Car will never start when the engine is hot

[Ste C]

Hello all.... I own a 93 rx7. When I had the engine rebuilt all was fine for a while but now the car wont start when the engine is at full temperature. So at the minute I cant even go to the petrol station with fear of not been able to start when I come to leave. Once the engine is cold again she will start first time. The car has been off the road and garaged up for nearly 2 years due to spending money on a new house but when I was last at WGT Pip said the compression seems lower than normal and he thinks he needs to have a look inside as another rebuild may be looming. Pretty annoying when the new engine has only done 5000 miles. Trusting Pips thoughts I just wondered if anyone maybe has seen this problem before...Cheers.

[clive]

Sorry to say that yes this is a problem that can occur with a Rotary and I always say to potential buyers to take the car for a run leave it 5 minuites then check that it restarts as Rotarys unlike piston cars at times will not restart when hot due to low compression at times.

One thing you can try is to put hotter plugs in the car as this may well get around the problem for quite a long time.

Hope this helps

[Ste C]

cheers clive, will swap them and let you know.

[gsb876]

Sounds kinda like low compression as Clive said bud

[Ricco_04]

Yup I agree.  Had this exactly before I changed my engine.  Compression went low and starting was almost impossable when engine was hot - getting petrol was a right pain in the bum! :o

[logicalChimp]

Likewise - had to call the RAC out to a service station due to the same problem :o

[Dr-Rotor]

Can also be a TPS problem. When the car is hot & running how dose it respond to throttle input? Eg: From idle if you slightly blip the throttle doe it just cut out or will it idle nicely?
 
Im not saying that its not the compression but its always good to eliminate other things first. I know that when the engine is hot & your TPS is reading a very low voltage it makes it very hard to start the car.
 
Good luck with it. Hope you get it sorted.

[nikp]

^^ That\'s very true. I had mine mis-aligned at one point and it would stall (OK, not the same, but as said it does have a bearing) as soon as it was warmed up.

[Ste C]

Can also be a TPS problem. When the car is hot & running how dose it respond to throttle input? Eg: From idle if you slightly blip the throttle doe it just cut out or will it idle nicely?
 
Im not saying that its not the compression but its always good to eliminate other things first. I know that when the engine is hot & your TPS is reading a very low voltage it makes it very hard to start the car.
 
Good luck with it. Hope you get it sorted.

blipping the throttle from idle has never caused it to cut out , it does idle quite nicely. Not knowing a great deal about engines what is TPS? Thanks for the interest people.

[Jono FD3]

TPS is a Trottle Position Sensor mate, it sits on the throttle controle acrm & tells the ECU how much loud peddle yoou have got on.

Jono

[Initial-D]

Try a new set of plugs or clean them up if there still ok. Mine were really black when I took them out and after a thorough clean the car starts from hot fine!

[Ste C]

had a look and I have 9`s both leading and trailing, where is the best place to get a couple of 7`s?

[Dr-Rotor]

Haaa...thats half your proplem. You need stock plugs for a stock motor. If you not runing more than 15psi you dont need 9s all round.
 
It dose make it slightly harder to start cars with cold plugs all round. Some cars seem to be fine & start up first time easy. My monster requires very slight throttle to start...if you try to start it without that little bit of throttle it will not work. HKS racing plugs seem to have that effect..haha. If I put NGK 7 & 9s in it will crank over very easily.
 
Also I still think you need to check your TPS. Do you have a power FC ECU with the hand controller? It will show you the voltage if you do. The first VTA needs to be between 0.75 & 1.25...with ignition on & engine off but the engine at opperating temp.
 
If you dont have a PFC...well then I will have to find out how you can check it.
 
If you would like the full manual for the car on your PC I can email that to you too if you like. Just email me to let me know. bmlove777@hotmail.com

[karl_tate]

i had a slight idle problem before my engine trouble so i think i will have a look at my tps when it goes back in and check the values on the pfc, i didnt know you could check it on there, thanks for that bit of info dr rotor.
 
ste, you can get 7\'s from pretty much any where, ebay, or most vendors on here stock them.

[Dr-Rotor]

No worrys mate!