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5 minute(s) of a 731 minute read
6-15-2020
Well, finally dealing with some issues. The Z has been pretty solid the last few years aside from the maintenance items I address every spring. I got a good couple months of driving in earlier than normal this year too; but the last month has been less than stellar. I finally got out for a cruise with some buddies and the car behaved great...mostly.
Towards the end of the drive I finally had a chance to wind it out, and discovered a misfire that would only occur at high boost, high load, in 4th. AFRs remained consistent which lead me to believe it wasn't a fueling issue. I realized I hadn't changed the gap on my plugs from when I went from 93 to E85 (but also never had an issue before this) so I took the opportunity to gap the plugs from .035 to .032. I did find one plug close to .038", so thought this might have been my issue. Sadly it was not. All of my coilpacks test good, but just for the heck of it I swapped them all out and this seems to have helped. Unfortunately I haven't had more than one solid test drive, so this solution is not yet finalized.
Getting at the rear coilpacks requires removal of the balance tube (red). Certainly not a big deal.
Tools of the trade. I don't totally trust my keychain gapper but its very easy to use. Verified with a feeler gage set.
Tools of the trade. I don't totally trust my keychain gapper but its very easy to use. Verified with a feeler gage set.
As found. All were left at 'exactly' .032"
As soon as I 'solved' the misfire issue I developed an immediate but not quite catastrophic coolant leak. I popped the hood after a test drive and discovered coolant sprayed all over the front of the engine, and collected inside the cooling fan.
Hard to see, but you can see a little puddle of green in there.
As usual I tested out the most likely/easiest solution first. Maybe I had an air pocket that was preventing proper coolant flow and allowing excess pressure to build. I bled the system...without any luck. Coolant everywhere again. Next I took a look at my aftermarket overflow tank that was needed to accommodate the MUCH larger SMICs I'm running. This is hidden in front of the drivers side wheel behind the intercooler. It turns out the inlet AND outlet were plugged solid with rust. I also found a pinhole in the tank which was empty when I removed it. It's possible/probably I had multiple issues here I wasn't aware of. I cleaned out the tank, eliminated the pinhole leak, and confirmed that it was able to function as intended with a mityvac on the overflow tube from the tank itself. Great!
I reinstalled the tank and tried to test it out by running a clear piece of tube from the radiator to the overflow tank and letting it idle in the garage. Despite getting it up to ~175F, it didn't build enough pressure to need the tank. Also no leaks were evident at this time. I reassembled everything last night but ran out of time to test drive. I felt good about this, as the condition I found the tank in explained all the issues I was seeing. I took the Z into work this morning and pulled over halfway...only to find coolant everywhere. UUuuuuugh.
Now I'm stumped. The system holds pressure, but also seems to be building too much despite temps staying normal on my dash gage and on my computer (two different temp sensors. Yay redundancy). I'll top it up before I leave work and should have no issues making it home. I really have no ideas as to what the problem actually is. Tonight I plan to pressurize the system to ~20psi with the hopes of finding where it is leaking from. If I find something that merits adjustment/fixing I'll give it another test drive. If not I'll probably pull the radiator, thermostat, and water pump and verify nothing is plugged or clogged. This is somewhat disheartening as I don't have much time to work on it, but I also don't have anywhere to go. Win some and lose some.
Somewhere in here I bled the slave cylinder too. I was getting touch and go gear engagement from time to time; so when I had 30 minutes I used the help of gravity and my MITYVAC to bleed both (yeah...both. Dumb) bleed locations. There is a bleeder on the slave, and a remote bleeder in the engine bay. I have no idea why and haven't taken the time to delete it. I didn't have an assistant thanks to COVID, and I wasn't sure how successful I'd be getting a complete bleed without someone activating the pedal. I did each location twice and everything shifts beautifully now. The car drives great, makes tons of power, blows nice cold AC...I'll keep looking on the bright side.