df115 4-2 fault

[redlowrey]

Plugs were dry. Injectors work when i use actuater tests from SDS but using a mechanic stethiscope they only click during the rare occurance it tries to start. They are quiet during cranking. The engine ran fine the first of the season and sometimes would be hard to start when moving from one fishing hole to another. The boat is normally docked in the water all summer but i have it home now. The first time i had the no start condition i did not have any fault codes so i attacked the fuel system. Drained tank, drained dsv, replaced fuel lines, eliminated antisiphon valve. No eveidence of water from any of it. Put fresh fuel in tank, started right up, went fishing a couple days, ran fine. Came back to camp 2 weeks later no start, no run, no fault code. Pulled it from water looked over everything and decided to change CKP because it checked open with voltmeter. After i installed the new sensor from boats.net i started receiving 4-2 fault code. I get the code as soon as i turn my battery switch on and turn on key every time, before cranking.

If you had of put this post up first it would have saved me a lot of typing. If you disconnect the battery and connect it back up the check engine light should not come up with a crank sensor code, it should be in its memory, the ecu does not know at this point the crank sensor is not working the engine has to crank and the ecu will read the crank signals while it is cranking. Still do that other test, you have not touched any of the wiring when you changed the sensor.

[redlowrey]

Also with the key on check what the battery voltage is on pin 30 then crank the engine and see what it drops too.

[Wwarden5091]

Rain holding north so far so did some more checks. DC voltage on pin 30 is 12.23 vdc with key on, 9.77vdc while cranking, Put test light on coil plugs had steady light on gray wires. Reversed gnd and had flashing light on other wire during cranking. Same on injector plugs, steady light on gray wires, reversed polarity and got flashing lights on other wire of all injector plugs.

[Wwarden5091]

also looking at SDS during cranking fuel pump goes to 100%, fuel inj pulse width 9368 microsec

[redlowrey]

That means that the ecu is receiving the crank sensor information, the internal drivers are grounding the coils and your injectors are triggering, do you hear the fuel pump run when you turn the key on, also stick a screw driver into one of the leads and see if there is any spark when you put it close to some metal cranking, Give your batteries a charge that voltage on crank is a bit low, low battery voltage means low primary and secondary voltage at the coils. Even though the sds is telling you there is 100% command on the fuel pump can you hear it, that just means on crank the fuel pump has a full ground.
I you have spark and it still won't start, open the throttle a small amount with the warm up leaver, remember there will be slack in the cable you have to over come first.

If it still won't start squirt a small amount of propane into the throttle if it trys to start you know you are looking for a fuel problem and I will tell you where to start checking.

[Wwarden5091]

i had fire on all 4 plugs during an earlier check but will check again. I can hear the high pressure pump run a few seconds and stop as it should and when i crack the fuel rail fitting fuel sprays out under good pressure with key on. If its fuel related any idea why the ckp fault indicates before cranking? batteries are charging as we speak. I have a trolling motor battery in the system ill charge as well

[Wwarden5091]

do you prefer propane over starting fluid?

[redlowrey]

do you prefer propane over starting fluid?

It does not matter what you use, I am just trying to determine if the problem is spark or fuel, I always thought that with a crank sensor problem on those early engines, disconnecting the battery the code will go into memory and the light will go out and when cranking if no pulses light will come back on, maby not, I will check this on the weekend on a df 140. Anyway the test you done tells me that the crank sensor is working.

I need to know how good the spark is from your coils, if you can remove a lead from one of the coils and insert a jumper wire the spark should jump half an inch, to metal , without an oscilloscope this is the easiest way to test for spark. With the key on what is the voltage on pin 29 map sensor signal should be nearly four volts, and pin 9 temp sensor, probably around 3 volts, and use pin 11 for your ground.

If the voltage on the map is around 2 volts, or the temp signal voltage is under 2 volts the computer won't be injecting enough fuel for starting.

[Wwarden5091]

Pin 29 MAP sensor voltage 3.93 vdc, SDS reads 29.39 inhg
Pin 9 cyl head temp 1.9vdc, SDS reads 96 degreesF
Pin 31 IAT reads 1.8vdc, SDS reads 102 degreesF Outside air temp today apx 85 degtreesF surface of engine via infrared thermometer is about 100 degreesF

Had good spark arc and also had flashes with inductive timing light on all for cylinders.

Now for the good news, using starting fluid was able to start and keep running somewhat with continued shots of starting fluid.
After first 20 seconds of running CKP fault went away on SDS and engine light on boat. Turn boat off, fault did not return. I ran a new fuel hose directly from front of motor into a gas can with known good fuel and eliminating any onboard tank issues i believe. Still would not run without the aid of starting fluid. Disconnected output of low pressure pump cranked over and some fuel comes out while cranking. That is where i am at so far.

[Wwarden5091]

I dont have a fuel pressure gauge

[redlowrey]

Pull the high pressure fuel filter off and blow through it and see if it is blocked, if it is not blocked connect one end up get some longer hose so you can run it into a bucket and cycle the key and check the flow coming from the filter if it still looks restricted their is a little gauze filter in the bottom of the vst which might be blocked stopping fuel from entering the high pressure pump.

There are little filter baskets inside the tops of each injector that can be removed and replaced, I wouldn't think all four would be blocked, did the engine run sweet before you could not start it or was it lumpy.

[Wwarden5091]

engine ran sweet except for being hard to start sometimes between fishing holes. Ill pull the high pressure filter and examine the vst. Its been a couple years since i changed it.

[redlowrey]

I should have said crank the engine, not cycle the key because you will empty the vst I was thinking, if you have blocked filter baskets the pressure required to push fuel through them might be at its limit or the pressure reg is dumping a bit of fuel. What I am saying over a period of time as the little filter baskets in the injectors block up from poor fuel and filtering the required pressure to push fuel through them will increase till it will not go through I have cleaned hundreds of injectors and only had this problem a hand full of times. You can check that without removing your injectors with a gauge flow meter watching a pressure drop while activating the injectors,
The good thing is the problem will be solved soon.

[Wwarden5091]

got it, will work it tomorrow, thanks

[Wwarden5091]

i had fuel flow from pump output into a bucket. Removed intake and seperated the vst and found this badly split and dry rotted rubber sear on output (top) of pressure pump. I know this is not good but is it bad enough to cause my problem? Causing low fuel pressure??