Engine problem!! Help!

NavyCTRC

Good morning forum!

Tried to take the boat out yesterday afternoon in order to test everything out and check systems.  Everything seemed fine, both motors ran well at idle, got up to operating temp, nothing was leaking, okay I thought, I must be good to go!  Left the dock and after idling out of the cove, pushed the throttles forward, ran fine at 2000rpm for about 2 minutes then tried to push them up to get on plane, the port motor originally hesitated then revved up to 4000 or so, then stumbled, sputtered and died.  Re-started it, let it idle for awhile, then same as above.  This happened a few times, now it won't start at all.  I thought maybe I had bad gas, but the port and starboard tank gas are the same age, starboard engine runs fine, I never use ethanol gas.  Genny runs fine.  I pulled the brand new fuel/water separator, looks fine.  It's obvious I have a fuel issue, but I need help to narrow it down. 

I have on/off valves on the fuel lines going to both tanks, I have always left them all wide open, can someone tell me how to isolate one tank?  What are the symptoms of a fuel pump issue?  Didn't I read somewhere on the forum that the fuel pumps have a little screen in them?  Anything else I check before I start buying random parts?

Thanks in advance guys!!

partlowr

Need more info, are you carbureted or fuel injected? Could be as simple as a clogged fuel filter as I believe each engine will have it's own fuel filter. If you are carbureted you could have one gummed up carb, most likely a main jet if it's having trouble with more throttle/fuel input and off idle.

NavyCTRC

It is MPI.  No carb.

212rowboat

get a pressure test at the rail.... 

a blown regulator could certainly explain the uncontrolled rev- metering the fuel to the injector/cylinder depends on steady predictable fuel pressure... 

you can pull the regulator off the running engine and put it on the down engine and see if the issue resolves/follows... 

you may be in the market for a fuel pump... 

Liberty44140

My 2006 350 MPI's have two fuel filters. There is a disc filter before the large round main fuel filter. Assuming you also have two filters you may want to check both. Also can you switch tanks? I am able to switch valves to run my port engine on the starboard tank and vice versa. If you can do that you can see if the problem is at the tank. 

NavyCTRC

Liberty,
I have the ability to switch tanks around, but there are like 5 handles in there and I don't know for sure which ones to close in order to isolate one fuel tank....are there any pictures or threads I could read to figure that part out?

NavyCTRC

This is certainly a fuel problem, but since the engine is MPI, I sort of don't know where to start with the troubleshooting.  If it had a carb, no problems.  Fuel/water separator is brand new, I don't think it would get full of water in about 30 minutes of running time, it looked okay and full of gas when I removed it.  I can hear and feel the fuel pump cycle on when I turn the key, I thought they would normally go bad all at once and engine would not run at all?  If they fail in a stepped manner, maybe that is the culprit?  Like I said, engine eventually would not start at all.  It ran okay at idle for awhile, ran at 2000rpm decently, but died when I tried to push up on plane.  I recently replaced the entire throttle body, the IAC and/or throttle position sensor went bad so I found a deal on a lightly used freshwater throttle body with both sensors on it for cheaper than I could buy both sensors new.  Is it even remotely possible there is something wrong with changing that part out?  If that was the case it seems it wouldn't have run at all.  I seem to be dealing with something progressive, as it started out not so bad and resulted in a non-running engine.  Any ideas?

212rowboat

get a pressure test at the rail.  get the gauge from auto parts store.. not much, and good to have hanging around if you need it.  just because you can hear and feel the pump doesn't mean it's pumping.

again, swap the pressure regulators between the engines... if the problem follows, then there you have it.  

MPI is fairly simple... known 'duty cycle' or how long the injector opens it's gates... known metering of fuel delivery based on size of injectors and pressure behind the gate... a bad regulator allows too much or not enough fuel past, either of which can cause a no start.  

you said it went from 2k to 4k and then died, after hesitating and after applying throttle... you said it did this several times before finally not starting... 

you need to do the easiest thing first, and that is check the actual fuel pressure.... rule it out... it HAS to have suitable pressure to run... after that checks out, and I wager it will, move to spark and run through that, which is where I think your issue exists... a crank position sensor (ckps) will do this just as you describe.  They generally misbehave at higher RPM's first, and then altogether.  The CKPS is how the engine knows to trigger spark, where the cam position sensor (cps) is how it knows to trigger injection... 

also, a gross vacuum leak could be the culprit... you said you swapped TB's... check carefully for a vacant port. 

