I own a n\a 87 rx7 and it will start right up on a "cold" start how ever once the engine is running for a while will not start? What could be causing this?

 

bad temp sensor behind the waterpump..

 

Check compression numbers? Did it gradually get that way, or was it something that just began full force one day?

Usually "hot start issues" can indicate low compression.

 

you mean most often it is low compression.

 

+3 compression

 

Well I've had starting issues the whole time I have had my rx7 but yea i would have to say it gradually got worse to where now it won't start warm.

 

If you feel like arguing semantics...

Yeah, definitely check the compression, that's usually a sign of weak compression and leads to a rebuild. MUCH cheaper/easier to rebuild an engine before it breaks than after..

 

What rebuild kit should I get I've been looking

 

Here is a good read. This should allow your car to start every time with this fix. Obviously the car runs good except the issue of not starting when the car gets warm. This might save you a mountain of money as well.

Rotary Resurrection home of the budget rebuild.

 

I've always just called up Ray Crowe, he used to be the parts manager for Malloy Mazda (rip Malloy Mazda) and can/will get rx7 guys SCREAMING deals on any and all OEM parts that are still in production.

For an NA engine I would probably just stick with the OEM parts, no need to go all fancy and aftermarket. But then again, I'm an FD guy so I'm not as focused on the intricacies of the 2nd gens. So there may well be a far superior option that I'm just not aware of. It's pretty tough to beat OEM in terms of quality and mating well with the engine though...


One thing I *would* suggest though, is to just go ahead and replace EVERYTHING seals/bearings wise. Spend a little bit more now and ensure that you're going to have the tightest, freshest, most pristine rebuild that you can.I see no point in pulling a motor, breaking it down, and then putting old/used seals back in it simply because they haven't fallen completely out of spec yet..

Check your irons for step wear, get them lapped if they're close to the limit (MAKE SURE you get them re-hardened after any lapping!!!) check your housings for any flaking or excessive wear in the chrome, etc., etc., replace all soft seals, replace your rotor and stat gear bearings, take the time to ensure that your clearances (Apex seals and side/corner seals) are super tight (at the tighter end of Mazda specs).

If you invest a little bit more time and money during the rebuild then you'll reap the benefits with a MUCH stronger motor, higher compression, better life span, etc., etc., etc. Then definitely restrain yourself during the break-in period and make sure you treat the motor gently for the first couple thousand miles (especially with all new bearings and tight seals) and it will treat you well in return.

 

Make sure it's not just leaky fuel injectors. Does deflooding do the trick?

2. Check or just replace water temp sensor.

3. Check compression

 

My compression is sitting at 60 for both rotars

 

Thats quite low, your numbers will be even lower with the engine hot. The correct fix is to rebuild it. You COULD add a fuel pump cut off switch, but its a big bandaid and no guarantees it will help