Another Emissions Adventure

[cutsham]

Failed on high CO and high NOx in an '89 325i...

I also have a small exhaust leak by the manifold I think. Not sure if it would cause these numbers though. I also feel like I don't get the best gas mileage.

[oldmann]

No magic bullet for this. Search "failed emissions" probably 3-4 hours of material to read.

Your #'s aren't terrible, do a stomp test, for codes. Go from there.

[jlevie]

I suspect that this will be a case of bad catalytic converters, but before I changed those I'd want to make sure that the engine was running as well as possible. That would mean:

A smoke test and repairs as indicated.
Fuel rail pressure test.
A new O2 sensor unless the one on the car has well below 100k on it.
New ignition wires, distribution, and fresh set of NGK ZGR5A plugs.
Valve adjustment.
Verification that the engine running at normal temperature (80C).
Verification of the ECT sensor data (at the DME connector).
Rebuilt and flow testing of the injectors.

That may not solve the problem and the catalytic converters will have to be replaced, but the engine will run better and get better mileage.

[cutsham]

I suspect that this will be a case of bad catalytic converters, but before I changed those I'd want to make sure that the engine was running as well as possible. That would mean:

A smoke test and repairs as indicated.
Fuel rail pressure test.
A new O2 sensor unless the one on the car has well below 100k on it.
New ignition wires, distribution, and fresh set of NGK ZGR5A plugs.
Valve adjustment.
Verification that the engine running at normal temperature (80C).
Verification of the ECT sensor data (at the DME connector).
Rebuilt and flow testing of the injectors.

That may not solve the problem and the catalytic converters will have to be replaced, but the engine will run better and get better mileage.

Thanks for this. And all my research said cats but I'd rather start with the small stuff.

The other day I pulled the fuel rail and jumped the pump relay to check for any drips and didn't see anything. (although I was missing a pintle cap on one injector)

I'm pretty sure the o2 is newer, but I still plan on checking the voltage. The valves were adjusted a few hundred miles ago, and the ignition wires are newer as well. Between this, and the bentley list, I have plenty to keep me busy...haha

EDIT: I also sometimes have a problem starting the engine when it's warm every now and then. Always starts, but takes a few seconds.

[jlevie]

Thanks for this. And all my research said cats but I'd rather start with the small stuff.

The other day I pulled the fuel rail and jumped the pump relay to check for any drips and didn't see anything. (although I was missing a pintle cap on one injector)

You still need to check rail fuel pressure. And just because the injectors don't drip doesn't mean they are delivering fuel correctly.

I'm pretty sure the o2 is newer, but I still plan on checking the voltage.

Pretty sure doesn't count here. If you don't have proof, replace the sensor. A voltage check only tells you that the sensor is doing something.

EDIT: I also sometimes have a problem starting the engine when it's warm every now and then. Always starts, but takes a few seconds.

That could be any of a number of things, but I'll bet on it going away when everything in the engine management system is running right.