Hey all,

I drive a manual magna tj sports, its done 280K and has generlly performed very well

heres the problem:
Since about 2 months ago my car has been severly underpowered, i mean accelerating to 60 in 1 minute, crawling up a hill at snails pace, barely able to tow my trailor... etc.
When i try to accelerate up a hill the engine sounds like its turning very slowly even if its actually doing 2K rpm.

Does anyone have any idea what could be the problem?

So far I have changed the following:
Spark plugs, spark leads, ignition leads, rotor and cap, fuel filter, air filter and oil change, even the oxygen sensor... but NOTHING :(((((
All of the above was very worn, so no loss in replacing the components.

the only other idea i have is the fuel pump

any feedback would be very appreciated.

My MR2 was similar to that.. Felt gutless and had no up and go!

We put it on a dyno and found a nasty AFR reading.

A little bit of a tune, a few replacement bits n pieces and she came up a treat!

SuFz :ninja:

im also thinking the air fuel ratio is probably off, but cant figure out the cause!
the oxy sensor didnt do it so now im a little bit stumped :(
do you know what parts were malfunctioning on your mr2?

Ignition coil? Blocked cat? Maf sensor?

If afr was far enough out to cause issues as bad as your describing, you would have fouled your plugs in minutes.

At a guess, I would check that the exhaust isn't blocked up, eg: by a collapsed catalytic converter as Life suggested.

Also, have you really annoyed anyone? Did they shove a potato into your muffler? That would certainly reduce performance :)

Oggy:
hahahahaha ill check for the pottato :P
actually have pulled out the front end cat, turns out its perfect which was a surprise!
i'll check through the rest of my exhaust because its soundg waaay deeper then its meant to be..

life:
maf sensor.. hmm good idea! :D

Woob:
"fouled your plugs in minutes." do you mean flooded or fouled - as in destroyed?

Clogged with petrol residue, unable to spark

My mr2 was oxy sensor and maf..

Get your local to run a diagnostic.. See what error codes come up..

SuFz

thanks peeps! hopefully the magna will be back to its original power soon :D

O2 sensor.

O2 sensor.

... Can you read? He's already replaced it!

LOL spud100 not every problem in car is regarding the O2 Sensor! Seriously! All I see you posting is "fix the O2 sensor..."

My recommendation is on the same line as the others - replace the maf/air intake sensor. I forgot to connect mine recently after fixing the rear gasket and my car's performance was terrible. They rarely kick the bucket but that doesn't mean it never occurs.

Update: I have checked the MAF sensor, throttle position sensor and fuel injectors. all of their characteristics seem to be within tolerances specified by the manual...
I think i might go crazy if i have to drive another day at 10 kph... :angry: !!!
only idea left is to test the fuel pump / pressure... :neutral:

I finally found something that could be the cause of my under powered ride :D... but Im not sure what to do next =/
I did an ignition timing test and found the timing to be 5 degrees ATDC at idle and 10 degrees BTDC at 2000 - 3000 rpm.
From what i understand the correct values should be 5 BTDC for idles and 10 BTDC under load.

But still i have no idea how to fix this problem, or if its even the reason my car barely climbs a hill

Any feedback would be very appreciated :)

If your worried about an exhast blockage, drop the exhaust and see if that helps, it will be noisy, but if the car suddenly moves, then you'll know.

I finally found something that could be the cause of my under powered ride :D... but Im not sure what to do next =/
I did an ignition timing test and found the timing to be 5 degrees ATDC at idle and 10 degrees BTDC at 2000 - 3000 rpm.
From what i understand the correct values should be 5 BTDC for idles and 10 BTDC under load.

But still i have no idea how to fix this problem, or if its even the reason my car barely climbs a hill

Any feedback would be very appreciated :)

I have a MUTTII here, we can hook that up and go for a drive, that will tell us what the advance etc is in that respect. My bet is on a blockage in either the resinator or muffler has collapsed internally, try just unbolting the rear muffler and go for a quick drive, that will eliminate the muffler.

Also, have you done a fuel flow and pressure test at all?

I have a MUTTII here, we can hook that up and go for a drive, that will tell us what the advance etc is in that respect. My bet is on a blockage in either the resinator or muffler has collapsed internally, try just unbolting the rear muffler and go for a quick drive, that will eliminate the muffler.

