darom

My current issue is with leaking oil and coolant. My head gasket is leaking coolant - this is between cylinder 1 and 2 on the RH side. I can see the coolant right at the edge of the engine/cyl head. When I installed the new timing cover, my head gasket got torn at the top. I made a gasket and used some aerobic silicone. The oil is leaking a little on both sides. The plan is to remove the cylinder head, take it to the shop to get it reconditioned (new stem seals, check the springs etc), put a new set of ARP stud fasteners with an OEM gasket. The new gasket will also stop, hopefully, the leak at the top of the timing cover. I checked the prices on the Nissan head bolts - they are in the hundreds now. Not sure what happened. The MSA is basically recommending to go cheaper ARP route (which used to cost more in the past, now it is reverse).

I also decided to re-address the lean condition on hot restarts. When it happens, the fuel pressure would bounce around, 18 - 22 psi. The FPR is set to 37-38 psi (w/o vacuum), at idle normal psi is around 31-32 psi with the vacuum attached. The FPR is an Aeromotive unit. Started with the fuel pump's (Walbro 255) voltage. 1. My original design - battery -> circuit breaker -> microsquirt's fuel pump relay -> main relay -> 30AMP relay (Inertia switch) -> Fuel Pump All wiring is 14 gauge. The voltage delta between the battery's and the fuel pump's was 1.5 Volts! 2. Re-did the ground - dedicated negative to the back panel's ground point where the tail lights get grounded. The delta was 1.2 Volts. 3. Installed a dedicated FP relay in the engine bay (Tyco 75Amp, with a 25amp fuse), with direct run to the fuel pump. The microsquirt's relay provides a trigger on post 86, inertia switch (in cabin) - ground. The delta is 0.3 Volts. Here is a diagram: Another possible issue might be related to the pre-pump's G3 Fram's filter being too restrictive (40 micron). Installed a 100 micron pre-filter: The pump is very quiet. The hot restart ends up with 14-15 AFRs for about 40 seconds, then it scales back to my pre-configured 13.5 at idle. I don't see a lot of fuel pressure fluctuations any more. As a precaution I added a 1979's 'hair dryer' to cool my injectors. I found it at a junk yard. I am using a time relay board which is set for 15 minutes. When I park the car, I can engage it from inside. I will test it on a hot day:

Installed a set of OEM engine mounts. They are still available, the cheapest ones are shipped from Japan (ebay source), about $120 total. Originally, I figured I would save some money and ordered a $20 special for a pair + s&h. Then I found some posts on classiczcars about their poor fitment, SAE threads (not with the pair I purchased), misaligned locating pins etc. Here are some pictures for comparison. The center bolt is longer on the after market one: The locating pin is way off: The OEM mounts fit like a glove, no issues.

It was the rear main seal leaking, I removed the transmission and could clearly see the oil around the seal:

After priming the engine oil and starting/warming up the car, there is a small leak around the rear main seal. It is either my side seals or the rear main. Considering how easy it is to bump the seal while installing the rear cap, I wouldn't be surprised. I guess it is time for a tranny drop operation. I will check with my endoscope.

