93 Camry V6 - distributor problem?

[hydroman]

Greetings. My Camry (107K miles) started running bad last week, so I adjusted the timing - it was so far off that you couldnt even see the mark. It then ran great for a few days, then started running bad again. Checked the timing, was off again, adjusted it, ran great for a few days, now it is running bad again, although intermittently. I will check timing after work, but I strongly suspect I will find that the timing has again drifted. What are possible reasons for the timing drifting? Is it a bad distributor? How do I check before shelling out cash for the part? Thanks in advance for any advice.

[davemac2]

I can't understand how your timing could change from day-to-day like that unless the distributor is moving or your timing belt is jumping all over the place. Timing belt idler? If you have never changed the timing belt, do it asap. As well, change your plugs and wires if it has not been done. It is due at 100K.

dave mc

[hydroman]

Thanks Dave. The timing belt was changed at 59K miles about 4 years ago/ 48K miles ago, so I was thinking the belt doesnt need to be changed quite yet. The plugs and wires were just changed about a year and a half ago. What/ where is the timing belt idler? Do you mean the tensioner? Or is the idler one of the pulleys that the belt goes around?

[davemac2]

sorry, i meant the tensioner. I think on this engine, it's a plunger type tensioner.

Are you sure the distributor is not moving around? Maybe put an alignment mark on it and the head the next time you adjust the timing. Otherwise, check that the pickup coils, magnetic pickup wheel and the rotor are all secured in the distributor.

As well, there is a vacuum advance mechanism I believe on this distributor. Make sure that is not sticking since if it is sticking when you make an adjustment, it will screw everything up.

dave mc

[BMR]

I doubt it's a problem with the timing belt jumping a few teeth. While that would shift the ignition timing because the distributor is driven via one of the cams, resetting the ignition timing wouldn't completely get it running right, because the valve timing would still be off.

Ignition advance is done electronically; no vacuum advance.

When you checked the timing, did you put a jumper across terminals E1 & TE1 of the diagnostics plug? You won't get an accurate reading if you didn't.

So either the distributor is moving on you, or it's defective, or the ECU that controls timing advance is going haywire. A possible problem with the distributor, although it's just a guess; In the picture in my Haynes manual, it appears the distributor shaft coupler that engages with the camshaft is held on with a pin. Perhaps that has sheared and it's allowing the shaft to rotate and get out of time? You'd have to remove the distributor to check that out.

[new echo owner]

The pin for the distributor drive is a solid pin, it would take something very drastic for that to shear, if it is it wouldn't start at all. I would be more incline to believe that he didn't jump the terminals when he check the time.

It would help if the OP would give more information about his drivability problem than what he had done to the car. Give us some symptoms maybe we can come up with some suggestions on what to check.

N.E.O.

[DFBonnett]

OP,
You might want to pull the cap and inspect the condition of the contacts and the rotor.