PollyMobiles Rebuild

2025-08-29 Print HT Lead Clips

These HT lead supports I printed 10yrs ago are starting to warp & crack from all the heat & clamping force, & they're also a PITA to unscrew whenever I need to remove the leads & plugs



So a new strategy is to print more of these plastic joins



& route the cables like this, little neater & easier to remove





Just enough room under the bonnet to arrange the leads vertically

Printed some blue clips the next day to contrast the red engine bay







Might as well include the rainbow too lol

2025-08-31 Replace Fuel Hose

I was watching this video about E10 and poor quality modern cheap fuel hoses degrading/cracking, reminding me to recheck my fuel hoses



The filter>rail hose and return hose (both replaced with R9 halfords hose from 2022) were fine, firm & still pliable.
The oem fuel tank evap pipe (usually connects to carbon canister but has been left open for yrs) has gone very stiff but not cracked.
Worryingly the fuel link>filter hose is rather squishy soft & flexible similar to a silicone hose so it might be good idea to replace it.







See the inner rubber layer has cracked



It must've been an original 32yr old factory hose cos it has the same markings as this in-tank hose



Gonna replace it with these 2022 R9 halfords hose







Curiously I found some old used R6 hose from 2010 in my box of hoses and they've gone rock hard





Not as flexible and cracks badly



So recommend u check ur hoses annually

2025-08-31 Test Sony Headunit RMS Voltages

Since the last time I tested the Sony headunits speaker output in June 2020, I've improved the connections & voltage supply throughout the circuit including:

Nov 2022 - Replaced engine bay loom



Nov 2022 - Replaced IGN loom with better crimp



June 2023 - Replaced battery extension terminal



Feb 2025 - Recrimped immobiliser wiring



So I remeasured the input/output voltages while playing various tone frequencies via bluetooth with the car running.

Voltage supply kept changing between 13.7-14.10v depending on the battery state-of-charge & whenever the radiator fan is triggered, which makes measurements slightly inconsistant (especially for calculating voltage efficiency)



With the equaliser set at default flat, all the frequencies create the same graph curve.
The improved power supply makes the lower volume settings louder but loses a little power above vol 45, which I normally never use anyway



With the equaliser values maxed out, the output of various frequencies are more scattered but the improved power supply now creates a much smoother & louder curve with a more progressive volume control



Comparing the input/output voltage efficiency of the headunit with the equaliser at default flat, the fixed power supply improves low volume efficiency but loses a little efficiency at high vol (this calculation might be due to the inconsistant input voltage whenever the radiator fan engages)



With the equaliser set at max, the fixed power supply really smoothed out & improved the efficiency curve above & below vol 30

The "switched 12v feed" for the headunit, which has to run through the IGN switch & immobiliser & extra crimps, seems to get only 13.67v compared to the "constant live 12v feed" which gets the full 14.03v and the battery itself receives 14.17v

To explore if raising the "switched 12v" upto full voltage will improve overall output, I simply shorted the constant 12v with the switched 12v using this yellow loop so that they both receive 14.03v



With a flat EQ, it's raised the output above Vol 35 by just 0.1v



With the EQ maxed out, it also raised the output above Vol 30 by 0.1v



Not a major difference overall cos I rarely turn the volume above 20 and mainly use Vol 16 when cruising

2025-09-01 Check Brake Wear

Discs are wearing smooth & evenly



All the pads wearing evenly, front inner pad has a slight lip



Front brake wear is normal, the inner pads usually wearing faster than the outer



Rear brake wear is also at a normal rate, inner pads wear faster than the outer

2025-09-02 Test Headunit Max Volume vs Frequency

To test how the equaliser setting & input voltage affects the max vol level just before 'clipping', I connect an oscilliscope to the output, setup the equaliser, play a sine-wave, turn up the volume until the signal begins to clip and log the max value for a range of frequencies.



The results are quite consistant.

With the EQ all set to -6, it has no problem reaching max vol 50 with no clipping of the signal.
With the EQ at the default 0, it reaches upto vol 39 on all frequencies before the signal clips.
With the EQ maxed out at +6, it reaches upto vol 30 before the signal clips.

