Main Relay

[duncan]

About to return on Sunday evening, Car took 3 goes to start, firing but not catching, then caught. 10 miles down the road, just died, speedo & tach dropped to zero, all ignition/dash lights came on, followed by alarm/immobiliser warning lights. Once stationary would crank, catch then die......remainder of journey on a recovery truck.
Watched Grand Prix on video.
Symptoms would indicate main relay,
Plan A; ordered on Monday, none in country December earliest date for delivery.
Plan B; Removed and opened main relay, re-soldered joints, refitted; same symptoms as before, crank, catch, die.
Plan C; Removed and re-opened main relay, followed manual and checked the 3 circuits for continuity, all tested OK. Refitted main relay, secondary check on listed fuses, all OK. Will crank, won't catch, won't fire.
Plan D; HELP
Either, bright ideas, something obvious.
Anyone with a working later type [RZ-0152] spare main relay I can borrow as a check.

[Hagasan]

Just a very quick thought ...... is the fuel pump priming/running? And sufficient fuel?

[Kaz-kzukNA1]

Hi, duncan.
Sorry to hear the news....

As I'm not familiar with your NSX, could you provide me with more information such as year model, aprox mileage, MT/AT, aftermarket/OEM security, etc?

Is it your everyday car or just 2nd, 3rd, ... car?

Did you re-solder all of the joints inside the main relay? By the way, if your relay contact is getting intermittent connection, re-soldering won't fix the issue.

Have you experienced similar issue recently?

Did you try to investigate the ignition switch contact? There were several issues reported with this part.

For some people, they simply couldn't crank the engine at all and for others, they managed to fireup the engine but when they released the key from 'START (cranking)' position, the engine just died. Sometimes, the dash didn't show any lights even in 'ON' position.

As you can crank the engine, the contact at 'ON' position would be the problem if your ignition switch was the cause of trouble.

For following test, please make sure that the gear is in neutral.

You may want to turn the key from 'ON' to 'ACC' and vice versa super-slowly to see any differnce in the way the dash lights comes on and off.

Also, if you managed to fireup the engine again, while the engine is still running, try to move the key anti-clockwise (towards 'ACC') for a tiny amount to see whether the engine stops or not.

Or, as you seem to be happy dealing with the electronics parts, it would be quicker to open the ignition key switch that is very back/behind of the key cylinder and have a look at each contacts. If you see black oxide, clean it with contact cleaner or if the contacts looked to be worn out, just replace it. It's not that expensive (but not sure in UK....).

Or, it could be completely different thing such as fuel pressure but one thing at a time...

Kaz

[duncan]

Kaz,
Thanks, UK supplied 1995 manual coupe [FBW throttle and JDM gears], 93k miles, last 34k in my ownership in last 5 years. Retro fitted Honda CAT1 security in ’97.
All pins protruding through PCB re-soldered. Relays ‘click’ across when coils energised, contact points could be breaking down under load.
No previous starting/running issues.
Threw EPS warning light [code 22] say 50 miles previously, cleared code, warning light didn’t re-appear. Then 30 miles on, EPS light on again, was going to re-check but the breakdown intervened. Prior to breakdown, aware that speedo and tach momentarily dropped to zero perhaps a couple of times.
Following flow chart for main relay, for the check that terminates in ‘replace IG coil’ fuse, this needs ignition to be switched on, I couldn’t record a voltage, I was going to re-test as I assumed that it could be my testing, hence quick continuity check on all listed fuses.
Can crank, full display of dash lights [until timed out by the security system].
No previous issues with ‘intermittency’ in ignition switch, I haven’t checked the ignition switch but will do, seems consistent with observations and it's 'mechanical'.
Duncan

[amo]

if you hold the key will it run ?? have to hold the key just passed the ignition on
mine went and its common prob

hope you get it sorted
thx amo