Well, we just installed a nice DOHC ZC engine into my gf's 89 Civic Si and it runs horrible.

I've done the same swap in my old CRX w/ no problems but this one was different.

First, there seems to be part of the block that protrudes to where we can't perfectly mate the exhaust manifold to the head.. hence a giant exhaust leak. It runs rich as hell, hesitates on acceleration, black smoke.

Also, there was a plug that is on the oil filter side of the block we dont' know what it goes to.. we have one for our oil sensor.. another sensor next to it, and one that goes to the back of the intake manifodl.. and there's one adrift.

So what could be the problem, exhaust leak or the wire to the sensor that doesn't exist?

 

I remember reading about having to grind the manifold on certain exhaust set-ups. I'll look for it. There is a coolant sensor above the oil filter, any codes?

 

The switch thats to the upper left of the oil filter (when viewed from below) is your collant temp switch. It just tells the fan when to come on so that shoudlnt cause a problem. What header/exhaust mani are you using? If you can see an obvious bulge on the exhaust mating surface then I'd talk to some machine shops. As for the extra wire you will have one connector hanging with nowhere to go. As for running rich what ecu are you using? O2 sensor good? Clean the injectors?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blah13 &raquo;</TD></TR><TR><TD CLASS="quote">The switch thats to the upper left of the oil filter (when viewed from below) is your collant temp switch. It just tells the fan when to come on so that shoudlnt cause a problem. What header/exhaust mani are you using? If you can see an obvious bulge on the exhaust mating surface then I'd talk to some machine shops. As for the extra wire you will have one connector hanging with nowhere to go. As for running rich what ecu are you using? O2 sensor good? Clean the injectors?</TD></TR></TABLE>

I'm using the old Si exhaust manifold and the Si ECU. I used it in my old Si rex and it ran fine.. i think i'm just going to grind the manifold later on tonight. As for the O2 sensor, i think i'm just going to replace it with the ZC one. The injectors weren't cleaned because they looked good..

 

are you getting any codes?? I'm in the middle of fine tuning my recently done zc swap

 

Did you peel all the old EXH gaket off? Just a thought. Any codes?

Blaze

 

Did you check the TPS?

 

I had to grind a little bit of my Chikara one to make it fit.

 

Just ground away at the manifold-- no more leaks.. BUT still runs like crap. It sputters out black smoke (rich). and bogs under acceleration, rough idle.

Checked Ignition timing- ok
Checked connections to TPS- ok.. no idea which one MAP is though

Yeah, a CEL is thrown and it's flashing a 5 and a 7.. no idea what that means.. So any suggestions?


Modified by ltho1998 at 5:37 AM 8/12/2003

 

CEL 5 is MAP....it should be located on the firewall near the throttle body. It also has a vacuum line that connects to the underside of it and the other end of the line connects to the throttle body.

CEL 7 is throttle angle and from what i remember thats the TPS sensor. Have u removed it or swapped it to another throttle body? If so it needs to be adjusted. Or perhaps u damaged it when installing the motor...check it out.

 

TPS = Throttle Angle from my understanding and I am using the one from the old Si motor which was still good when we removed it, the one off the ZC was trashed upon receipt-- as per the norm.

 

did u re-adjust the tps to .5 ohms when you put it on the car?

 

you have to install the TPS a certain way, i dont remember how but it has t be done a certain way

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CIV616 &raquo;</TD></TR><TR><TD CLASS="quote">you have to install the TPS a certain way, i dont remember how but it has t be done a certain way</TD></TR></TABLE>

read what i said just above you.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RexB16 &raquo;</TD></TR><TR><TD CLASS="quote">did u re-adjust the tps to .5 ohms when you put it on the car?</TD></TR></TABLE>

No.. i didn't no you were supposed to. I didn't with my old rex and it ran fine.. hrmm. How do you even adjust the TPS to 0.5 ohms?

 

It should read 5 volts (not Ohms) between the outer 2 pins on the 3 prong connector for the sensor. There is aslo a vaccum line that you need to pull a vaccum on to see if the voltage smoothly drop to 4.5 volts. Buy a Helms.

 

Sure, since there's just an abundance of helms manuals for the ZC engine in the US. and i was actually asked to help out when the engine was already pulled and nothign was labelled, and the guy bailed.

 

You don't need a ZC Helms for that or for a lot of Honda fuel injection/emissions questions.

 

The adjustment for the TPS on your ZC is the same for the 88-91 civic SI. Like the others said...go buy a helms or chiltons for the 88-91 civic and it will give u step by step instructions. If your TPS is out of adj., then that is most likely the cause of your crappy running motor.

 

how can i clear out the CEL on my zc swap in 89 crx hf

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sabertooth &raquo;</TD></TR><TR><TD CLASS="quote">how can i clear out the CEL on my zc swap in 89 crx hf</TD></TR></TABLE>

uhhh...fix the problem first then pull the ECU fuse and HAZARD fuse out (i pull both just in case) in the under hood fuse box.

 

Here is your zc helms http://www.acute.f9.co.uk/crx/...s.htm
You need to fix your dcodes. I am not usre, but I think the plugs for the tps and map might be interchangeable and might be switched. or maybe not hooked up right. The map is you main issue. It should be up on the firewall, squarish looking, and has a vacuum hose attach to the bottom. Make sure it is hooked up, wire waise and vacuum hose wise. The vacuum hose for it is the on ly vac hose coming off the throttle bodie. There will be 2 off it, on for the canister (bigger size than vac hoses) and the one for the map sensor. Next thing to check, if you have a auto zc, is the extra vacuum holes on the intake manifold. Make sure if they do not run to hoses the are capped off. Check all that and give us an update

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4drEF &raquo;</TD></TR><TR><TD CLASS="quote">It should read 5 volts (not Ohms) between the outer 2 pins on the 3 prong connector for the sensor. There is aslo a vaccum line that you need to pull a vaccum on to see if the voltage smoothly drop to 4.5 volts. Buy a Helms.</TD></TR></TABLE>
It should read 4.5 or 5 when at wot, and around .4 or .5 when closed.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DohcVtecCrx &raquo;</TD></TR><TR><TD CLASS="quote">Here is your zc helms http://www.acute.f9.co.uk/crx/...s.htm
You need to fix your dcodes. I am not usre, but I think the plugs for the tps and map might be interchangeable and might be switched. or maybe not hooked up right. The map is you main issue. It should be up on the firewall, squarish looking, and has a vacuum hose attach to the bottom. Make sure it is hooked up, wire waise and vacuum hose wise. The vacuum hose for it is the on ly vac hose coming off the throttle bodie. There will be 2 off it, on for the canister (bigger size than vac hoses) and the one for the map sensor. Next thing to check, if you have a auto zc, is the extra vacuum holes on the intake manifold. Make sure if they do not run to hoses the are capped off. Check all that and give us an update</TD></TR></TABLE>

There seems to be 3 vacuum lines that come off this thing on the firewall. One vacuum line comes out the top of a cylindrical object, that doesn't seem to have a place to connect so it's plugged, one comes out from the bottom that's connected to the TB, and 2 that goes into 1 via a tee that doesn't have a place to go either which is also plugged. The only code that is being thrown now is a "7" so TPS seems to be the issue. I'm going to adjust it but i need to get some torx bits to loosen the tps. It is an auto zc and those extra ports are capped off.