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-   -   Rev Limiter on 350 TBI?? (http://www.mastercraft.com/teamtalk/showthread.php?t=56312)

Mark rsa2au 07-27-2013 10:53 PM

Rev Limiter on 350 TBI??
 
Hi Guys, can any one tell me if there is an electronic rev limiter on the 310HP Preditor Motor/ 2001 350 TBI motor? If there is can I remove it? If not I still have a problem....

Once it gets to about 4500rpm, it seems to hit a wall and start to pull revs out to about 4300 then back up the 4500 etc. It is almost like a soft cut out rev limiter in a car, but lazy. Throttle is at about 2/3 and not full. Speed is about 38-39 mph.

Once run at high speed (Barefooting) and it hits this rpm, we shut down to get person in boat. Then I find the motor will start, kick over and die. It will do this untill I open the throttle and start on fast idle, then it starts ok and runs and starts fine.

Any ideas appreciated!!

Note the following parts have been replaced / repaired over the last 4 months:
Fuel filters, injectors, pump & pipes (pressure 25psi across the range). Also new sparkplugs, leads, distributer(cap and rotor), battery and cables. Also MAP and TPS, AIC. Also replaced all temp sensors, thermostats, impeller and pump.

Thanks a ton!

Mark rsa2au 07-30-2013 06:26 PM

I am going to be installing an automotive ignition module that is commonly used to see if it the electronics pulling revs out. Pick it up tomorrow.

Also any clues on the max rpm of the motors? I thought it would be arround 4800 - 5000rpm.

Just a thought, if I tested it on the trailer and it revs up to 5000 then it would not be an electronic rev limiter but another fault? Might test it tonight.

maxpower220 07-31-2013 08:31 AM

I believe the Indmar manual states a need for 30 psi. I don't know if that 5 psi difference would effect the boat like that or not. Sorry, my only thought.

JimN 07-31-2013 09:35 AM

Quote:

Originally Posted by Mark rsa2au (Post 961256)
Hi Guys, can any one tell me if there is an electronic rev limiter on the 310HP Preditor Motor/ 2001 350 TBI motor? If there is can I remove it? If not I still have a problem....

Once it gets to about 4500rpm, it seems to hit a wall and start to pull revs out to about 4300 then back up the 4500 etc. It is almost like a soft cut out rev limiter in a car, but lazy. Throttle is at about 2/3 and not full. Speed is about 38-39 mph.

Once run at high speed (Barefooting) and it hits this rpm, we shut down to get person in boat. Then I find the motor will start, kick over and die. It will do this untill I open the throttle and start on fast idle, then it starts ok and runs and starts fine.

Any ideas appreciated!!

Note the following parts have been replaced / repaired over the last 4 months:
Fuel filters, injectors, pump & pipes (pressure 25psi across the range). Also new sparkplugs, leads, distributer(cap and rotor), battery and cables. Also MAP and TPS, AIC. Also replaced all temp sensors, thermostats, impeller and pump.

Thanks a ton!

Check the fuel pickup in the tank and the anti-siphon attached to the aluminum block on the top of that. If it doesn't have an anti-siphon, make sure the fuel shut-off is fully open.

Stop replacing parts unless you can prove they're bad. I seriously doubt the MAP, TPS or IAC were faulty and the whole reason these engines have trouble codes is so time, effort and money isn't wasted on replacing parts.

The rev limiter kicks in at about 5200 RPM. The IC module isn't at fault- you already measured low fuel pressure and you need to keep going in that direction, IMO.

Mark rsa2au 07-31-2013 07:37 PM

Quote:

Originally Posted by JimN (Post 962353)
Check the fuel pickup in the tank and the anti-siphon attached to the aluminum block on the top of that. If it doesn't have an anti-siphon, make sure the fuel shut-off is fully open.

Stop replacing parts unless you can prove they're bad. I seriously doubt the MAP, TPS or IAC were faulty and the whole reason these engines have trouble codes is so time, effort and money isn't wasted on replacing parts.

The rev limiter kicks in at about 5200 RPM. The IC module isn't at fault- you already measured low fuel pressure and you need to keep going in that direction, IMO.

