New motor, new ECM no start

[Matt9712]

Messing around with the grounds........

BATTERY OFF...all ground posts back to negative on battery 0.2 ohms perfect!

BATTERY ON.... all ground posts back to negative on battery 7.8 ohms?? WTF??

What would change the resistance of a direct connection to battery? All ground posts to other spots on engine less then 1 ohm with battery off. The posts that hold the ground are bolted into the engine block, then the lugs are bolted to that stud and I even installed a new ground cable from starboard side post to port side and the port side is a direct bolted cable to battery... How is resistance varying with battery on OR off?

 

[Matt9712]

Checked resistance while cranking engine as well.... While cranking the resistance between my ground stud and negative battery post goes into the 39K ohms range!!

 

[tpenfield]

I do not think you can measure the resistance of a circuit when it is connected to another voltage source. . . . The Ohm meter wants to be the only source.

 

[alldodge]

I do not think you can measure the resistance of a circuit when it is connected to another voltage source. . . . The Ohm meter wants to be the only source.

Agree, you need to check for voltage drop, not resistance. Do it the same way as your doing ohm check, just make sure leads are connected in direction of current flow

 

[Matt9712]

With a voltage drop from negative battery post to engine block where battery lead is connected I have a .3-.5 V drop while cranking. With battery on OR off and not cranking I have 0V.
That sound weird?
I hooked meter up to my truck and did resistance earlier and from negative battery post to body ground the most I had while cranking was around 100 ohms. But my truck fires quick

 

[alldodge]

That sounds good, and don't think its as a voltage drop issue

 

[Matt9712]

Tried to do injector test with the rinda again today since I had cleaned and tightened all grounds. When i do the test the relay picks up and almost immediately drops out and I get an error for test and says can't perform. I tried disconnecting different sensors and kept trying and nothing changed that either. I have 12v at the feed but then the ECM takes ground away which applies about 2.5 v on ground and relay drops. Nothing on this boat makes sense!!! I'm also getting no codes on this either....so the plus is 0336 seems to have gone away but symptoms remain.

I found a service bulletin group 28-1 number 6 rev 1 for diagnostic test for coil and ignition module.

First remove fuel pump relay.
Pins are :
ICM
A. P/DG
B. Y
C.SB
D. Y/SB

Coil
A. P/DG
B. Y/SB


1. Remove harness from coil

2. Set DVM to volts connect the leads between pins A and B on the coil connector

3.Turn key to start position and while cranking the engine, observe voltage. Expect to see 0 volts before cranking

4. Is there a reading of 7-10V ( slight movement in readings indicating switched current)
YES- Then primary coil voltage is being produced. ICM and wiring is good. Coil secondary circuit is faulty. Replace coil
NO- go to step 5.

5. Set DVM to DC. Connect leads between A on the coil connector and ground on the engine. While cranking observe voltage.

6. Is voltage higher then 9V?
YES- Continue to step 7
NO- There is a low voltage in the ICM/COIL P/DG circuit that powers the ignition system. Check IGN fuse. Check P/DG wire for continuity between pins A at coil and fuse output terminal. Repair voltage supply circuit and and repeat steps 1-6.

7. Remove harness connector from ICM

8. Read ohms between pin C on ICM connector and ground.

9. Resistance 0.2 ohms or less?
YES- Go to step 10
NO- ( Infinity reading) Thhere is an open circuit in ICM ground wire. Check main system grounds for loose corroded connections. Be sure grounds are secure on studs at flywheel housing. Repair as required.

10. Set DVM to D.C. and connect leads to pin A on ICM connector and ground then crank engine.

11. Is it 9V or higher?
YES- Go to step 12
NO- There is low voltage for circuit that supply ICM. Check ignition fuse. Check for open wire repair and repeat step 10.

12. Check resistance between pin D on ICM connector and pin B on coil connector.

13. Resistance 0.2 ohms or less?
YES- Go to step 14.
NO- ( Infinity reading) ground wire is open for ICM. Check for open wire in circuit and replace or repair.

14. Set DVM to DC. Connect leads to pin B and pin C on ICM connector. Crank engine and observe voltage.

15. Is voltage between 3-5 VDC?
YES- Replace ICM
NO- Check continuity between ignitionmodule connector pin B and ECM harness for open circuits.

If all coil and ICM tests above have been completed and all wires checked for opens and shorts, the ECM has a failed ignition driver. This hardware in ECM is nonrepairable.

Reinstall all connectors

Reinstall fuel pump relay

Mine tested fine with exception of the switching in step 4 which seems to be same symptom as spark 3-4 times then stop. I have voltage initially then goes away and doesnt switch. Rinda tells me my ignition driver is good. Wrote the testing out just in case someone down the line might need it.

 

[Jason89sunbird]

Your voltage drop of .03-.05 while cranking is decent. If it was that high with just ignition on it would be bad.

Reading another post it was saying that the boat ecu will run on the crank position senor CPS with the CMP unplugged. You said yours ran on only the cps, but badly and very short time. Based off the pic in the link I sent you should be able to see the reluctor wheel with the CPS removed(good mirror and flashlight) It should be about 2mm away from the chain(based off the pic). I'm thinking the reluctor wheel might have been installed backwards and if it has it would be touching the chain.

 

[tpenfield]

With a voltage drop from negative battery post to engine block where battery lead is connected I have a .3-.5 V drop while cranking. With battery on OR off and not cranking I have 0V.
That sound weird?
I hooked meter up to my truck and did resistance earlier and from negative battery post to body ground the most I had while cranking was around 100 ohms. But my truck fires quick

You may have a bad connection from the block to the negative battery terminal. So you could certainly check and clean those up. The starter draws a lot of current, so it is not out of the question that you may get a small voltage drop across a wire. Wires do have resistance, just not all that much. That is why the starter and main ground leads are larger gauge.

