Engine Cylinder 5 misfire

GalacticPonage

Active Member
Jun 21, 2016
41
25
38
New Jersey
Okay guys I’m pretty stumped on this one. I took the car out one night and beat on it pretty good and it ran great. Parked it and went to fire it up the next morning and cylinder 5 was misfiring. I’ve since changed the plug, swapped the wire with a known good one, swapped the wire with a new one, swapped the cap and rotor with known good ones, checked spark with a plug out of the engine, rechecked timing, had the injectors flowed and cleaned, verified good voltage and pulse from injector harness, verified fuel pressure, rechecked grounds, checked that the pushrods were straight and rockers were set properly and performed a compression test and leak down test that all came back good. I can hear the misfire happening intermittently but it’s still pretty much all the time. Like tick tick tick tick . . . tick tick . . . tick . . . tick tick tick. Which tells me it probably isn’t a mechanical issue. If I pull that plug wire or unplug the injector the ticking stops. The car drives okay just cruising but if I go to lean on it it will sputter and stumble. My best guess at this point is that one cylinder isnt firing at the right time since it’s got good spark, fuel and compression. Could this be a TFI issue or distributor? And is there a way to test these? I’m running a microsquirt v3 so I don’t think checking codes is an option. Thanks in advance I’ve been chasing my tail for weeks now lol
 
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It's been a while since I've opened up TunerStudio, but I recall under the testing tab on the left, you were able to quite a bit.

Is microquirt batch injector firing?
 
Please provide me with a datalog and the tune file.

The micro is batch fire, if you are getting good spark to the offending cylinder then we need to make sure the tune is in good shape first.

Your ticking could very well be an exhaust leak at that cylinder, I would check this first
 
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Please provide me with a datalog and the tune file.

The micro is batch fire, if you are getting good spark to the offending cylinder then we need to make sure the tune is in good shape first.

Your ticking could very well be an exhaust leak at that cylinder, I would check this first

I’ll run it in the garage and get a quick data log and send everything up tonight. It’s not an exhaust leak because it’s intermittent and I can feel all around that port with my hand and don’t feel a leak. The car kind of falls on its face and sputters when trying to accelerate kind of hard as well. Definitely missing