12acole

Well my car has been starting on one rotor for a while now, and it takes 5-10 seconds for both to fire. I suspect that it is a slow coolant seal leak as it only does it if the car sits for a while. What is weird is that the issue got a lot better when my alternator belt and a/c belt both broke, and I ran on battery power only. It only took 1-2 seconds for both rotors to be firing with the belts off. Any idea why this was? The 5-10 seconds came back after replacing both belts which makes me now think that it's an ignition issue rather than a coolant seal. Any ideas are appreciated.

86 GXL

12acole

bump

12acole

no ideas?

hhn2002

the belts placed a drag on the motor causing it to spin slower thus lowered compression. low compresson = weak start.

clokker

iTrader: (2)

I don't believe that compression is speed sensitive.
100 psi is 100psi at 500 rpm or 5000 rpm.

12acole

I don't think the slower cranking speed would explain what I'm experiencing because I hold the rpms at 2500 waiting for the second rotor to start firing.

hhn2002

yes it is, we can all agree no seal is perfect be it rotary or piston, it will leak. if you take air at atmospheric pressure and compress it instantly to 100psi it will remain at 100psi only for a moment, the longer it remains pressurized the more the psi drops. at 500rpm the leak as 10 times the time span to leak than at 5000 rpm.

hhn2002

while its holding the rpms at 2500 before it starts, what its doing is recoating the the housing wall with oil to increase compression, after the five seconds it has then built up enough to fire. that would explain why it only does this after a sits for awhile because during that time period the oil film thins.

12acole

Right, but why would the problem dramatically reduce with no belts on the alternator or a/c?

Trupain

if it is coolant leaking in to one housing, no belt = no water pressure = less coolant forced into housing... just a thought

12acole

That's not a bad thought. Though I drove the car for two days with the two belts off and had no overheating issues so the water pump couldn't have been slipping much (the air pump belt was still connected ).

hhn2002

because even a 250 rpm increase caused by the reduced load can help compression enough to jump start the combustion process.
so you think that either the alternator or the a/c being run on start up is causing something funky that it takes longer to start, something more than just the rotational load they place on the engine right? ok well it definitely isnt the ac compressor because as long as the a/c clutch isnt engaged it cant do anything. so it has to be the alternator, and you think with the alternator running it is somehow messing up your ignition.
assuming that is what the problem is then disconnecting all the wires to the alternator(with all belts on) should solve the problem right? it should keep it from interfering with anything. next time you get the chance try that, see how long it takes. if it takes just as long then my assumption was correct and that it was because of the rotational load.