6.0L Denso A-bank camshaft trigger

(Bart Sowa) #1

Hi All,

This is a question to 6.0L owners with the Denso fuel system.
I am trying to find out how the Camshaft Position Sensor is triggered on Denso cars.
Is there a dedicated peg on the camshaft? Is the camshaft a different casting or some set screw is tapped into the cam?
Or maybe the sensor is triggering off of the cam lobe?

A photo of the camshaft with the feature would be very helpful.

(Jeff Watson) #2

G’day Bart,

There is a pin on the camshaft and a sensor mounted in the cam cover for that bank.

From what I know all it does is send a signal to the ECU telling it when the engine is on compression for initiating correct timing. If the sensor is faulty or missing the ECU will make a guess and try to fire the engine and if that doesn’t work it will try again one revolution later.

Once the engine has started it serves no purpose. I disconnected my camshaft position sensor and started my engine to see what would happen. The engine started just fine but cranked for a little longer.


(Bart Sowa) #3

Thanks, Jeff.
Do you know if the pin is drilled/tapped into the camshaft? What is the angular relation to #1 lobe?
I am working on converting my 5.3L ignition to distributor-less setup and would like to have a compression/exhaust TDC detection.
Since the EDIS coils run in wasted spark setup, I can fire the opposite cylinders simultaneously and it shouldn’t matter if I have the TDC detected or not. But if I can do it with a minimum effort, why not?

In any case, thanks again for your reply.

(Matt Furness) #4

There are 4 steel bolts holding the sprocket to the camshaft. I replaced 3 of these bolts with 316 stainless steel bolts which is non magnetic and is ignored by the VR sensors typically used on all Fords to detect position. These sensors have a small permanent magnet surrounded by a coil. When a piece of steel sweeps through the magnetic field set up by the permanent magnet the field is modified and the coil generates a small voltage. The ECU detects the voltage…so you can drill a hole in the face of the cam cover before TDC and detect the steel bolt as it passes the sensor. The SS bolts are invisible to the sensor. It works with a MS3Pro because I have full sequential injection on my 5.3XJS.

(Bart Sowa) #5

Thanks Matt.
It is a clever solution. I was considering 3 options for the cam sensor:

  • Denso solution with trigger on the camshaft
  • Some kind of cam sprocket solution
    - Trigger on the jackshaft (will not work. the jackshaft sprocket is the same size as crankshaft sprocket so it would generate two pulses in one combustion cycle)
    Seems that yours is quite simple and validated.

(Jeff Watson) #6

G’day Bart,

I don’t know any of those details, sorry.

Good luck with your project.


(Matt Furness) #7

Here is a photo of the solution I came up with. Requires a friend who is a machinist…And only requires a hole to be drilled in the cam cover.

The location of the cam trigger is normally specified in the manual of the ECU you are using. It shouldn’t be critical because it is just a pulse that tells the ECU to get ready for TDC on the trigger wheel…so some time before TDC…check the manual of the ECU.

(mike90) #8


You are the first person of which I am aware who is doing full sequential injection on this engine.

How do you find it? performance, economy, idle behavior, etc.?

Do you have more pix and map info available? Lots of questions! What trigger wheel, how are you doing ignition, etc., etc.



(Matt Furness) #9

Hi Mike
I used a 36-1 trigger wheel on the crank pulley and Ford VR sensor mounted on an aluminium bracket.works well with nice steady pulses.
Ignition is wasted spark via two Ford coil packs driven by a Nissan igniter. Nissans fire six coils on the 6 cylinder engine so the six outputs are wired to the six coils. The Ford coil pack has 3 coils on each pack creating 6 sparks so the 6 coils generate 12 sparks.
The cam sensor is as described above…but was problematic because the bolt sweeps past the sensor and gives a pulse when the bolt head arrives and then a second pulse when it departs…the MSPro can deal with this by setting the cam sensor to “Polling Only” which takes the first setting and ignores the rest. A lotta work to get this sorted!!..which is why I specifically mention it here so you can check the ECU to see if it can handle the input.
I haven’t dialled it in properly yet because I have rear suspension toe issues to sort out …but it idles very nicely at 650rpm …I used a Ford idle speed valve for the cold start and screwed the butterflies closed to get the 650rpm. I run about 22 deg advance and 13.5:1 AFR to get the nice idle.
The advantage with the programmable ECU is that you can set the engine up to run as well as it is possible to run and it will stay that way. Also really cool to see and adjust the parameters on a laptop!!! But it has to appeal to you as a project cos there is a bit of work in it.
If you decide to go,down that route I’m happy to help. I have some drawings of some stuff I had to make and can send photos. Just let me know.

