moldyviolinist

hi guys, got a problem with my fd.

bought an fd last year and it's been running flawlessly, tons of power, etc.
stock twins modded to parallel, power FC, hks twin power, high flow cat, bigger smic. boosts to around 15 psi.

driving on the highway (5th gear, 70mph, light throttle) on saturday it suddenly started shaking and shuddering, and i had barely any power. I noticed AFRs went rich - around 12, usually it runs about 14 on the highway. EGT was around 1300-1400 F, water temp around 170. Oil pressure looked normal, boost was kinda jumping around at 0. I pull off, and the car dies after I push the clutch. Couldn't start it again, cranking sounded weird.

I'm a noob and have no tools, so I towed it to a general mechanic, as I figured it was something simple.

They haven't been able to find the problem: so far, we know we have fuel pressure, we know we have spark and we changed the spark plugs. Catalytic converter is flowing fine. They were able to start it when it had cooled off, and it'll run with barely any power until it warms up a bit, then it'll die again.

mechanic performed a compression test with a regular compression tester (not rotary) and got 60-70 psi on every face, so he believes its low compression and is "flooding out". but there's no way every apex seal failed at the same time, and it definitely didn't have low compression last week (tons of power, no problems with hot start). Since the compression test is reading approx the same for each face, I figure the seals are fine. If i blew a seal, presumably one face would read lower psi right?

So, any ideas? current plan is to go get a proper compression test at the stealership, but would rather not shell out another 250 bux. also if anyone is local and wants to help me out, i can certainly provide beers and food

lduley

iTrader: (1)

60-70 psi is low, and did he perform the compression check with the engine warm since they were able to start it? Being warmed up i bet the #'s are lower

And don't waste your time at the stralership, at least this guy is checking things out for you, most dealerships see a rotary engine and just immediately think CHANGE IT OUT lol

Your up for a rebuild sorry to say it sounds like

moldyviolinist

Thanks for the reply, not sure if they tested hot or cold. My point was I'm pretty sure he did the compression test incorrectly. I read that if you do it with a piston engine tester it will pretty much always read low?

I mean, physically speaking, how can an engine go from over 300hp and easy hot start, to 60psi on every rotor face in one day? I'm not aware of any way to blow every apex seal at the same time haha. so I still think it's something else.

lduley

iTrader: (1)

You didn't blow any apex seals, if you did, you would have zero compression

And its not the first time a thread has been posted "was driving great than BAM"

And a piston compression tester is good enough to give you a pretty good idea, most dealerships probably don't even have the "proper" rotary compression tester anymore, if they do, probably no one knows how to use it

moldyviolinist

There are a lot of variables affecting the compression reading. Maybe fuel was still in the chamber from flooding, maybe battery was weak.

Anyway looks like an ignition coil is failing once the car warms up. No spark once the coil is hot. When the mechanic did the original assessment he assured me the coils were fine and everything was getting spark... I'm going to replace the ignition coil. Hopefully that does the trick!

I do appreciate the help Iduley, I was just convinced the mechanic was clueless with rotary compression and I don't have a compression tester myself

moldyviolinist

OK, ignition coils didn't entirely solve the problem.... Mechanic tested the ignitor and said it was failing... but that's a $600 part.

Anyone heard of an ignitor failing? What does this part even do? Is there an aftermarket alternative?

Tem120

iTrader: (5)

Ok , I have a cheap and free test for you . FIRST , check if the hose to the MAP sensor is hooked on correctly . IF IT IS ,


with the ignition on with the power FC , read what the vacume / boost settings are at with the engine off it should be very close to zero . but not zero because its inaccurate . unless its been calibrated to be more accurate

but basically It shouldnt read something crazy like 5 PSI with the engine off .

It could be something as simple as a bad map sensor .

good luck