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780 Bertone (PRV) Idling issue and some engine issues.

Moyni

Moyni

New member
Joined
Apr 1, 2019
Location
Greensboro, NC
Car is running super rich (see sparkplug image), has a funky idle where it seems fine in drive but when its in neutral / park it will surge the RPMs. Doesnt want to rev over 2500 without shaking like the space shuttle Columbia. I just did new spark plugs, wires, rotor and cap.

Thinking try a new MAF and a fuel pressure regulator possibly. I also havent ruled out a vacuum leak.

OzPA455.jpg
 
Pull the vacuum signal off of the fuel pressure regulator.... Fuel in that one? It may drip out or you may just smell it in the hose... Happens.

Coolant temp sensor and/or wiring to it. Ohm meter across the CTS... Open = pig rich.

Air mass meter much less likely; though everything about it is pretty old.

Give her a set of fresh plugs too. I'm fond of Bosch H6DC.

Check for vacuum leaks as doing so is good practice...Though a vacuum leak won't make her rich like this.
 
JohnLane said:
Pull the vacuum signal off of the fuel pressure regulator.... Fuel in that one? It may drip out or you may just smell it in the hose... Happens.

Coolant temp sensor and/or wiring to it. Ohm meter across the CTS... Open = pig rich.

Air mass meter much less likely; though everything about it is pretty old.

Give her a set of fresh plugs too. I'm fond of Bosch H6DC.

Check for vacuum leaks as doing so is good practice...Though a vacuum leak won't make her rich like this.
Click to expand...

Ill give these a look, plugs are fresh too, should have mentioned that. Luckily we still have a few scattered NOS B280 parts laying around in the deep dark corners of the shop I can throw at it.
 
Anyone have a diagram of where the CTS would be? I have the Haynes manual as well as the Volvo Green manuals but still cant find it based off the online part numbers.

This is the only sensor I have seen and I dont believe this is it
W5sew66.jpg
 
Footnote - If your thermostat is open, it should be replaced...this could skew temp readings by ECU.

Also, you most likely found the ECU's temp sensor...
 
So after talking with the bossman here in the shop, and doing some of our own research on the ol VIDA, it does seem like that is the sensor I need to replace. I am sort of firing the parts cannon at this motor in hopes of resolving this, however I still need to pull it back inside the shop on a slower day and take my time testing all the electrical components.
 
RE: firing the parts cannon

Replace coolant thermostat and coolant temperature sensor...Current CTS has been in there for "ages."
 
Moyni said:
Anyone have a diagram of where the CTS would be? I have the Haynes manual as well as the Volvo Green manuals but still cant find it based off the online part numbers.

This is the only sensor I have seen and I dont believe this is it
W5sew66.jpg
Click to expand...

Yes, that is the CTS :nod:
 
tomasss said:
One way or another, THAT is the CTS. It's condition is another thing, but the part has been identified correctly.
Click to expand...

Yeah the book calls it a thermotimer, but I was able to get a new Bosch one for about $20. Seems to have fixed the terrible rev issues it had, however it still has a seeking idle. I can unplug the MAF and the idle stays the same so I have a buddy sending me a new (used) MAF to test with. If that works, I should be able to take it out on the street for the first time since I bought it.

OgRfn42.jpg
 
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