E53 2003 4.4i Severe Pinging/Detonation under load, reduced power.

[Jusbok]

***UPDATE:
So.....still facing this problem....

Sometimes throws codes and flashing CEL and sometimes not, but ALWAYS has the same lack of power and pings (VERY BADLY) under acceleration - as if the car is in limp mode but with the added pinging (detonation)

Only the three same codes, ever thrown (see initial post below).

Done new fuel pump and filter, theres no blocked exhaust, checked every vacuum hose for cracks etc - nothing.

ANY ideas ANYONE.

Dealer/mechanic/nobody can give me an idea of what it could be.

DIY opinions!?


*************************** ^^^^


Hey Guys,

Been a longtime reader of this forums for the past 3 years, ever since I had my X5 - havent even needed to post to ask you a question, database searches prove wonderful.

Anyways, time to ask for some help...

Finally the X5 has stumped me, everything else (ALOT) that has gone wrong to date has been rectified, with the help of these awesome forums.

I will start with what the car is doing.

The Mrs reported lack of power one day and engine light flickering on and off. Immediately I took it for a drive and it under acceleration/load it would PING severely and have retarded power all through the rev range.

So what I have done:

Codes its throwing are as follows:
"P1341 - Multiple cylinder misfire with fuel cut off"
"P1343 - Misfire Cylinder 1 with fuel cut off"
"P1325 - Misfire cylinder 2 with fuel cut off"

I have, changed all coilpacks, timing chain tensioner, fuel filter, oil, sparkplugs.

It is unchanged however the cylinders seem to change with the misfire codes, after I erase it could be another cylinder misfire....

I have searched for these symptoms everywhere and everyone seems to get different symptoms to mine specifically - the car seems to idle fine, only happens under load/accelerations. The pinging is severe, there is NO SMOKE (white blue or any kind) coming from exhaust.

Another question/symptom, it seems I am only getting emissions from the left exhaust, the right seems to be blocked at idle with only limited pressure exiting the exhaust??? Is a blocked cat possible?

ANY opinions would be a godsend...

Thanks all

Justin

Perth Australia

[upallnight]

Perhaps you got a bad tankful of gas. The gas is so low in octane that the DME is retarding the timing which is the cause of the lack of power and the pinging is just a confirmation that the gas is probably bad.

A block exhaust whether it's the cat or muffler could also be the problem with the low power since an engine is nothing but a pump, pumping air in and pumping air out, but if the pumping air out is blocked, then the amount of air being pumped in is also reduce.

You can remove the 02 sensor and install a compression tester to see what the psi is in the exhaust system.

There's a youtube video on how to do this.

I had an Opel Manta that had a block exhaust and the only way the car would gain speed was if you had the pedal to the floor. The exhaust had a hissing sound, but once I replaced the exhaust the car drove normal.

[Jusbok]

Originally Posted by upallnight

Perhaps you got a bad tankful of gas. The gas is so low in octane that the DME is retarding the timing which is the cause of the lack of power and the pinging is just a confirmation that the gas is probably bad.

Sorry, forgot to mention this is ongoing with multiple fills of gas - we only have 98 octane here in perth and that is all I use from BP..

I also ran an octane booster and fuel system clean through it...

No avail..

[upallnight]

See the edited version of my post about the blocked exhaust.

[Jusbok]

Originally Posted by upallnight

See the edited version of my post about the blocked exhaust.

Thanks upallnight - any opinions on the severe Pinging? Timing?

Theres no timing chain noise, so under the impression the guides are fine...

Car is not throwing any codes for sensors etc?

Thanks again

[upallnight]

The severe pinging could be related to the block exhaust. Did you find the Youtube video for testing for a block exhaust?

[Jusbok]

So.....still facing this problem....

Sometimes throws codes and flashing CEL and sometimes not, but ALWAYS has the same lack of power and pings (VERY BADLY) under acceleration - as if the car is in limp mode but with the added pinging (detonation)

Only the three same codes, ever thrown (see initial post above).

Done new fuel pump and filter, theres no blocked exhaust, checked every vacuum hose for cracks etc - nothing.

ANY ideas ANYONE.

Dealer/mechanic/nobody can give me an idea of what it could be.

DIY opinions!?

[TiAgX5]

When was the fuel filter last changed?

Check the fuel rail pressure, simple 10 min test, $20 fuel pressure test tool. The test verifies idle/low load pressure, rate of rise and WOT pressure (when vacuum hose on pressure regulator is removed), shows filter, pump and regulator are OK.

If no dealer/indy you've been to has verified proper fuel rail pressure, you need to find a real shop!!!

[LeiZ]

Sounds like a clogged fuel injector to me. It reported suddenly, so it's not due to some overdue maintenance, it has to be something gone bad.

Good luck!

Originally Posted by TiAgX5

When was the fuel filter last changed?

Check the fuel rail pressure, simple 10 min test, $20 fuel pressure test tool. The test verifies idle/low load pressure, rate of rise and WOT pressure (when vacuum hose on pressure regulator is removed), shows filter, pump and regulator are OK.

If no dealer/indy you've been to has verified proper fuel rail pressure, you need to find a real shop!!!

[Rockit]

Could also be a bad knock sensor or crank sensor.