Pete_89T2

iTrader: (4)

Background - My FD which I've had since Nov 2019 never gave me any issues starting, always fires right up on the 1st crank. Anywho, since these FDs are such little attention ******, mine decided not to start this weekend when it was time to leave a local cars & coffee that I frequent. No clicks, and no cranking, but I could hear the fuel pump priming on key on, and since I had my laptop hooked up and running my Link G4+ tuning software, I knew all systems were go - the only thing keeping my car from starting is getting juice to the starter.

Figured it might be the clutch safety switch, so I used a piece of wire as a jumper bypass to that... Still no clicks/no start, so I texted Dale to ask what else can be preventing the starter from getting juice, and he mentioned the Starter Cut relay which is part of the FD's theft deterrent system. Taking apart the kick panel to get to that relay would have been slightly difficult without proper tools (didn't want to damage the kick panel plastics), and since there were still enough able bodied folks to help give me a push start, I opted for the latter - car fired right up with a push start, and I drove it home without incident.

Upon getting the car in my garage and shutting it down, I tried starting it again - of course it started right up in my garage, repeatedly, so this is one of those intermittent electrical gremlins. After deep diving the FD wiring diagram, and the Body Electric Manual (BEM) for the Theft Deterrent System, and applying some EE kung fu, I figured out that there are 2 likely failure mechanisms at play here. See excerpt below from the BEM to go along with my explanation:



In this diagram, the yellow highlighted part of the starter cut relay gets +12V thru the 15A ENGINE fuse when the ignition is switched on, and IF the CPU#2 is working correctly, the other side of that relay coil should be pulled to ground completing the circuit via pin #2D. The blue highlight shows the current path thru the relay contacts; +12V when the ignition switch is in the START position, and off to the starter current flows (after passing thru the clutch safety switch which is not shown here).

So there are two failure mechanisms - the folks that get the CLICK/CLICK - NO START symptom more than likely have a starter cut relay with burned/corroded contacts. Easy fix, either get a new relay or install a bypass jumper. Banzai Racing makes a nice plug & play bypass for this relay - Starter Cut Relay Bybass Or you can do the same thing with a short length of 12AWG wire and a couple of male spade terminals.

But in my case where there was NO CLICKING, it's more likely that my problem lies in the CPU#2 failing to pull pin #2D to ground to complete the relay's coil circuit and energize the relay. Only way to verify which is the culprit is to (1) Bench test the relay for functionality and (2) Go thru the extensive system check flowchart for the Theft Deterrent System in the BEM. After testing my relay and verifying voltages at the connector, I found out my relay was fine, but after going thru the BEM procedure to verify proper operation on the Theft Deterrent System (who's "brains" reside in CPU#2), I found out that my FD is acting weird. The alarm oddly enough works when I functionally test it, but the security light doesn't blink as it should during the arming process though the beeper sound does work. So it would appear I have a buggered up CPU#2, and for now to prevent the NO CLICKS/NO START problem from happening, I'm bypassing the relay with a jumper.

Topolino

iTrader: (2)

A new CPU2 is your ultimate friend. However, if NLA and or too pricey, simply short-circuit your starter cut relay, H302, and you'll be good to go starting-wise.

DaleClark

iTrader: (55)

Bad contacts in that relay can cause the click-click-start problem. But that is not a total culprit, I actually replaced the relay with a NEW one and still had click-click-start problems. After re-doing EVERYTHING in that system I finally gave up and installed one of the starter booster relays 10 years ago, haven't had a problem since.

If you get a turn the key no start/no click, most likely it will be one of two things -

- Rubber pad for clutch switch failed and the switch peg is just going through a hole in the clutch pedal where the pad should be. A rubber stick-on hardware store pad will fix this or get the Nissan part that is floating around. Short term you can just physically push that button and start the car to get home.
- Starter relay bad/stuck/not energizing. Bypassing with a jumper wire is the easiest route there.

The starter cut relay is to prevent someone from starting the car if the alarm is going off. Some insurance gives a discount for this feature. But I think it's actual usefulness is pretty low, it's a VERY specific set of circumstances that it prevents - burglar breaks window or jimmies lock, alarm goes off, they get in car and try to Hotwire or force the ignition with a screwdriver. This will keep them from starting the engine in that scenario, but they could pull the battery then re-connect to stop the alarm going off then start as usual or of course just tow it off .

Dale

MWillzz

iTrader: (4)

I am going through the exact same issue! I was getting ready to fire up my fresh build when I encountered the "click click no start." I tried the starter cut relay jumper wire bypass and had no luck. I replicated banzai racing's starter relay solenoid kit to see if that would solve the issue...it did not. I checked to make sure the rubber pad was intact on the clutch switch peg...all looked as it should. I ended up making a jumper wire from the clutch switch harness directly to the starter solenoid in the meantime. Once I get my car going I will further diagnose. Also, I noticed that when my key is in the ignition, no beeping occurs and the ignition key hole light is not illuminated.

REnaissance_Sle7in

iTrader: (8)

Another thing to check for this is all the grounds around the starter and the battery fuse block. I was having the same issue, and figured it was time for a new CPU#2, but while I was waiting for a good/used one to ship to me, I decided to try and clean up all the grounds. Ended up fixing the No Click/No Start for virtually all of last season (I did start to get the symptoms intermittently the last few weeks I had the car on the road). I still have my good CPU#2 in my pack pocket just in case, but I was very surprised with how much more consistent that car would start by just cleaning up those grounds.

rousu

I had random cases of no reaction when trying to start. After a few tow jobs, I
put a jumper bypass to the starter and had to use it a few times. Worked.

But then later, there was a bigger problem, requiring cleaning up the circuit board behind the speedometer and replacing all the capacitors there.
That fixed a host of problems - odometer, auto transmission, engine fault light, ...etc
AND, since then I have not experienced any failure to crank instances.

May not be your problem, but cleaning up the speedo board is good preventative maintenance.

jla001

Just a quick correction to the above comments. The starter cut relay is a "normally closed" (NC) relay meaning that when the coil is NOT energized the relay is closed. Therefore in the diagram above the signal at 2D must be at 12V to de-energize the relay coil and complete the circuit to the starter's solenoid. This is for an FD. Not sure about other version of the RX7. So if you're checking CPU2 to verify operation of the starter cut relay signal (2D), the signal should be at 12V when the combination switch is either the ignition or start positions.

The advice about adding a jumper to bypass the starter cut relay is OK because the starter will only energize when the combination switch is in the start position. Note: The the starter cut relay may also prevent accidental engagement of the starter if the engine is running (not sure about this and do want to test it). Maybe someone who really knows the ins and outs of CPU2 can chime in.

silverTRD

iTrader: (37)

Maybe I missed it but what about if you install the relay and you still have click click issue? I have the Banzai relay and it worked for a bit but now I have the clicking again. Thanks