andrewstein

Hello, I purchased an 87 na manual FC 214,000 km on the body a fee month back with supposedly 40,000 on the engine with no documentation aside from "trust me, bro." within a month and a half or so before I parked it in the winter (end of October) it developed an issue where it would flood on hot starts unless there was that seafoam fuel additive/ fuel system cleaner in the fuel system (only additives i have tested). Before anyone asks about a compression test, it turned out fine when I tested it before parked it. Has anyone had similar issues? Or would anyone know how to properly fix it aside from always running some sort of additive?

mazdaverx713b

iTrader: (91)

When you performed the compression test, was it performed at normal operating temperature and with a rotary compression tester? If not, do a proper compression test first to establish a good baseline. You want to make sure you're working with a good engine and not throwing money at a tired engine, bandaiding an issue.

Second thing we often see with higher mileage FC's is leaking or sticking injectors. If you don't know the history of the injectors, I would recommend removing them and sending them out to be professionally cleaned and flow tested. These are the two basic first steps in diagnosing hot start issues.

Next, how old are your spark plugs and wires? The ignition system can play a big part in starting the engine warm. The resistance in the coils can be out of spec when warm but fine when cold. Consider testing them per the FSM hot and cold.

andrewstein

yea it was normal operation temp. I’m not too sure about injectors. I’ll have them looked at and I have new spark plugs and wires to go in once it’s warm enough to work on the car again

mazdaverx713b

iTrader: (91)

Do you recall the compression numbers on each rotor? Should be three different numbers per rotor.

andrewstein

they were mid to mid 90's across the board. from my minimal research and knowledge that's a bit on the lower end of acceptable. disclaimer, that is completely from memory, ill try to find the numbers, I wrote them down somewhere

mazdaverx713b

iTrader: (91)

That's acceptable as 85 psi per face is the minimum. I would definitely consider having the injectors cleaned and flow tested. They are know to leak when the engine is off from the pressure in the fuel rail. This has been something we have been dealing with on these cars for the past 20 years honestly. I remember guys installing fuel pump switches to cut fuel when cranking so the engine didn't flood. To me, its easier just to fix the car properly.