Removed the heads and had the valves and seats worked. Got everything back on and in place without much trouble...until it came to the timing adjustment. I´ve actually posted about this before but have a different line of question now. I inserted the distributor sprocket so that the correct timing would fall withing the range of possible distributor adjustment. I get the time adjusted correctly (i.e. the marks on the drive pulley and block) and everything runs well enough but within a few seconds the RPMs drop and the engine lopes as though the timing were way off. I adjust to the distributor to one extreme and it gets a bit better, but no where near where it should be. Another thing is that even though the engine might sound a bit better adjusted way over, the same pulley/block marks are way off what they should be.

Naturally, I pulled the distributor and moved the sprocket over what I´m near 100% sure is one tooth relative to the cam shaft. I can get a much better adjustment judging just by the sound of the engine. But again the distributor is at one extreme of it´s adjustment range AND the pulley/block marks are easily 10-15º off of what they should be.

So my questions are (1) Is it even possible for the engine to run being that far out of adjustment? I´ve been driving it around like that and it runs at best ok while really burning through the gas. (2) What might be another explanation for the engine suddenly dropping RPMs and loping when I originally had it adjusted - air flow, EGR, computer? I have the feeling the original distributor/cam setting I had was correct but that there was another element at play.

Any advice or experience you can share would sure be appreciated!

 

1. Buy a timing light and stop trying to guess what the ignition timing is.

2. Could be a number of other things. Idle set too low?

3. Have you checked for codes? Or do you just like stabbing in the dark at things better?

 

You said you removed the head"S". So I am guessing 3.0 or 3.4? Might put what motor you are working on and get some more responses. A timing light would tell you alot of what could be going on.

Just noticed your avatar of 93, which says 3.0 to me, so maybe others might have a some suggestions. I dont know the 3.0 so cant say.

 

It´s a 93 with a 3.0. I have a timing light and that´s exactly how I know that the timing is so far advanced. When I said that I adjusted it well originally I was referring to using the timing light to adjust it to about 5º, but that´s when the RPMs drop off and it acts like it were way off on the timing adjustment. It feels like a real puzzle.

 

5 is to little. Shoot for 10 jumpered set the hot idle at 800 then check timing jumped again.

 

5° BTDC? On a 3VZ-E? You're kidding me right? 10° BTDC is the factory setting. A lot of folks(including me) run theirs more advanced than that to boost performance.

And he wonders why it runs like crap.

NOTHING you could POSSIBLY do would make it run good with the base timing that retarded.

 

Are you SURE you got the timing belt aligned for BOTH cams correctly? It's easy to be off a tooth, with 1 tooth of SPARE belt between the two cam pulleys.

There are TONS of write-ups about this on here.

 

Double checked the timing with a light. At 800 RPMs with the engine warm, the timing mark on the damper goes off the scale. I´d say it´s at 20º or more!

TNRabbit, It took me many attempts putting the timing belt on. The issue was with tensioning. I would get the belt on and everything lined up correctly, I mean the mark on the crank and the marks on the two camshaft timing sprockets. When it came time to rotate the crankshaft through two complete revolutions that things would go wrong. The two camshaft marks would come back around and match up with their respective marks on the rear timing belt cover, BUT the mark on the crankshaft would not come back to TDC or 0º. It would consistently be 5º off, which I would estimate to be about one tooth on the belt. Nonetheless, that extra tooth isn´t between the cam timing sprockets. What am I missing to get those lined up? I´ve followed Haynes, the factory manual, and many posts here at YotaTech to the letter, but without that final alignment being correct.

 

Wrong size timing belt.

There's 2 sizes for this engine. 1 for 88-92, 1 for 93-95.

 

Autozone belt, I assume that they would get the right part, since they ask you the year of the vehicle. I didn´t compare the new and old belts before installing the new one.

I see on the Autozone site there are two different part numbers depending on the year you select. But it seems strange that they would get it wrong since they asked me the year of the vehicle.

Something to check I guess..

Thanks!!!

 

i'd re-check your cam timing. when you are installing your belt, you're most likely leaving a little slack between the water pump and left cam causing it to be off a tooth. even at 5 degrees, the idle should be smooth, a little low but still smooth.

 

Thanks for the reply oldblue...I like the name!

When positioning the timing belt initially, there´s no way to be off a tooth on that side, INITIALLY, since the belt itself has marks. That said, when I give the crankshaft two turns there does seem to be slack on that side.

The engine idles okay, not great. I´ve got the idle adjust completely closed and that barely brings it to 750 RPM. The exhaust smells noxious. So I think if it´s not the timing being so far off, there should be another issue, which was my original question - if I bring the distributor back over one tooth is there something else I should check to bring the idle back up (beside the idle adjuster, which I´ve played with)

 

ignore those damn marks on the belt!!! i see new guys struggle with this a lot in the shop. line your cam and crank marks up, install the belt keeping any slack out, the only slack you should have when its installed is between the left cam and tensioner. pry the tensioner pulley over a little with a screwdriver to hold some tension and roll the engine over twice and check your marks. if they don't line up, re-do. if all is well, then yank the pin out of the tensioner and you're good to go.