PCM no spark! HELP

[Tige12]

2012 Tige RZR with the PCM 343 (gm5.7 base)
Ecm was toast when I bought the boat last june. Replaced that and it had some hiccups but none that I could fix.
Currently it Cranks but will not fire up, no spark. All fuses look good, Replaced ignition control module, ignition coil, distributor cap, crankshaft position sensor. With no luck.

ECM takes signal from the crankshaft position sensor to initiate spark. boat will occasionally fire up for no more than a minute and lose spark. My problem ( at least I think) is that I only get 5volts at that sensor where it should be 12v. Since it's not getting full voltage, the ecm can't get a proper signal. Can I temporarily hook up 12v to the wire and test it? If so, and if it works with the test wire, that would conclude that the harness is bad somewhere? (Side note, I pulled the motor harness and inspected it, no visable breaks or rub thru marks.)

 

[dubs283]

I only get 5volts at that sensor where it should be 12v.

all the sensors on the engine use a 5 volt reference, not 12. the voltage you are seeing at the cps is correct. the reason for 5 volts is because the ecm provides the voltage and anything above 5 volts can cause internal damage to the ecm. do not apply 12 volts to the sensor

its possible that your issue is fuel related, either pump failure or a restriction somewhere in the fuel system

your best option is to first investigate the fuel system, then use a proper scan tool/diagnostic software system to verify ecm operation and check for any active or stored fault codes. i've found diacom to be the most comprehensive system for diagnosing gm based pcm engines

fyi not all harness related issues are blatantly obvious, to investigate properly you need a wiring diagram and remove all electrical tape to inspect connections and wiring

 

[Tige12]

all the sensors on the engine use a 5 volt reference, not 12. the voltage you are seeing at the cps is correct. the reason for 5 volts is because the ecm provides the voltage and anything above 5 volts can cause internal damage to the ecm. do not apply 12 volts to the sensor

its possible that your issue is fuel related, either pump failure or a restriction somewhere in the fuel system

your best option is to first investigate the fuel system, then use a proper scan tool/diagnostic software system to verify ecm operation and check for any active or stored fault codes. i've found diacom to be the most comprehensive system for diagnosing gm based pcm engines

fyi not all harness related issues are blatantly obvious, to investigate properly you need a wiring diagram and remove all electrical tape to inspect connections and wiring

I pulled the entire harness from the motor and unwrapped it, didn't see anything.
I get 12 volts at all the other sensors besides the crank sensor wire, which is why I pulled the harness to inspect the wires running to the crank sensor.
I brought the boat to the dealer and they can't even get a connection from the ecm, (that's been an issue since day 1) PCM confirmed that ecm had died from corrosion. So they sent a new one, it's been running great and everything was good for the most part. But even with the new ecm hooked up right away they still couldn't get a connection to the ecm.

I get fuel pressure and can smell fuel from the exhaust when I was trouble shooting for the spark... so fuel and air are good.

 

[Scott Danforth]

Did you plug in Rinda?

Did you check the easy things like the MOB switch?

 

[alldodge]

Which ECM/PCM do you have?
I'm looking and think I'm seeing it as a MEFI-4

Does it look like the one in the pic?

 

[Tige12]

Did you plug in Rinda?

Did you check the easy things like the MOB switch?

Dealer tried 4 times. 2 different laptops. 3 different Rinda cables.
Bypassed the lanyard and still no change.

 

[Tige12]

Which ECM/PCM do you have?
I'm looking and think I'm seeing it as a MEFI-4

Does it look like the one in the pic?

 

[alldodge]

Thanks 555 ECM

 

[alldodge]

Dealer tried 4 times. 2 different laptops. 3 different Rinda cables.
Bypassed the lanyard and still no change.

Dealer isn't a PCM dealer. I would normally say look to Rinda, but being this is a PCM 555 (and not a Merc PCM 555) it doesn't look like Rinda had anything to read it.

Sorry to say, but I'm out of my league to help.

 

[Tige12]

Dealer isn't a PCM dealer. I would normally say look to Rinda, but being this is a PCM 555 (and not a Merc PCM 555) it doesn't look like Rinda had anything to read it.

Sorry to say, but I'm out of my league to help.

Boat is a Tige, brought it to my closest Tige dealer, they have the diacom software to read it, but it won't connect/read anything. They hooked it up to a 2014 with the same pcm 343(gm5.7) system and it reads everything.

 

[alldodge]

I got nothing
Guessing from first post:

Ecm was toast when I bought the boat last june. Replaced that and it had some hiccups but none that I could fix.

The ECM was fired somehow. You got another ECM but did not find out what fried the first one prior, so it fried the second

I hope that is not the issue, but just guessing

 

[Tige12]

I got nothing
Guessing from first post:


The ECM was fired somehow. You got another ECM but did not find out what fried the first one prior, so it fried the second

I hope that is not the issue, but just guessing

** "Nothing I couldn't fix"
I hope not. Waiting on pcm to send me pin out values on the ecm for testing.

PCM said it was from water intrusion, corrosion on the pins and inside. (Sealed aluminum housing, which is weird..)
No symptoms that I had with the fried ECM.

 

[Tige12]

Figured it out. Dealer couldn't connect the it, engine harness had corrosion on some of the plugs, assuming that traveled into the wiring itself. Bought a new harness $$$ & installed it.
Boat runs great. And the dealer can connect to it now! All 8 coded were consistent with a corroded harness