View Full Version : 5.7L TBI issue
07-09-2010, 06:07 PM
Believe it or not, both my local MC dealer and Indmar are stumped. I guess it's because I have an "old boat": 1995 Maristar 200VRS. Indmar says that ALL of their fuel injected engines have rev limiters. My Indmar manual also states that the 1994-2002 ECMs have a rev limiter that keeps the RPMs low until the motor reaches operating temperature. I just got off the phone with a tech at Indmar and he had never heard of the temperature equation in the rev limiter....because it's an old boat. He told me to get the engine S.N. this weekend and call him back.
I mentioned in another post that my boat runs fine in gear, pulling skiers and barefooters up to WOT. I put the transmission in NEUTRAL and slowly increase the throttle and it reaches 3000 RPMS and then drops back to 2000 and starts to run a little ruff. I won't list every thing I checked. I contacted another member (dcjm6602) who has the same year boat and his boat does the exact same thing. I don't think this issue is a problem, so anyone who has a 95 MC with a 5.7L TBI, could you please see if your engine does this too? I'm just curious.
07-09-2010, 07:27 PM
I have a '95 Prostar with the 5.7L TBI. I have not had the issues you describe or any other problems.
07-09-2010, 08:02 PM
What I find funny is that my MC dealer said he knows of NO rev limiter in the Indmar engine (which is why I would never take my boat to him). My former MC dealer said that he isn't sure, but he believes there are two rev limit settings: One for being in gear, and one for being in neutral. Neither the MC dealers or Indmar were aware of the limiter related to the engine temperature, but I plan on testing this out this weekend. This chart was taken right out of my Indmar manual. I donít think that itís a coincidence that two of us with the same boat have the same issue at exactly 3000 RPMs. Other than that, the boat runs great.
barring the above chart. It sounds like a weak fuel pump it must deliver 40 psi continuously. If you turn the key on but don't start the engine you should hear a "solid" pressure build up. A high pitched whine for about 2 secs then quiet. If you don't or it keeps whining that would be my first guess as to what might be wrong. Also the inline fuel filter should be replaced at least annually. I have a 1995 225 VRS, 2 fuel pumps and 1 starter in 11 years of ownership, the only parts I have replaced except plugs. I would consider my use of the boat 'heavy". I do have a dock start platform so although I don't like to "hit it cold" I have, it runs great even before it warmed up.
07-12-2010, 09:33 PM
Fuel filter has been replaced, fuel pump screen cleaned and the pressure has been tested. Had to buy a GM adapter to put in place of the filter in order to put a pressure gauge on the line. If it were a low pressure problem, it wouldn't be able to pull footers at 41 MPH. The fact that one other posters boat does the same thing at the same RPM tells me it's programmed into the ECM (it may only be the Maristar 200VRS). I'm not replacing any more parts until Indmar has a chance to check my serial number and check the program. I just think it's funny that my present MC dealer said there was no rev limiter at all, but it's clearly stated in the manual. I trust my former MC dealer, he believes it's programmed that way but he's not 100% sure. Like I said, the boat runs great!! Just don't rev it up in nuetral :rolleyes:
07-14-2010, 10:09 PM
Pretty sure my 2000 and 2003 TBI's do not have "Neutral Position" input to the ECM. The MEFI controller could likely handle that input, but i haven't seen it on my two MC 5.7L TBI's. No ECM input means its can't rev control based on being in neutral.
Think if it runs fine under load and also with normal neutral engine loads, it probably is fine.