Fritz_X

iTrader: (1)

Well I guess the motor had a problem already we hooked up a straight pipe because the cats were clogged. We went out to test it out and make sure it ran alright, didn't creep stayed at or under 8.5 psi the whole time. A couple of runs on the highway in 3rd and 4th to check a/f ratios with the wideband, still running rich. Shift from 3rd to 4th, no power, shift back into 3rd, no power, pull off to the side of the road and crank with fuel pump switched off to see if flooded, even pulses but only half as fast as usual. Drive back, car dogs out like all hell so we leave the hazards on and are in the uber slow lane. Get back to the garage do a compression test, rear rotor 90 90 90, front rotor 0, 0, 0. Well I guess even if you are careful, it doesn't pay off, the motor never pinged it ran rich we had an FCD and the stock airbox was in place restricting airflow and the **** still blew up on me. The car is getting rebuilt this week, Haltech install etc, we are pretty sure that the front rotor had a cracked or chipped seal to begin with from the extra heat of the clogged cats that were on there for quite some time, and the 9 lbs of boost were all it needed to bid it's final adeiu. I don't understand why so many people hate rotaries so much? They take so well to mods! Seriously though I guess it is a blessing in disguise because I wasn't going to start this project (haltech install streetport rebuild) until later this winter or next year. Guess my car had different plans. Oh well. The '7 never loses!!!!

--Fritz

Rxmfn7

iTrader: (4)

That really sucks to hear. Exact reason an LS1 swap still nags me from the back of my head... [whisper] rumble rumble [/whisper]

Fritz_X

iTrader: (1)

How many motors have you lost to the fickle rotary gods Lenny? Just out of curiousity.

--Fritz

Rxmfn7

iTrader: (4)

None yet... *knocks on wood*. The one Im about to drop in my car will have the highest HP output of any Ive owned though, so it makes me a little nervous.

Fritz_X

iTrader: (1)

Well good luck, with the haltech and proper tuning and other supporting mods you should be fine. Or at least that seems to be the theory we all work under, when it comes to these cars.

--Fritz

hondahater

iTrader: (2)

Well that just sucks! I've been doing alot of mods to my car lately for preformance but mostly preventative measures like bigger radiator, oil pellet, fmic, and soon to be wideband however if all of these don't make this car reliable I'm going to be very pissed.

Mark'sMazda

next time get teh injectors cleaned..a frined of mine blew his at 9psi also..due to poor spray pattern.

jon88se

How many miles were on the motor? It was likely just tired and the victim of father time. Can't beat the clock

ddub

Yah if it was old the apex seals might've just been ready to give out anyways.

Fritz_X

iTrader: (1)

Car had 91,000 miles. Pretty pathetic if you ask me....

--Fritz

hondahater

iTrader: (2)

well I got my injectors cleaned as well but damn 91,000 miles that is pretty pathetic.

ddub

Are you the original owner for all 91k? The previous owner/s might've used and abused it you never know, could cause for shortened apex seal life.

Fritz_X

iTrader: (1)

That's what we are assuming, it was owned by an old Russian guy in his 60's before me but the original owner was his ex-wife, however she bought it before marrying him and he said she was pretty crazy, which would explain why at 91,000 miles the car is bone stock, yet had a snapped in half front diff mount, a tranny that made more noise than a Ricky Martin concert, and shifter bushings that hitched the last train back to the coast. The car was definitely beat on in it's stock form in it's early years, not to mention it was only driven 3,000 miles a year for the last 5 years up until I bought it, and put 11,000 miles on it in 11 months. The OMP is also suspect as we lost a half of a quart of oil after driving it for 15 minutes, which is A LOT more than it usually burns/leaks.

--Fritz

jacobcartmill

iTrader: (6)

exactly how rich is "rich" ?

there are other things that can cause detonation that just AFR's.

NZConvertible

The way you say you had a FCD sounds like you think this would help protect the engine from harm. This couldn't be further from the truth. A FCD is not a safety device; it disables a safety device. It allows you to run more boost than Mazda thought was safe, and holds ignition timing static instead of allow it to retard further as boost increases. This increases the chance of detonation.

Since you didn't exceed 8.5psi, the FCD wouldn't have contributed to the engine's death, but you should be aware that it's not a safety device and should always be used with caution.

RETed

Aw come on, can we drop the preaching?
I find the overboost fuel-cut to be dangerous.
So how can you tout it's a SAFETY "device"?

So what is your option to the FCD?
Are you like BDC and tell us we all over to go stand-alone EMS???

Pull the plug to the boost sensor???


-Ted

NZConvertible

Ted, I know you believe fuel cut blows engines. I don't.

I'm not saying you shouldn't use a FCD, I'm just pointing out that it's not a safety device. It's purely there to get you around the boost limit. There are inherant risks in using one, but if you're aware of these risks and compensate for them, you won't have a problem. If you think a FCD will protect your engine from all harm, you're in trouble...

coldfire

iTrader: (1)

^this should get interesting^


btw, Fritz said he has 0 compression on all three sides, is that even possible, lol?
because that is pretty crazy to be boosting 8.5+ and running fine and then BAAM, 0 psi on ALL faces of the front triangle...

RETed

Yep, seal lets go and takes out all three apex seals.
Rotor housing typically gets killed in this kinda failures.

BTW, I get tired or repeating myself...
I've put this **** in my FAQ section.
http://fc3spro.com/TECH/FAQ/fuelcut.html


-Ted

NZConvertible

From Ted's site...Peak stock boost is 6.56psi and 8.25psi as per the FSM. Fuel cut for the S4 is definitely not 6.5psi, since I ran 8psi for two years without ever hitting it.

Not retarding the ignition as boost increases can be just as dangerous as not adding more fuel. Either will eventually lead to detonation unless you make some allowance for it like I said. Lowering intake temps (cold air intakes and intercooler upgrades) and/or adding more fuel are obvious ways to do this.

Please explain how this could cause a lean condition. No fuel means no combustion. The injectors are either opened for a normal cycle or not opened at all. Even if some fuel somehow gets into the chamber, it needs to be enough to actually support combustion. Lean conditions are bad because of the high resulting combustion temps. A small amount of fuel burning in the chamber is not going to create enough heat to do any damage. And where does this fuel come from? I'm not just arguing for the sake of it, I really want to know.

hondahater

iTrader: (2)

I think everyone just needs to invest in the rtek 1.5 chip or soon to be 2.0 chip so that it will retard the timing when boosting over 9psi.

jon88se

If it was the original motor that is the answer...you have no idea how the car was treated since the first owner took it out of the dealer. You don't know if they used crappy gas, if they didn't change the oil regularly, if they beat on it when the motor was cold etc...

Rebuild it and drive happily for another 91K

RETed

Think about it...
It's a FUEL-cut, not an ignition-cut.
The ignition is firing all the time.

Yeah, I guess the page is not meant for you, since your logic is not consistent with mine.


-Ted

Fritz_X

iTrader: (1)

It wasn't even BAM no power, it was just shift and no power. I wondered if maybe the fuel cut on decel that is programmed into the factory ecu could have also contributed. Remember we heard no ping, no signs of detonation it was just shift into no power, and that was all she wrote.

BTW the exhaust of a blown motor is quite unique, with just the rear rotor going it sounded like this trying to turn over, FUOM FUOM FUOM FUOM FUOM FUOM. Jeez and when it turned on it sounded like my freaking John Deere ride-along mower.

--Fritz

RETed

If everything else was in check, then it HAS to be an ignition timing problem.


-Ted