I just changed the valve stem seals on my '99 Montero Sport LTD. It has the 3.5L 6G74 SOHC engine. The engine ran great before I took it apart, except for the cloud of blue smoke after idling. EVerything seemed to go well, and it all went back together just fine. I triple checked things like ignition wire firing order and there are certainly no loose connectors or vacuum hoses. I took meticulous notes on disassembly, and followed guides that are posted here. I'm fairly competent mechanically, but I've never worked on a car with electronic ignition or fuel injection, so I'm a bit clueless about diagnostics at this point, and would really appreciate some basic pointers.

The engine turns over just fine. It just won't fire.

I did have the battery out. Is there an immobilizer or anything like that, that needs to be reset. I've only had the montero for a few weeks, and I don't yet have the radio code, so I guess I'll have to go to the dealer for that.

Thanks very much for your help, and sorry if this kinda thing has been covered here a lot. I'm searching archives right now

--Peter

 

So I plugged an old spark plug wire into one of the coils, and held the other end near the intake, while cranking the engine, to check for a spark. I found no spark. I then took the connector off the coil with the ignition on and checked the voltage. When I check the terminal on the right, I found no voltage, but the terminal on the left has full 12 V.

Any ideas?

 

OK, I figured it out. It was a dumb mistake, of course. I tested the signal at the coils and got no pulse when cranking the engine, so I went back from there. I tested the signal at the ignitor, and it was pulsing there. So I put that connector back on, and pressed it down much harder. Then it fired right up. Looks like I just didn't have it seated well. duh.

It drives very well now and the smoke from the tailpipe is gone! yay! Unfortunately, there is a CEL now, and the idle is wacky. It idles OK momentarily, and then surges. When I shift into drive, the rpms drop below 200 before picking up again. There also seems to be smoke in the engine compartment, mostly coming up from down around the cat. Hopefully that's just loose oil and solvents burning off. Looks like my valve covers are sealed well. I don't have an OBD reader, so I'll have it read tomorrow.

Thanks again to all of you who have written here in the past about valve seal replacements. I followed your advice and it wasn't that bad. I'll write up some comments of my own as soon as everything is back to normal.

--Peter