Hard Starting PFM

[Extreme1]

So when starting the engine, should I not touch the gas pedal? Give it partial gas pedal?

It takes several tries for it to start. Am I doing something wrong?

When it starts it runs fine, no smoke, plenty of power, etc.

[red_z]

How's your battery strength? These things rely on rotational speed to generate compression, so a weak battery will make them hard to start - and the ECU will actually not even let it fire if the voltage is too low. It should crank over pretty fast. Its deceptive too because a weak battery for a rotary will sound like its turning over pretty good relative to starting a piston motor...

The other 'trick' that we have found works pretty well is to pump the throttle fully open 3 times in a row before you try to start it. Have the ignition on and everything and if you listen carefully you will hear a valve actuate after the 3rd pump. Then you should be able to hit the starter and it should fire right up.

Do you notice if it's harder to start when cold or hot?

Dave

[Extreme1]

Thanks for the response Dave.

It seems harder to start when it’s cold. It’s 93* here today, so it’s not too cold. I keep the battery on a tender, but I don’t know how old the battery is. I’ll try your way of starting it the next time. I keep the throttle closed after the third gas pedal pump, correct?

[red_z]

How about engine cold vs. engine warmed up and hot? Is it easy to restart after it has been running? If the seals are going bad, one sign is that the engine will be difficult to restart after it has been run awhile. Doesn't sound like that is your issue though.

Yes, you should be able to keep the throttle closed or just partially open to get it started after the 3 cycles and then just rev as normal once it catches.

Dave

[Extreme1]

Okay thanks for the help.

[mikey]

As mentioned cranking rpms and voltage are important. Always use an external jumper battery.
If the motor is getting worn you ma be down a bit on compression which leads to harder starting.

[Extreme1]

Thanks Mikey

[FastFrog]

Like Mikey said, booster battery when starting it cold is key, that's why it has the external battery connector, also only hit the starter after the fuel pump has done its thing and I give it a bit of gas.

[Extreme1]

Thanks everyone. I think I have a tired battery, I’ll try a jumper battery.

[FastFrog]

Thanks everyone. I think I have a tired battery, I’ll try a jumper battery.

even a fresh batter struggles with the car cold, If memory serves one of the manuals said to always use boost and reserve the battery for if you need to restart it on track, its small and does not contain enough juice for many attempts.

[mikey]

while the cars do hate the cold, I found a BIG difference in starting after I finally replaced the engine in mine. I bought my PFM with a motor that had probably 2000 miles on it, ran until 4000 miles. Always had tough time starting, but didn't think much of it as I was told these cars hate cold starts (even if ambient is 70+) and I never owned a rotary before.
When the new engine whet in, the car fired up almost immediately, as you would expect a normal street car. Perfect compression was the difference.
if you're low on compression, you get to crank for a long time, even with a boost battery sometimes.

you can check your compression with a regular compression tester but watch youtube for the method. You have to remove the schrader valve and then record the gauge movement while cranking. I used the slow-motion recording feature on my iphone. Each pulse is one side of the rotor (x3).

google: "how to check compression on a rotary engine"

[Fred Michael]

Like others have said, tired apex seals will make for difficult starting as they are not providing the proper sealing to generate compression.
ALWAYS use a jumper battery

[Extreme1]

I just had a chance to read the newest posts. Thanks everyone.

[Extreme1]

How's your battery strength? These things rely on rotational speed to generate compression, so a weak battery will make them hard to start - and the ECU will actually not even let it fire if the voltage is too low. It should crank over pretty fast. Its deceptive too because a weak battery for a rotary will sound like its turning over pretty good relative to starting a piston motor...

The other 'trick' that we have found works pretty well is to pump the throttle fully open 3 times in a row before you try to start it. Have the ignition on and everything and if you listen carefully you will hear a valve actuate after the 3rd pump. Then you should be able to hit the starter and it should fire right up.

Do you notice if it's harder to start when cold or hot?

Dave

/////Update/////

Hi Dave,
Your trick worked! After opening the throttle the third time before starting, I heard a muffled pop like a valve opening, and it fired right up without an auxiliary battery. I’m still going to get an aux. battery. Probably a jumper box and I’ll solder the quick connector to it that matches the one on the back of the car. What is everyone else using for an aux. battery? I’d like to avoid a heavy battery and cart if I can.


Thx,
Mike

[FastFrog]

/////Update/////
What is everyone else using for an aux. battery? I’d like to avoid a heavy battery and cart if I can.

This is what I have been using, it does the job but doesnt get great reviews so Prob wont go with the same brand again.
https://www.amazon.com/NOCO-GB150-Ul.../dp/B015TKSSB8

[starfmguy]

We just started using an Anti-Gravity Lithium Ion battery, ATX-20 HD, with 900 CA, 30 AH (PbEq). & weighs 5 lbs. It started my Pro FM cold easily at the beginning of the race weekend (after doing the normal "2 or 3 pump" set up) & we did not use a jumper battery all weekend. It turns over much quicker (the engine likes that) & fires quickly. Works great ! Nice not having to use a jumper battery (we had one on standby), especially on pre-grid. Plus, it makes you smile every time you turn the starter & the engine starts right up !
Mel