I've had intermittent difficult start, failure to start, barely running, missing on my 97 Acura 2.5TL. Car is driven by my son out of town, which makes diagnosis/repair tedious. At times the car would run fine for extended periods.

First time problem appeared there was a code set for mass air flow sensor. Checked and it appeared to be faulty. Got a used sensor and replaced. Problem was fixed for a week and then returned.

I checked fuel pressure and it was fine when car was not starting. So, I'm thinking it's got to be loss of spark. The ignitor/coil is a combined unit. No time for further diagnosis, so I again purchased a used part and replaced, or rather my son replaced as I was on vacation. Car again ran fine for perhaps a week and we thought problem was fixed. NO, car failed (very poor running) again and my son barely made it home.

After this I decided I had enough long distance diagnosis/repair and asked my son to tow the car home (rental truck and dolly) where I could work on it at my convenience. We have a spare vehicle for him to drive.

I got to work on the car first time yesterday. I first drove while monitoring w/ my OBD2 scanner (Obdscan from Harrison Engineering). Car ran fine fo 30 mins. Only codes present were P0450 (Evap Emissions control system pressure sensor fault) and P0304 (miss on cylinder 4). P0450 is strange as it is not mentioned at all in shop manual, but car does have an evap emission control system pressure sensor. Manual has similar codes P0452 and P0453 for electrical faults in evap emissions control system pressure sensor circuit.

I tried spraying wires and distributor w/ water mist to see if there was a short somewhere. Nothing.

I decided to remove the distributor and examine as this was last component of ignition. The 2.5TL distributor is nothing but a rotary switch that distributes spark to each plug. It has no internal electrical components. Since car ran fine most of the time, I was not too optimistic I would find anything. Distributor is a real PIA to remove, requiring removal of battery for access. I also found the two bolts very tight. An offset 12mm closed end wrench worked well to grip and break the bolts loose. Inadequate room for a ratchet and socket.

Upon removal the problem quickly became apparent. Copious amounts of oil ran out of drain port. I removed distributor cap and found the entire cavity flooded w/ oil. Apparently, engine will work till a carbon arc path is established through the oil to ground, then it either runs very bad or won't run at all. Amazing it runs as well as it does. I've ordered a replacement distributor (used again $50). A new OEM unit is almost $500!

The oil is entering the distributor through the shaft seal. I've overhauled my 94 Accord EX distributor and replaced this shaft seal. I looked at the 2.5TL arrangement and it appears similar (same shaft size, bearing, and seal) and should be repairable, however the distributor shaft is not easily removed. the shaft end inside the distributor is "staked" to the distributor rotor attachment bracket.

The distributor key that engages the camshaft is attached to the other shaft end w/ a pin that is removable. However, the distributor base extension prevents the pin from being extracted. I've developed a repair procedure that gets around this problem, but that's another post, after I try the procedure. The used distributor is insurance in case my repair plan goes awry.

If you have a 1st gen 2.5TL, you may want to check your distributor for leaking shaft seal and avoid getting stuck somewhere. Ultimately this oil drains out of distributor housing, so this may be a source of oil leakage onto the ground for some 2.5TL's.

Regards