NavyCTRC

212, thanks, that will hopefully get me to the bottom of it. 

rasbury

Good info 212...also, how did you determine the parts you replaced were bad? Might be the same problem you started with, just have nor found it yet!

Black_Diamond

I bet if he runs both engines off the tank the one engine works on, then ooen the valve to the other tank it will start drawing fine. Been there. 

NavyCTRC

212, Al, MT, everyone,

So, after replacing the following, I am no further along than when the problem started, hopefully someone can help me out.  Symptoms: Sometimes will run on the hose at idle perfectly, most times has a surging idle, then it just doesn't start.  I will layout the things that have been fixed or ruled out.  Reminder: VP 4.3Osi EF version.

1.  Replaced the entire throttle body assembly and both sensors (IAC and TPS), fairly pricey but found an almost new used one on ebay.

2.  Drained fuel and replaced with new, (lots of $$$)

3.  Replaced spark plugs

4.  Replace the filter on the fuel pressure regulator with the clip according to the bulletin from VP

5.   Swapped fuel pressure regulator from good engine to bad, no change in symptoms.

6.  Thoroughly cleaned the flame arrestor, it was pretty dirty.

7.  Did what 212 suggested and got a fuel pressure gauge, checked pressure, had zero on the low side pump, high side was okay.  Replaced fuel pump ($$$$).  After replacing fuel pump, (Wednesday night in the dark)  initially the engine started up and ran on the hose on Thursday afternoon, purred like a kitten, let it run for about 15-20 minutes, all seemed to be good to go.  Went to put boat in water on Saturday morning port engine started but did that scary surging idle between 1500-2300RPM, let it do that for about 3 or 4 minutes, then shut it off.  It restarted after a few minutes, idled nicely for about 2 minutes, then died, wouldn't start again. 

8.  Pulled a spark plug, (it seems pretty dirty for a brand new plug), grounded against the block and cranked it over, I did not get a "regular" spark, but I did get one nice bright one in about 10 seconds of cranking the engine over.  I might have not had a good ground so I am currently not putting very much faith in this test.

After consulting a family member who used to be a mechanic he said it could be coil, they can go bad intermittently and potentially cause the surging idle, and no start condition.  The only surging idle situation I have ever fixed was resulting from someone setting the timing wrong.  But we have not messed with the timing, as I wouldn't know how on an MPI engine.  Going to try to pull coil from good engine and put it on the bad engine to see if changes anything.  After that, about the only thing I can think of is the actual set of ignition wires, plugs and coil.  Although I have looked them over, and they don't seem worn at all.  Engine only has about 350 hours on it.

What else can it be?  Al, have you seen anything like this?  I would take it to a shop, but they are so backed up this time of year, I will be lucky to see my boat before summer is over, not too mention I hate taking it in if I don't know what to tell them to replace, that has a tendency to get expensive as they throw parts it just like I would.  I have already spent almost two grand and this has got to be something simple because the engine does run, sometimes.  Any help, or advice you guys can provide would be GREATLY appreciated.

zaverin1

When you say on the hose ? You mean running it right from a external fuel source like a gas can?

NavyCTRC

garden hose for water, running while on the trailer

zaverin1

Reason I say that is because it could be the fuel tank pickup tube.
i personally replaced some that were broken in half or split in the middle causing low vaccum. Some even have screen filters on them.if you have two ya ls try running on the other tank.
i would check the timing for sure.
if she starts and runs then firing order should be good. Check coil and check compression next.
also check that leads to the fuel pump are good and providing good voltage.
I did see fuel pumps go bad out of the box for many different reasons. So double check the fuel pressure again.!

NavyCTRC

actually, I did test fuel pressure on the new pump, 7-10psi on low and almost 50psi at the high pressure rail.  That is from just cranking it since it wouldn't run at that point.  I thought about the possibility of getting a "bad" brand new fuel pump, so I checked it.  It's close to specs.  Funny you mention the fuel pickup tube, as after I drained the fuel I wanted to check all the lines for a blockage so I pulled the fitting from the top of the tank in order to get to that hose.  My fuel tank, at least the port side, does not have a fuel pick up tube that goes to the bottom of the tank.  I think it MIGHT be built into the tank, I stuck an old gun cleaning rod in the hole and there is not any "relief" on the bottom side of the hole past the threads, it seems like it is a built in tube that goes to the bottom of the tank.  But now that has me thinking to check the other tank to see if it's the same way, or if I am missing a fuel pick up tube and this has been my problem.  But how would it get enough gas to even idle at times if this is "missing"?  Maybe Al knows if the Rinker fuel tanks were built with the pick up tube welded in?