Also, have you done a fuel flow and pressure test at all?

thanks madmagna

I have already tested the exhaust for blockage by taking off the cat, all it did was make more noise :P
Fuel pressure test has also been done. It seems perfect - 40 psi at idle and up to 50 psi when revving / under load... having said that the regulator also seems fine.

MUTTII sounds amazing, what area are you from? im from greensborough

Just an update in case anyone is interested where this goes:

After visiting a few generous mechanics i have been advised that the most likely problem is the distributor (They had exactly the same problem with another magna that was fixed with a new distributor).
Il be checking / replacing my distributor over the weekend. hopefully this resolves this very annoying issue :)

Found the problem and Thought i would finish this thread...

Turns out my crankshaft teeth are completely threaded, and plate on the back of the crank cog is torn off :eek2:

No idea how this happened but i think im already crying :cry:

Now im left with the big decision of what to do!! peace

Found the problem and Thought i would finish this thread...

Turns out my crankshaft teeth are completely threaded, and plate on the back of the crank cog is torn off :eek2:

No idea how this happened but i think im already crying :cry:

Now im left with the big decision of what to do!! peace

I didn't expect that, hope you work it out mate.

Crankshaft issue.... Ohhh
Can you glue it on with liquid metal? :)
Sorry to hear that.

Found the problem and Thought i would finish this thread...

Turns out my crankshaft teeth are completely threaded, and plate on the back of the crank cog is torn off :eek2:

No idea how this happened but i think im already crying :cry:

Now im left with the big decision of what to do!! peace

Finding the problem means you are half way to fixing it, so stop crying.
You will need a new crank cog, and new crankshaft angle sensor at the very least.
If you can put up a picture of what you mean by "crankshaft teeth are completely threaded" we may be able to give a more accurate list of the parts you need.

Usually these parts get destroyed if the cam belt is damaged through wear and bits flap about. Have a look at it.

PM Madmagna, he should have the second hand parts you need.

Finding the problem means you are half way to fixing it, so stop crying.

Ahhh AMC, where you find great advice and the occasional harden the F**! up :D

Ahhh AMC, where you find great advice and the occasional harden the F**! up :D

No, honestly! I meant it sincerely and in a much less aggressive manner! If someone's car has a problem, a lot of people randomly replace parts in the hope it will fix things. Knowing what the problem is saves time and money. And crying will just make it harder to see what you are doing. So it helps to know what the problem is, and not to cry over it! ok?

Of course, when your car has a problem and it upsets you, I will gladly tell you to HTFU. lol

Finding the problem means you are half way to fixing it, so stop crying.
You will need a new crank cog, and new crankshaft angle sensor at the very least.
If you can put up a picture of what you mean by "crankshaft teeth are completely threaded" we may be able to give a more accurate list of the parts you need.

Usually these parts get destroyed if the cam belt is damaged through wear and bits flap about. Have a look at it.

PM Madmagna, he should have the second hand parts you need.

hahaha yeah i ended up hardening the f*** up!! found out crank shaft actually doesn't have teeth on it (miss leading because the cog does)
I can post up some photos if anyone is interested but here is the resolved case:

Issue: plate behind crank cog was completely removed from cog (means crank angle sensor doesn't read anything useful) also the key that holds this cog on the crankshaft was bent by ~10 degrees (this is why i had idle ignition timing 5 deg ATDC)

Reason this happened in the first place: I believe one of two:
1: i didnt screw the bolt into the crankshaft tight enough 80,000 K's ago
2: Engine mounts are completely destroyed (possibly high vibration caused this bolt to loosen more so)

And yeah all issues were fixed by replacing cog, key and crank angle sensor (it was cracked so decided to play it safe)

As a result my car is back to life and ripped an awesome burnout just to prove to myself its got its original power back :D

And thanks all for the feedback! :D (im one happy kid now that my car works after a month of slaving over it :P )

Excellent! Did you work out why it self destructed? Cam belt OK or did you need to replace it? I hope you got that crank bolt tighter this time.

Good hint for anyone chasing power loss though, to check the ignition timing. If it is way off, suspect that key on the crank cog.

Good to see its all fixed and you can rip killa burnouts!

:)