greasemonkeygarage

THE CAR
JDM FC3S S5 Turbo. Recently rebuilt with Atkins Rebuild Kit ARE146 (Mazda Corner seals). It's Stock except for a 3" Exhaust system (from turbo), Electric fan, K&N Pod filter, EGR delete and the battery is relocated to the back (0 gauge Wire).

THE PROBLEM
Car starts perfectly normal when cold but doesn't want to start when hot. However it will start right up if kicked start effortlessly. The starter turns over fine and it has a new battery (825 CA). Car drives perfectly normal, Idles good, no smoke etc.

What can be the possible causes for this? Any help would be appreciated!

diabolical1

iTrader: (3)

welcome to the board.

Trinidad, eh? good for you.

if you can, i would check the compression.

from what you can remember, were the housings in good shape? what did you do for side seal clearance?

mazdaverx713b

iTrader: (91)

I second a compression test. Perform a proper rotary compression test with a rotary compression tester. If the engine was recently rebuilt, it can still have low compression if the housings or irons are worn or were not lapped properly. You may also want to check for injector leakage. The injectors could possibly be leaking into the engine after the engine is shut off, flooding the engine.

greasemonkeygarage

Thanks, yep all the way from Trinidad.

Will go weekend and do a compression test.

The housing were in good shape with normal signs of wear. Not sure about the side seal clearance.

greasemonkeygarage

Yeah will do the compression test. However i do feel it's flooding.

So I checked to see if it had any engine fault codes and code 11 came up which is Intake Air Thermosensor (engine). So will replace this sensor and see if it helps. Could this faulty sensor make it rich out causing it to flood?

MidnightOwl

I had the same issues on my rebuild at first, and I did the switch thing in this thread:
https://www.rx7club.com/2nd-generati...oblems-499744/

It worked, but after a few hundred miles it worked itself out when it broke in so now it just works without having to use the switch.

greasemonkeygarage

Thanks midnightowl will look try it and see how it goes.

greasemonkeygarage

UPDATE:
Changed IAT sensor (no more codes).
Installed new spark plugs.(correct plug as stated in FSM)
Rechecked timing, was off by 1 tooth(fixed now).
Did a compression test(Rotary specific tester), had good compression on all 3 phases.

CAR STILL HESITATES TO START WHEN HOT!

ANY IDEAS?

Going to check injectors/fuel system next.

Howudoin89

No smoke might be your problem.
Try pre mixing

chrisaleggett

Send your injectors out for flow test & cleaning, it's good to do even if not the root of your hot start problem.. Not sure if your trinidad CA or trinidad in the caribbean? Besides leaky injectors make sure thermostat is operating correctly, check coolant temp sensor for computer, TPS is quick check.

When problem happens are you able to start it by depressing gas pedal all the way to floor?

greasemonkeygarage

I have always used idemitsu premix in this car.

greasemonkeygarage

Yep going to service the injectors either way.
I'm from the Caribbean.
I checked and adjusted the tps recently.
Will check the coolant sensor and thermostat.

It will only start if i pump the gas pedal repeatedly.

chrisaleggett

[QUOTEIt will only start if i pump the gas pedal repeatedly.[/QUOTE]

starting from 89 or series 5 rx7 has flood clear while cranking when holding gas pedal all the way down wide open throttle. No need to pump the gas.. when it doesn't want to start just wot while cranking and left off gas soon as it turns on.
And premix good

greasemonkeygarage

starting from 89 or series 5 rx7 has flood clear while cranking when holding gas pedal all the way down wide open throttle. No need to pump the gas.. when it doesn't want to start just wot while cranking and left off gas soon as it turns on.
And premix good[/QUOTE]

Yea I knew depressing the pedal fully helps, but it seems to start quicker when I pump it.

chrisaleggett

One other idea that would help in preventing flooding is upgrading the 1.2kw starter to a 2kw starter

Rotary Alkymist

Have you timed it with a light?

Have you inspected the PRC system?