Thanks Jim

Great info! RPM limit 5200, boat does not get even close to this, 4500 max rpm from 3/4 throttle to WOT.

I will check the anti-syphon / fuel shut off is all good. Fuel pump module was removed, cleaned and new filter installed. Loads of muck in fuel pump inlet screen, fuel system now clean and performance has improved.
I also read in the manual that the fuel pressure is meant to be 25psi, although I have measured this at ignition, idle, and up to 2000 rpm and it holds 25 psi.
Because of the inherrant risk of holding a fuel pressure guage on the motor at full throttle on open water I have not done so but will be installing a fixed guage (and then removing it) for a test. The PO I believe turned the screw on the bottom of the pressure regulator out by 3 turns (because of a previous over fueling issue) so I might screw this back in as well.

The list of parts was either checked / repaired or replaced. ( not all replaced) This was meant to give a little history so those more experienced than me can see what has been done so far and provide me with addidtional valuable info... Which is excatly what you have done. Thanks!!!

JimN 07-31-2013 07:41 PM

Quote:

Originally Posted by Mark rsa2au (Post 962692)
Thanks Jim

Great info! RPM limit 5200, boat does not get even close to this, 4500 max rpm from 3/4 throttle to WOT.

I will check the anti-syphon / fuel shut off is all good. Fuel pump module was removed, cleaned and new filter installed. Loads of muck in fuel pump inlet screen, fuel system now clean and performance has improved.
I also read in the manual that the fuel pressure is meant to be 25psi, although I have measured this at ignition, idle, and up to 2000 rpm and it holds 25 psi.
Because of the inherrant risk of holding a fuel pressure guage on the motor at full throttle on open water I have not done so but will be installing a fixed guage (and then removing it) for a test. The PO I believe turned the screw on the bottom of the pressure regulator out by 3 turns (because of a previous over fueling issue) so I might screw this back in as well.

The list of parts was either checked / repaired or replaced. ( not all replaced) This was meant to give a little history so those more experienced than me can see what has been done so far and provide me with addidtional valuable info... Which is excatly what you have done. Thanks!!!

What manual? We were told the pressure should be 30 pounds. The regulator isn't user-adjustable. It's possible to adjust it, but it's NOT supposed to be without doing it without the proper procedures.

Mark rsa2au 07-31-2013 09:34 PM

Quote:

Originally Posted by JimN (Post 962693)
What manual? We were told the pressure should be 30 pounds. The regulator isn't user-adjustable. It's possible to adjust it, but it's NOT supposed to be without doing it without the proper procedures.

AAHh yes...... the on line manual that says 30psi:( oops you are right, my bad!
Yes the fuel pressure regulator is adjustable via a screw below the bowl, (although should not be required) and he did unscrew it 3 turns. :confused:

I dont know how this will affect the fuel pressure at full throttle, as my limited understanding suggests fuel flow / volume will be the issue. If there is insufficient fuel flow then the pressure may be acceptable at low - medium revs but when full throttle is called for, the lack of flow will starve the engine for fuel and result in a low pressure reading. This is why I am installing a fuel pressure guage.

Regardless I will install guage and measure... Will let you know

Mark rsa2au 08-04-2013 03:56 AM

Ok so I pulled on the arctic gear, pulled the boat out the garage and started playing. First thing to note is how much water is needed... I sucked my 2000lt rain water tank dry (528 gallons):eek:

Timing: The last time I checked the timing it was set at about 10 degrees at 1000rpm (using paperclip), but as it was hunting arround I set it about in the middle. NOW after much work the mark was a lot more stable and seemed to be about 2 degrees out. Set is exactly on 10 degrees, checked, turned off and resterted and checked again... stable at 10degrees:D

Fuel pressure: At key up and idle it was about 25 to 26psi. Adjusted Fuel pressure regulator to 30psi at idle/1000/2000/3000 rpm.

Also changed oil and oil filter while I was there.

Does anyone think the 2 degrees timing and the 4psi fuel difference would solve the issue of the lack of revs??

