Advice on safe boost to suit maf issue

Hi guys,
Bit of long one here, sorry about that. I've done a search and can't find anything relative.
Bit of background, 2000 zd30 patrol, auto, 270,000kms.
Mods
Provent, new maf, egr block, inlet clean, Full nads setup, ecutalk and uafc voltage modifier.

Basically my issue is:
Tested the maf and voltage was out of spec so replaced it with a new genuine one.
That didn't really seem to help.
I got it really cheap as it kept going into limp mode. Did the full nads on it along with boost and egt gauge.
When setting up the nads setup I followed the directions from northern 4x4 but with max boost set at 16psi and boost at 100kph about 9-10psi it kept going into limp mode. Egts would get up to about 500 by 0-100kph
Tested maf voltage by putting in a diode which dropped maf voltage .5v. This stopped it limping.

I then got an ecutalk and uafc and removed the diode. This confirmed maf voltage was causing limp.
I setup the uafc as basically a voltage clip at 3.9 v and eliminated limp mode. But egts were still to high imo 500 degrees from 0-100kph launch.

The only way I can keep my egts in a reasonable range is by running the max boost at about 20 psi, boost at 100 is about 12-13psi.
Max egts have dropped to about 425 degrees. And sit on about 300-325 usually.
My question is, is that boost level safe considering egt levels.
Car runs beautifully and I'm not chasing power, just reliability and lower egt.

Cheers in advance, sorry for the long post.

Justin.

My max boost is about 19/20 psi, and I run about 15/16 psi at 100kmh, no problems for me and keeps my EGT under control.

How do you know your EGT is accurate? You may have a faulty/inaccurate gauge.

Quote:

---

Originally Posted by BillsGU

How do you know your EGT is accurate? You may have a faulty/inaccurate gauge.

---

A very good point, it's a brand new red arc boost/egt combo. I know some things are faulty straight out of the packet, but I'm reasonably confident.

Quote:

---

Originally Posted by Pumpdogg

A very good point, it's a brand new red arc boost/egt combo. I know some things are faulty straight out of the packet, but I'm reasonably confident.

---

True - but if it is faulty you'll go mad chasing a fault that doesn't exist. Not sure how you would go about checking it. Obviously screw in another pyro and connect another gauge - but you would have to replicate the exact same conditions. Not sure either if you can send the pyro and gauge away to be tested. Maybe ask Redarc? Or - put the pyros side by side in a workbench vice and heat them with a butane torch?

Just my 2 bobs worth.

20 psi is perfectly fine. Even 25psi is. My old Di ran 25psi with zero issues.
Just remember that max boost and your cruise boost are relative. So if you raise your max boost you need to wind in the needle valve a tad to increase spool up and there for increase cruise boost levels.
But 20psi is good. It seems you are cluey and know your way around tricking the maf. Something that needs to be shared with all 3ltr owners. Those mafs are a devil in disguise.

Sent from my GT-N7105T using Tapatalk

I tested my EGT probe with boiling water.
I boiled a container of water with a thermometer in it, then I just put the probe in it with the ignition on, if both temps are the same your probe should be okay.

I forgot to add, if your gauge doesnt read that low, you can use a hot air gun to heat the probe, then check with a inferred thermometer.

Cheers for the suggestions on checking the egt probe. I think I'll go with the heat gun and infrared thermometer method as the gauge starts at 300c.

The car has been running a treat, returned 12.5l per 100 on an 800km trip towing a reasonably loaded 7x4 cage trailer. Sat on 110km/h with the ac on the whole time. Egts sat about 400c and maxed about 500c going up a rather steep hill.

I started it one morning though and it spat an afm code which I cleared and hasn't returned.
Still get the occasional limp about 2200rpm on a cold morning. Will give the uafc a bit more of a tweak.

As for tricking the maf sensor, it was a simple as measuring the voltage drop of a few resistors and diodes I had laying around (old circuit board).
Finding one that gave me the correct reduction to get my maf voltage inline with what it should be.
Installation was as simple as soldering the diode/resistor inline with the maf to ecu voltage wire (red wire on a 4 wire maf). I did it about 100mm from the maf plug for ease.
Just keep in mind diodes are directional, as in current will only flow one way. If it doesn't work, spin it around.
Cheers for the suggestions and thanks mudski for your help initially setting up the Dawes and needle valve.

Cheers.
Justin.

Hey Justin. It would be great if you were to do a write up on what you exactly did and used, what diode was used etc etc on the MAF, with pic's. As I said the MAF is the the devil and is the one major component that hampers these motors. I went the simple, yet expensive, way around this when i had my ZD and bought the HPD billet maf housing. I could run 30psi and still not go into limp, where as before, a tick over 16psi and I would hit limp mode.

Quote:

---

Originally Posted by mudski

Hey Justin. It would be great if you were to do a write up on what you exactly did and used, what diode was used etc etc on the MAF, with pic's. As I said the MAF is the the devil and is the one major component that hampers these motors. I went the simple, yet expensive, way around this when i had my ZD and bought the HPD billet maf housing. I could run 30psi and still not go into limp, where as before, a tick over 16psi and I would hit limp mode.

---

I'll do a bit of write up when I get home, away for work at the moment.

Thanks mate. This info is invaluable and if its as easy as I think it is, it will save a lot of people a whole lot of pain.