This ignition coil has a crack where marked. See pictures below for more details
We had a couple of issues come up with the Saurus car. While at Cars and Coffee one weekend, it decided to start to run funny. It wouldn't go into boost without cutting out. I drove it back home and started some diagnostics . It appeared that fuel pressure wasn't rising with boost. I figured that a line in the tank might be leaking. However it turned out that it actually had two fuel pumps in the tank, and one had failed.
Ernie replaced one dead pump with another stock pump we had. Installed an Apex Electronic Fuel Pressure Gage. Fuel pressure was good, but the car was still cutting out. Onto the next step of troubleshooting, the ignition system. Removing the center plate and harness, it was a little crispy, and a couple of the connectors had pieces come off them. New Wiring Specialties harness, and that issue was cured. The next thing was cleanup, and sparkplug change. Since this is a special car, I broke out a set of my "best" plugs for an RB26. For this car I had a full set of 7436-9's and they went in.
We pulled the boots of the coils, and Ernie noticed one of the coils had a more pronounced crack at the parting line. We noticed, it but we didn't actually do anything about it. Just noted.
Around the crack, you can see marks/scratches where it appears the spark was leaking
New plugs, new harness, cleaned all the coils up, put dielectric grease, and took the HKS twin power out of the loop (for testing). Went out for a drive, and while it was much better, it was still misfiring at about 12 psi of boost. Back to the shop, pull the cover back off. Hit that one coil. Replaced, out for a drive, and its cured. Car is running as it should again.
When you see something wrong, it probably is something wrong. Observation in troubleshooting is big. Sometimes you just need to take a minute with some light, and look at things. Make sure you see or don't see something.
Around the crack, you can see marks/scratches where it appears the spark was leaking
The RB26 ignition coil harness is in the valley of the head, and gets hot. Really hot. That heat cooks the harness. Not only does it cook the harness, the connectors get brittle and break. If you are having misfires on your RB make sure you look at your ignition harness.
Supertec Racing VR38 to RB26 adapter kit allows for fitting of VR38 coils from the R35 GTR. These are a huge improvement over stock coils and rated to around 2000hp as demonstrated by some high powered R35s using factory coils.
RB26 ignition coil missing a spring. Idled and ran fine under low load. High load had a misfire
We recently had a Nissan Skyline GT-R that ran great at idle. Would pull smoothly through the gears, but at high rpm, and high load would break up.
The first thing we thought to check was the spark plugs, and ignition coils. Since the idle was smooth at 1000 rpm, and it didn't sound like it had any vacuum leaks, this seemed the first spot to start troubleshooting.
When the coils came off, there was a bit of dirt/carbon on the coil packs and boots. Dirty coils can cause misfires. Electricity can conduct through the dirt and carbon build up. We cleaned up the coils, boots, and added some dielectric grease to them.
Once we removed the boots from the coils, we noticed one missing contact. About 99% certain we had identified our issue, we put it back together to test. A short drive later, problem solved.
Lots of vehicle issues can be identified and fixed, with just some observation, and a little bit of work. From loose electrical connectors,loose grounds, broken solder joints, to small parts missing. On vehicles over 25 years old, things will come up. Before randomly buying new parts, and replacing them, spend just a little time troubleshooting to at least narrow down the issue.
Coils
Coil on plug. R32/R33 are the same.
The front two ignition coils on each side of the V in a early 90's Infiniti Q45 are the same
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?
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?
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.
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.
Ignition and the ignition system. When you have a misfire, on an engine, you effectively are losing the horsepower for that cylinder, wasting fuel, and potentially causing damage to the engine.
There are two types of coils, ignition systems on a stock RB26DETT, the R32/R33, and the R34. The coils on the R32/R33 are the same, both have an external igniter. The R34 have a built in igniter (same as series 2 RB25).
NISMO R32 GT-R stock coils
We have heard that the stock coil output is 45kV. However we haven't seen any confirmation on that number. A coil on plug setup like an RB26 is superior to a normal coil/distributor cap, as each coil has more time to charge and discharge, cool off, vs a single coil setup. It also allows direct control of coil dwell time, and firing time.
The coil is the other end of a harsh environment. In the combustion chamber, where the spark plug has to fire, is a bad operating environment. It probably should be against OSHA.