JimN 08-04-2013 07:42 AM

Quote:

Originally Posted by Mark rsa2au (Post 963755)
Ok so I pulled on the arctic gear, pulled the boat out the garage and started playing. First thing to note is how much water is needed... I sucked my 2000lt rain water tank dry (528 gallons):eek:

Timing: The last time I checked the timing it was set at about 10 degrees at 1000rpm (using paperclip), but as it was hunting arround I set it about in the middle. NOW after much work the mark was a lot more stable and seemed to be about 2 degrees out. Set is exactly on 10 degrees, checked, turned off and resterted and checked again... stable at 10degrees:D

Fuel pressure: At key up and idle it was about 25 to 26psi. Adjusted Fuel pressure regulator to 30psi at idle/1000/2000/3000 rpm.

Also changed oil and oil filter while I was there.

Does anyone think the 2 degrees timing and the 4psi fuel difference would solve the issue of the lack of revs??

Which way was the timing off- low, or high? If it was low, it can affect idle, but it shouldn't be a major factor. At WOT, it wouldn't have much affect because base timing + maximum advance at speed would be near 40BTDC vs 38 and shouldn't cost you 400RPM.

Did you put the ECM in diagnostic mode? If you saw the timing mark jumping around, your base timing ISN'T at 10. The mark jumping means sparl stabilization is still operating and in diagnostic mode, it isn't. This is mandatory for setting base timing. You can put it in foagnostic mode by inserting a paper clip into terminals A and B of the DLC and setting the idle at 1000 RPM. The timing mark should be rock steady. Set it at 10BTDC, snug the bolt, check it again and tighten it before removing the paper clip.

As far as 4psi, if the pressure isn't high enough, the fuel won't atomize properly and this is important because it needs to do this in order to burn completely. If it doesn't burn completely, you can't develop full power. Also, if you didn't check the pressure at WOT, it may be close, but not exact. However, it will be closer than before and noticeable.

Mark rsa2au 09-01-2013 07:22 AM

I am now over this POS!

Today ran the boat on the lake, Fathers day over here and a very nice spring day to get out on the water.

Last few weeks checked everything I can think of. Fuel pressure ( on trailer 30psi and on lake full throttle approx 30 PSI across the range). Timing at 10 degrees as per manual. All sensors checked or replaced. Plugs, leads, distributer and rotor replaced. Battery cables and connections replaced, earth connections cleaned and checked.
Boat starts first time every time. Dash guage shows temp slowly warming up to 160 and stays there give or take slight movement. Then the engine check light comes on so I disconnect the switch ( note this is just the on off switch- set to 180F- to the check engine light not the temp sensor).

Boat is now running rich again... on occasion have black smoke (replaced everything related so far except ECU), and will still not run above 4500rpm with out spluttering and poping or misfiring. Below this it pulls like a freight train.

Then the water intake hose splits at shower connection, and we almost sink...water over the floor boards. Lucky we now always cary tools on the Disastercraft, so wrap plastic and race tape (strong Duct tape) arround the pipe and carry on. No apparant dammage to motor dispite not having water. ( did not care anyway I'm so over this thing) Impellar checked and all good.

Guages still work on and off when they feel like it. Oil pressure guage now no longer works after today. Speedo's still slow to react and still leak from below dash (have replaced with new tubes as well).

Used a full tank (32 gallons) in just short of 3 hours measured on Tacho. Mainly water skiing, some wake boarding and a couple of tube rides. Boat cannot get to barefooting speed so we cannot foot behind it.

Finally the check engine light came on at the end of the day and stayed on, we were worried it would not restart so we left the engine running untill we put it on the trailer. Now parked on the verge as I could not be bothered to park it in the garage. No I have not checked the code yet..

The Disastercraft is THE most unreliable boat I have ever owned ( 5th boat). I have never had to work so hard to get a boat to run properly especialy one with just 270 hours on it.

Of course the Malibu in the team keeps purring along perfectly as it has done for the last 5 seasons, and the Australian made Sleekline (also 350 chev motor) still runs like a Swis Watch after 20 years. We can no longer ski our favorite spots because the family are scared the Disastercraft will break down and not get us back.

Does anyone have any ideas on what to check/replace next? Or we will have to trade it before summer.


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