Category: ignition timing

Stock Spark Plug for an RB26DETT

NGK PFR6A-11
* P = Premium platinum
* F = 14, 19mm(3/4″) reach, 16mm (5/8″) hex
* R = Resistor
* 6 = Heat range 6
* A = Firing end construction
* -11 = 1.1mm gap (0.044″)
Heat range for NGK plugs 2 HOT – 11 Cold




Spark plug gap. The “gap” is the distance between the ground electrode and center electrode. The further the two are apart, the more potential (voltage) that is required to arc, or jump that gap. Some people run a super tight gap, because of misfire issues. If the car is pretty stock, then it should have no issue arcing or firing across 1.1 mm or 0.044 inch. At bigger power you might go down to 0.8 mm or 0.031 inch. Generally a bigger arc is going to give you a more complete burn in the combustion chamber. 

A good stock replacement spark plug for an RB26 is a BCPR7EIX. Its an NGK Iridium plug. Heat range is 7 which is one heat range cooler than stock. Its readily available in the US. I would use them up to about 500 horsepower on an RB26. Above that I would look at an 8 for a street car, cooler if its a track car.

More spark plug information here – RB26DETT Spark Plugs

Back to the ignition, coils, wires, etc. The first thing to do, if you think you have a misfire, or problem with your ignition system is to observe.

1) Does the car have a noticeable miss? Shaking a little, won’t rev up correctly? An RB26 should idle pretty smoothly at 950-1050 rpm.

2)Can you rule out anything obvious? Aka vacuum noise, vacuum lines off, intercooler hose popped off, electrical connections disconnected?

3) Remove center plate from engine – finishing plate, so you can access coils.

4) Reconnect igniter. Start engine. Disconnect one coil at a time, to isolate cylinder that is misfiring. If you notice no difference, then double check them all. There is another way to do this with Consult software, but standing in front of the engine, its normally very obvious which cylinder has little to no change when disconnected.

5)When you locate the misfire, turn off engine. Pull that coil and plug. Double check all connections. Is the connector damaged? Any signs of overheating on the coil? Is it dirty? Do you see a large amount of carbon? Check the wiring harness. Any loose or broken connectors?

Missing part of the connector

6)Pull the coil boot off, look at the contact. There are two styles of contact, a carbon, and a spring. The carbons wear, the springs can also fall out. Make sure something is there, and doesn’t look corroded, or damaged.

Notice anything missing? High boost, and RPM misfire identified!

7)Pull the spark plug out and look at it. Does it look normal? Does it have wet fuel on it? Is it missing an electrode?

8) Clean or replace spark plug. Recommend replace, but that isn’t always practical

9) Clean and put dielectric grease on the boots http://www.gtrusablog.com/2014/04/gtr-rb26-misfire-under-boost-and-coil.html

10) Fire it up, see if that fixed it.

11) If it fixed it, then you are golden. If not, then continue

12) If the car is an R32/R33 then it has coil, igniter, wiring harness, ECU, power to fire the coils. If the car is running, the power is good, so don’t bother look at the main power. That narrows it down to coil, igniter, wiring harness, ECU.

13) Next thing to try, is figure out if the coil is bad. Take the coil that showed as misfiring, and move it to another cylinder. AKA #2 was bad, move it to #3, or #1. Doesn’t matter where. Did the misfire follow that coil, or is it still showing same hole as bad?

14) If the misfire followed the coil, then its probably a bad coil, replace, test again.

15) If the misfire stayed in the same location, then its either wiring harness, igniter, or ECU. Could also possibly be bad plug. Swap plug, test again.

Check out the center pin on this connector. Wiring harness

16) The last two cars I had this issue with, turned out to be fixed by removing the wiring harness from the ECU in the passenger side kickpanel, and reseating the ECU connector. It was that simple. Both cars started firing on six cylinders again

17) If this doesn’t fix it, the next step is isolating the wiring harness, the igniter,and the ECU to figure out which component isn’t working.

