'08 XC70 3.2 Starts readily, runs a few seconds, quits. Throttle body wiring suspect.

Faust · Post by **Faust** » 31 Jul 2025, 15:30

After my recent, rather lengthy, alternator replacement I decided to start her up (Throttle body not connected to air filter). It stared easily and ran about 3 seconds then quit; I did this repeatedly without any difference from the amount I depressed the pedal. Engine speed would increase, and it seems to quit faster. So my question is what could do this?

I think it important that in my laborious alternator replacement I managed to pull a few wires from the six-pin connector at the throttle body. The obvious repair seemed to be to pull the connecter off a '05 I have kicking around. I removed it, cutting it to allow six inch pigtails. '05 is a completely different color coding. So, using a wiring diagram provided by a member here, I carefully connected the wiring. I don't know that there is anything wrong here, but I also don't know how to test.

Faust · Post by **Faust** » 01 Aug 2025, 17:40

Solution, first it is time for me to realize that I am still just a points and carburetor kinda guy and stick to my old Mopars. In any case after of hours of checking wiring, loose nuts, sensors connected, etc. etc. I noticed there were wires coming out of my air filter which I had not reinstalled, obviously whatever sensors were in there were not getting the message. So, I connected the air filter and everything is beautiful.

Post by **abscate** » 02 Aug 2025, 05:06

Faust wrote: ↑01 Aug 2025, 17:40 Solution, first it is time for me to realize that I am still just a points and carburetor kinda guy and stick to my old Mopars. In any case after of hours of checking wiring, loose nuts, sensors connected, etc. etc. I noticed there were wires coming out of my air filter which I had not reinstalled, obviously whatever sensors were in there were not getting the message. So, I connected the air filter and everything is beautiful.

Stick to Volvos , Faust. I’ve spent days trying to start a P80 with the rotor in the wrong place.

As a new owner of an 3.2 equipped XC90 you probably just saved me the pain of leaving a connector off in my future

Well done figuring it out, and thanks for documenting here

Post by **volvolugnut** » 02 Aug 2025, 17:33

We all have to evolve. When I got my first Volvo with mechanical fuel injection, I was mostly baffled. At least it still had a distributor. It was 1975 240.
When I got the 2001 V70, I was completely baffled - computers everywhere, code readers, electronic throttle.
Both times I learned.
Carburetors and points are simple, but electronic fuel and ignition are much better when they are working.
volvolugnut

Faust · Post by **Faust** » 02 Aug 2025, 23:05

Re: Abscate's rotor problem. My first automotive memory, only slightly antediluvian, was aiding a teenage friend in tuning up his car. His car was already quite old at the time, I believe it was a '51 Ford, in any case a flathead V8. Completing the tune up we found it wouldn't start, in fact wouldn't even turn over. Using the Navy method of halves, we quickly spotted that the rotor was 180 degrees out of position. We adjusted the distributor and the car started right up. Who would think that poor timing would prevent it from cranking?