Timing/Idle/Emissions, etc.

M

mjquillici

New member
Hello,

I live in California and it's time for my 4runner to pass emissions. In preparation, I checked the timing to confirm that everything was set as it should be. I jumped the connectors (check engine light flashing) and noticed that my timing was way advanced (maybe 20 degrees BTDC). So, I adjusted the timing to 10 degrees BTDC. Now, it runns terribly (even less power). I have checked the timiming with and without the connectors jumped, and it seems to have not affect on the timing. Additionally, my 4runner has never really idled. When fully warmed up, it's always been at about 1000 rpms.

Is it possible that the throttle position sensor isn't properly adjusted and the idle circuit isn't acutally engaging? I am thinking if the ECU doesn't realize that the engine is idling, then jumping the connectors would have no effect, and I may have retarded the timing to close to zero.

What are your thoughts? Please help! Emissions were due in April!

Thanks!
 
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I hate smog time! Just got my truck to pass last month, stupid reasons for it to fail, like a bad ground to the block and a faulty brand new Denso o2 sensor had me failing with crazy-high numbers!

As for yours, I'd go through all the regular stuff first:

oil and filter change
air filter change
new plugs
new cap/rotor

Once all that is done, then go through and check the TPS setting. Its touchy to get it right, and is much easier if you're able to unbolt the whole throttle body and throw it on a bench, but its not impossible to do on the vehicle. Personally, I think it takes the same amount of time to pull it and do it on the bench vs. leaving it on the engine and fiddling around with the multimeter while turning the TPS to dial it in, but that's just me.

You should definitely notice a drop in idle when you short the diag connector for timing, and the timing should retard a bit when its shorted. If you don't see a change in that, then either the diag connector has a wiring issue or your tps is off.

You'll need to have the tps set properly before you set timing, and I'd get the idle close to 750rpm before timing it. You won't be able to pass with the idle above 1,000rpm IIRC (forget what Cali requires, but they were pretty specific on everything, including checking the gas cap for pressure/vacuum!).

There's a ton of writeups on setting the throttle body properly, I'd do that first before you go any further with the truck, aside from the list of things to change I listed above.
 
Picked up a new TPS at AutoZone. First, they tried to sell me an original (used) Denso, which was clearly returned by someone trying to scam (successfully) the system. Went to a different store and purchased a new one. However, there is no continuity or resistance across any of the terminals regardless of position. Headed to a third store tonight.

Making me crazy. . .
 
Finally got it working again. Ended up going to the dealer and buying a factory part. The aftermarket version from AutoZone did not do the trick. After getting it back together, I set the timing, and took it in for Emissions testing, which it passed with flying colors. Glad that's done!
 
I have a 22re but I literally just did the TPS today. I got one from oreillys here. Expensive part but it did the trick.

I followed those instructions as well. From what I gather the main things you need to check is the resistance between IDL and E2 when you have the feeler gauge in place.
 
diponyou said:
I have a 22re but I literally just did the TPS today. I got one from oreillys here. Expensive part but it did the trick.

I followed those instructions as well. From what I gather the main things you need to check is the resistance between IDL and E2 when you have the feeler gauge in place.
Click to expand...

That makes sense. The problem that I had with the AutoZone part was that the wiring harness would not snap together, so it made intermittent contact. It sounds like O'Riley sells a better aftermarket part.

I'm just stoked to have it running again and for passing smog. I was headed out on a trip and was nervous about leaving without having the registration current.
 
Not sure how I missed this thread until just now!

Glad to hear you got it sorted! That site on setting the TPS is the exact one I've been using for years! I printed it and threw it in my binder so I don't have to remember where it is on the pc. With a supra and a pick up, I have used that guide on many, MANY occasions!

Its amazing just how touchy the TPS is when setting it, eh?
 
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