Ok so here I'm puzzled and any thoughts would be appreciated.

Problem: Major loss of power, can't go over 3500-4000 RPM with 1/4 pedal, engine will shutdown if I give to much gas. It will not restard right away, it cranks and everything but it doesn't seem to spark.

How it happened: I was about to get on the highway, 3rd gear with about 3/4 pedal , and the car had a stutter... changed gear, got on the highway and everything seemed ok. I did a couple of mile in 6th at steady 65mph trying to figure if it was a random misfire or something else, everything was still good until the moment I got out of the highway. The car started to stutter again under load, and I was absolutely out of power when a had to climb a small hill, I when from 4th to 2nd and the car died a the top and was able to restart on compression while going down. Parked the car, checked if cables weren't plug correctly, let the car cooled and decided to head back home since it restarted and idled fine. I almost got home by avoiding highways, early shifting and going smooth on the gas pedal, but again it died while climbing a little hill and wasn't able to make any power.

The car had 2 codes:
P0103 (MAF related)
P02 (WTF is that?)

cleared them at some point and didn't come back, maybe I didn't drive enough. To be honest I had the CEL on for about a week and didn't bother checking/clearing it since it appeared when the engine sucked a bit of water during a rainshower (MS CAI) and thought it was a misfire code that stuck.

The car:
2004 MT
15 000 miles reman engine
religiously premixed
Mazdaspeed intake
brand new spark plugs
brand new cables
oem ignition coils getting a bit old



Sooooo what's going on here?

-No overheat, had a reading around 200°F.
-No drop in oil pressure.
-I checked the MAF, it's a bit dirty and will clean it out tomorrow, but I highly doubt it would make my car undrivable.
-No misfire code, doubt the coils would have died on me just like that.
-Low compression/blown engine? will get it tested tomorrow, but the car starts/runs fine untill 3500-4000 RPM
-Too much/not enough gas? Since the problem seems to be occuring near the secondary injectors kick in point it's probably related. Injectors stuck open flooding the engine or injectors not providing enough gas under load. Maybe this is even triggered by a faulty MAF?

So what's up?

Here's my dyno chart from 2 weeks ago (mustang dyno)

 

More infos, cleaned the MAF and decided to test the car in the middle of the night because it's bugging me :P

Car started as usual, clean and smooth power up to the redline, got over confidant and tried it on the highway, again in 3rd it jerked close to the redline and this time I saw the CEL flashing meaning misfire and then it went downhill until I ran out of power, got home by chance I guess lol.

So to me it looks like an electronic part that can't handle heat, so when the engine gets to full temp it start sending wrong signals (MAF) or just can't deliver power (ignition coils). I'll try to swap some parts tomorrow, we'll see.

Can we cross blown engine, injectors and fuel pump from the problem list since I was able to get full power after a cooldown?

 

Codes from last night

P0201 Injector related
P1301 Misfire Detected (High Temperature Exhaust Gas)
P02 ???

 

Could it be the SSV stuck closed and not throwing a code? Just trying to figure out the possibilities here.

 

Not necessarily. It sounds like an overheating fuel pump could be causing your problems. If that's the case, it would be less likely to happen with a full tank. What have your fuel levels been like when experiencing the problem?

Replacing the pump might be a good idea in general with a car of your vintage. I'm thinking about doing mine (04 on its second engine as well) as a preventative measure. I did overheat it once long ago while I was on track running below 1/4 tank of gas. Hasn't caused any problems since, but it worries me.

 

The tank is half full, I changed the coilpack this morning and it didn't help at all. Ran a compression test with the TR-01 and it doesn't look good at all

So is it possible that even with low compression I'm able to achieve close to normal performance all the way up to the redline until the engine heats up a bit? Car ran 10min without hesitation early this morning and then the stutter came back, same thing after changing few parts this afternoon, but this time it died after 3 minutes...

TBH at this point I think the engine is gone, but I want to be sure the way the engine behave is typical of a low compression. On the otherhand a bad fuel pump is possible, considering it all happened very suddenly and during the hottest day of spring yet.

 

you have a cat? if you do check it.

 

Still have the cat, will look into that also...

 

good luck my friend, good luck

 

A little update, did a bit of datalogging and tests tonight. Temperature was very cool and I didn't ran into any problem in about 30 min of idle and 15 min of cruising around the neighborhood, no CEL, no code, nothing... Too bad I don't have reading on fuel pressure through OBDII

As for the cat, not getting the typical glowing red color, nor bad smell and the air flow seems unaltered.

The more I think about it the more I believe it's a faulty fuel pump probably overheating as mentioned by fizzer. Hopefully Mad666Max will hook me up with is old pump for some more testing. More info to come

 

What readings did you get with the TR-01? Haven't heard of that before, is it known to be accurate?

Hopefully the fuel pump fixes it. Rockauto.com has one for almost half the price of Mazda.

 

http://www.twistedrotors.com/

a little search would have answered you my friend, i own the tester and works great.

hope its the fuel pump too...cant find my spare one...dammit

 

Did you clean the ESS? It's worth a shot!

 

Bumping this up, big thanks to all who helped but i'm still a the same point as of right now...

-Changed the fuel pump for another OEM Mad666Max lend me: didn't change a thing
-Plugged an Autometer voltmeter to see if a drop of power would cause the fuel cut: steady voltage around 14V even during the stutters

So basically the car idles/drives fine for about 10 miles and then gets some sort of "cut" at 7000rpm, then 6000... all the way to being undrivable or simply stalling. Most of the times the car would start right back up and will drive ok for a few miles...