mor

I was driving my car pretty hard yesterday, went mountain racing with my friend's new Lancer then while going home I was WOT in 5th so I'd say somewhere around 130 mph but it stopped pulling.

When I exited the freeway and my rpm's dropped to like 2000 my vacuum was fluctuating from 2-4 in. hg and my car felt like it was about to stall but I think the ISC raised it back up.

I thought I blew a seal, still not sure but I don't think so anymore because I heard a leak somewhere near the firewall behind the UIM and then sprayed some carb cleaner and the motor would almost stall so I'm guessing I have a vacuum leak somewhere back there. I didn't notice any hoses popped off so it might be some gasket.

Any ideas? Or did I blow an apex seal? My car still runs pretty smoothly when above 2500 rpm. Needs a little more throttle than before but the pull is still smooth.

I'm thinking DT, AWS, or ISC gasket or related hoses. Could be under UIM too like on solenoid rack but I didn't notice any hose popped off. I'm in desperate need of help, thanks!

911GT2

Sounds like the MAP sensor hose problem, but I didn't think the symptoms went away above idle. Hmmm....

BigIslandSevens

iTrader: (4)

There are 4 hoses that connect to the UIM on the firewall side(i remember 4 anyways) MAP,DT,and 2 from the rats nest to the UIM nipples. 1 of these 2 have a green/white check valve in line. Those are the hoses that I think you can check without pulling the UIM. My bet is that it is a vaccum related issue rather than a blown seal. Good luck!

mor

I found the leak, it was the hose with the check valve by the firewall. Connects to the "switching" solenoid valve that works the ACV. I reattached it and I'm still having the same problem.

Do you guys think I blew a seal?

911GT2

When I blew an apex seal, the car wouldn't idle unless I held it at about 3000rpm. There was a good amount of black smoke coming outta the exhaust, and NO power below 4krpms. I had to slip the clutch to get it moving, and keep it up above 4krpms to move the car at all. It would not go over 40mph, period.

Based on that, I'd say you probably didn't blow an apex seal, you may have cracked one, but I don't know too much about that.

mor

I have no power...and vacuum/boost gauge fluctuates across whole powerband.

No black smoke whatsoever.

I can still drive all the way until 80+ mph. Just a little less responsive.

I'm lost! I'm scared too! =(

BigIslandSevens

iTrader: (4)

do a compression test. Even if you don't go to a dealer. Get a traditional tester and make sure that the readings come up in smooth, even pulses. It's not the exact readings for each chamber,BUT you can get an idea of if you have a blown seal. I diagnosed my blown seals without the thousand dollar mazda tool! Make sure you hold the throttle wide open and have the igniter disconnected so you don't get spark while testing.(probably will need a friend or GF to help out) I think you may still have leaks(other leaks) Did you pull the UIM off? Also what boost levels did you see while runnig on the highway?

mor

Yeah, I think I'll have to do a compression test. What readings should I see?

Maybe I do have other leaks...I was planning on doing the sequential simplification anyways so maybe I'll just do it now.

I did take off the UIM earlier today and put it back together. I don't have the leak like earlier but symptoms are still the same.

Prior to the incident, my boost pattern was 12-8-12 or close to that. I didn't notice any boost creep or spike. Today I could still boost but I didn't go full boost maybe just to 8 psi and never secondary.

Herblenny

iTrader: (13)

I don't think you blew the engine.. My guess is also MAP sensor hose.. But I could be wrong..

Since you are also having boost issue.. It could be the hoses.. I changed to simplified seq turbo and it helped a lot.. also make sure to check all the one way valves..

I used to have secondary turbo problems and one way valves were the problem.. 3 of 4 were bad.. Now I have primary turbo issue.. only when the car warms up.. its crazy..

BigIslandSevens

iTrader: (4)

Herblenny took what i was going to say next. Check all your check valves for proper opration.. Not just that they aren't cracked but that they only flow air in the proper direction. One of the most common ones is the green/black one under the pressure tank. Also check the normal things such as all the couplers to and from the IC for leaks/cracks. As for the compression I like to see at least 100 psi total after cranking. It may be more it may be less.. The most important thing is that the readings are consistent with eachother and they climb evenly.( no cracked seals)...........Just a thought but what does your car boost if the pills or boost controller are off? (I don't know if it's different than the stock ECU'S 7 psi) Check the hoses going to the valve unit of the boost controller.

RexTech

Once my car had a similar problem and it was the map sensor hose, it was out of place. Check the map sensor (pressure sensor), page F-181 in the workshop manual.

Does your car has any error code?

good luck,

RT

mor

Nope, no error codes. And I will check all turbo related hoses, however, this is not a turbo issue. I have absolutely no power at low rpms (vacuum is almost 0 sometimes).

I've checked the map sensor several times and it seems okay. I've raised the idle temporarily to compensate so I won't die out on the road.

When a seal is cracked, what does it feel like? Or when an apex seal breaks what are the symptoms? Similar to mine? I guess the compression test is the next step. I'll let you guys know how it goes. Probably be done on Tuesday. Thanks for all of your replies!

