Rodbolt Need Help Post!!

[rquint04]

like I said, lets try to keep this on the forum.
the CCS system is rather quirky. below about 800 it runs on all 6,from about 800-1200 on 5, from about 1200 -1800 on 4.
sometimes it gets jiggy.
we need to know O2 sensor output voltage, TPS input reference voltage at TPS voltage output at idle.
did you send the injectors out for cleaning when you did the rebuild?
did you try to find out why the last piston failed?
a failed piston is a symptom of a problem, not the problem.

Answer: Ok I will check O2 Volt, TPS Volt and report back here. I didn't touch the injectors, I will look into that also. I understand what you mean about the symptom not a problem. I assumed that Water had caused the piston failure. The previous owner had used the wrong fuel cap and water was getting in the tank. The engine cut out from 4200 rpm 3 times when I took the boat out in choppy conditions. When I checked what was causing it I saw all the filters full of water (the Racor Fuel Water Separator and the engine filter) I emptied the water and headed back. Next time I went out after only 5 minutes on plane I heard the engine failure from the piston. Was I wrong in the assumption??

 

[rodbolt]

Re: Rodbolt Need Help Post!!

dunno, I try not to ever assume anything.
I try to simply look at the facts.
with the water in the fuel history you really should go back, send the injectors out, reclean the VST and pressure regulator screens and the run a fuel system vacum test.
also remove the check valve between the engine filter and VST if its still there.

 

[rquint04]

Re: Rodbolt Need Help Post!!

Thank you! I have just replaced the screen in the press regulator and new plugs. I'm gonna send the injectors for cleaning and check vacumm. Now an interesting point is that of the check valve... Should I do away with the check valve or replace with a new one?? Also from where to where should I check Vacumm press?? and what's a good reading, 2-4 pounds?? Thanks for your input when I finally figure this out I will be in a better position to help others with my experience with this engine.

 

[rodbolt]

Re: Rodbolt Need Help Post!!

ok, here in the states vacum is expressed in inches of mercury, yamaha says 225-f350 can have as much as 6"Hg at the lower lift pump inlet, I dont like anything over 4"Hg.
you can T in between the fuel pump and the engine filter.
toss the check valve between the engine filter and lift pump if its used, its totally useless and adds another restriction point.
you will also need to monitor fuel rail pressure, must stay 35 PSI plus or minus 2 PSI throughout the RPM band.
you can clean any filter at 9 am but if trash/debris is introduced at 9:30 am, guess what ?
your local yamaha dealer should have the fuel system in a box and can check fuel system vacum on the trailer thus reducing the risk of piston failure due to lean running.
if they dont find one that does, can be done in 30 min or so and wont use any gas.

 

[rquint04]

Re: Rodbolt Need Help Post!!

Ok got it. I will T in the Vacum gauge, Toss the check valve, and report back here thanks again....

 

[rquint04]

Re: Rodbolt Need Help Post!!

Rodbolt, I measured the Vacuum by putting a " T " between the engine filter and the lower pump just like you said. At low rpms the vacuum is 1.5 - 2 inches of hg, on acceleration the vacuum drops to almost nothing. All three pumps are brand new from Yamaha. The high press. pump had 35 psi constant at all rpms. I also eliminated the check valve in the intake of the lower pump. The engine is really struggling to stay running when accelerating at low rpms, from 1000 to 2900 rpms. When you accelerate, and it gets to 3000 rpm, it runs better. I noticed that the engine runs better at idle when outside the water. What does this mean? What can I do next? again thanks for your help!

 

[rodbolt]

Re: Rodbolt Need Help Post!!

your vacum numbers are puzziling, almost like it cannot happen as it takes more fuel, hence more suction to run at 3K than it does at idle.
however if it maintains 35 PSI at all ranges odds are good its getting enough to the VST.
try to check the ign timing when accelerating as well as the TPS reference and output voltages.
the diagnostic test lamp may catch it but remember that ECU wont store codes, it will only display any active codes.
did you ever send the injectors out for testing/service ?
do you have the TPS test harness and a digital volt meter? do you have the O2 sensor test harness ?

 

[rquint04]

Re: Rodbolt Need Help Post!!

Rodbolt, I have not sent the injectors out for testing/service yet, but I will shortly. I have ordered all the test harness, but so far only received ignition coil and charge coil harness. The others are in back order and will be a couple of weeks. I measured TPS output voltage before with my volt meter and it looked normal. The O2 sensor is new with around 2-5 hours of use. But I will check O2, and TPS again when I get the harness. How do I check ignition timing with a timing lamp? In neutral or running? Do I check crank Position Sensor?

 

[rodbolt]

Re: Rodbolt Need Help Post!!

if your going to attempt to troubleshoot, test and maintain this engine yourself, do yourself a favor, buy the diagnostic test lamp part # YB-06444.
will save a lot of time chasing ghosts.
the only thing not monitored is the O2 sensor.
other than that if it blinks code 33 until warm then shifts to code one its eliminated about 8 checks/sensors.

 

[rquint04]

Re: Rodbolt Need Help Post!!

