Smarty pants, I really could use your help! 350 Mag trouble SOLVED?? MAJOR UPDATE

Black_Diamond

Bit confused on a 'burnt' fuse that split voltage to the pumps. 

Wildboating

I work in tech/ electronics.  I can not make sense of it either.  

dalek

As a fuel test of absolute last resort, I would still ask you to consider connecting the fuel rails from both engines together and see what happens. In my humble opinion this could be dangerous but would give you a definitive answer. Does anyone see why this test should not work with this engine? Feel free to point out any errors in my thinking. I have used this method before but I am no specialist in this particular motor.

Wildboating

Dalek,  What will this accomplish that running from a 5 gallon tank or swapping port and starboard fuel lines to opposite motor?   

reneechris14

I see his thinking pump(port) to fuel rail(starboard) and visvesra , would isolate problem to pump or rail . As I type this the ECM would not like this reading wrong pressures bad idea. 

Wildboating

I am told these are not ECM driven pumps.  They are a constant voltage and speed.   I have now replaced the Boost pump and High Pressure pump and we can eliminate pumps from the equation.

Black_Diamond

The issue with the orange wire is about providing alternator voltage (13+) and not battery voltage (could be lower) to the ECM and the fuel pumps. Per Al. 

Wildboating

So you are correct here BD.   I need to get this connected up, i just have not yet as I wanted to discuss this in further detail.   I am seeing 15V out on my alternator.  Are we POSITIVE that the ecm can handle this?  This would be a significant boost to the battery voltage of 12.5 to 13.1 at the ECM.

Black_Diamond

I had that same discussion with my marina guy. The reason it is cut on dual engine boats is for the battery isolater. Al said you can run it connected anyways.  

Here is his note to me on this:

The orange alternator wire is the original charge wire from Mercruiser.  This was removed during Rinker assembly for the use of a battery isolator.  I have found that many boats are having a volt/ amp drop to the ecm and fuel pumpwith this wire removed.   Hence the fuel pump is only getting battery voltage usually 12 B+.  With the wire reattached the pump and ecm will see alternator output of 13.5-14.2 B+.    Note some motors had the orange wire cut at the starter area.  An easy test for this is to expose the wire at the alternator and check the wire for voltage. Most had the eyelet terminal cut off.  If this is the case simply crimp and seal another 1/4" eyelet on.     Your fuel pump will thank you.  Al 


My marina guy suggested checking the alternator voltage too, as some are as high as 16v he said.  Seems odd.  That said it is or should be connected on a single engine boat and would see the higher voltage. 

Might be worth pinging Al directly.  For your own peace of mind. 

Wildboating

This is correct, Al has shared this info with me as well and I was ready to rewire the fuse block to the alternator.  However prior to doing this I decided to check Alt voltage and discovered it to be in the low 15v range.  I want to confirm that the ECM can handle 15v's and that the V regulator is working properly as 15 seems a bit high to me.

Wildboating

I am also ordering a 10 pin harness to fully eliminate the boat side electrical system

dalek

Wildboating said:

Dalek,  What will this accomplish that running from a 5 gallon tank or swapping port and starboard fuel lines to opposite motor?   

As you are already aware, the pump outputs quite a high pressure and the remainder is bled off back to the filter.  As far as I know the pressure is controlled mechanically by the regulator and not by the ECM. These pumps are either on or off. If both fuel rails are connected together so that fuel may flow freely from one to another we can be sure that the pressures on both rails are the same. Moreover, if one engine is running out of fuel, the regulator on the other engine will attempt to compensate and more fuel will be supplied across from this rail, so both engines should have nominally the same amount of fuel available. If your symptoms still persist, I think you can rule out any fueling issue. If your symptoms are cured, or shared between engines, there is only one place the problem can be.
There is also the possibility that I am trying desperately to justify my own pet theory that the starboard engine is running out of fuel, so keep an open mind.

Dream_Inn

The whole orange wire thing is a bit of interest to me as well.  Mine is cut and I've always wondered why (at least I know that now).  But I also wondered if it really should be connected.  I've never had issues, so I guess it is ok.

Willhound

My Orange wire was connected (single engine) but there was an inline fuse that was vibrating loose causing a loss of power, a cut out, and finally a no start situation. Tightening up all the. Injections resulted in the boat running great. 

Wildboating

Dalek,  I appreciate your honesty.  However with the port motor able to make significantly more rpm, and the starboard with new fuel filter, water fuel separator, boost pump and low pressure pump criss crossing the fuel lines and running of opposite sides tanks in theory would still achieve what you are looking at.  With that said, I will investigate the possibility of making this connection safely.  

Wildboating

Anyone notice anything here?   I have been spending more time learning about how Speed density / open loop ecm tuning works.   I also spent some time really digging in and learning more about the diacom software i have.   I have found a few concerns.  

First off, notice the purple line, TPS voltage flat lines briefly as does the blue line right as there is a major voltage spike down exactly where the green line is set.  From that point on,  the voltage continues to drop as the rpms come up.  Look to the right off the green line at the red voltage line.    

