MAF Delete (CDI 2)

[stumo]

Oh I see you took the EGR plumbing out, maybe thats what made removal easier? Usually you have to remove the rail because the EGR plumbing doesn't allow clearance for the manifold to come out.

By "heat exchanger" do you mean the EGR cooler, or the oil cooler behind the oil filter housing? That exchanges heat between coolant and engine oil and ATF. Why do you want to remove it? They usually don't give any trouble have you had cooling issues?

My advice would be to do the EGR delete first, and then run it to make sure there are no codes with a real MAF sensor. Then do the MAF delete once you know for sure the EGR delete is working properly. Note that you may need to use a higher resistance value for the MAF delete, the last one I did needed an 8k2 resistor rather than 5k6. You need about 2.2V on MAF pin 5 when the EGR is off and 1.5V when EGR is on.

 

[MLFaN]

Oh I see you took the EGR plumbing out, maybe thats what made removal easier? Usually you have to remove the rail because the EGR plumbing doesn't allow clearance for the manifold to come out.

By "heat exchanger" do you mean the EGR cooler, or the oil cooler behind the oil filter housing? That exchanges heat between coolant and engine oil and ATF. Why do you want to remove it? They usually don't give any trouble have you had cooling issues?

My advice would be to do the EGR delete first, and then run it to make sure there are no codes with a real MAF sensor. Then do the MAF delete once you know for sure the EGR delete is working properly. Note that you may need to use a higher resistance value for the MAF delete, the last one I did needed an 8k2 resistor rather than 5k6. You need about 2.2V on MAF pin 5 when the EGR is off and 1.5V when EGR is on.

Yes it was easy getting it out with the EGR system removed. By heat exchanger i meant where the fuel lines and coolant hoses go into the alloy housing above the manifold. No issue, had just seen it done and assumed it may help. Was of the impression it warmed the fuel for cold climates. Im trying to source a 3/8 Tapered tap so i can get the plugs in. Will visit trade tools in the morning. Couldnt get brass BSP bolts and had to settle for big grub screw style plugs. Ill go grab an 8k2 resister as well and see if that helps the MAF delete after i get everything else sorted. Will be another couple of hours at least getting it back together. Fortunately im off work all week. Will send an update within the next couple of days. Thanks heaps for all the help mate. Its appreciated greatly.

 

[stumo]

Thats the fuel cooler, not a fuel heater. The fuel gets very hot under the extreme compression of the HP pump. Thats what that little radiator in front of the main radiator stack is for. It pre-cools the coolant below the normal 85deg so it can then be used to keep the fuel temperature well below 85c.

 

[oigle]

Will slow down your engine warmup considerably. Even when left in place, the egr delete stops the egr opening and thus reduces the amount of heat traveling through the heat exchanger but removing the exchanger would really slow the process down. Not good if you live in a cold country. Even in Oz, it would slow it considerably. I noticed the change when I did the delete of the EGR.

 

[MLFaN]

Thats the fuel cooler, not a fuel heater. The fuel gets very hot under the extreme compression of the HP pump. Thats what that little radiator in front of the main radiator stack is for. It pre-cools the coolant below the normal 85deg so it can then be used to keep the fuel temperature well below 85c.

Well i best reconnect it all then! Cheers mate

 

[oigle]

Will slow down your engine warmup considerably. Even when left in place, the egr delete stops the egr opening and thus reduces the amount of heat traveling through the heat exchanger but removing the exchanger would really slow the process down. Not good if you live in a cold country. Even in Oz, it would slow it considerably. I noticed the change when I did the delete of the EGR.

I obviously assumed you meant the EGR heat exchanger. Forget my post there.

 

[MLFaN]

I obviously assumed you meant the EGR heat exchanger. Forget my post there.

All good. I still appreciate the input mate. Cheers

 

[MLFaN]

Anyone have any idea what the tension settings are for the inlet manifold bolts? Thanks in advance

 

[MLFaN]

I had that issue from new and resorted to a remap to fix it.

G

Ok I just did this mod on another ML270 today. I tried my theory of a more simple EGR delete first but that was a no-go. It doesn't drive the EGR transducer like I thought it does.

So I did the normal EGR delete first (https://forums.mercedesclub.org.uk/index.php?threads/disabling-egr.68928/). Then the MAF delete. This ML needed a 8k2 resistor and diode for the MAF delete. It seems to pull more current into the ECU on the MAF pin that mine does. Mine uses a 5k6 resistor. On this ML the voltage needed on the MAF signal line is around 2.2V when EGR is off, and 1.5V when EGR is on. I have yet to measure the voltages on mine - it just worked first time.

I have no idea why the 2 cars are different. They are both 2002 facelift Oz delivered and only 1 month apart. Mine is April and this one is March. Weird. The good news is the MAF delete has fixed the dangerously slow initial lag this ML had when pulling away. Maybe that issue is related to the difference in current I have seen here who knows. We certainly couldn't fix the issue with a new MAF and there were no codes. It just took forever to pull away from stopped. Mine never had that issue.

Stumo,

Would you know the torque settings for the manifold?
Cheers

 

[MLFaN]

Cheap MAFS are usually a disaster unfortunately. With stumo's mod, it becomes irrelevant so maybe you need to persevere with the egr delete and his latest mod. My egr delete has functioned perfectly for 100000km now. Have yet to do stumo's extra mod.