Hi CalZ, It is https://www.amayama.com/en

I have been dealing with some consistent oil leaks around tranny/engine block, and front RH lower part of the timing cover. The worst leaks would happen when the car was parked at an incline. I replaced my original TC with a new unit (there is a company selling them from Japan), total shipped was around $100. My original cover had some stripped threads. The water pump's long 80mm M6 bolt (at 10 o'clock) was broken inside the block. I had to weld a washer with a nut to remove it. The oil pan gasket that I sealed 10 years before, with permatex gray/gasket sandwich started leaking on the RH side. The removal of it was a major pain. I decided to get an aluminum pan from AZC since I am considering a turbo upgrade in the future and that pan already has provisions for the oil temp sensor and turbo oil return fitting (I went with the 8AN fitting). The pan is solid and straight. I 'glued' the cork oil pan gasket with the permatex black to the pan to prevent the gasket movement while I was installing the pan. My hope is the fact the pan is a solid aluminum piece, there is not going to be much flexing/worrying about dimpled surfaces etc. While the pan was off, I also replaced the rear main side seals. Mine looked old/brittle when I removed the rear main cap and inspected them. I tried pulling the metal inserts with a pair of needle nose pliers, but they were stuck really good. The rear cap was removed using an improvised slide hammer (the taped part is a bunch of heavy washers): It took about 10 minutes to remove the cap: I didn't see any sealant in the corners in my engine. I am hoping this might explain the oil leaks. Per FSM: Before the cap installation, I put a bead of gray ultra in the corners on each side. The side seals got a coat of gray as well when I inserted them. The rear main cap was in a freezer. Its installation went smoothly. I haven't filled the engine with oil/coolant yet. If I see more of oil leaks around the rear part of the engine/tranny, I would probably pull the transmission and replace the rear main seal along with the transmission's gasket/seals.

Hi @Mike280zx, if you don't get answers on this forum, i'd advise to post on https://www.msextra.com/forums/index.php Regards and good luck with your project.

Thanks, Tom, will add a little more fuel. I noticed my cold -> warm cycle follows a pretty predictable AFRs curve per the table and my manual tuning I did at idle a while back (I was aiming for 13.5-13.7). Things go out of wack somewhat when I restart a hot engine, the AFRs are leaner until they stabilize later on.

Update: Today I worked on correctly setting up the initial target RPM table. Took two readings per each rpm step, in my case, 850, 950, 1100, 1200 and 1300, when the car was semi-warm and hot. Then added another 10 percent per: https://www.diyautotune.com/support/closed-loop-idle-pwm/ Then from 100 to 170, interpolated vertically. Since I didn't know what steps would be at lower temps, left them the same at the bottom: I switched to using CLT table (not MAT) since I am still clueless where I can find it (unless TS uses the same table for both and it will be just different temp ranges there). I also noticed at hot restart, the AFRs are very lean, 15-16 range due to the injectors getting heat soaked. Searched on the msextra, found some posts about guys using a band-aid fix by adding ASE and taper at higher temperature. I experimented with mine and added some: It does help somewhat in the beginning. I added EGO correction of 8 percent above 800 rpms. This helps as well, and my AFRs get back to normal range. I am posting my updated tune, plus the idle log. I haven't taken the car for a test drive yet. 2025-07-06-v106.msq 2025-07-06_10.40.07.mlg

Hi Tom! 1. I ordered another TPS sensor (different vendor) to test. I also noticed that it is not 100 percent stable. I am using the sensor ground for it per microsquirt manual and the 5V feed. My throttle blade is completely closed, the spring is strong in this Protunerz' throttle body. I do have a throttle cable slack. 2. I think what is happening at 16.833, is that for -200 rpm correction per the 'Idle Adaptive Advance Timing' table, it will kick 6 degrees of timing. My running RPMs are 996, when the target is 1200. So the ECU is adding 6 degrees to raise the RPMs. When the RPM of 1200 is matched, for ex., at 27.366sec, the correction advance is almost at 0 degrees, 0.6 actually. 3. At 26 seconds, i was backing out of the garage in reverse, with almost no TPS input. No sure what is happening here either. I also see a -280 RPMdot that follows. 4. At 93sec, there is a TPSdot of 14, maybe this is why my AE is enabled? My target RPM is 1183, the running RPM is 972, I see the Idle Correction Advance is adding another 6 degrees. I am wondering if I should move from 6 to 3 degrees max for CLI control? It might be too much of a change to adjust the RPMs? I will try that and will make another log. Overall, the CLI is the most confusing part for me. When it finally started working (kind of), it surely made my day :-) Appreciate you taking your time checking out my progress! I do have a few questions for you - per your tune: a. you have Shift Settings -> Leave Valve Closed Above:(rps) - 7,000, For this number of seconds - 0. Basically, you don't want the IAC valve to close at all? Any benefit from this setting? b. you are using the table for CLT in the CLI Settings (Use CLT or MAT In Table Lookup). Do you have any heat soaking issues? I read some posts where it was advised to use the MAT table. Any other benefits? Should I use the CLT table as well? I asked the question on the msextra forum why the ECU still checks the CLT table, but no one has responded yet: https://www.msextra.com/forums/viewtopic.php?t=82151&sid=ccd10333b5cfba1911eaded17a655060 Thanks! Den

