Cozmikk

I have a '97 DX (D16Y7) that threw a rod, so I swapped in a D16Z6. I'm currently trying to get it running right. Here are the details of what I have:


-P28 from a manual car (mine is manual)
-Intake that I believe is from an '89-ish CRX Si (says "PGM FI" on top, and that's what the previous owner pulled it from when he upgraded to a B18)
-Original OBD2 harness with jumper to the OBD1 ECU
-Swapped internals from my distributor to the one that came with the Z6, so it fits the head and is plug and play with my harness (Y7 distributor won't bolt up directly to a Z6)
-Y7 OBD2 injectors that are clean and have a good spray pattern (engine was previously running OBD0 injectors, I think), installed with fuel rail that was on the Z6 when I got it
-MAP sensor from my Z6, connected to a vacuum hose around the center of the intake plenum
-TPS shows ~0.75V across D1-D11 pins when closed; ~4.5V at WOT; no dead spots through the range of operation
-Adjustable FPR - appears to be a Z6 OEM FPR with the top removed and a different top installed to make it adjustable. Sounds a bit cobbled from my description, but it appears to be put together well and I don't see any reason it wouldn't be functional.
-Cam timing is correct - I verified this
-Spark at all four cylinders, as verified by timing light being triggered by each of the ignition wires
-At last check, ignition timing was advanced a few degrees, but it hasn't been idling well enough to fix this properly
-4 - 2 - 1 header with a catless exhaust (~2 3/8" dia, system, I believe)
-IAT sensor is plugged into CAI before the TB
-Z6 sounded healthy before it was pulled, and compression is good
-Grounds are properly installed, from what I can tell
-VTEC solenoid and oil pressure switch are installed correctly (soldered and heat shrink on connections) and pinned to the ECU plug
-Plugs are nearly new, NGK, and correct for the engine (I don't recall what part number offhand)
-Removed and cleaned IACV

Car was running very rich and had no bottom end. It was bogging really badly off the line to a point where it was basically not driveable. Plugs were black, with #1 being less black, and black exhaust sooting my bumper. Cleaned the injectors to address the inconsistency (pressurized carb cleaner from a can, popping them open with a battery), but I don't think they were a big issue because they came out of my Y7, which ran great. Spray pattern looked good when I was done.

I've verified no vacuum leaks with ether while the engine was running.

I verified that the fuel pump was supplying proper pressure but had to return the gauge before I figured out that the FPR was adjustable. Last night I backed off the adjustment to bypass more fuel to the tank at idle, and that seemed to help with the bogging, at least sitting in the garage, and it didn't smell like it was dumping as much gas in. (Buying a fuel pressure gauge to address this properly.)

Now I'm at a point where the engine starts, idles okay for about 10 seconds, then the speed picks up briefly and it dies.

Looking for what else I should be checking.

tony_2018

TPS .75 NO

Cozmikk

What do you mean? Are you saying that this is bad?

tony_2018

If you don't know what I mean than how did you know to check the TPS voltage?

egsleepercivic

Here you go
https://honda-tech.com/forums/tech-m...e-tps-2947986/

.48-.5 to 4.5 WOT

mk378

Put a stock fuel pressure regulator on. No reason to have an adjustable one here. The vacuum port needs to be connected to the intake. Note that if the FPR is blown it can dump gas through that vacuum line and cause very rich / flooding.

hondave36

is your jumper harness OBDIIA to OBDI or OBDIIB to OBDI? 96, 97 and 98 civics are OBDIIA, 99 and 00 civics are OBDIIB

Cozmikk

Thanks for the input.

My mistake on the TPS voltage at closed throttle; since it's an OBD0 intake manifold, it has a dashpot on the TB, and I forgot to account for the fact that with the engine off (no vacuum), it holds the throttle open slightly. I'm down to 0.41V, which is still not quite 0.5 specified in the manual (or the 0.48 in the link above), but is within the range I've seen on other threads / forums of about +/- 0.1, and it seems it shouldn't be enough for the engine to run this badly.

I was going to swap over the FPR from my Y7 but the hole pattern is different, so I put the adjustable FPR back on. After adjusting as noted above, I was able to get it to run a little better but it only got me to where I am now.

Jumper harness is OBD2A to OBD1.

Digging around more, I see the OBD0 intake / TB setup, in addition to the dashpot, has an IACV and no FITV. The manual for the Z6 says EACV and fast idle valve. Is this setup substantially different than the IACV on the OBD0 manifold, to the extent that it shouldn't run worth anything? If needed, I can round up an intake setup from a Z6, but I'd really like to not do that, since I live in an area where there are basically no junkyards (minimum one hour drive each way to get to a junkyard that has anything I might need), and as interchangeable as the Honda parts seem to be, I'd like to think what I have should work.