Hesitation under load

[HitmanAU]

Hey guys,

Loving the 225 so far but it has developed an issue on very hot days (35-45 deg C) when aircon is on.
When ever I put my gut down hard the revs build then power does then comes back then dies and continues to donut sporadically until I back off.
Does it in all gears too.
If I then turn the aircon off the car still does the same thing.
If I clutch in and boot the revs it won't cut, it's only under load.

Also if I drive in the same heat without the aircon on at all, it doesn't seem to do it.

Plugs are new, coils and injectors are not.
It idles a little lumpy sometimes too but idle revs are always at 800rpm.

Any ideas? I'm thinking running some injector cleaner through it just as an interim.

 

[Red21]

How many Km (miles) have you done as they are due at 120-130,000 miles, but this is local market dependent.
If you do remove the tank unit do it with an empty tank and refit the tank nut to prevent distortion of the tank.
When refitting do so with a new nut & seal kit.

 

[HitmanAU]

120,000 KM have been done.
So there really in only one in tank filter. Does the fuel tank sit under rear seats?
Can you access from there or not?

 

[DaveL485]

120,000 KM

120k KM is only 74.5k Miles (Rich said 120,000 Miles)

 

[Red21]

120k KM is only 74.5k Miles (Rich said 120,000 Miles)

But I also said it's local market dependent, as in some areas there is more dust etc due to dry conditions which can find its way into the tank.

 

[HitmanAU]

I think our local model has a separate fuel filter as well. Just trying to confirm but from what I've read online it's in front of passenger rear wheel.

 

[HitmanAU]

By the way half way through this tank and no hesitation yet. This is pointing more and more to contaminated fuel

 

[DaveL485]

By the way half way through this tank and no hesitation yet. This is pointing more and more to contaminated fuel

Fingers crossed!

 

[HitmanAU]

Looks (sounds) like my fuel pump is dying

 

[HitmanAU]

That's with a smooth idle but every time I tried to drive the car would just die.

 

[HitmanAU]

Took electrical connectors of the fuel pump and gave the pins a light sand, connected back up and pump is no longer making that noise.
Could this be a blocked filter? (Australian delivered RS225 have an external filter in front of the rear passenger wheel) or a TPS or TDC sensor issue?
Where is the TDC sensor on a meg 225?
My plugs are new and gapped at .7mm and this is not a coil issue.

 

[DaveL485]

Thats an odd noise from the pump... i'm not that experienced with the newer kit though. Bizarre.

 

[andybond]

Have you had the injectors checked out ? Does the car cough at idle ?

 

[Red21]

Even if there is an external filter the pump/tank unit will still have a pick up filter and from the sound of the tapping noise from the pump area it could well be restricted or the actual pump veins failing and unable to deliver sufficient fuel when required.

I think it has now come to a point where you will have to do some sequenced diagnostic tests instead of guessing the cause.
I would start by checking the fuel pressure at idle and under load with a gauge & checking the tank pick filter up etc.

 

[HitmanAU]

Ok so today the car ran faultlessly. Pump also had no noise at all. Pulled hard all way to redline easily and without any stuttering. Could it be that the terminal on top of the pump were an issue? I guess next hot day will tell. Yesterday where I live it was 42 degrees C. Today it's rained all day and is a top of 23 degrees C. Gotta love Melbourne weather in Australia!!

 

[DaveL485]

Today it's rained all day and is a top of 23 degrees C

Lucky you, today here it's pissed it down all day and it's barely above freezing! Brrrrr.