'94 4Runner -ECM controlled timing (3L V6)

Hi;
1994 Toyota 4Runner.
I have some concern that the timing under control of the ECM is not
working, or not
working as it should.

For instance, if, after setting the timeing to 8 degrees using the jumper,
I then remove the jumper, the timing should read 10 degrees at 800rpm,
which it does.

I believe that you should then be able to rotate the distributor away from
its correct setting 10-20 degrees and have the timing hold correctly.
After all, is that not the point of ECM control.

I remember my brother asking how he could set the timing on his Audii. He
said he could rotate the distributor cap 180 degrees and not affect the
timing. Apparently he did not know how to do the equivelant of using the
jumper as Toyota does, in order to disable ECM control.
The reason I'm even looking at this question, is this.

If I set timing by the book, I pass Californica Dynamic Smog testing very
nicely... lots of margin on all tests, better than "average".
However my power and mileage are hurt significantly with this setting..
something like 11mpg. If I advance the timing to 20 degrees, my mileage
jumps to 15mpg, and power is very good.

Advancing the ignition leans the engine, which means it runs hot, I
believe, although water temperature stays steady at normal under all
running conditions, no sign of overheating, knocking or any other symptom.
But given the history of HG problems, I do not want to leave this problem
unsolved.

I've had the truck for less than a month, so little personal history with
it, although I've a long history with the 22RE engine on my SR5, knowledge
on the V6 is limited to a lot of reading of this board.

The only troubleshooting I've done so far is to verifty the TPS function.

Any thoughts would be welcome.
Richard Harper
Morgan Hill, CA

rdhrdh wrote:[color=blue]
> Hi;
> 1994 Toyota 4Runner.
> I have some concern that the timing under control of the ECM is not
> working, or not
> working as it should.
>
> For instance, if, after setting the timeing to 8 degrees using the jumper,
> I then remove the jumper, the timing should read 10 degrees at 800rpm,
> which it does.
>
> I believe that you should then be able to rotate the distributor away from
> its correct setting 10-20 degrees and have the timing hold correctly.
> After all, is that not the point of ECM control.
>
> I remember my brother asking how he could set the timing on his Audii. He
> said he could rotate the distributor cap 180 degrees and not affect the
> timing. Apparently he did not know how to do the equivelant of using the
> jumper as Toyota does, in order to disable ECM control.
> The reason I'm even looking at this question, is this.
>
> If I set timing by the book, I pass Californica Dynamic Smog testing very
> nicely... lots of margin on all tests, better than "average".
> However my power and mileage are hurt significantly with this setting..
> something like 11mpg. If I advance the timing to 20 degrees, my mileage
> jumps to 15mpg, and power is very good.
>
> Advancing the ignition leans the engine, which means it runs hot, I
> believe, although water temperature stays steady at normal under all
> running conditions, no sign of overheating, knocking or any other symptom.
> But given the history of HG problems, I do not want to leave this problem
> unsolved.
>
> I've had the truck for less than a month, so little personal history with
> it, although I've a long history with the 22RE engine on my SR5, knowledge
> on the V6 is limited to a lot of reading of this board.
>
> The only troubleshooting I've done so far is to verifty the TPS function.
>
> Any thoughts would be welcome.
> Richard Harper
> Morgan Hill, CA[/color]

Sorry I can't help but was wondering, as I have the same year, engine
and problem, would you mind telling me exactly where that jumper goes?
I'd like to check mine as well. Thanks.

dennis
in nca

Dennis.. If you really have the same problem, which could well be the
case, I may have some very good news for you.

Not only is my problem fixed, the fix makes sense. Here is what I did:

All it cost me was a lot of time on these boards and a TPS from ebay for
$17.5 including shipping. Yesterday I had just about given up for now,
when I got the sense from flash319 that my problem was still OBVIOUSLY the
TPS, despite the fact I'd come to understand how the TPS works, what it
does, and I'd correctly adjusted it. (the TPS from Ebay did that, turns
out my TPS was good, but it was worth the $17.5 not to have to take it off
the truck, plus I was able to play with it and understand how it works)

Well, given all that, I thought I'd try one more thing. Since I knew the
TPS was correctly going from high continuity (10.5 ohms), to infinite just
as it should, I loosened the screws and, while the engine was running,
adjusted the TPS by hand (after warm-up). Sure enough, the RPM jumped from
500rpm to 1100rpm. I'd played with the timing and throttle body idle screw,
so it was running on the high side now. So I carefully set the TPS adjusted
so it was just detecting idle, by this method, tightened down the TPS
screws with a just-right phillips bit (crazy glued into a 1/4" socket).

An advantage of setting it this way is that you get immediate feedback by
the rpm shift. Since the TPS is acting like a 0/1 (off-on) input to the
ECM, the rpm shift is immediate and obvious. Makes setting the dang thing
very simple, and quick.

The socket/bit adjust method allowed me to get the right distance and a
right angle to apply enough torque on those very hard to get to, screws.
Not as good as replacing the screws with hex type, but then I didn't have
to wait for the hex screw kit to come in, or make a trip to town, or risk
dropping one of the screws down where I couldn't get at it.

Anyway, then, while E1-TE1 (in a grey box 1" by 1/2" located to right of
fuse box (on passenger side of the engine compartment) )were still
jumpered, I set the timing to 12 degrees, set the TB Idle Adjust so that
with no load on the motor my rpm's were now at 800.

Buttoned it all up and test drove it. Power excellent, idle excellent.
Beautiful. Fini. Done. I'm a happy boy.

Thanks to all who took the trouble to write on the idle/timing/TPS
problem.. In particular flash319 and Mark... and Mike.

Ebay purchase price was 3k. 150.4K miles. Loaded and pretty.

I was prepared to put a lot more money into it, as basically, because of
my experience with my '85 4WD SR5 long bed (which the wife also loves), I
decided Toyota was worth investing in. Now I've got a truck when I need
it, and a grocery/Great Dane hauler when we need it. All paid for.

Life is good.

Richard Harper
Morgan Hill, Ca