DumpdEJ6

Hey Honda-Techers, I have a conundrum for ya!

I just picked up a 1989 CRX DX with a DOHC ZC engine. It had a few spots of rust, I'm sure you can guess where...but overall it was in good shape, minus a headgasket failure that I had to fix. <sarcasm> And some sweet, uber rare chrome altezza taillights, chrome projector headlights, and an exhaust muffler so rare I bet no one has even heard of it: an Aero Turbine Fartcan! </sarcasm> lol

Anyway, the guy told me that before the headgasket failed, it had a misfire and didn't like idling...I found out after fixing the headgasket that it would idle, but barely, and ran very rich. And after adjusting the TPS I found he had it set to 2 volts at idle to mask the problem, what a dipshit. That explains how hard it was to drive, you barely blipped the throttle and it acted like you were at WOT...which of course to the ECU, you were!

So after adjusting that it would just die at idle if you didn't constantly give it gas, after adjusting the idle screw throughout its full range it still does the same thing.

I'm pretty broke at the moment, so what checks can I do to rule out bad parts? I'm getting fuel, I'm getting spark, and the timing is dead on, I've checked it several times. Anyone have an idea or something I've missed?

puertoricanboy90

Unplug your IACV solenoid at the back of the manifold and see if the idling issue remains the same or worsens. Also check for gunk around the fuel injector's body (all 4 of them) to see if they might be leaking (there will be a film and soot contamination if the injectors are leaking where the dirt is sticking to the fuel) and causing a severe loss of fuel which would cause poor idling.

DumpdEJ6

Ok I tried unplugging the IACV solenoid and it made no difference. Here's a video I uploaded, hopefully you can hear me. Basically what it does is it starts up and immediately dies unless I give it gas, most of the time. Every once in a while it starts up and idles extremely low, maybe around 200rpm, basically sounds like a Harley, just barely staying running.

If I give it gas immediately before it dies, it will rev up and anything above 2000rpm it will stay running, but 2000rpm or less and it runs for about 10 seconds and then starts stumbling and dies.

http://www.youtube.com/watch?v=bFrWv-DsghM

DumpdEJ6

Oh and I know the injectors aren't leaking, not only did I check them just now just to make sure, but everything is completely cleaned of carbon and any gunk buildup. I thoroughly cleaned everything as I was changing the headgasket, piston tops, combustion chambers, valves, injectors, the whole head is spotless.

I'm just confused as to how its running so rich, and dying at the same time...

JDM*JUNKY*EF9

get rid of the dohc zc,,lol naw check the screw on the rotor inside the the dizzy maybe it can be bad dizzy or try diff ecu

DumpdEJ6

Hey now, I like the ZC! lol I wouldn't trade it for the B16A in my hatch, I actually have power before 5400rpm with the ZC, as well as being able to drive it on the highway without it running over 5000rpm in 5th gear just keeping up with traffic.

It came with a PR4 ECU and I changed that, hoping that was the cause of it running rich. I tried a PM6 which ran it as well, but didn't get rid of the problem, so a buddy had the PM7, which is the best ECU for the DOHC ZC and thats what I have in there now.

The screw is fine

JDM*JUNKY*EF9

lol true i wouldntgo b16 either ....damn maybe main relay u said u checked tps right? injectors not leaking?

DumpdEJ6

Main relay wouldn't allow it to start and run, correct? I adjusted the TPS and checked it with a multimeter, its working perfectly. No leaks anywhere.

Compression is 1-180 2-180 3-165 4-175. I know cylinder 3 is a bit low, but nothing that would cause this...

4drEF

How is your mechanical and ignition timings?

DumpdEJ6

Mechanical timing is spot on. I haven't checked ignition timing except for rotating the dizzy to where it idled best. I know, I know, thats a ghetto timing job, but the previous owner also scratched a mark on the housing and the camshaft holder that lined up perfectly with it idling well. Before I adjusted the TPS correctly, anyway.

DumpdEJ6

FIXED! HAHA MOTHERFRUCKERS! lol the previous owner had the vacuum lines wired up slightly wrong. I figured instead of just being confused as sh*t, I'd use that handy-dandy LED on the ECU to tell me what was wrong. Also, I slapped myself in the face for not checking it earlier.

It was a code 5, MAP sensor. So I'm looking around online, googling my little heart out trying to figure out how the damn vacuum lines go, because I have one that comes out of a T fitting that just goes nowhere. Seems wrong, right? Guess what that line connects? Thats right, the MAP sensor and the fitting on the TB. So me being the diagnostic genius I am, I pulled the extra T fitting off and just ran it straight to the TB.

It started up and did the Honda wandering idle thing they're known for, I blip the throttle and it goes away and idles right at 800RPM. Took it for a drive and it it drives perfect!

Thanks for helping me out HT, hopefully this helps some other dumb sucker with vacuum line problems. In the picture below, the T fitting coming from the MAP sensor that is plugged (why make it a T fitting then?) is the one that was the culprit.

Charith Wattage

hi im having the same problem here but my vacuum hoses are in the correct order. can you please explain how to check the fault codes? i cant find this connector im suppose to bridge? i have a 1989 honda integra zc

mr.jdmcrxzc

If your cel comes on and check the blinks on your ecu 1 long blink counts as 10 short blinks are 1