NavyCTRC

And how could I get a solid stream of gas out of the fuel line that goes to the water seperator and pump without a pickup tube?  I think it must be built in.

zaverin1

I would check other tank for sure 

Robs_232

I would try switching TPS and IAC for motor to motor. Not sure if this is when your problem started but start with where problem started. I replaced dist. cap, plugs, and plug wires last year and then it had a midrange miss. Took to my dealer and he finally replaced cap, plug wires, and plugs. Probably one plug wire with issue even though it was new. Just a thought.

Rob

212rowboat

get a can of ether, or even lysol handy.

see if you can start the engine, let it idle while carefully spraying (in really short bursts) around the throttle body, and then around the perimeter of the intake manifold...  if or when you have a surge in RPM's, you've found the vicinity of a vacuum leak... 

it may be sealed sufficiently on a cold engine, but when the engine warms it may be pulling unregulated air... 

212rowboat

and by the way- coils are goofy like described... 

they generally have an epoxy fill around the coil (inside the casing, obviously), and often have imperfections... when they warm, the imperfections turn to cracks... after they've cracked for a while, and while on a warm engine, they'll separate- and often stop functioning.... until they're cool again, where the cycle begins all over again.

NavyCTRC

Rob,

Thanks, I was thinking plug wires next.  I am unfamiliar with the distributor set up on my engine, but replacing the wires should be easy enough.

Patrick

212rowboat

plug wires aren't your culprit... they may cause rough running, but you've still got 5 other cylinders if one is bad... 

you know what, though?  take the COIL ignition wire off one engine and put it on the other, and see if that is your issue... I've seen the filament flat out rot... and that center coil wire (follow coil to dizzy cap) see's six times the fire as the other ones... if one is worn, it's that one...

your described issues are consistent with that coil or that coil wire being bad... If it's been a while, that could be it for certain.  

dalek

Try watching the engine run in the dark. The darker the better. If any part of the HT is tracking to earth you will see it. Costs nothing to try.

NavyCTRC

212,

Good stuff.  I will change that out tonight.

dalek,

I can try that, if I can get to run.  Sometimes it starts, most times not.

Thanks!

Patrick

zaverin1

When engine has no start condition
wires will show no spark or a weak spark
easy test

NavyCTRC

I am going to swap out the coil wires tonite, does anyone else have any idea where I should be looking?  This has been the most frustrating issue!  What other problem could I have that I haven't even thought about?

212rowboat

I'll mention the crank position sensor (CKPS) and the Camshaft position sensor (CPS) again... I'm not sold on either, and only suggest it because you have a functional engine right beside the ailing one, and swapping parts isn't a big deal because of... 

it's the non-requested increase in RPM that has me tilting my head... sounds like uncontrolled induction of air, and nothing to do with spark... the rest of it sounds like spark... 

t/s'n through the interwebz is difficult at best... no? 

NavyCTRC

It's killing me.  Around here, if I take the boat to a shop and I don't know what is wrong, they might not even look at it for three weeks and then they will do the quickest t/s they can and tell me I need some part or another.  When that part comes in and doesn't fix the problem they will say it's another part and the process of investing one hour per week in my boat will continue until I am broke and the season is over  I will see if the CPS is an easy swap and put that on the list. 

Al,
My distributor cap is strange looking, I am assuming it's all electronic on the inside since it's a 2005?  If it was like the older ones, I would have swapped it out already.  Engine electronics intimidate me, mechanical things not so much.

Thanks for the tips...I will update asap.
Patrick

212rowboat

are you dealing with original engines?  does it have a cap and separate distributor cap or is the coil and cap built together?  

in my experience, a cracked cap will do the opposite- they are a BEAR to get started when there is moisture in the cap, but when the moisture burns off they're fine (fine'ish)... just to cause you grief next time you try to start cold... that said, it could separate all the same. 

NavyCTRC

They are original engines.  I have the same experience with cap and rotor issues, plus they will usually run horribly for the first few minutes on top of being hard to start when cold.  I will be looking hard at all the ignition related components tonight.