EGR delete sorted along with manifold mod. Running well. Will try the MAF delete again, maybe tomorrow. If the original shunt does not work I'll try the updated resistor.

 

[MLFaN]

Gday mate.
Just an update and to let you know I've done the MAF delete and so far so good. Used the 8kv2 resistor. Seems to improve the lag a bit. Due to the MAF now being out of the picture, do you know if I can increase air through modification such as a snorkel or will it need work to the ECU or retuned via the MAP? Cheers in advance.

 

[MLFaN]

Gday mate.
Just an update and to let you know I've done the MAF delete and so far so good. Used the 8kv2 resistor. Seems to improve the lag a bit. Due to the MAF now being out of the picture, do you know if I can increase air through modification such as a snorkel or will it need work to the ECU or retuned via the MAP? Cheers in advance.

 

[stumo]

Gday mate.
Just an update and to let you know I've done the MAF delete and so far so good. Used the 8kv2 resistor. Seems to improve the lag a bit. Due to the MAF now being out of the picture, do you know if I can increase air through modification such as a snorkel or will it need work to the ECU or retuned via the MAP? Cheers in advance.

Glad it worked for you too. Ours is running fine all this time as well.

There is no point adding air because the ECU won't make use of it. You would need an ECU tune that increases the fuel and MAP, before you start screwing with the intake air. Just be aware that the transmission is not going to like it. Mine crapped out at around 275k stock. The car has plenty of power for what it is anyway, even for towing.

 

[MLFaN]

Glad it worked for you too. Ours is running fine all this time as well.

There is no point adding air because the ECU won't make use of it. You would need an ECU tune that increases the fuel and MAP, before you start screwing with the intake air. Just be aware that the transmission is not going to like it. Mine crapped out at around 275k stock. The car has plenty of power for what it is anyway, even for towing.

Thanks for the quick reply mate.
The more I drive it the better it seems to go...might be my imagination.
Previously I changed the induction and ran a tube to under the grill to the airbox. The car went like a rocket! At least until it burnt out the MAF. So would the MAF of been feeding more fuel while it needed until it burnt out? I know running lean does not cause greef for a diesel so was hoping to fit a snorkel for a big across country tour.

 

[oigle]

Only advantage would be ingesting cooler/denser air will attract more fuel and, as a result, give a little more power until max fuel setting reached. Only mapping can improve it any further.

 

[oigle]

Following on from my last post, perhaps now that you have deleted the MAF, the cooler/denser air will have no beneficial effect. The MAF is also supposed to monitor air temperature along with air volume.

 

[MLFaN]

Following on from my last post, perhaps now that you have deleted the MAF, the cooler/denser air will have no beneficial effect. The MAF is also supposed to monitor air temperature along with air volume.

Ahhh got it. Thanks mate. I'll do a bit more investigation reference a snorkel. I'll get a mild ECU remap if required. I'm ok with the transmission issue down the track, because like you guys I'm keeping my 270. I've had a lot of cars but I've got a thing for this one. Not sure if it's the character or the fact that I've done so much work on it. Just got to fix the annoying steering rack thing now. It kicks back around sweeping bends. So far I have a quote for it to be repaired here in capalaba for 1200. I'll keep you guys updated with her progress. And thanks again you have all been more help than I could have paid for.

 

[oigle]

Ahhh got it. Thanks mate. I'll do a bit more investigation reference a snorkel. I'll get a mild ECU remap if required. I'm ok with the transmission issue down the track, because like you guys I'm keeping my 270. I've had a lot of cars but I've got a thing for this one. Not sure if it's the character or the fact that I've done so much work on it. Just got to fix the annoying steering rack thing now. It kicks back around sweeping bends. So far I have a quote for it to be repaired here in capalaba for 1200. I'll keep you guys updated with her progress. And thanks again you have all been more help than I could have paid for.[/

I did a couple of things to mine to remedy the steering. Decent front shocks (Bilstein) was the main fix, followed by using narrower tyres - 235's, and then getting steering alignment played with to get the best benefit. From memory, need about 4mm toe-in and maximun castor with minimum camber (about -1° I think). Mine steers really well now on rough corners that used to make it bounce around.

 

[stumo]

I second what oigle said. The front shocks get a real workout on these, and when they are worn the car is downright dangerous at highway speeds. I put on new Bilstiens when I first got mine and that fixed it right away.

Note there is an odd issue with the power steering on these, it seems to have a dead zone where it briefly loses assistance on a sudden direction change. Think driving forward into a parallel park - The direction change when you turn from left to right often gives you a sudden loss of assistance for a split second. This could be what is happening as you fight to keep stability with the worn front shocks.

So look at the front shocks first before throwing good money at the steering rack. You can easily disconnect them at the bottom joint and see if they are actually doing anything free of charge.

 

[Blobcat]

I second what oigle said. The front shocks get a real workout on these, and when they are worn the car is downright dangerous at highway speeds. I put on new Bilstiens when I first got mine and that fixed it right away.

Note there is an odd issue with the power steering on these, it seems to have a dead zone where it briefly loses assistance on a sudden direction change. Think driving forward into a parallel park - The direction change when you turn from left to right often gives you a sudden loss of assistance for a split second. This could be what is happening as you fight to keep stability with the worn front shocks.

So look at the front shocks first before throwing good money at the steering rack. You can easily disconnect them at the bottom joint and see if they are actually doing anything free of charge.

Or get someone to drive beside you and see if your wheels are bouncing up and down al lot as you drive along