This is where the correct spark plug comes in. We have heard, that it takes 5,000 less volts to fire an iridium spark plug vs a conventional plug. Copper is a great conductor, however it wears much faster than other types of metals. We prefer the double fine wire racing iridium. Some people like changing plugs every week. Some people don't like the iridium, we have been using them for more than 15 years in high performance vehicles. NISMO race car mechanics recommended the double fine wire iridiums to us, and we trust what they have to say.
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.
This is from NGK on spark plug gap.
"Although the NGK factory will set the gap to a preselected setting, this may not be the right gap for your particular engine. The incorrect plug gap for your engine can contribute to a high rate of misfires, loss of power, plug fouling, poor fuel economy and accelerated plug wear. It is always best to check the gap against the manufacturer's specifications. If adjusting the gap on fine wire or precious metal plugs such as platinum or iridium, be very careful not to apply any pressure or prying force to the fine wire center electrode or insulator as they can be damaged. The gap should be adjusted by only moving the ground electrode.
Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005"."
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.
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?
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?
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.
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.
R32, R33, and R34 GT-R are all unique. One of the few parts on these cars that are
Grounds are important. The older the car, the worse the grounds get. Take them all off, wire brush, clean, and reassemble. Grounding kits really do help.
Electricity is lazy, and takes the path of least resistance
This Wiring Specialties coil pack sub-harness is plug and play to the R32/R33 RB26 OEM harness. Make the install very simple and make more power instantly.
Allows for R34 Smart-Coil mounting in the OEM coil location for R32 and R33 applications
Plug and Play
Harness eliminates the ignition chip
R32 Pro Harness
Brand NEW Construction
High Temp Nylon looming with adhesive shrink tubing
High Temp wire (280 degrees)
OEM connector specs (no cheap aftermarket connectors that fall apart)
Designed for a factory-like installation
OEM wiring connections and 'T' junctions. No soldered connections at all
Fully tested after production for an easy plug-and-play replacement
Battery direct harness. About $180. Takes battery voltage though a relay directly to the ignition coils. We never did a before and after test, but will have to one day.
HKS Twin Power
A compounding ignition system of full transistor type + CDI (Capacitive Discharge Ignition) type which is an ideal performance in a wide range of engine speeds from low RPM to high RPM.This system will improve in starting, more torque at low and medium speed range, reliable ignition in high boost pressure, and better response.
This is a compact and lightweight, so it can be mounted anywhere. In addition, because of high efficiency power circuit, we were able to keep to a minimum level of impact on the alternator. And we offer a broad range of products for installation to your vehicle.
Because of the high power, engine tune-up can cause a trouble in ignition or starting failure. This system is ideal for those cases, and also best for those who have idling problem or people want the NA vehicle power-up.
*Full transistor type: It has long duration of discharge and could obtain stable combustion at a low RPM *CDI System: It has fast initial rise of current discharge so it has strong ignition energy which is good for high RPM.
B&M New Volt
Voltage booster. They have been discontinued for a long time, however there are similar boxes that are used to increase voltage to fuel pumps. The more voltage you have going into a coil, the more voltage it is going to put out. More or less.
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.
The Nissan Skyline GT-R ignition coil harness lives in the valley of the engine. The RB26 is a coil on plug engine, and in the R32 and R33 in addition to the coils there is a ignitor box. On the R34 they eliminate the separate ignitor box, and build the ignitors into the coils. The coil harness is one of a few unique, not shared parts on the R32, R33, and R34 GT-R RB26DETT.
The problem is that the coils, and the coil harness gets hot. It gets cooked. If I am racing, I pull the center cover off. Leave the coils open as below.
The engine doesn't look as finished, but when you are racing, much better to try and keep from cooking the coils and harness. Often when you are taking an old coil harness off, its crispy, and the connectors break in your hand.
Resistance increases with temperature. Electricity takes the path of least resistance, and excessive heat often can cause misfires. Check out this post I did a while back, when I found out about the Do Luck Direct Ignition Harness Strengthening Kit. Not only does Do Luck have an upgraded coil harness, they have a direct wire option. The direct wire option adds a relay, and pulls 12 volt power directly from the battery.
The install is straight forward. Remove the old coil harness. Install the relay for direct power from the battery. Plug in the new harness. If you don't know when the last time your ignition system was maintained, then this is a good idea. Buy one here in the US at this link. While you are in there, put a good set of spark plugs, and do the coil pack fix as detailed here.RB26DETT Ignition System troubleshooting.
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