Update: I figured out why my RPMs were so low and the IAC wasn't adjusting its steps. My TPS in the Closed-Loop Idle PID Activation Settings, was set at 0.8. The actual TPS was 1.1 that day which meant that the CLI would never kick in when I was sitting in the car at idle. I re-calibrated it and decided to play it safe and set at 1.5. Today the car's CLI worked as intended. I am still dealing with wonky IAC which can be at steps 90 and barely allowing any air in. Also, I noticed that even if I select the MAT table to be used for reference, the ECU was still looking up the CLT settings. I posted this question on the msextra site, maybe it is a code glitch or this is how they designed it or I am missing another table. I might just use the CLT reference table and call it a day. I am posting the updated tune and the drive log. 2025-07-03_12.14.29-drive.mlg 2025-07-03-v104.msq

Update: replaced the mustache bar bushings, re-torqued the strut lock nuts. I don't hear any more banging noises now. Still not sure what fixed it though. When I was checking my rear Bilsteins with springs compressed, I didn't feel any extra movements to give me that noise. I also swapped my master, slave clutch cylinders and clutch hydraulic hose. The old ones had some 'brake fluid sludge' inside from the internal leakage. I adjusted the clutch pedal at 8 inches (i have a carpet/sound insulation), the master cylinder rod of the replacement unit was the same length, no need for an extra nut. I could put the pedal at the max height (over 9.5 in) and the rod was still good. The free pedal travel is within specs, 15 mm. I was observing the operation of the slave with my $20 endoscope, 15 mm of the clutch pedal before the slave starts its movement. The clutch fork throw is half an inch (12.5 mm). I could push the slave's rod back towards the front, the rod gets back to its self-adjusting position. I did some searching - it sounds like 15 mm is a better number. My reverse and 5th get engaged without grinding noise and without any difficulty. The clutch operation is smooth. I used Rockauto's Luk's: LMC245 and LSC199 parts. Appreciate your guys' help. After fiddling with my closed-loop idle, I am still chasing my tail. I posted a thread on the msextra.com forum at: https://www.msextra.com/forums/viewtopic.php?t=82151 The RPMs get dropped very low, the ECU is not commanding enough steps for my IAC (or it is telling to give, for ex., 60 steps with not much difference). The car is driveable, but with rpms sometimes hitting low 300-400s, which is not good (CLI is not even running when it happens). Here is my updated tune and drive logs if anyone wants to take a peek. Thanks, Den 2025-06-29-v102.msq 2025-06-29-cold-start.mlg

Cool, thanks AtoZ! I will check the rod length, if needed I will weld a nut to extend it a little.

I set up the closed loop idle finally. This is the one of the best things since the invention of sliced bread. I still need to tune it, I will post my updated tune. I took the car for a test drive and noticed annoying loud rear-end noises going over any crack and pothole on the road. It is not clunking. My reverse gear is also hard to engage, I ordered a new clutch master/slave - it looks like the slave doesn't extend fully its rod, I think my clutch is dragging and my clutch pedal is out of adjustment. I will be replacing my mustache bar bushings and re-checking the torque of the locking strut nuts in the rear. Meanwhile, I decided to address my heat soaking issues with the intake, fuel rail and injectors. I found my old heat shield, bend it to contour the intake/exhaust ports and installed it. I checked with the remote temp gun, there is a 30F difference now (fuel rail/injectors were showing 170F):