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is it a misfire?

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hi,

i have toyota land cruiser 1fz-fe with link plug-in ecu and there is small fluctuation with map sensor at idle about 1kpa is this normal?

the default firing order was 1-5-3-6-2-4 and i changed to 1-6-3-4-2-5 as this was labeled on the coilpacks and the idle improved but still seems to be misfiring, i checked the spark wires and they had the order of 1-2-3-4-5-6 as the wires where made to length and not like they where not installed properly, (the coil pack is wasted spark if this would make any difference)

i changed spark plug, spark wire, coil pack and cleaned injector and throttle body and the performance got way better but there still the 1kpa fluctuation

is there any way to diagnose a misfire with link ecu , i tried to disable injector but the ecu doesnt seem to allow it

It's not uncommon to have the MAP value fluctuate slightly and the 1 kPa you've mentioned isn't something I'd be concerned about. The firing order worries me a little though as this isn't something you want to change. It's an aspect of the engine's mechanical design and as such is a fixed order set by the manufacturer. A quick google suggests that the order for this engine is 1-5-3-6-2-4 which matches what Link offer by default. I will say however that this isn't an engine I have had any experience with.

If you want to disable a particular cylinder you can simply disconnect the injector while the engine is idling and note any change to the engine idle quality.

Misfires can also be caused by mechanical aspects such as poor compression or valve sealing so it might be a good idea to perform a compression and leak down test.

this is an idle log of 1-5-3-6-2-4 i think the idle is not as smooth as 1-6-3-4-2-5 but the driveablitiy and wot is exactly the same

Attached Files

The scaling on your MAP graph is so tight that it makes any fluctuation appear to be huge. The entire graph is only spanning 2 kpa. If you span this between 0-100 kpa you won't even see that level of variation. As I've mentioned, it's quite common to have the MAP signal fluctuate slightly at idle and this isn't necessarily indicative of an issue. Have you performed a leak down and comp test?

i havent done compression test as the engine is low mileage but im gonna consider doing it soon, but for now im gonna leave it as its

thanks andre