With the EQ values tuned by-ear to 'pink-noise' (yellow line), the curve matches my EQ settings:
32hz +4
63hz +6
125hz +5
250hz +5
500hz +3
1000hz +3
2000hz +2
4000hz -1
8000hz +2
16000hz +2



To check if the extra electrical load of the cooling fan & heater fan affects the clipping point, I play a 1k sine wave tone on the headunit, equaliser set at 0, turn vol upto 39 where it just begins to clip and turn on the fans...



So with the extra drain off the cooling/heater fans, the voltage supply drops from 14v to 13.20v, the headunit amp doesn't have enough juice to sustain the signal and it begins to clip at vol 38 rather than vol 39

Not that I ever play the stereo at such volumes but it displays just how important it is to ensure the unit receives a strong & stable input voltage

2025-09-02 Replace Bosch FR7 DCX Spark Plugs

With the old Denso K16TT worn out, it's time to replace them.
Previously I would've used the good NGK BKR5E11 but curiously according to Haynes the required plugs are Bosch FR 7 D+X with a 1.1mm gap.
Hmm I dunno what the original factory plugs are?

Ordered these Bosch 0242235667 which are marked as FR7DCX



Pretty bog standard plug design









Hmm it comes too tight with a 1.0mm gap



Opened it out to the required 1.1mm gap



Marked where the spark gap side is (I often prefer the old trick of indexing all the plugs towards the intake side for a tiny improvement)



But they're not all made equal
Some almost face the intake while others point to the side, not ideal but meh, see how it performs in the coming months

Ah I should've checked with the nissan4u OEM charts first which shows the factory spark plugs are indeed NGK BKR4E-11 / BKR5E-11 / BKR6E-11
So Haynes says a different plug.
According to cross ref, these Bosch FR7DCX are the same heat rating as a cooler BKR6E

pollyp said:

2025-08-29 Inspect Worn Denso K16TT Spark Plugs

These Denso K16TT I fitted in 2021 are getting old now.
You can see in the following pics how the sharp square tip has worn away after approx 10-20k

View attachment 90407

View attachment 90408

View attachment 90409

View attachment 90410

View attachment 90411

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Here's a timelapse of the tip wearing away

View attachment 90413

Time to replace them

Click to expand...

Marketing b/s implied platinum & iridium type long life plugs (Denso K16TT spark plugs) were for inaccessible engine bay applications & good for 100K, or the useful economic life of the vehicle where your pictures/mileages indicate otherwise?

Can I ask what fuel grade/brand are you consistently recently using, if any?

Micra Paul said:

Marketing b/s implied platinum & iridium type long life plugs (Denso K16TT spark plugs) were for inaccessible engine bay applications & good for 100K, or the useful economic life of the vehicle where your pictures/mileages indicate otherwise?

Can I ask what fuel grade/brand are you consistently recently using, if any?

Click to expand...

These Denso K16TT are just regular cheap nickel coated electrodes with a thinner double-pertruding tip design (smaller area might've given a more focused spark but it wears away faster imo)

My time line est it might've lasted upto 30k until that thin tip has worn down to the broad base and the grounding tip would be out of spec

Filling with regular morrisons e10, less debris in tank.
I stopped filling at tesco now since March cos previously my tank/strainer kept getting lots of debris/rust etc

2025-09-03 New Fake Makita 9Ah Battery

Ordered a new 9ah 162W/h battery off ebay and hmm it's abit smaller than my old 9ah one? either the tech's been improved & miniturised or this is a fake 9ah?





The old 9ah battery has a circuit board facing up with multiple wires monitoring groups of cells whereas the new battery has the circuit facing downwards with just the +ve/-ve wires at the end of the packs and LED charge level display



The old battery uses x15 cells labelled VANON18650LZ22R 202204 3.6v





The new battery simply monitors the battery temp by this sensor dipped loosely into some white thermal goop above one of the cells



It uses x10 cells labellled +RH YG18650 OY10C 24SEPT13 3.6v

2025-09-03 Inspect Spark Plug History

I chopped open the Denso plugs to inspect the insulator which seems to be in the correct heat range, hot enough to self clean without burning up the electrode





Opened up the rest of my spark plug collections and this is interesting

From left to right:

# Denso K16TT, appear to have the same insulator length as an NGK BKR5E plug, fitted from 2021-2025 running N/A, just as I began to use E10 fuel, and also had to leaned out the high end of the fuel map to keep the AFR correct, resulting in a very clean insulator.

