My 96 rx7 is difficult to start when hot and it wont idle when it's hot either. It runs fine when its cold but crap when its hot. The exhaust fumes smell lean when its hot as well. I don't know where to start ,the check engine light does not come on so I can't use the computer diagnostic to try and diagnose.I checked the bulb and it was ok. Does anybody have any ideas for fixing my problems. It just one thing after another on this car.

 

how do you know it smells lean when hot??? what rpm are you idling at?

 

Oh a mechanic said it smelled lean. It will just idle real low then stall<700. The vaccum is a bit low too its about 400mmHg.

 

idle should be at 750-850, up the idle

 

Check the fuel pressure regulator. If you can start the car hot by holding the throttle wide open, it's a good bet it's the FPR.

 

when I say hard to start when hot I mean it takes a couple of cranks and you have to touch the gas pedal to get it to fire.

 

That could also be dripping fuel injectors. With age they can't fully keep back the immense fuel pressure they have to deal with, wheter the car is running or standing.

This depends quite often of the mileage; what is yours?

Patrick

 

yeah somebody else told me that could be the problem. But i would of thought it would flood itself quite often. Mine has done 70,000kms, why would it only affect the idle when its hot??

 

Actually, if injectors are leaking it does not depend on engine temp condition. You will have flooding all the time.

Your mileage in kms is quite low to enforce that injector prob.

Throttle full open makes me think about a general problem with too much fuel in the combustion chamber.

Does the car start immediately (cranking 2x-3x, not longer than 2-3sec.) in cold condition?

Patrick

 

yes there are some other things to look at but if it idles and starts fine when cool i would look at the fuel thermosensor.

 

Anyone,

Can that be because heat soak of ic....hot intake temp?

 

Pressure Regulator Control solenoid.

If you want to know for sure if it is a fuel delivery issue, jumper the fuel pump at the diagnostics box (do a search, it's been discussed many times) to put the fuel pump into high pressure mode. If it starts immediately then most likely your PRC solenoid is not functioning - as this solenoid effectively does the same thing as jumpering the fuel pump to high-speed mode.

 

I will jump on the bandwagon with the FPR solenoid. If the car runs fine other than hot start and idle issues this is it in many cases.

 

I have just started to pull the injectors out to have them tested. I forgot to relief the fuel pressure and was surprised that there was no fuel pressure in the fuel rail. Does this point to leaky injectors. Im yet to check the fuel pressure solinoid.

 

Ok I tested the fuel thermo sensor thats working fine. I checked the fuel pressure regulator solinoid that is fine too. I unbolted the fuel rail and pressurised it with the fuel pump bridging the terminals on the diagnostic box. None of the injectors appeared to leak after approximately 10mins of leaving the pump running.
What now . The car won't idle when its hot I don't think the prs is the problem as it only works for 1 minute after starting the car when its hot.

 

your water seals. Poor hot starts were the first indication of mine going. Do you have any of the following symptoms?

- Whooshing water sound coming from under the passenger/dash area?
- sudden spikes in your water temp gauge, or does it occasionally move off of half-way up to 3/4's of the way or more?
- Coolant light comes on/coolant needs to be added regularly?

I truly hope you don't have anything like that, but if you do, coolant seals are gone. That 'lean' smell could be burnt coolant......

Beast

 

I've just recently pressure tested the cooling system so Im pretty sure its not that. It doesn't use any water either.

 

Disconnect the EVAP solenoid and plug the line. See if it makes any difference at all.

 

Excuse my lack of knowledge but is the evap solinoid the solenoid that allows fumes from the charcoal canister into the intake manifold? I have checked that the solenoid is functioning correctly. What about the tps being out of adjustment?

 

oh my car is a 96 it doesn't have a check engine light. Is there a way of running the diagnostic without the check engine light?

 

Here's something to think about. My first motor that blew had a cracked apex seal. When it was cold it would fire right up. When the car reached normal operating temps, it was hard to start. I had to push the gas down to get her to start. After that, she idled fine(little lumpy of course) but held a good 800~ rpm idle. My vacuum was lower than normal and erratic, but I didn't think it was any cause for concern(at the time). When I finally tore here down, both front and rear had one cracked apex seal. Just something to think about...

 

seems like your compression isn't sufficient enough at low idle, when hot - sounds like losing compression to me. and As far as that whooshing sound around passenger area - especially when Revved - is normal, just your waters finding their way. ah.....anyway wth do i know, i ain't no kenichi yamamoto for that matter. Too many things gotto do with fuel alone. good luck.

 

Mazda Techbook says the following:

Starting difficulties

- Insufficient compression
--- Rotor housing worn or deformed
--- Side housing worn or deformed
--- Rotor bushings worn
--- Apex seals deformed or whacky
--- Apex seal springs worn or tired

- Oil metering pump failure

- Fuel system failure

- Electrical system failure (whatever that is...?)

We can leave out blown water seal then, right?

Hope that helped.

good luck

Patrick

 

I had hot start problems up the ying yang did everything ,people did not believe I did a good compresion check , I knew I did, so my last straw was buy some brand knew injectors or resort to the switch method , so I bit the bullet and bought 4 brand knew injectors from marren motorsports in derby ct , finally I can say I resolved the problem on a hunch, no more embarising moments.

 

I had similar problems, and faulty injectors tend to keep spraying at low levels, consequently briefly flooding the chamber. It eventually closes by the time the car is cold.
The solution to my problem was my alarm system screwing up one of the coils(ignition kill crap).