Stock Coils

Pros

• You already have them
• No extra cost
• 45kV output (according to our Nissan sources)
• R32/R33 22433-60U01  or 22433-60U02
• The front two coils on a early 90’s Infiniti Q45 are the same
• R34 22448-25U00 (coil assy)
• R34 22465-59S00 (boot)

Cons

• Maybe failed
• Lower kV output (45kV ?)
• Extra parts
• Replacement parts are generally high cost
• Should be cleaned and lubed – http://www.gtrusablog.com/2014/04/gtr-rb26-misfire-under-boost-and-coil.html

Stock coils showing signs of water in the engine valley

Aftermarket Coils
Pros

• Possibly higher kV output
• Possibly less parts

Cons

• Cost
• Added complexity in some cases
• Could be worse than stock
• Could be Chinese made junk

Stock Wiring harness

• R32/R33 to R34
• Wiring Specialties offers harness
• R32/R33/R34 to R35
• R35 coil connectors are the same as R32 to R34

More wiring modifications and new harnesses for RB26dett


Understanding, Testing and Calibration of Ignition Coil Dwell Time

Supertec R35 Coil adaptor for RB26

• R35 Coils
• Adapters available
• OEM Nissan parts
• Proven to 1500+ hp
• May be able to use other Nissan coils with boot change

Supertec R35 Coil adaptor for RB26

RB26 single turbo with Audi coils from Almasi Tuning

IP R35 coils vs stock R35 coil output at various charge times

• Audi coils
• Plug and Play harnesses for R32,R33,R34 from Almasi Tuning
• 38kV-40kV output according to what we have seen. 
• 100% Plug & Play Coil pack harness for Audi R8 coil pack on RB20DET, RB25DET Series 1, RB25DET Series 2, RB25DET NEO, RB26DETT R32/33 or RB26DETT R34  
• LS coils
• GM/AC Delco D585 “LQ9” Coil Issues, Fixes, and Warranties
• Early in the use of these coils Many of the ECU manufacturers were recommending dwell times of 5-6 MS. This seemed to work well but soon reports of blown engines began to appear, apparently with the LQ9 coils as the cause. It was found that when excessive dwell is used, the coils will sense a charge overcurrent and self discharge in advance of the ignition pulses’s falling edge, effectively advancing the the spark to a dangerous and sometimes destructive degree. The fix for this is to limit dwell to 3.4 MS or less.
• http://www.mojoperf.com/?q=node/4
• Mercury Marine
• Honda CBR
• Yaris Coils

• R35 Coil vs Yaris Coil Debate. Platinum Racing Products pits the coils head to head. 

Buy USA Legal R32 Skylines at Importavehicle.com!
Buy-R.com for Nissan Skyline GT-R and GT-R parts.

Buy USA legal JDM vehicles over 25 years old here

Stock Spark Plug for an RB26DETT

NGK PFR6A-11
* P = Premium platinum
* F = 14, 19mm(3/4″) reach, 16mm (5/8″) hex
* R = Resistor
* 6 = Heat range 6
* A = Firing end construction
* -11 = 1.1mm gap (0.044″)
Heat range for NGK plugs 2 HOT – 11 Cold




Spark plug gap. The “gap” is the distance between the ground electrode and center electrode. The further the two are apart, the more potential (voltage) that is required to arc, or jump that gap. Some people run a super tight gap, because of misfire issues. If the car is pretty stock, then it should have no issue arcing or firing across 1.1 mm or 0.044 inch. At bigger power you might go down to 0.8 mm or 0.031 inch. Generally a bigger arc is going to give you a more complete burn in the combustion chamber. 

A good stock replacement spark plug for an RB26 is a BCPR7EIX. Its an NGK Iridium plug. Heat range is 7 which is one heat range cooler than stock. Its readily available in the US. I would use them up to about 500 horsepower on an RB26. Above that I would look at an 8 for a street car, cooler if its a track car.

More spark plug information here – RB26DETT Spark Plugs

Back to the ignition, coils, wires, etc. The first thing to do, if you think you have a misfire, or problem with your ignition system is to observe.

1) Does the car have a noticeable miss? Shaking a little, won’t rev up correctly? An RB26 should idle pretty smoothly at 950-1050 rpm.

2)Can you rule out anything obvious? Aka vacuum noise, vacuum lines off, intercooler hose popped off, electrical connections disconnected?

3) Remove center plate from engine – finishing plate, so you can access coils.

4) Reconnect igniter. Start engine. Disconnect one coil at a time, to isolate cylinder that is misfiring. If you notice no difference, then double check them all. There is another way to do this with Consult software, but standing in front of the engine, its normally very obvious which cylinder has little to no change when disconnected.

5)When you locate the misfire, turn off engine. Pull that coil and plug. Double check all connections. Is the connector damaged? Any signs of overheating on the coil? Is it dirty? Do you see a large amount of carbon? Check the wiring harness. Any loose or broken connectors?