# NGK BKR5E, fitted 2019-2021 on a N/A CG13, still using E5 fuel, appear to have a grey, sooty & colder running insulator, maybe cos the fuel map was slightly too rich at the time?

# NGK BKR6E, fitted 2018-2019 when she was running a T2 turbo, Shell E5 V-power, has a slightly less exposed insulator so it's cooled by the cylinder head more, appears to run just hot enough with the hotter boosted cylinders to keep itself clean

# NGK BKR7E, came fitted by the previous owner of my spare used turbo engine (from the complete turbo kit I brought off ebay in 2010) which had this terribly rich nistune map and it looks pretty obvious that this plug was wayy too cold & fouled with soot

2025-09-04 Check Peugeot 307 Plugs

I haven't checked the old peugeots plugs in awhile

Haynes says it should be Bosch FR7ME with a 0.9mm gap, which isn't sold anymore.
The alternative one's currently fitted are NGK LFR6B



Insulator & ground in good heat range but the electrode has worn to a 1.2mm gap
I closed the gap to 0.9mm for now but it'll need replacing soon

pollyp said:

These Denso K16TT are just regular cheap nickel coated electrodes with a thinner double-pertruding tip design (smaller area might've given a more focused spark but it wears away faster imo)

My time line est it might've lasted upto 30k until that thin tip has worn down to the broad base and the grounding tip would be out of spec

Filling with regular morrisons e10, less debris in tank.
I stopped filling at tesco now since March cos previously my tank/strainer kept getting lots of debris/rust etc

Click to expand...

Appreciate you’re above & beyond analysis interpretation of plugs set ups as I never thought to cut them open only looking at the tips with magnifying glasses under bright light, now still learning new tricks after 40 years of my DIY men in sheds maintenance of my old bangers cheap as chips motoring?

Keep up the good work.

Micra Paul said:

Appreciate you’re above & beyond analysis interpretation of plugs set ups as I never thought to cut them open only looking at the tips with magnifying glasses under bright light, now still learning new tricks after 40 years of my DIY men in sheds maintenance of my old bangers cheap as chips motoring?

Keep up the good work.

Click to expand...

Thanks for your support Micra Paul

Always something new to learn when you're curious enough

yup cheepaschips ftw

pollyp said:

Thanks for your support Micra Paul

Always something new to learn when you're curious enough

yup cheepaschips ftw

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Cheap as chips motoring suits me as I drive on into my motoring Sunset with many more K11 years to keep it going.

I keep it seriously simple, put fuel in the back & the Mrs & myself in the front, out & about when the Sun is out.

Happy days.

2025-09-06 Print Stronger HT Lead Clips

The previous thin lead clips were getting loose with the heat



Designed a thicker & stiffer clip



See how it holds up soon

2025-09-06 Replace Ground Straps to Fix Electrical Issues

For the past few years I've often thought the electrical systems were getting little weaker resulting in:
- battery not being fully charged and draining slowly over days
- battery dropping to 13.5v whenever cooling fan or heater fan are turned on
- fuel pump not getting enough power
- audio system beginning to clip when pushed moderately hard while turning on fans

I attach a long wire to the alternator output measuring the voltage drop of each circuit relative to the alternator output,
& then attach to the alternator casing to measure the actual voltage at each point of the circuit.

Alternator Output: 14.23v
Battery Extension Terminal: 14.18v (0.068v drop)
Battery Fuse: 14.20v in (0.50v drop), 14.19v out (0.57v drop)
Battery +ve Terminal: 14.17v (0.066v drop)
Battery -ve Terminal: 0.010v drop
A-Pillar Connector: 14.06v in (0.173v drop), 14.02v out (0.240v drop)
Fuel Pump Relay: 13.44v in (0.825v drop), 13.42v out (0.840v drop)
Fuel Pump: 13.27v in (0.975v drop)
Subwoofer +ve: 14.15v in (0.083v drop)
Subwoofer -ve: 0.012v drop

Comparing these voltages to the previous values in Feb:
2025-02-11 Test Fuel Pump Voltage Drop
After fixing the dodgy immobiliser connection, the fuel pump & battery values have slightly improved but overall the electrical system is still struggling, especially whenever the cooling fans drain all the power.