BigIslandSevens

iTrader: (4)

When mine went it smoked(blue) like a bastard! Idle was OK then it would just stall. Smoked real bad as it got worse! Stalled at the lights if i didn't keep it reved. Did I mention it smoked bad!And stalled. The compresion test will tell you alot. Hopefully it is good news.

mor

I don't have any odd amount or colored smoke. It just stalls, not all the time but it definitely will if I have AC on. I raised the idle to compensate so hopefully it won't die at the lights.

Compression test it is! Let you all know soon enough.

mor

Front: 25-25-100.
Rear: 100-100-100.

I can't understand what went wrong! I thought I was running super conservative from the M2 Stage 3 ECU.

I wasn't overboosting, yeah I had a midpipe but I also ported my wastegate and I never got boost creep.

What the hell could have done it?

I sure don't want to ruin another engine. I only had that engine for 5 months. I rebuilt it with my mom's boyfriend and it was running fine.

Here's what I'm thinking of doing:

Malloy Mazda Reman, $2340 shipped. Stock injectors (send to RC), Walbro 255 fuel pump, and stay with the M2 ECU.

I know it would be wise to get a Power FC, larger injectors, and tune it. I don't know if I can afford it though.

twinturboy

You said you heard a vacuum leak near the firewall and had found the line disconnected with a check valve in it. Are you sure that wasn't the map sensor. If your map sensor line got blown off from the boost, it wouldnt give a correct reading of the manifold pressure and would run the engine very lean. I assume you were boosting at least 10psi, and with that much air and the map sensor reading 0psi, the motor would surely detonate itself to death. Thats what I think happened.

mor

It wasn't the map sensor line. But hmm...the hose that popped off was from the manifold so it would definitely cause a pressure drop. Well...next engine is gonna have sequential simplification and not silicone hoses...I'm gonna use some sturdy rubber hoses and glue them all.

pomanferrari

iTrader: (1)

So your engine is blown.

I don't see an Intercooler. Air temp coming out of the turbo can be as high as 300+ deg F; the stock IC sucked as once you're hard on the car it doesn't drop much more than 50-75 deg F. So if your intake temp is high and running stock injectors and pump, you couldn't put enough fuel to cool the engine so as to prevent detonation and cracking of the apex seal.

BigIslandSevens

iTrader: (4)

bummer bro!! I was just going to pm you and ask whatthe results were. I'd be leary of that ecu for another engine. Yes the FC does cost alot and tuning is extra but new engines are by your quote at least 3k installed and working properly. Thats more than the cost of the ecu and install+tuning. Dammit! I hate when people get bad news! But hey you sure took care of that front rotor! Also i be leary of rubber hoses. Those are what causes evryone to go with silicon in the first place. just my thoughts! Sorry again dude.

rynberg

Umm....no. When the MAP sensor hose disconnects, the ecu immediately goes into "limp home" mode. As anyone can tell you that's experienced it, your scenario is impossible.

MOR:

I wouldn't be so quick to blame the ecu, even though you are running it with a streetport and a midpipe, which are no-nos. You said you and your mom's boyfriend rebuilt the engine? Do either of you have experience doing so? No offense, but I think you have to look at that fact as a factor in your blown engine....

In any case, you said you never had boost creep but did you make sure you weren't spiking at the transition?

Sorry about your engine. Good luck with the next one.

mor

My next mod was going to be the Greddy 2-Row FMIC. Now I can't do that until I get the new engine and decide on how to do the fuel system.

The reason I went with M2 and stock fuel was because all I was planning on was full exhaust, intake, intercooler and 12 psi. Plus I have street port so I thought that would be good enough.

Now I'm thinking even if I upgrade the fuel system it will be safe...but it's just an overkill by far. Argh!

mor

Rynberg:

No offense taken...when rebuilding yeah we skimped on a lot of stuff so yes I have taken that into consideration.

No boost creep, no spike...for sure! I'm always concerned with that so I pay close attention.

So what advice do you have for my next engine. Stock fuel system with cleaned injectors and new pump? Should I stay with stock ports? M2 ECU okay still?

Yes, I'm being cheap and if that's stupid then please feel free to explain. No I don't want to blow another motor, I didn't think I would the first time but I did so obviously I need to make some improvements. Any help is much appreciated, thanks to everyone so far!

Snook

iTrader: (12)

how many miles were on the old rotor housings that you reused? That's most likely a big factor

Rule the ecu out

If you want a very reliable car get your stock injectors cleaned get a supra fuel pump get a reman with the longest warranty possible have the turbo simplification done or go non sequentail have a shop do all of the work and on that ecu run a downpipe catback and intake and maybe a highflow cat but no midpipe and no streetporting.

Also 10psi should be adequate for street driving if you want to be super careful. You won't blow a motor running like that. I can't imagine how long a properly built motor would last with those mods.

Seldon

PowerFC... all I can say