Missing part of the connector

6)Pull the coil boot off, look at the contact. There are two styles of contact, a carbon, and a spring. The carbons wear, the springs can also fall out. Make sure something is there, and doesn’t look corroded, or damaged.

Notice anything missing? High boost, and RPM misfire identified!

7)Pull the spark plug out and look at it. Does it look normal? Does it have wet fuel on it? Is it missing an electrode?

8) Clean or replace spark plug. Recommend replace, but that isn’t always practical

9) Clean and put dielectric grease on the boots http://www.gtrusablog.com/2014/04/gtr-rb26-misfire-under-boost-and-coil.html

10) Fire it up, see if that fixed it.

11) If it fixed it, then you are golden. If not, then continue

12) If the car is an R32/R33 then it has coil, igniter, wiring harness, ECU, power to fire the coils. If the car is running, the power is good, so don’t bother look at the main power. That narrows it down to coil, igniter, wiring harness, ECU.

13) Next thing to try, is figure out if the coil is bad. Take the coil that showed as misfiring, and move it to another cylinder. AKA #2 was bad, move it to #3, or #1. Doesn’t matter where. Did the misfire follow that coil, or is it still showing same hole as bad?

14) If the misfire followed the coil, then its probably a bad coil, replace, test again.

15) If the misfire stayed in the same location, then its either wiring harness, igniter, or ECU. Could also possibly be bad plug. Swap plug, test again.

Check out the center pin on this connector. Wiring harness

16) The last two cars I had this issue with, turned out to be fixed by removing the wiring harness from the ECU in the passenger side kickpanel, and reseating the ECU connector. It was that simple. Both cars started firing on six cylinders again

17) If this doesn’t fix it, the next step is isolating the wiring harness, the igniter,and the ECU to figure out which component isn’t working.

Stock Coils

Pros

• You already have them
• No extra cost
• 45kV output (according to our Nissan sources)
• R32/R33 22433-60U01  or 22433-60U02
• The front two coils on a early 90’s Infiniti Q45 are the same
• R34 22448-25U00 (coil assy)
• R34 22465-59S00 (boot)

Cons

• Maybe failed
• Lower kV output (45kV ?)
• Extra parts
• Replacement parts are generally high cost
• Should be cleaned and lubed – http://www.gtrusablog.com/2014/04/gtr-rb26-misfire-under-boost-and-coil.html

Stock coils showing signs of water in the engine valley

Aftermarket Coils
Pros

• Possibly higher kV output
• Possibly less parts

Cons

• Cost
• Added complexity in some cases
• Could be worse than stock
• Could be Chinese made junk

Stock Wiring harness

• R32/R33 to R34
• Wiring Specialties offers harness
• R32/R33/R34 to R35
• R35 coil connectors are the same as R32 to R34

More wiring modifications and new harnesses for RB26dett


Understanding, Testing and Calibration of Ignition Coil Dwell Time

Supertec R35 Coil adaptor for RB26

• R35 Coils
• Adapters available
• OEM Nissan parts
• Proven to 1500+ hp
• May be able to use other Nissan coils with boot change

Supertec R35 Coil adaptor for RB26

RB26 single turbo with Audi coils from Almasi Tuning

IP R35 coils vs stock R35 coil output at various charge times

• Audi coils
• Plug and Play harnesses for R32,R33,R34 from Almasi Tuning
• 38kV-40kV output according to what we have seen. 
• 100% Plug & Play Coil pack harness for Audi R8 coil pack on RB20DET, RB25DET Series 1, RB25DET Series 2, RB25DET NEO, RB26DETT R32/33 or RB26DETT R34  
• LS coils
• GM/AC Delco D585 “LQ9” Coil Issues, Fixes, and Warranties
• Early in the use of these coils Many of the ECU manufacturers were recommending dwell times of 5-6 MS. This seemed to work well but soon reports of blown engines began to appear, apparently with the LQ9 coils as the cause. It was found that when excessive dwell is used, the coils will sense a charge overcurrent and self discharge in advance of the ignition pulses’s falling edge, effectively advancing the the spark to a dangerous and sometimes destructive degree. The fix for this is to limit dwell to 3.4 MS or less.
• http://www.mojoperf.com/?q=node/4
• Mercury Marine
• Honda CBR
• Yaris Coils

• R35 Coil vs Yaris Coil Debate. Platinum Racing Products pits the coils head to head. 

Buy USA Legal R32 Skylines at Importavehicle.com!
Buy-R.com for Nissan Skyline GT-R and GT-R parts.

Buy USA legal JDM vehicles over 25 years old here