Next I test the grounding straps by engaging all the fans & lights to heavily load up the circuit, & measure the voltage between the alternator casing and each end of the ground straps:

Cyl Head to Chassis: 0.06v
Gearbox to Chassis: 0.07v
Starter to Chassis: 0.08v but 0.18v at the crimped head?

All the ground straps were very bad & need replacing



Here's the 3 old engine ground straps.

Top: some generic awg10 speaker/subwoofer power cable used to ground the cyl head to the chassis. (now I realise it ain't suitable for grounding an engine )

Middle: OEM gearbox to chassis ground lead (terribly old, rusty, oxidised)

Bottom: halfords ground strap with a bigger M10 lug crimped over the existing end to ground the starter to the chassis (the crimp over another crimp created more resistance from corrosion)



Replaced them all with new halfords M8 braided ground straps



Bolted the black ground strap from the head to a wirebrushed chassis point



Bolted the shorter M8 straps to the gearbox casing bolt rather than the M10 starter motor bolt (so I didn't need to crimp on a bigger lug like before)



Bolted the 3rd strap directly onto the gearbox bolt (eliminating that bad rusty oem spade connector)



The end result of replacing these straps is a major improvement!

Alternator Output: from 14.23 to 14.42v
Battery Extension Terminal: from 14.18 to 14.42v
Battery +ve Terminal: from 14.17 to 14.39v
A-Pillar Connector: from 14.06/14.02 in/out to 14.27/14.23 in/out
Fuel Pump Relay: from 13.44/13.42 in/out to 13.63/13.61 in/out
Fuel Pump: from 13.27 to 13.36v
Subwoofer +ve: from 14.15 to 14.33v

Cyl Head to Chassis Strap: 0.004v drop
Start/Gearbox to Chassis Strap: 0.003v drop

Covered the exposed braided strap with heatshrink to reduce corrosion



& neatened the cables









When I turn on all the cooling fans, heater fans, lights etc the battery used to drop to 13.50v but now it stays at 14.13v
And while cruising, the battery voltage has now gone from 14.07v to 14.30v and is charging up fully

In conclusion the engine grounding straps are just as important as the power cables for a efficient electrical system but is often forgotten about.
So I recommend you check or replace it, especially if it's a 32yr old Micra

2025-09-08 Dolly & Hammer Kit

Brought a cheap 7pc dolly & hammer kit off ebay





to learn how to fix these spare dented front wings I got from 2020

https://micra.org.uk/threads/pollymobiles-rebuild.35251/post-782101

2025-09-09 Datalog Analysis

Recorded a datalog of the current setup after fixing all these electrical issues to compare how it runs compared to previous setups



Good thing about recording all these detailed logs of Kassandra for the past 2 decades is being able to spot any small differences in the data as the car spec evolves

~~ Car Specifications ~~

Here's a list of specs & changes made in the 4 datalogs I'll be analysing:

# 2009-12-31 (Cold Winter) ~~~~~~~~~~~~~~~~~~~~~
Intake: OEM TB, Airbox, CAI
Exhaust: Janspeed 421 header & light 1.8" cat-back system, 2nd cat
Fuel pump: Original fuel pump
Fuel: E5 Shell
Diff: Open diff
Clutch: JUN with standard clutch (light weight)
Brakes: OEM Discs
Wheels: OEM 13" alloys

# 2023-06-03 (Warm Summer) ~~~~~~~~~~~~~~~~~~~~~
Intake: Teflon spacer, TB elbow, Pod CAI
Exhaust: Enlarged OEM mani, 2nd de-cat, 1.8" light Janspeed Silencer
Fuel pump: Old Walbro fuel pump
Fuel: E10 Tesco
Diff: Open diff
Clutch: JUN with worn 200mm helix disc & PP (Heavier)
Brakes: GTIR Discs
Wheels: 15" Alloys

- Sunroof deleted
- Added subwoofer weight

# 2024-11-17 (Cold Autumn) ~~~~~~~~~~~~~~~~~~~~~
Intake: Teflon spacer, TB elbow, Pod CAI
Exhaust: New short 4-1 equal length manifold, Fake CAT, 2nd de-cat, 2.25" heavy Powerflow Silencer
Fuel pump: Old Walbro fuel pump, facelift in-tank
Fuel: E10 Tesco
Diff: LSD diff
Clutch: Blueprint clutch disc, Old 200mm helix PP
Brakes: GTIR Discs
Wheels: 15" Alloys

