So you bought an M30. What are the basics and what to look for:
In a nutshell:
- Long 2 door coupe
- VG30E SOHC V6
- 4 speed Automatic
- Coupe or convertible availabe
- 90-92 production years
More indepth information is here:
So then the next question is what is your motivation, intentions and direction of your car?
- Many want to drift
- Some want to swap motors/transmissions for _____
- Some want to have recognition for building an M30
- Then there are enthusiasts and owners who want to keep their M30s going.
Motors that have been put in an M30
I want to build/rebuild an M30, what is available?
- You will soon find out that parts are SCARCE. Infiniti has also stopped production many parts.
- Aftermarket wise? Very little is available. It is why many people have given up on the M30. Options are in Japan.
Wear and tear issues – These cars’ interior were mostly leather. After years of in the sun and people sitting, seats are typically torn. The back seats as well, usually the top of the seats are cracked and hard or ripped at the seams. Also with convertibles, the tops can be torn or ripped and if there is a back vinyl window, that could be damaged or broken too.
What are the common issues?
Older car – older car issues / Older convertible – convertible issues.
- Leaky fuel injectors (RECALL)
- Broken exhaust manifold studs
- Digital climate control display and function(digital in coupes)
- convertible top doesn’t go down. (convertible only)
- Rear quarter windows doesn’t go down (convertible)
- Leaks in sunroof when sliding (coupe only)
- screwed over radio/antenna
- broken trunk release switch (CAN get very annoying, but easy to fix)
- Driver side of dash is warped(common)
- Passenger side vent broken (common)
- Chassis cracks (common in coupes)
- Broken/missing seat switch
- transmission problems ( trans. shift solenoid & “hard” shifting)
- Doors sag, so doesn’t close easily
- Sticky column trim pieces/dash/glove box
- Leaky fuel injectors – This is a recall (NHTSA Safety Recalls)
- Broken exhaust studs is TSB: ITB94053 (Technical Service Bulletins) – These studs are old anyways, so when it’s time to replace them all, mind as well do the manifold gaskets too.
3. Digital climate control: There are a couple issues going on. The display disappears or buttons don’t work. Most likely the digital climate control board needs to be re-soldered. The other is fan speed. This might have to do with the resistor behind the glove compartment. For the digital climate control – For the the Resistor – Blower resistor replacement
4. In convertibles, the top might not come down, so people have to lower manually. This is typically do to the top motor or the actuators.
5. Rear Quarter glass won’t go down (convertibles). The rear quarter glass has 2 square nylon guides that let it slide up and down, once the nylon piece is broken, the sliding doesn’t happen easily or at all. 
6. The leaks in the sunroof are due to plugged drain hole. Open up the sunroof and you can try and clear it. Additionally, its good to look at the condition of the weatherstripping and lubricate the tracts of the sunroof itself.
7. Radio antenna won’t go up or down. Usually a bad motor or mast. Could also be connection or lubricate the antenna itself.
8. Broken trunk release switch – Most of the time broken. To replace you can us another gas switch, but the nicer option is a G35 switch (it is flush)
9. Driver side dash warp – Unless you are gonna redo your dash, the most you can do is hide it. It’s definitely unique to the M30. Besides finding a better condition dash or using a dash mat to cover, the only other solution is to have the dash done.
10. Passenger side vent is broken – In some way, shape or form, the vent is broken. Either bezel around it, the fins or the part that holds the fins on the sides. The fins move individually. Solution – if you can find one intact. Dealership doesn’t stock anymore!
11. Chassis cracks – once you open the door, there might be a crack along the be pillar. This is due to the M30 be long, but also being heavier. Convertibles don’t have this problem as they are reinforced. Solution – gotta have it welded. Chassis crack
12. Broken/missing seat switch. Driver side seat is electronic. Most of the time, the switch is gone, but the switch mount (white) is there. Functions, just annoying since it is an easily abused part. The black switch is often missing.
13. Transmission issues – The M30 has known to have auto issues. Different solutions were posted. with hard shifting. Replace shift solenoids (inside transmission) and the other was adjusting the throttle position sensor (TPS).
“Setting the Throttle Position Sensor
Install throttle position sensor in throttle chamber but do not tighten bolts.
Connect throttle position sensor and idle switch harness connector.
Start engine and warm it to operating temperature.
Leaving harness connected, measure voltage by inserting voltemeter probes through the back side of the harness into terminals [a] and on the sensor side.
Adjust sensor by rotating throttle sensor until output voltage reads 0.4 to 0.5 volts.
Once correct voltage is reached, tighten mounting bolts.” – VJ
14. Door sag – M30s have long and heavy doors. It is common for them to have door sag. Often times this is due to the door hinge pin and bushings.
MarkJM did this recently:
- PN – Hinge pin – 80406-V5002
- PN – Bushings – 80410-01L00
15. The vinyl surface of the pillar columns and even the glove box becomes sticky. This is the material that’s been broken down over the years. Thoroughly clean it and apply a water based vinyl protection spray.
16. Convertible top becomes bubble. People glued the top to the bow. I believe if this happens, it’s time to replace the top or have a convertible top shop fix it.
