... I plan on checking for vacuum issues when we go back to work on it and we're going to test for codes again as well... My "teacher" in all of this is almost certain it's a timing issue, but i'm leaning toward a vacuum or intake problem... up till now my only experience with hondas was on seventies four-cylinder motorcycles (they rule!) so all this sensor crap and cpu stuff is totally new to me....
I was also wondering if anyone knows what the compression ratio should be on this particular swap, and what kind of exaust would be best for this motor (the cx exaust is tiny).
 

92civicb18b1

The Trisexual
I think it's timing too, thats like the number one problem people have when they swap heads. I hear that question ALL the time, whether it was someone trying to replace a headgasket on a neon, or trying to put a z6 head on "x" d series block or whtever requires removal of the head.

I also agree though, I had the vacuum lines wrong on my LS, ran like ass so I just went at it blindly. I don't know what i did but after starting it would try to take itself to redline, I shut it off before it could. I finally got it right and it smoothed out the idle A LOT. I still have the timing issue so it will cut out if I try to floor it.
 

barbarian

Junior Member
Is there anywhere online that I can find schematics for vacuum line routes for a head swap such as this? If I could print something out it would make it super easy to determine whether or not routing is an issue....
 

xj0hnx

I wanna be sedated
VIP
Usually when the timing is out, either it will start, or it won't start, it doesn't taper off from running fine.
 

92civicb18b1

The Trisexual
Oh, I'm using a civic dizzy tied down. When the motor torques back I think it moves the dizzy cutting timing completly, therefor making it cut out, that's why if i try rev it slowly it's fine.
 

ksrcivic

Senior Member
no code for the fast idle valve it will jsut idle jacked up until you fix it... here is the vacumm diagram you were looking for

 

barbarian

Junior Member
Thanks for the suggestions... I'll update after I put on the new distro and camgear (also going to check vacuum routing and check for intake leaks)....
 

dwengines

Junior Member
Could also be the fuel injectors. If those get screwed up your idle will do that. Pretty much exactly what you descibed. You never know though, there really are a million things that can go wrong. Sometimes you just have to keep on trying until something works. Good luck!

Originally posted by barbarian@Jan 21 2005, 12:03 PM
Thanks for the suggestions... I'll update after I put on the new distro and camgear (also going to check vacuum routing and check for intake leaks)....
[post=449152]Quoted post[/post]​
 

Riceras

Senior Member
Yeah I dont see how its not throwing codes?? Is it backfiring a little bit as its starting to die??? Also How cold is it? I Have a 97 Civic CX and One day when it was really cold I went to start My engine and it would start then in about 4-5 Seconds it would choke it self!!! I kept doing this Cause Im an idiot and it gave me piston3,piston4 misfire!!! Does your car sound really bad while its running??
 

barbarian

Junior Member
Originally posted by saturn_boy96@Jan 27 2005, 03:53 PM
i think it's timing too, when it starts cold where does the idle start at?
[post=452196]Quoted post[/post]​


At first it idles a bit high, and just drops as it continues to warm.... we haven't set the idle on it yet though. waiting to get it to keep running first.
 

barbarian

Junior Member
Originally posted by Riceras@Jan 28 2005, 10:43 AM
Yeah I dont see how its not throwing codes?? Is it backfiring a little bit as its starting to die??? Also How cold is it? I Have a 97 Civic CX and One day when it was really cold I went to start My engine and it would start then in about 4-5 Seconds it would choke it self!!! I kept doing this Cause Im an idiot and it gave me piston3,piston4 misfire!!! Does your car sound really bad while its running??
[post=452529]Quoted post[/post]​


It idles a bit rough but no backfiring, when it craps out it just coughs and puts a bunch, like it's trying to keep going but cant... Put it this way, if it didn't bog down after a few minutes I would just set the idle and run it like that... no missing that I can tell as of yet... It just won't stay running. As far as how cold, I'm in cincinnati and we've been getting hit with a bunch of arctic shit for the last couple of weeks, so 20 or below.
 
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