- Richer high end fuel map

# 2025-09-08 (Late Summer) ~~~~~~~~~~~~~~~~~~~~~
Intake: Teflon spacer, TB elbow, Pod CAI
Exhaust: New 4-1 Equal length manifold, Genuine CAT & 2nd CAT, 2.25" heavy Powerflow Silencer
Fuel pump: New Walbro fuel pump, facelift in-tank
Fuel: E10 Morrisons
Diff: LSD diff
Clutch: Blueprint clutch disc, Old 200mm helix PP
Brakes: GTIR Discs
Wheels: 15" Alloys

- Fixed wiring & ground straps
- Cleaned injectors & filter
- New Bosch spark plugs
- Leaner high end fuel map

~~ Cold Start Analysis ~~

Analysing the cold start sequences frame by frame, first we look at turning on the IGN power with the engine stopped & stone cold.
The logs in 2009 & 2024 were during winter so the coolant sensor is reading correctly below 10c whereas 2023 & 2025 were recorded during a warmer summer so it reads near 20c ambient.
Battery voltages are all reading approx 12.0v



When cold cranking the engine, the starter motor drops the battery down to 9-10v except for in 2024 were it reads 8v, possibly due to bad ground straps.
Injector timing shoots up to 20-30ms with a 1-2% duty cycle due to the low rpm.
Notice the increased injector duty cycle during the colder climates.



Immediately after cranking, injector timing drops down to 4-6ms but maintain 4-6% duty cycle due to the engine spinning upto 1.3k rpm.
Battery drops from 12.0v to 11.2v cos the alternator isn't charging yet



ECU automatically blips the rpm upto 1.6-1.8k rpm by raising the timing to 25deg and inject more fuel.
Alternator is now spinning fast enough to charge the battery at 14v



Once the engine has fired up and settled into a stable rich fast-idle, timing stays approx 25deg but injecting less fuel at 6-8% duty, dropping it to 1.3k rpm.
Alternator now sending a full 14.2v to charge the battery after the intense cranking..
All 4 logs showing the MAF reading at approx 1.70v



~~ Compare WOT Pulling ~~

In all the videos I go WOT in 2nd gear upto red-line down the same sliproad to join the carriageway, which I can use as a rough dyno to compare the overall performance of each setup.

The old 2009 setup shown RED seems to be the fastest due to being lighter, improved breathing from the 421 header with matching janspeed exhaust, less inertia from the standard wheels/brakes/clutch.

2023/2024 setup in BLUE/YELLOW is the slower due to more weight & inertia from the bigger wheels, bigger brakes, bigger clutch, heavy subwoofer & toolbox and the 4-1 manifold wasn't optimised for the bigger & heavier powerflow exhaust (it was meant to run turbo).

2025 setup in GREEN is marginally faster at high rpm due to improved voltages, higher MAF reading, leaner fuel map



~~ Compare Sensor Readings ~~

The MAF sensor seems to rely on a strong power supply & earthing
So the old bad grounding straps in 2023/2024 (YELLOW/GREEN) gave the lowest MAF readings, which affects the overall map calculations.
Replacing all the bad earth straps & terminals gave the 2025 setup a stronger MAF signal (BLUE) closer to the 2009 setup (RED)



The current 2025 fuel map is slightly leaner (BLUE) than the 2024 map (GREEN) when I first fitted the new 4-1 manifold, therefore the injector timing is reduced.

The original 2009 janspeed 421 map had a richer mid-range (RED)



Looking at overall injector duty cycle, the 2023/2024 layout (YELLOW/GREEN) ran richer whereas the 2025 map (BLUE) is running leaner to maintain a stable 13-14AFR.
Original 2009 map (RED) ran rich in the mid-end but leaner at the high end.

2025-09-13 Datalog After Removing Weight

The gearstick had a slight buzz during high rpm so I trimmed the inner bearing bushing to reduce some side-to-side play which helped



Removed the heavy subwoofer & my toolbox for a more accurate comparison cos it's slowing the car down in the datalogs whereas in 2009 the car didn't carry such weight



Went for another drive before it rains



Now comparing the same 2nd gear WOT pull, the current lighter setup without the heavy sub & toolbox (GREEN) accelerates approx 0.48sec faster than before (YELLOW) especially after it reaches peak torque at 4500rpm but still not as fast as her old 2009 setup (RED)