Author Topic: lacking power @ higher revs... (Read 3677 times)

B318M42W · « **on:** April 17, 2009, 04:57:49 PM »

Yesterday I noticed that the engine lacked a bit of power arround 5200 Rpm. like it pulls ok to that point and them seems to just pull less hard than usual.
and this morning, it acted up on me. no power at all! couldn't get passed 1500 without it stumbling and wanting to die, but it idled fine?!( about 30 minutes of semi-spirited/fast driving before incident) no codes. restared the car and it was ok, but still feel like it's lacking power. Does anyone have an idea of why it did that??
so far i've got 2-3 theories...
- AFM is going bad (not again!??!?!?

)
- vacuum leak (but got all the hoses changed last year??)
- FPR going to M42 heaven? (since it might be the culprit, it's going to hell...)

help greatly appreciated.

xwill112x · « **Reply #1 on:** April 17, 2009, 06:16:27 PM »

my money is on fpr, or fuel filter.

any stumbling is usually air/fuel related.

cheers,

will

mjnov · « **Reply #2 on:** April 18, 2009, 02:28:02 AM »

pressure reg or fuel filter. doesnt sound too serious. u hope anyway lol

B318M42W · « **Reply #3 on:** April 18, 2009, 05:29:15 PM »

more info on the problem:

as a test, i redlined it twice under lead (2nd gear) and let it sit for about 5-10 minutes. i had trouble getting it started as it would crank about forever and then get a very low idle for 5-10 seconds and then she was fine.

fuel filter was last changed about 12-15K kms. Same time as the fuel pump.

thanks for the input!

B318M42W · « **Reply #4 on:** April 19, 2009, 07:06:13 PM »

BazE30 · « **Reply #5 on:** April 20, 2009, 03:25:57 AM »

I would change the plugs!

Also, check your battery is properly connected (perhaps clean the contacts) and clean out the AFM and idle control valve.

B318M42W · « **Reply #6 on:** April 22, 2009, 08:13:17 PM »

update:
it left me stranded today... (runs now, but still got an issue,)so I did the following things:

took out fuel pump and cleaned it.
cleaned fuel level sender
replaced fuel filter
cleaned ICV
cleaned AFM
replaced the fuel pump connector (seemed sluggish)
checked electrical connections (all seem good)

so now... it left me stranded because the fuel pump fuse (#11) blew up. why did it blow up??? after a test ride, i blew another one up??? why do they keep popping???! when driving hard, it pulled good. but it did sorta cut twice during accel. (threw a CEL for a moment, but it didn't give me another code than 1215 (that i created about 4 days ago by unplugging the AFM) Also, i noticed that the fuses popped when taking a fast turn.

ohh and by the way, the fuel tank is garbage and needs a deep clean. orange/red colored gas came out the old fuel filter along with a ton of crap.

Does anyone have any idea what the??? is going on!!!???!?!
any input greatly appreciated

twright · « **Reply #7 on:** April 23, 2009, 06:44:48 AM »

The fuel pump fuse is blowing because the pump is drawing too much current (or the fuse you have is too small in value.).

So either the pump is bad or its full of crap and can't pump. To confirm this, put a fuel pressure gauge in the engine compartment. If it won't pump 40 psi with the engine on, you found the problem.

B318M42W · « **Reply #8 on:** April 23, 2009, 04:28:18 PM »

update: got the fuel pressure tested and it came out to 37 PSI! not good! so either it's the FPR that's toast or the pump:( blew out 2 fuses in about 5 minutes. getting serious.

nicknikolovski · « **Reply #9 on:** April 24, 2009, 04:29:22 AM »

Test the fpr, remove the vacuum hose at idle, the fuel pressure should increase, and then drop back to normal when you re-connect it. (You can even re-connect the gauge and see what happens to the pressure when you test the fpr).

If you saying it blew fuses then thats not fpr related because it doesn't operate on electrical power. Check the fuel pump relay - could be playing up.

B318M42W · « **Reply #10 on:** April 24, 2009, 09:17:20 PM »

could it be possible that the pump could have trouble sucking in fuel and cause it to internally short?

Jtuner · « **Reply #11 on:** April 24, 2009, 10:42:41 PM »

Check your wiring again if you replaced any connectors, and make sure you're getting a full 12v at that pump connector.. Excess resistance will show a drop in your voltage (if you didn't already know that

) Gluck with it bro

B318M42W · « **Reply #12 on:** April 25, 2009, 09:10:35 PM »

so i pulled out the pump again and took a closer look. I noticed that the fuel flow from the pump was weak and fuel pressure didn't seem very high either. I emptied out the rest of the fuel from the tank with the pump still in. the new fuse on the new wire heated up (but didn't bust) I think that my fuel pump is failing:( no big pressure or even a decent fuel flow (maybe it's just me... took about 4-5 minutes to fill up 2.5-3 gallons.) oh and when i tested the pump resistance when it was working, I'm not sure if i got a possible #... 975 on the scale of 2000 K Ohms on the multimetre. seems a tad to big compared to the 1.4 ohms when it's off.