06-14-2010, 10:16 PM
Join Date: Mar 2007
Location: Snohomish, WA
What I Drive: 88 5-speed XR4TI
FF Reputation: 180
Buy-Sell-Trade Rating: (6
I seem to post a lot of my ecu and electrical problems here not relating to the Focus. lol oh well.
I have a 1.5 liter 89 Honda civic that I bought as a daily driver. Its the base version with the 4 speed manual and the D15B1. One of the dual point injected models.
Anyway. Did a timing belt and full tune up on it. The thing is an absolute dog because it is running so rich. I took it to work and hooked it up to the 4 gas analyzer and HC is up around 2000PPM at idle and CO is around 9%. Ridiculous. I do a power balance test to find very weak spark on all cylinders. Pull the distributor cap to find the main post on the secondary circuit of the coil completely destroyed. So I replace the coil. Power seems up a bit but its still running VERY rich. So rich in fact that the exhaust at the tailpipe isn't even hot from being so wet inside...
The O2 sensor is new so I backprobe it at the connector and it reads a constant 1.06 volts. Basically saying "oh God make it stop im drowning!!!" So we know its working. Fuel pressure is where it outta be with and without the pressure regulator plugged into vacuum. No hole in the regulator diaphram. If the pressure tester is left on the system after you shut the motor off the system holds pressure so I know the injectors aren't mechanically stuck open.
ECT resistance is where it should be when fully warmed up at about 250 Ohms. MAP sensor checks out fine.
So I end up backprobing the main injector with the lab scope and injector pulse width at idle is about 2.5ms when it should be down around 1.25. So something is telling the injector to stay on way longer than it should even with the O2 telling it to pull as much fuel as possible. At this point I am stuck now going to the ECU itself and backprobing each pin and consulting a pinout chart as to what each pin is and what it should be putting out or recieving trying to find perhaps a bad wire, ground or if everything checks out a bad ECU. I dunno.
I am quite frustrated. Anyone have any suggestions as to what else to check out?