Wildboating

Shouldn't the battery voltage be higher at upper rpms?  Notice the spike up once i get off the throttle.   I would think this would behave opposite.  My voltage would be higher at high rpm and lower at low rpm.
 @Alswagg
Any thoughts?

Wildboating

I have also discovered some really bad spikes on my port side engine.  

Wildboating

The first spike is 11.98V and second one is 12V

Wildboating

Another strange thing is sensor power, Starboard seems to be heavily and rapidly fluctuating compared to a much more stable port motor.   I wonder if the diodes are bad in my alternator causing this A/C like fluctuations.  

dalek

Put a "colortune" plug in it. They are not expensive and only take a few minutes. They are also strangely watchable.
You may well pick up on fueling inconsistencies or firing order/ timing issues.

Black_Diamond

Great detailed info there.  Those voltage drops are interesting.  I would think bench testing the alternator would show if diodes / regulator are ok. I would think AutoZone or similar could check. 

Another place to check might be the battery isolater too. 

Dude_Himself

Similar output for the good engine?

212rowboat

you fellers are blaming the alternator, which it could very well be, but that ain't where i'd personally head first.

realize:  i always pick the longest lasting line at the grocery store no matter how many people are in it, so... there's that, and yes- it bleeds right over to trouble shooting too.. always, around my elbow to get to my- well... backside. 

alternators are designed to run in a specific 'common' range.  you aren't producing the juice down low off/idle that you will in it's range. You're producing too much up high, so the regulator takes command... obviously the size of the pulley makes a big impact... but this isn't what we're seeing here with these dramatic trembles in that graph.  

my first thought after reading all these posts re:alternator and voltage was "so how does that impact your performance?".... it shouldn't impact it all that greatly, frankly.  I mean it does- but generally speaking it is obvious when it does.  I don't think this rates that.... but something DID look 'a might' suspicious.  

those trembles, to me, represent your regulator struggling- but not of fault of the regulator, because it is likely doing precisely what it's supposed to do.  

cutting to the front of the line:  Sir Wild Boating dude- you got's a short. 

and you also have funky spark plug reads across the valley.  

and you've struggled with fuel delivery.  

I humbly request you to do this old futz a favor:

Please remove the EV6 connectors off your injectors one by one, take a picture of both sides, and hang them here.  

Once upon a time I encountered one of the most puzzling things when trying our level best to track down a misfire on an individual cylinder of a Mopar Small Block of the Magnum family... plenum gaskets were checked after exhaustive exterior intake leaks tests... wires were swapped along with rotors caps and plugs... sensors starting with C and ending with S were swapped- them both... these were brand new injectors in a brand new rail with brand new plumbing/orings throughout... they tested near perfection, until we found something... and it seemed like no big deal at the time, but guess what? it's a big deal.  

those EV6 connects use little FLAT spades to fit into the recepts.  one of those was oh so slightly bent- no big deal, right?  it's still connected, right? juice FLOWS man, it ought not impact anyth.... uh, wait a second... those things fire off of ohms.... resistance is NOT futile... if they aren't getting what they need in the partials's of nanoseconds in the upper ranges of engine speed,  guess what happens?  they sit there and act DUMB..... but unlike Lucy holding that fooseball(it's of the devil), they fire every once in a while just to keep you off-balance.  

my reckon is this:  you've a bent spade, or a bad connect, or a chafed wire... and it's creating a momentary ground sucking off the voltage enough to SNAP and CRACK that graph you presented like some sort of hyperactive bull whip.  Or PO'd snake... or my fat ****'s heart after making a B double E double R you N during a commercial break between quarters of the finest football team ever to take the field (go Vols).. 

check you harness and those connects... specifically your harness that lays across your intake-to-rails.  

Michael T

....btw if you blew your diodes wouldn't the alternator stop charging the batteries and kill them fast....am I right or just another alzheimers moment?

Dude_Himself

Or a bad ground - that's the first thing comes to mind when voltage intermittently tanks with RPM.

dalek

Surely, if this was a rectification issue, the frequency of the spikes would increase in exact proportion to the speed of alternator rotation. They do not appear to do this in your graph, but I can't see a timescale on it.

Wildboating

@212rowboat

Were you drinking during the last post??  Haha while entertaining for sure its a bit outside of your typical tone....lol

I will pull the EV6 connectors and snap a photo as well as do some through inspections.


I have 1 question no one has answered yet.   What does a properly working charging system do at higher rpms.  Does it increase in voltage or does it decrease?   If you look at this plot, I'm  only stating that the voltage drops from idle range speeds until throttle is let up.   Also, the diacom software auto calculates the Y Axis (vertical) which is also important to look at.

Battery voltage range during this test run:  12.75 - 13.41  ( seems reasonable, until you realize the lower of this range are at 2800-3800 rpm)

Engine Speed:  557 - 3673

TPS: -1 - 99.5 %


This is the entire run length from 16h:11m:46s  thru 16h:14m:16s   

Handymans342

I would have the Alternators bench tested after seeing this graph.

davidbrooks

So I was out today and ran from 6mph to 40 at wot.  Alternator readings never budged. Both alternators are new and one read 13v and the other 14v the whole time.