ddub

No, 250, that's cranking rpm.

xtremeskier97

ah...learn somethin new everyday...thats what I love about forums. Thanks.

CSM RX7

Obviously, there could be a few different reasons for the hot start problems. Not to say I know anything, but when I replaced my fuel pump my problems went away. But with these cars, a lot of problems can be caused by several different things.

Monty

Icemark

85 PSI is at sea level and 250 RPM is the absolute bottom figure that Mazda suggests.

In my book, if it is that low, chances are that it is past rebuilding, and new housings will be needed to be on the order, not just a gasket and seal kit.

And lets face it... at 90 psi, you are way too close to 85 psi for me to feel safe. But then I guess that is why I have not ever been stranded or had a blown motor. I rebuild at 90.

Icemark

That would be related to the anti drain back valve in the fuel pump, and would just add about 5 extra second of cranking... regardless of warm or cold (actually more likely when cold or has been sitting).

dennis blackstone

well we seem to agree my compression is decient, dont forget i got my injectors cleened ,and remember it started happenig when i put my walboro in,so i did my own test to see if it was the pump, by putting my old pump in ,the same problem arised,could it be the ecu not turning the injectors of

dennis blackstone

mazdatrix makes a gizmo , witch reliefs pressure when the engine is shut off has any one used this , and what was your results

Icemark

The gizmo as you call it only fixes the problem if your injectors are leaking.

It shunts any pressurized gas back to the gas tank when the fuel pump is off.

Icemark

well, if you are happy with your compression then the next step would be subsituting the ECU.

If subsituting the ECU solves the problem then you have at least one bad transistor in your existing ECU.

dennis blackstone

whot transitor is it 801 what every body is talking about ,and how does that affect floodind

Icemark

If the transistor is damaged, the ECU doesn't allow the BAC to open while cranking for extra air when the engine is warm, so it makes it more likly to flood on cranking (same effect as if you pumped the gas pedal while cranking).

dennis blackstone

on the hot start subject can some tell me how that happens and why

SureShot

I'm running with low compression.
It was no sweat until I upgraded the fuel pump.
Since then it wants to flood on startup.

The real fix is to rebuild, which I'm saving for.
In the meantime I put a simple pushbutton under the dash to ground the fuel pump low voltage relay.
I just hold it while cranking.
That keeps the fuel pressure low until it begins to run.

oregano

iTrader: (1)

lol. it sounds like u rebuild your engine every year or sumthing.

xtremeskier97

I have to check my compression once I get my engine turning...though I will prolly do a rebuild anyway.

dennis blackstone

my engine has only 30000 on it with excelent compresion,there has to be a raeson for this floodind

ddub

Could be that your injectors are leaking.

dennis blackstone

i had all my injectors cleaned at marren motor sports,could it be tha the injectors are worn out inside,and when they clean then they dont get the injectors hot enough for the to leak , just a theory.

dennis blackstone

i think we are getting somewhere now

Icemark

90 PSI peak on a motor with 30K on it is not excellent compression.

100+ psi would be normal for 30K

dennis blackstone

well we tested 3 other rx7 and they had the same compresion ,they did not have a hot start problem,thats why im so confused over this issue.it seems we are getting some good input on this issue,we should not give up on this sooner or later we will solve this problem.

dennis blackstone

Now we no compresion is not an issue by majority vote and all my buddys rx7 compresions are the same as mine and they don't have a hotstart problem so ,are the injectors worn out,remember I had them cleaned.

Rotor13B

You need to take and have your compression tested with rotary compression tester. All your test shows is that all your friends cars can make the tester read the same reading, What are the odds of that?

RXSevenSymphonies

iTrader: (2)

Here check this stuff:

Fuel Pressure
Fuel Pressure Regulator Solenoid Valve
Intake Air Temp Sensor
Water Thermo Sensor
Compression
Fuel Pump/Fuel Pump Wiring/Fuel Filter
Vacuum Hoses
TPS
Timing
Spark Plugs
Spark Plug Wires
Coils
AFM
ECU
Fuel Injectors
Air Filter

dennis blackstone

Like I told you one of my buddys has 5000 miles on his and one has 79000 on the other so like every one saying compresion in this case isn't an issue