PDA

View Full Version : Whits end 94 Prostar205 TBI 350


rspiecha
07-11-2006, 10:45 AM
I've been fighting an issue for a long time. My TBI 350 engine runs great when cold, or any other time, but not when hot and at idle. I have a rough idle when the engine is hot. I have had it in the MC shop several times over the years. I have replaced the following:
computer MEFI 1 -> MEFI 2 (dealer)
MAP (skidim)
TPS (dealer)
CTS (skidim)
filters (dealer)
CAP/Rotor (summit)
coil (summit)
spark plugs (skidim)
spark plug wires (summit)
prop (oj 13x11.5 3 blade)

The boat runs great when moving, plenty of power, good top end, but when I idle when hot, or start hot, I get a smell of richness from the back of the boat and sometimes white smoke.

thanks for any help

Rob

André
07-11-2006, 10:55 AM
Did you check your IAC,idle air control?
It's like a plunger that controls air at idle,located on the driver side of the throttle body,toward the rear.
How many revs do you get at idle?
That engine should idle like a champ...

rspiecha
07-11-2006, 01:47 PM
The IAC in my opion is working great. Cold start, engine revs up to 800-900 for a couple of seconds, then back down to around 500-600 rpm for the idle. When hot, and when I'm having the problem, the idle is at the same when cold, around 500-600 rpms.

The only items I haven't check into yet, is the fuel pump is too high of pressure for idle. Can the bypass on the pump get clogged and I'm having to high of pressure for idle???? Can the two injectors be the problem????

Thanks

BIGBADBLUE
07-11-2006, 02:50 PM
My '94 PS205 was doing the same exact thing and no one could figure out the issue. We replaced the IAC and life was good. You may want to try it.

Kell
07-11-2006, 02:58 PM
The IAC in my option is working great. Cold start, engine revs up to 800-900 for a couple of seconds, then back down to around 500-600 rpm for the idle. When hot, and when I'm having the problem, the idle is at the same when cold, around 500-600 rpms.

The only items I haven't check into yet, is the fuel pump is too high of pressure for idle. Can the bypass on the pump get clogged and I'm having to high of pressure for idle???? Can the two injectors be the problem????

ThanksI'll defer to others more knowledgeable on this, but I had a cold start issue on my 99 Maristar 210 VRS, 330 LTR two years ago. Posted the problem here and JimN suggested to have the ECM checked out prior to replacing various parts like IAC, TPS etc.... So, I took the boat to dealer, they pulled the ECM, and then sent it to Indmar for reflash of calabration or whatever its technically called. Turns out that the calibration/software/Rom OR what ever (?) in the ECM was two generations behind. So Indmar reflashed and updated to the latest generation. I have not had any cold start issues since the reflash. Just something you may want to explore further before changing out parts and I don't know if you even have an ECM on your TBI motor.