1998 Volvo Penta 5.7GSi Wiring Harness

[DrBabyfood]

Fellas,

So I've got a 1998 Volvo Penta 5.7GSi out of a 1998 Chris Craft 210 Bowrider that started idling around the 1800 rpm range. Background info: the boat was a gift from my father in law and he's always taken very good care of his toys. I took the boat out with my pops and it ran perfectly. We got to one area and noticed it seemed to be running a little rich however it didn't give us any problems and ran fine the rest of the day on the water. The next day, I hooked the water up to it to flush it out and upon cranking it I noticed the idle immediately started to increase up to around 1800 rpm.

I've checked the throttle cable and the physical mechanics of the throttle body and cleaned the throttle body as well. Took it to the mechanic where they replaced the IAC sensor. They replaced the ECM and distributor but it didn't correct the issue. It seems that the timing is off which is causing [COLOR=#67B045 !important]the high[/COLOR] idle? They told me this year and model of VP engine was notorious for wiring harness problems and that they are unable to get fault [COLOR=#67B045 !important]codes[/COLOR]from the ECM because the wiring harness isn't communicating with it. The wiring harness according to VP is obsolete nowadays. I've tried searching [COLOR=#67B045 !important]online[/COLOR] to find new/used ones and have been unlucky thus far. I believe the VP [COLOR=#67B045 !important]part number[/COLOR] is 3855929. Anybody have any ideas or know anyone will to part with their wiring harness? I appreciate it!

 

[Scott Danforth]

I would troubleshoot the harness and look for the bad connection vs trying to replace

a wire harness is a pretty simple device - connectors with wires. easy to trace, easy to diagnose, easy to repair.

 

[Fishhead-1]

Before changing parts I would double check for vacuum leaks like throttle body base gasket or intake manifold gasket. Any vacuum leak the tbi will idle fast not to mention that speed will be hard on drive shifting into gear

 

[DrBabyfood]

I would troubleshoot the harness and look for the bad connection vs trying to replace

a wire harness is a pretty simple device - connectors with wires. easy to trace, easy to diagnose, easy to repair.

And how exactly do you recommend doing this? If the wiring harnesses are known for going bad, then multiple areas could be bad and I'd be shelling out $$$ for the labor hours vs just replacing it? The mechanic shop is recommending either replacing the motor with new/rebuilt or converting to carburetor. I'm not really a fan of either. Just trying to find the best option.

 

[DrBabyfood]

Before changing parts I would double check for vacuum leaks like throttle body base gasket or intake manifold gasket. Any vacuum leak the tbi will idle fast not to mention that speed will be hard on drive shifting into gear

All of this has already been done. And I'm not currently using the boat because I don't want to trash the drive by slamming it into gear with such a high idle.

 

[Scott Danforth]

You pick up a multi-meter and start tacing the circuits.

If you have to pay for a mechanic to do this, it will be expensive. However a few beers and a few hours and you should be able to troubleshoot it yourself

3 hours with a $10 multimeter is cheaper than paying a mechanic

 

[DrBabyfood]

So my mechanic said the problem is that if you try to isolate the problem wire in the wiring harness then several others break. He said the wiring harness is very brittle. He's recommending I convert to a carburetor because he thinks having a new replacement wiring harness made will cost $texas and doesn't guarantee to fix the problem.

What do you guys think? Have a new wiring harness made vs. carburetor conversion?

I think I'm leaning towards having a replacement wiring harness made. I simply don't have the time to run the entire wiring harness and I'd hate to miss yet another boating season. Anyone have any recommendations for places that will make replacement wiring harnesses?

 

[AList233]

Unfortunately, that harness is damn near impossible to find. I had the same issue with my '95 VP 5.7Gi PHUS in my Albemarle. I did find that the 4.3 V-6 harness is the same, but you may need to extend some of the wires.

I was able to locate a harness from Fresh Water Volvo Parts. They have a website and list on Ebay. Sorry, not an endorsement, but they have quite an extensive inventory of VP parts.

Good Luck, I know the trials of locating the harness!!