Low power 150 Diesel - can I borrow your MAF Adelaide or any other suggestions?

[RealPrado Junior Member Find all posts View Profile Close RealPrado]

Hi guys

I am really scratching my head on this low power issue I’ve been having for some time.

Vehicle is a 150 GX Diesel.

I have a low power issue which has been intermittent over the last couple of years. The power drops and car becomes sluggish, boost response is very slow and maxes around 11 psi if pushed hard to get it to that, but when normal the boost rises pretty quick to just under 15. Coinciding with sluggish boost I see the EGT become a lot more reactive and rises very quick under load, which would be expected with not enough boost.

The low power is still drivable, so not like a limp home low power, just really doughy.

Interesting thing is when this occurs there are no fault codes, and after a day or 2 usually goes away.

The intermittent problem has now become normal, not actually going away for almost 2 weeks now. So perfect time to get in to the workshop for them to have a look.

Outcome of this is that apart from being doughy all data presents normal. No boost leaks, no over fueling, variable vane appears normal, exhaust and intake are not blocked, fuel filter ruled out.

The MAF is a little dirty beyond being able to cleaned, but they don’t believe this is the issue.

To note, I have the EGR turned off, but no blanking plate, I have catch can and second fuel filter and engine is 195k and otherwise healthy.

So, before I start throwing money at sensors and other parts, does anyone local to Port Noarlunga in SA have a 150 that would be happy to meet up for exchange of a 6 pack to swap MAF sensors briefly to see if this is the cause?

Does anyone else have any other suggestions?

Cheers
Cam

[Mike-B Junior Member Find all posts View Profile Close Mike-B]

Hi Cam,

What values are you getting with regards to MAF and MAP when this problem occurs? Might also be worth checking your O2S1 air fuel ratio.

[RealPrado Junior Member Find all posts View Profile Close RealPrado]

Hi Mike, off the top of my head I can’t tell
you but Llordan diesel have advised these are all normal.

[RealPrado Junior Member Find all posts View Profile Close RealPrado]

Hi Cam,

What values are you getting with regards to MAF and MAP when this problem occurs? Might also be worth checking your O2S1 air fuel ratio.

Mike, I am seeing approx 18.5 g/s at idle for MAF and 94 kpa MAP

[SamSta Member Find all posts View Profile Close SamSta]

Old thread but thought i'd throw my 2 cents in for others searching for answers:

I'd start by replacing the fuel filter. This has fixed very similar issues for me once on a Nissan Navara and again on a Mitsubishi Triton and it only costs $20 and half an hour of your time. Failing that (or as part of a regular maintenance schedule), run some MAF sensor cleaner over the MAF sensor and any other sensors in the intake system. Check for air leaks, splits in hoses or loose hose clamps throughout the air intake system particularly between the air filter and throttle body. If you've removed any of this for any reason recently, make sure you've done all the hose clamps up tight and that the hose clamps are working and not damaged.

If you have installed a boost T on your turbo or possibly even due to installing a performance chip, the increased pressure in the small black hoses going to the MAF sensor/intercooler/throttle body can pop off while driving (especially up hill or under load) under the increased turbo pressure resulting in the ECU not getting correct readings from the MAF sensor so the car goes into a pre turbo-like state. I found using small zip ties to clamp all the small hoses to their respective inlets/outlets resolves this issue.

These are just some ideas. I hope it helps someone out!