My 95 is running rough and dropping a right bank lean code. Fuel pressure reading is only 37 psi so I am thinking the fuel filter needs replaced. Not sure about the code though. Any experience from members?

Tom

just the one bank?

Yes, just the one bank. I had a similar problem last year and changed the O2 sensors and cleared up the problem. Not sure what fuel pressure was back then, can't remember but did not think there was a problem there. Fuel pressure is low now, but can't justify the lean condition only on one side. Just started running rough a couple of weeks ago. This is a daily driver with 70K miles, and stock condition.

Note that the 64 code will come and go while driving. Runs pretty smooth in open loop.

Troubleshooting:

37 psi? Static pressure? Or dynamic? What's leakdown times???

37 psi at idle and will spike up if I rev the engine but returns to 37 psi at any rpm. I will change the filter and see what happens. I was just trying to see if anyone could justify the single bank lean code. Seems to be it would be lean on both sides with low fuel pressure.

Matatk thanks for the pictures of the FSM. I do have the set and have been using them. I do not have scanner capability but have an ALDL cable ordered. Just hoping it is not the fuel pump or pressure reg. If fuel pressure is not the problem, will do some scans. Work keeps getting in the way of the troubleshooting process!

Google 'Static Dynamic Fuel Pressure Leakdown', and I KNOW that as many times I've posted this, it will come up...

You NEED TO KNOW Static motor off pressure, and leakdown time. THat's why I posted that.

And have a pencil handy.

I'll explain maybe how too low fuel pressure could be too MUCH fuel, and a LEAN reading, after static readings and L/D times...

I would suspect the pump or regulator more than the filter, although changing the filter is good maintenance.

It can be a bad sensor - an easy and free check is to swap sensors on each side and see if the code moves.

It can also be clogged injectors. You can check the spray by removing the rail and letting it spray into a Dixie cup. You can also swap injectors to the other side and see if the code moves.

New fuel filter installed. Static pressure at 42 psi with no change over 30 minute period.
Scanner shows right bank O2 sensor voltage at 0.04 to 0.06 at all times. Thinking this O2 sensor failed.

Sounds like the O2, but check the wiring as well.

You had 0 PSI leakdown after :30? First time ever heard of that.

O2 Sensor should swing lots more than that. Swap rt + lft sensors and re-check...

Quote:

Picked up a new O2 from O'Reileys yesterday and jacked up the car and put it on stands. Changed out the O2 sensor with the new one and back to normal.

Schrade, the other day I put the fuel pressure guage on and turned on the key to start the fuel pump. Pressure went to 42 and I turned off the key and let it sit.

Pressure stayed at 42 for the 30 minutes I left it.

O'Reileys is going to refund the cost of the O2 sensor since it is still within the 1 year warranty.

Thanks all for the help.

No leakdown is a PRIME indicator of overall general condition of the mill. VERY GOOD.....................