(Mark Eaton) #10

“… it idles very nicely at 650rpm …” is a clue that you are doing something right. Something that the OEM system is frustratingly unable to do.

(Matt Furness) #11

Yes…My original system had an annoying stumble on idle…my new system …when I set it up with about 10 degrees advance at idle and 14.7:1 AFR had the stumble. I agreed with Philip L and his interesting post on idle advance…because I ended up dialling up more advance and the engine ran faster and faster…one of the beauties of programming via laptop and watching live AFR and timing info!!!.. Seemed to steady at early 20 deg advance…so I adjusted the butterfly valves more closed to lower speed but still had stumble…then richened AFR and idle smoothed out nicely at about 13.5:1 . Ha HAAAH…too easy with a laptop!!!

(Bart Sowa) #12

“Something that the OEM system is frustratingly unable to do.”

Mark, OEM’s typically work with some constraints we ignore or are unaware of. In case of idle operation, advanced timing and rich mixture increase NOx, HC emissions and do not allow the catalyst to operate properly. I assume they had to trade off the idle quality for retarded timing to increase the exhaust temperature in order to keep the catalyst at lightoff temperatures, and cycle the AFR rich-lean to recharge the oxygen storage.

Matt, I hope your car does not have the catalytic converters. Years ago, when I finally tuned my idle with Megasquirt (finding similar solution as yours), I found an overwhelming and surprising odor of sulfur (or rotten eggs). My catalysts were melted and I assume it was due to excessive HC during rich idle operation. Catalysts were converting (burning) those HCs to a point of thermal breakdown. I still do not know where the sulfur smell came from, maybe from oil in the crankcase vapors?

(Matt Furness) #13

Hi Bart
No cats on my NZ new 85XJS-HE…!!

(Ole WĂĽrtz) #14

I don’t know what causes the smell either, but years ago when catalysts were a new thing, some friends and I found some makes of cars would smell and others not.

(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #15

Back in the day, sulfur smells were blamed on bad fuel. A catalytic converter will raise a stink if there’s sulfur in the fuel, but there’s not supposed to be sulfur in fuel any more.

I think sulfur in fuel can also wreak havoc with nikosil cylinders.

(Bart Sowa) #16

Enjoy your smooth idle then!

(Bart Sowa) #17

Sulfur, along with lead, phosphorus and others are damaging to the catalytic converters and have been removed from fuels. They can be still found in coolants or lube oils, so anytime the engine is dumping oil or coolant into the exhaust, it can damage the catalysts.
Additionally, when low loads enable condensation, sulfur can form sulfuric acid and eat away anything susceptible to it, as Kirby noted (including liners, valves and other ferrous metals).

(MarekH) #18

Dear Bart,
If you browse the photo albums posted under the old website and search either for Megasquirt or some of my albums, you’ll see similar solutions to those already proposed.

The Denso system runs its fuel either semi-sequentially - it pairs 3B/5B, 2A/4A, 1B/4B, 3A/6A, 2B/6B and 1A with 5A or fires all twelve at once (during startup?). This is why it’ll start without a cam sensor or run after the cam sensor gets subsequently disconnected. The pairing choice does let it set the fueling differently on each bank (each bank has its own MAP sensor). The cam sensor is thus used to tell it which bank it is fuelling and adjust each bank’s fuelling accordingly if an O2 or MAP sensor tells it to.

The cam sensor is there also for OBD2 compatibility as the ECU has to detect misfires and diagnose which cylinder is at fault. It can only do that last function and maintain OBD2 compatibility with a working cam sensor as it won’t know which bank is firing otherwise.

Aside from OBD2, the Megasquirt is a more sophisticated setup.

kind regards

(Bart Sowa) #19

Thanks Marek. For some reason I can only see the thumbnails of photos on old website and can tell the details. Did you weld some kind of a boss onto the valve cover to accommodate the sensor?

(MarekH) #20

Yes I did. The sensor triggers off a longer bolt on the camshaft sprocket, the other three being standard bolts.
Some of the photo albums work better than others.

kind regards