gte718p

I just picked up a new toy. Its a 87 4runner with 245k miles. Everything is in fairly good shape. It has a new head, time chain, water pump and all that stuff.

Being in CA I had to get the thing smogged. I failed miserably. Not even in the ball park. Turns out it was not to hard to fix. I basically had to retard the timing back to stock.

Before I was running a +27 degrees. That seems a little high for an engine that is supposed to be at +5. When its set to +5 the truck runs like crap. It idles badly and it has no power. I've had a couple of different suggestion on what could be wrong from the different mechanics/smog techs who have worked on it. One was that the timing chain may have slipped a tooth and one was that the throttle position sensor/mass air flow sensor may be not be calibrated correctly. It also seems possible that the distributor was stabbed incorrectly. What seems most likely and how should I go about trouble shooting this.

80W90

make sure the engine is at TDC, on the power stroke, realign the distributor.

does it have codes?

theres no calibration for the AFM. only a wheel inside to lean or richen the air fuel mixture. if the cover looks like its never been off, then its not going to need adjustment. if it has, it will be trial and error to get it back to stock. just mark it where it is now, so you know how far its turned.

is the egr valve stuck open?

are the valves adjusted properly?

there is a calibration procedure for the TPS. use the search function to find it.

80W90

here is a post i just made on diagnosing the egr valve

https://www.yotatech.com/50730442-post8.html

Flash319

Are you sure that the computer is going into base timing when you jump the diagnostic terminals to set the timing? Sound to me like your TPS idle circuit is not closing at idle thus your timing is not going to base when you go to set it. This will cause bad emissions because A. your timing is way, way retarded and B. the computer does not know when you are in idle mode thus your idle e-test will be very bad.

When you jump the TE1 and E1 terminals the engine iidle should drop and your timing should go to base (5 degrees). Then when you pull the jumper is should jump back up to in the 20's advaced. If when you put the jumper in and the idle does not change then you are not in base timing, so if you start retarding to get to 5 degrees you are actually going way past that.