98 12 valve ess replacement
#2
Registered User
Did you gap the ESS properly? How far off is the tach, and how do you know (scan tool or photo tach?) ? The tach is not to be considered accurate - that's why the factory service manual says not to rely on it when setting idle speed.
#4
Registered User
The fluctuation at higher speeds makes me wonder if there is a wiring problem. The wiring harness turns down at the front of the engine and can rub through there and cause a short.
I'm trying to remember offhand if my tach (not tack!) is marked as low as 400 RPM. Assuming you aren't touching the throttle pedal, is the 400 reading at idle fairly constant? And you're sure that isn't a (relatively) accurate reading?
I'm trying to remember offhand if my tach (not tack!) is marked as low as 400 RPM. Assuming you aren't touching the throttle pedal, is the 400 reading at idle fairly constant? And you're sure that isn't a (relatively) accurate reading?
#6
Registered User
I'd be looking for a wiring issue, first. Check that spot I mentioned for a rub-through. Check along the length of the harness for other possible issues. Check at the connector to be sure you aren't intermittently losing the reference or ground. Loss of either of those ESS inputs means loss of output.
Do you have a factory service manual? The FSM will have the connector pinout and expected reference voltage (I don't remember if it is 5V or 8V).
Do you have a factory service manual? The FSM will have the connector pinout and expected reference voltage (I don't remember if it is 5V or 8V).
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nothingbutdarts (10-08-2023)
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Performance and Accessories 2nd gen only
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11-18-2008 08:00 PM