Rodbolt, you mean the winky blinky? I already have it. I used it on the engine and did not give any code just the one blink for normal operation. I thought I had mentioned it. I read another post where you had said that the ECM does not store codes but I ran the boat with the test lamp while the engine was acting up and always read normal operation. So I didn't think it was very helpful/useful

 

[rodbolt]

Re: Rodbolt Need Help Post!!

see, you have already eliminated stupid stuff like testing the CPS, keep chasing your fuel issue. dont chase anything the ECU monitors as long as code 1 is displayed.
the winky blinky, like a laptop, is rather stupid, wont tell you whats broke but it will tell you what is not

 

[rquint04]

Re: Rodbolt Need Help Post!!

Well,, hello again,, I have already sent and received all the injectors out to be serviced/clean. They were all in good shape according to the computerized report I got back from the machine shop. I also tinkered with the TPS without measuring the voltage and the engine ran better. But I got my volt meter and adjusted the TPS to specs. The engine continues to misfire when accelarating from 1200 rpm to 2600 or 2900 rpms. I am now thinking that it may be an electrical problem. Oh! also the overheating alarm is going off every time I go over 3500 rpms. I don't know if is because the water temp was 87 degrees or what...I feel like dumping this engine in the ocean...Could I have an electrical problem like timing??? How does this engine regulate timing??

 

[bowhuntrrl]

Re: Rodbolt Need Help Post!!

I'm not anything near an expert, but after reading this thread I had a thought. Rodbolt will need to verify this but don't Yamahas have a low speed and high speed set of ignition coils ??? If this is the case, maybe the low speed set is weak. Once again, not certain on this but seem to remember reading this somewhere in this forum.

 

[rquint04]

Re: Rodbolt Need Help Post!!

Thanks for trying but I don't think thats the case. There is only one set of coils I want to know how does the engine control timing. do you have any ideas?

 

[rodbolt]

Re: Rodbolt Need Help Post!!

main ign timing determanite is the TPS modified by input from the CPS,the CTS and the knock sensor.
timing specs are published but not adjustable.
the 3.1L motors do not use a high and low speed charge coil, even though thats what it says in the tuneup spec guide.
the charge coils on the 3.1L are port and starbord bank and will shut down 3 cylinders if it fails completely, but can carse a misfire if its partial failure.
a quick read with a DVA meter can quicly isolate or eliminate that issue, no other way as the ECU does not monitor charge coil voltage.
remember the CCS system is going to drop one cylinder, then 2 cylinders below about 2000 RPM or so and sometimes slow acceleration can make it seem funny.
the overheat is going to be a seperate issue, when was the last water pump kit change? is the pump housing melted at all, any sign of melt means its scrap.
and I have seen the block pencil zincs break off with age(lack of regular replacement) and block off the cooling water flow inside the block.

 

[rquint04]

Re: Rodbolt Need Help Post!!

Hey thanks again for that info about the timing. As for the overheating, I still have to determine if it is real or just electrical error. The water pump kit has about 70 hrs on in and it is original yamaha parts. I will need to check the housing. As for the zincs, they are all new, replaced 60 hrs ago when I did the powerhead. All water passages were sand blasted clean, popit valve was cleaned with new grommet. I did noticed the telltale stream a little weaker than usual though....I will keep checking things and post again...

 

[rquint04]

Re: Rodbolt Need Help Post!!

I check actual temp with a lazer thermometer at idle outside the water and at fast idle (700-1400rpms) the starboard side is about 15-20 degrees hotter than the port side. 140 degrees starb. vs 125 degrees port side measured around thermostats. It didn't overheat with the ears and hose for about 15 mins. I'm not too worried about the overheating... I just want to fix the other problem electrical or otherwise. I'm gonna check or replace knock sensor and crank position sensor. My resistor though is out of specifications could that cause a problem?

 

[rodbolt]

Re: Rodbolt Need Help Post!!

I would not sweat the resistor that much unless its more than 20% out.
it controls high pressure fuel pump speed below about 1200 RPM.
after 1200 or so its out of the loop and the pump ground path bypasses the resistor to allow full pump speed.do you have a DVA capeable multimeter?
why are you going to replace the knock or the CPS if the diagnostic lamp tells you they are ok ?
if the ECU saw either return signal out of range you would get either a code5 or a code2. code 1 means the ECU sees no abnormal paremeters for any monitored function.
have you checked the spark plug cap resistance ?

 

[rquint04]

Re: Rodbolt Need Help Post!!

Yes the spark plug caps are all new and I checked them with an ohm meter and they are all within specs. I meant I was going to check those (CPS and knock sensor) and replace if needed. I know the lamp is not telling me they are bad, but I'm just going crazy with this issue. I'm even thinking like you said, that it could be the transsition between the 4 and 5 and 6 cylinder operation. But the other day when I advanced the TPS to out of spec position, the engine ran well. So if the TPS and CPS and the knock sensor control timing I thought that was the problem. About your question I have a meter but I don't know if it is DVA capable. What is DVA capable?