My rx7 is having hot start problems. It starts fine, then when its warm and you shut it off, it wont start for like 15-20 minutes. It kinda starts each time you try, it spudders alittle but wont start untill it sits for a bit. I tried going about 50 mph, and I shut it off and tried starting it with the key, it spins but wont start. Then I put it in gear and popped the clutch and it ran fine. Any ideas?
oh its a 93 with minor mods

 

It needs a rebuild. It just has too low of compression to start when it is hot. Search the term "hot start" on this forum. There is a lot of info about it. It is a typical sign that the engine needs a rebuild. Do a compression test and I imagine the results will come back in the 60s-70s.

David

 

David might be right if the compression is really low. It takes really low compression for it to be the single cause of the hot start. I have a car at the shop right now exhibiting the same symptoms but the compression is in the mid to high 80s when hot. The car should still start. The particular car has a problem with the fuel injectors.

 

i had the same problem a few weeks about and i tried everything and i called everybody but we rebuilt the engine and still had the same problem it just turned out i had very low oil pressure so i replaced the oil pump cause it was pretty bad and i did the oil pump mod now my car runs like a bat out of hell no problems starting at all

 

What kind of mods?

Does it have a power FC?

Miles on the motor?

If so, it could be a tuning issue.

Hot start issues don't necessarily mean a rebuild is in order.

I've had hot start issues on a 600 mile motor, and it was just a tuning issue.

There really wasn't enough information given here for a proper diagnosis.

 

It does have a power fc. But there is no real tune, all stock settings. The oil psi does get low sometimes after warmup also. Maybe I'll try swapping in the stock ecu.

 

define "low"

It's normal for the oil pressure to decrease at idle after the car is warm.
IIR my FD runs about 45 psi at idle after warmup, that's at 1k RPM.

Yes, it idles kind of fast. The motor also has oil passage mods, which affects the oil pressure a bit.

 

The injectors may be leaking when hot. Also, what plugs are you using?

thewird

 

ok so i'm having the same issue... the car won't start when the engine is warm... when the engine is cold, it floods and i have to use my switch to de-flood it and then it starts... it runs pretty good also.. it just idles hella rough and to keep it runnig i have to idle it at about more than 1500 or else it'll stall, once it's hot, it doesn't even sound like it's flooded nor anything.. it just cranks and cranks but no change if the pump is on or off any ideas? i'm tihnking leaking injectors.. but i'm not sure

 

If I may add to this, my car was having a hotstart problem months ago, not had any problems at all lately, it did it like 3 times where it would staul in traffic, and I wouldnt be able to start it for like 15-20mins and even then it would spudder around and I could barely give it gas. I am going to try and clean the injectors and replace the spark plugs with 9's.

On another note, my oil pressure when it did that was sometimes as low as 10psi or just under, and both my greddy and stock gauge say that, possibly part of the problem.

 

I found that having 9's in the leading made the car harder to start hot. You may just want to try fresh 7's and 9's.

thewird

 

Go to your cranking ms under settings on your PFC then go to water temp correction. You should see a screen for your water temp correction but this is for driving correction. If you hit over twice it should take you the starting table. Look at 80 degrees it should be 12. you can add a little more fuel to it and see if that helps it start. Try putting it at 14 instead.

 

Alright I might try that, I am just going to see in the summer if it does still do this though, and if does I will do 7's and 9's.

If not I think I will still do 9's, just because when I first got new 7's and 9's put on it it got rid of this kind of bad idle I was dealing with, then it just came back, so I was going to try all 9's to see if it stayed idling good.

 

Going to 9's wouldn't solve that problem, if anything it would make it worse. The point of using a colder plug is to be safer under boost since its cooler, it helps nothing other then that.

thewird

 

really?, looks like i will be using 7's and 9's. Thanks thewird