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Discussion Starter #1
I recently purchased a brandnew GU Patrol (named as the Patrol Super Safari) with the 3.0 ZD30Di engine. Here in the Philippines, the GU is still being sold with the Di engine. CRDi version is not available. With less than 200kms in the odo, I decided to install all the modifications with the intention of protecting the engine right from the start. I've had prior experience with the modifications since the previous GU I owned had all the mods also. I sold it since someone offered a good price for it and I wanted to upgrade to a newer body with the boxy flares, new dashboard, and better interior.

Anyway, here are a few pics of the installations:

Intercooler Fan:


Provent Air/Oil Separator:


Dawes valve:


Purge valve for Oil catch can:


Needle Valve with in-dash control:


AEM EGT (celsius) and Boost gauge (PSI) customized to fit in the dashboard. Panel may still be closed for a discreet look:


After all the mods were in place, we proceeded with tuning the setup. Here were my observations:

1. With the new Super Safari, it looks like Nissan has adjusted the ECU boost sensor settings to more conservative levels. When we installed the mods, we initially capped the boost to 13psi using the Dawes valve with moderate spool up rate with the needle valve adjustments. Prior to tuning the setup, I noted some engine cutoff when running around 80-120kph with aggressive throttle play. We initially thought that our spoolup rate was a bit aggressive so we tamed it a bit by rotating the needle valve counterclockwise. This partly solved the problem but there was still some engine cutoff.

2. We proceeded by lowering boost ceiling setting via the Dawes valve itself. We brought it down to about 10-11. No more engine cutoff no matter how aggressively I played with acceleration.

3. Just out of curiosity, we wanted to find out what was the stock boost level that the ECU was playing with (factory boost setting) since we never got to determine this right from the mods installation because all of it was done at once. We disconnected the Dawes and just run the engine as is without it. We were surprised that the ECU limited the boost to only 10psi. So anything above that would cause the ECU to go to failsafe and cut off power to the engine.

4. Knowing this information, we decided to play around and maximize upper end boost cap before the engine cuts. We found out that we could put it to a maximum of 11psi boost. No engine cut off anymore. We then played around with the needle valve spool up setting to the upper limited just before it would trip the ECU. We finally got the setting and no more cutoff ensued.

5. From this information, we generalized that for the New Super Safari series, Nissan has employed newer safety measures built into the ECU itself to remedy the problems of the past models, at the expense of lowering boost pressure. Maximum of 11psi boost is all that we could put in with final adjustments to the needle valve as well.

By the way, EGT was within normal limits all the time.

I'm looking for opinions to my observations. With my previous GU, we adjusted the boost to give a maximum of 16psi and we had no problems. However with my new unit, it cuts off with anything higher than 11.

Thanks for your time!
 

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That seems a very low boost level. Does this Patrol seem slower than your previous one ? If not I'm wondering whether your reading is correct, ie possibly the gauge is wrong or there's a restriction in the line? Under heavy load at such a low boost level I would expect the EGT's to go high very quickly!
 

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Discussion Starter #3
I testdrove 2 brandnew units prior to ordering my unit. Straight from the showroom, it is sluggish! Very poor acceleration. When you floor it, there is some delay before the engine pics up. The performance of my unit now is a far cry from when it left the dealer. Now, my Patrol I think is just as fast as the previous one.

As an update, after reading some posts on Patrol 4x4, some forumers recommended that an ECU reset should be done after mods were installed so that the ECU would relearn all the new settings, most especially since EGT block, boost, etc. have been altered. I did an overnight reset of the ECU last week by disconnecting the negative cable from the battery. I noticed that after doing this procedure, engine performance seemed to have improved. Boost spoolup rate was faster with an increase in overall "perkiness." Knowing that it might just be a placebo effect, I did not mention to my Dad what I did and I let him drive it as is. When he got home, he was the first to tell me if I did some setting alternations since he observed the same effect too.

This new developments will be put to the test again this week when I hopefully find time to retune the needle valve and even perhaps the Dawes valve since the ECU might have reset itself (and hopefully reset the upper boost limit which was previously at 10psi before engine cutoff).
 

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Hi there

That is a very low boost level.......

Have you bypassed ECU control of the turbocharger completely?

I can get to 18psi, and just touch 20psi under heavy acceleration. The overboost protection on the motor normally kicks in at 21psi. I would back off the dawes, and wind the vnt stop screw out. You are in a position where you could be in a fuel rich state which will drive EGT temps up.

