3rd gen starts when cold but no crank when warm
 

So my rx7 starts when cold but when warmed up wont crank. When warm up i can by pass the starter by push starting the car and it starts and runs. I tried a few things like checking battery, changing starter, checking connections to battery and starter. I am stuck what else should i do

When you say it will not crank once the car is warm, what do you mean? Do you hear the starter engage and turn the flywheel? Or when you turn the key to start the car you hear a "click" or no sounds at all?

No sound at all. I even got under the car and moved the connecting wires to see if i heard anything while my buddy tried to turn th car on.

There could be some computer logic malfunction and/or starter may be degraded. Have you pulled the starter to have it tested? Have you looked at the clutch switch? The factory alarm (in Body CPU) may also be a failure point. Have you noticed any other unusual electrical problems, such as locking the car, factory alarm arming/disarming?

Cpu is a microtech and the starter is good. As far as the security system it is factory. I tried the clutch switch by bypassing it and it still would not crank. What gets me is it only does it when its warmed up. If it sits it will start with no hesitation. If it is cold it wont evwn crank.

The microtech is an aftermarket ECU (Engine Control Unit) or PCM (Powertrain Control Module). The Body CPU controls all the ancillary electronics on the car like turn signals, door locks, alarm, etc...

The starter has been tested. Not sure what cpu you speak of. Where do i find this cpu. The alarm appears to work correctly

Did you already test the starter to remove any doubt? Assuming both ECU and starter are good, have you looked at the wiring schematic for the starting system?

Have you also checked the "click-click no start" thread? The Body CPU is also a highly searched topic...but it is found next to the fuse box.

Things have not checked is the ignition switch and the relay. This car does only have one safety clutch switch correct?

Just started the car. It is about it is about 60 degrees here in Fl. It started first shot. I let it run for no more than 20 seconds tried again and got no crank. This is crazy

https://www.rx7club.com/3rd-generati...-relay-872841/

After sifting through the above thread, locate the security relay (H302) inside the left side kick panel. Disconnect the connector, and jump the two largest wires on the connector. If this action solves your starting issues, you likely have a bad CPU#2. At that point, you can either get a new one for about $250 or simply live with the jumper fix as most on the forum generally do.

Hope this info helps!

If you turn the key and nothing, it's either the wire that's going to the starter that tells it to turn over and that circuit or the starter. Plain and simple.

Read the click-click-start threads, that points to a lot of the troubleshooting. Also, if you have a situation where it won't start when hot, jack up the car and put a meter on the small wire going to the starter. Have someone else turn the key. With the key to On, you should see 12v on that wire. If you don't, it's something in that circuit - the clutch switch, the security relay, something. If you do see 12v, it's something with the starter.

Dale

Going to try that. I read a lot of the threads on the click click situations. I wish i got a click click but my car either starts or i dont get anything at all. Not even a click. Thought it may be one of those common rx7 problems but i see its not. Going to take the starter out and just make sure i did not put the original starter back in. Both starters are jdm.

Topolino i am going to read that thread. Going to remove the starter and have it tested just in case i got the old starter mixed up with the good one. If not i will try that also

Jumping the H302 relay is the easiest thing you could do on your own. I'm the least DIYer on this forum, yet I was able to jump the relay with ease. Still, I always had in the back of my mind a sure-fire permanent fix; hence, replaced CPU#2 eventually.

Good luck, friend!

Update
 

Pulled the starter and had it tested again. Starter is good put it back in and started the car three times. Started with no issues. I let it warm up and bang no crank. I dont know if this is related but my coolant buzzer is going off and the car is not overheating or needing oil or coolant. Wondering if it is a safety if the buzzer has gone off you cant start the car

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.rx7club.com/new-member-rx-7-technical-256/add-coolant-warning-buzzer-even-though-coolant-reservoir-full-914328/&ved=0ahUKEwjBgNn39JnXAhVr5oMKHVWSDDIQFggcMAA&usg= AOvVaw2-Pm_YUw6VlOoodfCvILAx

I guess the stupid link didnt work, but there are some similar issues around that ended up air puckets in the coolant system and/or bad coolant sender. Look it up and you might find the fix sooner.

There's no "low coolant car won't start" circuit. It's all in the shop manual - ignition key to clutch switch, to security relay, to starter.

It's either that circuit, the starter, or the battery/battery cable going to the starter. That's it.

Dale

The link was for the buzzer going off. What Dale said make all sence though. Its pain the rear chase electrical issues,.

In line with Dale's recommendation and advice on the starting circuit, verify that the ground cable is firmly connected to the battery and the chassis. Also ensure there are no corrosive buildups, kinks, or breaks along this cable. I would also advise that you verify the condition of the Positive cable to the starter, again looking for kinks, breaks, or corrosive buildups. Please disconnect/remove the battery when verifying these cables as it will provide a "shocking" experience!

Thanks
 

Thanks Dale. Going to try to bypass that damn security relay today.

Crazy
 

Started the car today drove it ten miles turned it off and then back on. No problema. I bought some wire and some connector s just in case it does the no crank stuff. If it does it again i will over ride the security relay

Topolino diagnosed your car on 10/29. It sounds like the security relay went bad, which happens to every single FD sooner or later, and won’t allow the car to start after it overheats. Jump the two thickest wires and you’ll never have this problem again. I had to do mine just a week ago. Stop making it harder for yourself by uninstalling your starter again. The starter is good.

Nick