pasadena_commut

My wife's 1999 Accord EX (California model if there was one that year, valve cover says "ULEV") occasionally has a near stall or stall. Yesterday we drove it on surface streets all the way across LA, with the A/C on part of the time, with no problems at all during that drive. However, this morning it was fine for the first 5 minutes, awful for the next 5 minutes - almost stalling whenever the car slowed down, and when I put it in park. Then it got better and drove normally for the rest of the day. It could be the IAC, EGR, or several others of the usual suspects, it will take time to sort it out since it "does not fail reliably". There seems to be a slight tendency for it to happen after the A/C is used, but that could be just my imagination.

In any case, a visual inspection turned up only one odd thing, the IAT on the driver's side of the intake manifold was covered with what looked like soot. Not just around the nut, but also all over the outside of the connectors. This is really peculiar because the rest of the engine compartment is remarkably clean. The car has less than 70K miles on it and has never had any problems of the oily sort in the engine compartment.

What would cause the IAT to get like that? I can see how a small vacuum leak there might pull in filth on one spot or another, but cannot imagine how it would lead to the outside of the electrical connectors becoming so dirty. It probably isn't the cause of the stalling, but I'm thinking of changing the part anyway, to see if the new one stays clean.

holmesnmanny

Possibly a bad pcv valve

pasadena_commut

Here are two pictures of the IAT. Sorry, neither one is very good, my camera didn't like focusing past all the tubes in the foreground. The second one is a little out of focus on the IAT, but in it you can see the small clean part of the bronze nut, with something that looks like oily black soot over the top of the nut and around the entire connector. But nothing else nearby is at all dirty (note the two shiny nuts just below the IAT), and you can see that the rest of the engine compartment is very clean. I looked up and down and around that area and there just didn't seem to be any nearby source for this black stuff, so either it is coming out of the intake or the IAT is somehow acting as a soot magnet. Most of the dark area on the side of the intake near the IAT is not dirty, that is a shadow.

holmesnmanny

http://www.hondapartscheap.com/auto-...ttle-body-scat

pick up another part number 14 and call it a day

Use some carb cleaner and clean the sensor off. Its going to be dirty inside.

pasadena_commut

Thanks for the link. Well, that might have worked, but in the end I replaced the whole thing.

When I took the connector off and pulled the IAT out the sensor was oily everywhere, not just around the outside. The inside of the sensor was oily around the contacts, and the electrical connector it plugs into was oily in the same places. (It took quite a few shots of contact cleaner to wash the oil out of the plug.) Also the O ring was intact and not visibly smashed. The part of the sensor that pokes into the intake was baked on brown looking, but not wet. Oddly the threads going into the intake were oily for the first two turns and completely clean further in. We have all the service records for this car, and that part had never been replaced. The car has never burned much oil, less than a quart every 5000 miles, so it seems a bit odd to me that that much oil would accumulate in this one part. A couple of shots of throttle body cleaner washed most of the oil out of the inside (contact part) of the sensor but didn't make much of a difference on the baked on crud.

Car runs the same with the new one as the old one - so the old one must have still been working mostly OK. Hopefully this fixes the intermittant stalls, but it is too soon to say.

By the way, how much torque should one apply when reinstalling this part? For now it is just hand tightened to a bit more than snug.

Edit: I used a deep 19mm socket to remove/replace this part. There isn't a lot of clearance between the various lines running nearby, leaving just enough "swing" for 1 click on my ratchet.