Are you manual or auto? If you go and sit on the freeway at 100km/hr or whatever your legal limit is, what is your boost pressure.
 

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Discussion Starter #5
Yup it is a low boost level. I guess the new ECUs have more conservative settings. I have an automatic GU. ECU control of boost has been completely bypassed. I am sure of this. Boost levels at 100kph were definitely less than 10. EGTs were about 350-400 if I recall correctly.
 

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Discussion Starter #7
We had some old dashboard components lying around. We just cut it to size to fit the dimensions of the compartment. Made 2 52mm bore holes to fit e gauges. A small corner hole wa made at the back of the compartment to accomodate the wires
 

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Discussion Starter #8
Had a chance to do an open highway run this morning. I tightened the Dawes adjustment 2 full turns and made a run. Engine cut off as expected around 100-110kph. Loosened it by one full turn and this time no cut off. Added another half full turn and still no cut off. Settled for this adjustment. From a 11psi limit previously, I am now able to do 13psi boost without any cutoff. This could be due to the ECU resetting itself and reestablishing a new upper limit. I also experimented adjusting the needle valve to increase spool up rate. Previous setting was a quarter turn before maximum. Now, i'm able to maximally close the needle valve with no cut off due to aggressive spool up rate. Turbo can now spool up faster resulting in more perky acceleration. EGTs are maintained at 550C. Tonight I'll reset the ECU again and test it on Thursday when I have another highway run and see if I can still increase the boost cutoff limit.
 

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LED ZEPPELIN
1995 GQ TD42 NA
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Great info and some very nice work with the installations there. Thanks for sharing!
 

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NISSAN GU PATROL
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I still think you have a low boost setting...my Auto Patrol runs up to 16 psi boost and around 400 C at 120kph dropping to 12 psi boost setting with needle valve fully closed.

Another guy up this way has the new Patrol and has his set up exactly the same with reasonable mileage..

I still think you can get more boost from the vnt screw and reset your Dawes valve to limit it to Max of 16psi.

As the other guys have said you may be in a low boost high fuel setting which would give you the higher engine temps..

cheers
 

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Also I have noticed you are using a boost guage that reads a negative to positive boost reading which are more suited to the petrol engines and in my experience these guages can be out by as much as 5 to 10 psi....

just my veiw but I could be wrong...
 

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ZD30-help ID this oil leak

sorry, wrong post..........
 

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Discussion Starter #13
Isn't there a way to increase the threshold of the ECU boost limit before it cuts the engine? Like in my case, the ECU limits it presently to only 13. Anything higher causes it to cut off. So even if I adjust the VNT screw to increase boost but if the computer still has a low upper limit, its still pretty useless.
 

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Premium Member
2003 ZD30 Di Patrol (The rare Gold one)
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Are you sure it is the max boost that is causing the ECU to cut fuel?
It may be that it is spooling up too fast at too low a boost pressure.
 

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Wiretap, If you have bypassed the ECU controlled solenoid completely with the Dawes setup, what is telling the ECU to cut out the engine?
 

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Discussion Starter #16
skeg: I made sure the the spoolup rate wasn't that fast: 6psi at 1500rpm, not more than 10psi at 2000.

FIRSTGU: Thats what I want to know. Needle valve setting is where it should be. If I adjust the Dawes to have an upper boost limit of 16, it cuts. But if it is at 13, it doesn't.
 

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ZD30 Out - L77 In!
nissan patrol
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what is telling the ECU to cut out the engine?
The ECU uses the boost sensor on the intercooler to determine when boost is too high for a given throttle position and rpm.
 

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Discussion Starter #19
Hello again. Just wanted to resurrect a previous thread of mine and see if any more inputs could be added to my case.

I still would want a higher boost level without the cutouts inorder to decrease egr temps
 

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ZD30 Out - L77 In!
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Hi wiretap MD,

After doing some more research on this issue, I’m starting to think that the MAF signal is what’s causing the ECU to go into limp. It seems that even if the boost signal isn’t too high it happens, but in my case, if the MAF signal gets above 4.2v at lower rpm and boost, it still goes into limp mode and cuts the engine well before reaching full boost under a heavy throttle.

Also, after it cuts the engine, there’s no code or fault light. The solution may be to reduce the MAF voltage.
 
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