www.iFourWinns.com

Have a 1997 vista 258 with a 7.4 VP/DP.

I've been having problems with engine overheat and I'm slowly working my way to the solution.

If you notice on the photo I have circled in red one of the senders. There was a wire attached to this sender at some point because it is cut off in on the sender itself. I can't how ever see any wire not connected anywhere around it that is not connected.

Can someone verify for me where this thing is supposed to be attached? A pic would be great PM me for my email if you are not able to post pics.

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

I would recommend you find a Volvo Engine manual.

There is an iboats.com forum with information on VP manuals.

http://forums.iboats.com/showthread.php?p=2360521#post2360521

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Terry
Current: 07 Crownline 255 CCR cuddy - 350 Mag MPI/B3 "Casi Cielo"

Previous:97 245 Sundowner 5.7GI/SX

Tow vehicle: 1986 GMC 2500 Camper Special 454/TH400

VP V8's from around then had 2 temperature senders; one for the gauge, and one for the ignition control box, which put the engine into safe speed mode if it detected an overheat. They also had 2 senders for the oil pressure first one for the gauge and the other for engine protection. The one you indicate looks to be screwed into the water pump, so it's more than likely one of the 2 coolant temperature senders.

Graham.

If you have previously overheated and the boat still ran, then that may be the sensor for the ignition control box that Graham mentioned. I overheated this same engine on my old boat and the engine went into "limp home" mode and would not rev above an idle.

Perhaps the previous owner wanted to disable this function.

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Martin
04 268 Vista - Knot Again
08 Boston Whaler 130 Sport - Double Good
Previous Boat:
97 278 Vista - Buoy Howdy

Well everything turned out good.

Replaced thermostat, Put in missing exhaust bellows and reconnected the lines from the thermostat housing directly to the risers.

At idle the temp varied from 88 to 100 on risers and manifold and the thermostat housing hovered around 130 to 150. I did idle it a 1200 rpm for a minute to let it warm up.

The temperature gauge did indicate 230 after the first minute of running but no sign of overheat below?

While I was replacing the bypass that had been made I realized that the intake had been reduced from 3/4 to 1/2 I don't know if this would of been bad for the starboard riser?

Will take her out on the weekend and monitor the temps some more and let you know how it works out.

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

Thanks for the link Terry helped me get my problems fixed.

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

Well the trial was a no go.... The temp at the thermostat housing was good it was also good at the risers. Around 90 degrees. It still went into limp mode??? I guess this leaves the switch?

I will try to disconnect the switch tomorrow in order to try and be able to use it for the weekend.

U think that will work? I have no spare gasket to take out the thermostat

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

Sorry to hear that. I would think they'll have designed it "fails safe" so if the switch is faulty, it goes into limp home mode. Also, if it's disconnected.

I did look at the wiring diagram a few days ago, I can't remember which colour wire should be attached, but it is the same as the wire attached to the low oil pressur "limp home" sensor. The manual also indicates the resistance values for the sensors. My guess is that it would be the same one as fitted to GM engines, maybe easier to find than a VP one.

Graham

It's working guys sender and switch dissconected working ok

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97 258 vista 7.4 VP/DP......... 2008 GMC Yukon XL Denali


96 sundowner 5.7 vp/sx (SOLD)

Instructions:
Turn off the power to the circuit. Open up the breaker box and flip the breaker for the circuit.
Open up the cover plate on the electrical component.
Remove the switch or outlet. The switch and outlet both have screws on either side screwed into the box.
Look for a plain copper or green covered wire. Also locate the black wire and hot wire, which are the hot and neutral wires.
Pull out and hook up the copper or green covered wire. At times, some electricians won't hook up the ground.