Tumble or miss after rebuild

[quailchaser]

I'm having issues after I rebuilt my 98 Montero 3.5L SOHC. I did a complete rebuild at 200,000 miles. It turns out the only major issues were one bad exhaust valve and worn cams. I had the heads done and had the cams ground. I went ahead and replaced all the bearings, honed and reringed the cylinders, etc. I put everything back together and it is running like it is missing or something. I'm stumped. I've replaced the fuel filter, checked for spark, checked compression and timing, checked for air and vacuum leaks, get no codes.

It occurs at idle and on acceleration. The exhaust sounds like a put-put-put and the engine shakes both at idle and speed. Any ideas?

 

[EyeInTheSky]

Were these symptoms present before the rebuild?

You said you checked air and vacuum leaks and saw no codes... did you actually have a full leak down test performed?

 

[nwoods]

Does it sound like a misfire? did you replace the spark plug wires? LOL (sorry, inside joke because that just happened to me)

 

[quailchaser]

No symptoms similar before rebuild. Before the only symptom was smoke. No smoke now. New plug wires installed. I have a leak down test kit. I'll try that next. My other thought may be a clogged injector(s). I'm just not sure how to diagnose that. My last idea is that maybe the cams were machined improperly. Also not sure how to check that. Would it meet factory specs after a grind?

 

[EyeInTheSky]

A quick YouTube video would help so we could hear the sound.

 

[RyanY]

Doing a compression test will tell you whether you've got a mechanical issue or just something with the fuel or ignition.

 

[quailchaser]

Compression is good. About 170psi (I am at 3700 feet) with no more than 5 psi between cylinders. I'll try the youtube thing for help. I looked at some videos and it sounds like a misfire. I'm not sure why it isn't throwing a code. Could an injector seal leak cause it without a code? If so, how can you test them on this engine? That stuff seems impossible to get to. I tried using propane around what I could reach, but no idle changes.

 

[Salonika]

Surprised you aren't getting any codes if it is that bad. How many miles / how much time have you put on it so far? Mine ran rough for several drive cycles right after my first start following my rebuild, enough to make me nervous, but it worked the bugs out on its own after a little driving.

 

[quailchaser]

Leak down test showed good on every cylinder. It is a cheap harbor freight gauge, but all cylinders were really close to each other. The only thing somewhat unusual about the plugs was the Number 4 (front driver side) insulator was slightly brown, where the others were still white. No signs of fouling or lean burn.

I have put very few miles on it due to a valve cover leak. I think I got it with some permatex. It did throw an egr code (PO400, I think) early on, but it hasn't re-appeared after I cleared it. The timing was also off when that happened. I rechecked it and straightened that out.

As soon as I put everything back together, I'll video it so you guys can here it.