MAF voltage, AAC and boost drop ?

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August 13, 200817 yr

Finally got the old heap back on the road but the MOT tester said there was an issue with emissions - rich at idle and lots of hydrocarbons, he let it go anyway as he said it wasn't a prob for a jap import and especially at that age. He did say it had a prob of some kind though to make emissions that bad.

I've been messing about with it this evening and found a couple of things which I'm not sure about, the AAC is reading partially open all the time and varies with RPM - is this correct? Secondly, the MAF is usually around 1.26V at idle but occasionally dropping to zero volts.

I'm pretty sure the MAF is ok as the car still revs ok, is an occasional zero reading to be expected?

Last thing, I logged the boost curve as I suspect I may still have a leak somewhere, I've not attempted 1 bar yet as I need to set the car up properly first. For a constant throttle setting the boost ramps up ok, levels off and then begins to drop gradually. Is this normal behaviour? If so I can compensate for it with an increasing duty cycle v RPM, or is it indicative of a boost leak?

Cheers

RobH

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OEM Brake calipers - aluminium vs cast iron

Thanks Jim. Great heads-up on the discs - I stopped using M tec a while ago as they just didn't last a year without warping. And I would definitely have come down to yours earlier, had I known about the caliper issue!

By RichardS · 3 hours ago3 hr
Weekend trip to France

Short stop over to Wisques Sat/Sun

By arthur · 11 hours ago11 hr
OEM Brake calipers - aluminium vs cast iron

Both the aluminuim & steel calipers suffer with piston issues.I rebuild them at work & would have done yours Richard if you had asked.A few hours is all it takes & a kit is about £60.I think Nissan used cast iron as a money saver only & not because of any benefits personally.Brembo discs here are made by Euro Car parts & are not the Brembo quality being honest.I would say they are no better than M tec that awful E bay brand.I use Blueprint discs for stock set up,s.I would try those .

By jimmer · 11 hours ago11 hr
ADAMZX's OEM+ 2000spec Version R Replica Conversion & Rebuild Project Build Thread

HYDRAULIC BRAKE PISTON RESTORATION PROCESS
The next phase of the brake caliper restoration process involves inspecting and restoring the hydraulic brake pistons that were removed from both the front and rear brake calipers.
The goal here is to put the pistons through one final cleaning process and then assess their restored condition to determine whether they can be reused or be replaced with brand new hydraulic pistons.

https://i.postimg.cc/Mph2qvG8/1_All_Brake_Hydraulic_Pistons_2_(Before_Polishing).jpg
(Above) The current condition of all the hydraulic pistons after undergoing a deep cleaning and de-rusting cycle in the ultrasonic cleaning machine.
Before beginning the restoration work, I took a closer look at several areas of the pistons that still required additional cleaning.
https://i.postimg.cc/P5BsTPqs/2_close_Up_Of_existing_rust_inside_pistons.jpg
(Above) Rust deposits still remaining inside the inner barrel of the hydraulic pistons.
(Below) Some staining or contamination present on the outer surface of the pistons.
https://i.postimg.cc/9Qv5Crfh/2_Staining_or_marking_on_outer_surfaces_of_both_front_and_rear_pistons.jpg
Grinding Process
To tackle the remaining rust deposits first, I attached a small brass wire brush bit to my Dremel and carefully began grinding away the corrosion. This method proved to be very effective at removing the rust while leaving the underlying metal clean and shiny.
https://i.postimg.cc/NjWqB50F/3_After_wire_wheeling_inner_barrels_of_all_brake_pistons_1.jpg
(Above) Nearly all of the rust deposits have now been removed from the inner barrel surfaces, revealing clean metal underneath.
https://i.postimg.cc/Mph2qvG7/3_After_wire_wheeling_inner_barrels_of_Front_brake_pistons_1.jpg
(Above) The front brake caliper pistons came out looking great, with all rust removed. Only a couple of pistons still show minor pitting at the bottom of the inner barrel.
(Below) The rear caliper pistons actually turned out even better than the fronts after the grinding process.
https://i.postimg.cc/fbm4LD3V/3_After_wire_wheeling_inner_barrels_of_Rear_brake_pistons_1.jpg
I’m very happy with how well the wire brushing process worked. The pistons have cleaned up so nicely that I’m now unsure whether I should paint the inner barrels or simply leave them as they are.
What do you guys think — should I paint them or leave them bare?
Polishing Process
Next, I moved on to removing the staining or contamination that remained on the outer surfaces of the pistons.
To do this, I set up my electric drill in a bench vice and attached a cone-shaped polishing wheel. This created a simple DIY polishing rig that made the process much easier to control.
https://i.postimg.cc/wBLKvgtt/4_Polishing_Setup.jpg
(Above) With this setup I can safely hold the piston while polishing, without having to manage both the drill and the part at the same time. This gives me much better control and allows me to polish the piston surfaces more effectively.
Here’s the starting condition before polishing the first piston.
https://i.postimg.cc/bvkXJpGg/4_Test_of_polishing_process_on_outer_surface_of_Brake_Piston_(Before).jpg
(Above) It’s a little difficult to see in the photo, but there is a thin ring of staining along the upper section of the piston’s outer barrel. The goal is to remove as much of this contamination as possible using the polishing process.
After about five minutes of polishing, the results were impressive. All of the staining on the outer barrel of the first piston was completely removed.
https://i.postimg.cc/SKC0skXM/4_Test_of_polishing_process_on_outer_surface_of_Brake_Piston_(After_1).jpg
https://i.postimg.cc/zfKmB8Lw/4_Test_of_polishing_process_on_outer_surface_of_Brake_Piston_(After_2).jpg
(Above) As you can see, the contamination that was present on the piston surface has now been completely removed.
All that remained was to repeat the process on the rest of the pistons. Just like the first one, the results were excellent. The polishing process removed all visible contamination from the outer surfaces, making the pistons look almost brand new again.
https://i.postimg.cc/q7yfR4t1/5_All_Pistons_Polished.jpg
(Above) The polishing process was quick, simple, and extremely effective. I’m very happy with the results so far.
After successfully removing the rust deposits from the inner barrels of all the pistons and eliminating the contamination on the outer barrel surfaces, I am satisfied that these restored brake caliper hydraulic pistons are suitable for reuse. They can now be reinstalled into the front and rear brake calipers during the final stages of the restoration process.

By DJ_Party_Favor · 17 hours ago17 hr
ADAMZX's OEM+ 2000spec Version R Replica Conversion & Rebuild Project Build Thread

This month I wasn’t able to dedicate as much time to the project as I had hoped, but I still managed to make some progress. The focus was on cleaning up and polishing the hydraulic pistons in both the front and rear brake calipers.
These components still had varying amounts of residue and rust buildup left over from the earlier cleaning and de-rusting process, so this stage involved carefully removing the remaining contamination and improving their overall finish.
YouTube Channel: https://www.youtube.com/@ADAMZX Instagram: instagram.com/adamzx_z32

By DJ_Party_Favor · 17 hours ago17 hr

MAF voltage, AAC and boost drop ?

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