 

[alldodge]

At this point you have checked and/or replaced everything. The motor should run but it doesn't and with no codes its either something like the reluctor or the ECM. While there are some complicated items which control things there not that complicated. When it ran rough the one time (post 71 other thread) it ran until the throttle was touched.

The CPS needs to be close enough to the reluctor to pick up the slots in the wheel, if its not close enough nothing works. The running rough one would think either, fuel pressure, timing, some plugs not firing. Why did it die and not restart after throttle was touched. don't know. Not running is something is missing from what is needed to start, but running rough is everything is there but not in the correct sequence/amount.

Maybe the one time the CPS picked up enough to cause it to signal the ECM, ok but only one time, unknown. If unable to try another ECM I would be at the point of getting at the reluctor wheel and find out if its the right part, installed correctly and is there an issue with the cover

 

[Matt9712]

One reason I don't think it's the reluctor wheel is i hand cranked the engine and verified I was getting the 5volt on then off signal as the reluctor wheel passed the sensor. Also with the CMP unplugged the coil fires consistently. Which if I am correct the CKP is what tells it to fire which makes me believe the reluctor wheel and crankshaft position sensor are working correctly.

What is really getting me is the whole camshaft position sensor unplugged it fires. When i tested the ignition module with the service bulletin above it has voltage but does not switch... after first loss of power it doesnt come back. So with that being said could the distributor have some sort of air gap that is not breaking the circuit of camshaft position sensor as it passes through it? The camshaft position sensor has a little channel that the rotor of distributor passes through which I'm assuming switches it on and off once every rotation. Is there anyway to test it while on motor? I bench tested it and got different readings from different ones with process posted here a couple days ago. And since I had weird readings I bought a new one (CMP) and it didn't change anything....

Is there any other sensor that could be failed making ECM shut power down? And anyway to test that sensor? ie. Oil pressure sensor, TPS sensor, IAC sensor, Knock sensor, ECT sensor. I think those are the only ones I haven't replaced.

 

[tpenfield]

I looked back through your prior threads just to see if something basic was not right from the outset.

You initially brought the boat/engine to a mechanic that did not seem up to the task. Who actually did the final assembly of the engine from the long block and presumably components from the original engine?

I'm wondering if the fuel and ignition components were not assembled correctly, or something of that nature :noidea:

Like AD said, you have checked just about everything.

 

[Matt9712]

I did the long block swap myself with the help of a couple mechanic friends whern questions arose.. It did come with the timing chain already installed so pretty much all I had to do was unbolt everything off old motor and install new gaskets and bolt to new engine. So the only timing thing I haven't checked was timing chain installed correctly as I just assumed it was good when I received it ( still assuming it is just one thing I have not checked )

 

[tpenfield]

You might be able to verify the timing chain by checking TDC on the #1 cylinder vs the valve train vs the distributor.

 

[tpenfield]

Have you done a compression test ? That may also indicate if the valve train is in sync with the pistons.

Not much else to check . . .

 

[Dave-R]

Matt my engine is a 2011 5.7 and I had to replace the TPS to get it fire. On mine there were two actual TPS senders TPS 1, and TPS 2. The ECM compares the value of each, and if they don't jive, the ignition does not fire. You seem pretty savvy on the electronics, much better than me. My engine had been under water for months, after the rebuild I just started to replace things until she ran. I never had to replace the Cam sensor, or knock sensors, O2 sensors, or oil pressure sensor. Did have to replace both the TPS and the throttle positioner, and a new ignition and coil. I don't remember if both TPS 1 and TPS 2 are in the actual throttle positioner, or split between the TPS and the throttle postioner. I will see if I can fine the operation description, as to what happens when there is a fault. Dave-R.

 

[Jason89sunbird]

I think you are right about the reluctor wheel, I looked everywhere and it seems you can't put it on backwards like the LS version of engine.

What brand disirubutor cap and rotor? I don't trust anything but GM for that style. I have seen several aftermarket ones fail and test good with no load spark test i.e spark plug wire sparking to a bolt. here is a tester that works under load.

https://www.google.com/search?q=865...60j69i61j0.10615j0j4&sourceid=chrome&ie=UTF-8

 

[alldodge]

What is really getting me is the whole camshaft position sensor unplugged it fires.

With it firing with the CPS disconnected, then this would be the area where I would look further.

 

[Matt9712]

No I haven't done a compression check but I will do one this week.

I'm going to look into the TPS1 and TPS2. That would be awesome if that was it. Were they 2 separate sensors?

I'm not exactly sure brand of distributor cap. I want to say A.C. Delco but I might be way off.

I checked the CMP yesterday for proper output and it works fine. I ordered a new ignition module to see if that is bad even know it tested good at AutoZone. It did fail the testing I posted above for step 15. I must've skipped over that before .... realized when I was typing steps out that I had missed that.

An easy way to check CMP in case anyone else needs to do in the future.

1. Remove CMP from distributor housing and reinstall plug.
2. Install a voltmeter ... one lead on the signal wire and one lead on a good ground. ( might have to research which is which as they are not all the same in different models I will check what wires mine were when I get home tonight and post it here)
3. Insert something metal in between the magnets where the wheel on distributor would go in.
Voltage should cycle on/off as you insert metal. I used a pocket knife due to it being a very skinny spot. Mine was cycling on/off at 4.5V but I have read some boats will be 12v.
Just a quick check in case someone else might think they need a CMP.... that would have saved me some money had I known.

 

[Matt9712]

Well got new ignition module..... thinking about giving up this whole waste of money called boating. Only my luck that I would buy a POS boat and run into issue that no one has never heard of