Is the timing set through the distributor?

Kreutz · Apr 21, 2005

At one time, a mechanic told me that there was no way to set the timing on my '90 xj. Someone recently told me that you set it by the distributor. Now, someone else said that I will need a timing gun. I was just wondering if I could set it without a gun and how to do it?

Eagle · Apr 21, 2005

Timing is controlled by the ECU, using input from the Crankshaft Position Sensor (CPS) and a couple of other inputs. The distributor is not adjustable.

Kreutz · Apr 21, 2005

ok, so there is no physical way to set the timing. is that right?

Eagle · Apr 21, 2005

Kreutz said:
ok, so there is no physical way to set the timing. is that right?

Eagle said:
The distributor is not adjustable.

PaulJ · Apr 21, 2005

You can advance it a fixed amount by switching to the high altitude CPS.

red91 · Apr 21, 2005

Kreutz said:
ok, so there is no physical way to set the timing. is that right?

Eagle said:
The distributor is not adjustable

I KNOW what you were really thinking Eagle.

Read: timing is not adjustable it is controlled through ECU. Or you can play with it a little by useing a hi-altitude CPS.

wrong1 · Apr 22, 2005

I ran accross a site a while back where somebody took a cps and welded longer ears on it. They then bored/enlarged the original holes into slots so they could adjust it a lil more.

I belive they did it to retard the timing.

xDUMPTRUCKx · Apr 22, 2005

is there any advantage or disadvantage to running the high altitude cps vs the normal cps?

Eagle · Apr 22, 2005

The high altitude CPS is available only for the Renix years -- 1987 thru 1990. It allows a few degrees more advance, which under light load (highway cruise on level terrain, for example) should translate into slightly better fuel economy. The Renix models can handle the additional advance without worrying about pre-ignition ("ping" or "knock") because the Renix system uses a knock sensor that retards the timing when it detects ping. The 91 and newer Chrysler system does not use a knock sensor, and there is no high altitude CPS available.

xDUMPTRUCKx · Apr 22, 2005

the auto parts store had a high altitude sensor for my 86' 2.5, would i benifit from better fuel economy by installing this or am i gonna get knock>?

Matthew Currie · Apr 22, 2005

xXJx said:
the auto parts store had a high altitude sensor for my 86' 2.5, would i benifit from better fuel economy by installing this or am i gonna get knock>?

The 2.5 TBI system does have a knock sensor, so it ought to work.

Is the timing set through the distributor?

Kreutz

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Eagle

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Kreutz

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Eagle

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