As the title states, I have a 98 V70 wagon that recently had the engine replaced, now I am having a very strange problem. The engine wants to stall whenever the power windows are operated. Tonight it also wanted to stall when the turn signal would flash. I have checked the alternator voltage output and it is 13.4 to 13.7 volts. With the ignition disabled and the starter cranking for about 15-20 seconds the battery voltage dosen't drop below 10.5 volts.

Any help would be greatly appriciated, I have to drive it back to Yellowstone from CA in a few days and I am hoping I can fix this relatively inexpensively because of Christmas and all.

Thanks,
Scott

 

Someone that replaced the enigne messed up something.
Maybe a plug in the wrong spot or a bad ground.
Check the battery voltage with the car running.
But use the engine as a ground and see if it is good.

 

The problem is intermittent. Sorry forgot to mention that. Voltage was 13.7v with the engine running using the block as ground. It is becoming more consistent but when it dosen't happen it runs great and dosen't throw any CEL.

 

Ok the gounds so far are good.

I would start checking connections form starter,Alt, and other main things.
Also check the relay panel there is a pain positive cable in there.

 

[>:] OK. So I cleaned the terminals the battery because there was a little bit of corrosion on them on this afternoon and drove it around for an hour + without a single hiccup. Checked voltage using the block as ground 13.7v checked voltage using the battery as ground 13.7v. It was about 66 degrees outside. This evening the car won't stay running, whenever you request something electrical it wants to stall and eventually does. Limped it home, checked voltage with all accesories off down to 13.3v turn headlamps on and the engine stumbles, voltage drops to 12.5v. Hooked jumper cables between a new battery and the existing battery and still stumbles/stalls. All visible connections and grounds are clean and good. [sm=wtf.gif] At this point the alternator is what I suspect I don't know why it would be charging fine at one point and then not charging later that when the only chenge is outside temperature.

 

The starter connection is clean and tight?

 

Yep. As far as I can tell. No problem starting the car. Only keeping the car running when there is an electrical load applied. If I turn off all of the accesories (lights, radio, etc.) The car will run and drive fine. With the engine running fine I wiggled every connector, ground wire, etc. that I could find and nothing made it stumble/stall. Only when an electrical load is applied to it. I tried installing a new battery out of another car and it did the same thing, so that kinda leads me to the alternator. I will double check the starter connection though.

 

OK so I have checked every connection I can see. Its not the alternator, or the battery, or a fuel problem. There are 4 components that trigger the stumble/stall, the front wipers, the headlamps, the turn signals, and the power windows. Does anybody know if there is a wiring harness that all of the above mentioned components share? None of the other accesories will trigger the problem, I can activate the A/C, the rear wiper, brake lights, reverse lights, heater, etc. without a single problem.

 

Make sure the B+ cable is ok. The terminal at the engine fuse box gets very hot from a bad crimp and will cause the voltage to drop.

Check out this pic.

http://profile.imageshack.us/user/tr...1010731dq0.jpg

This may be your problem, hope it helps.

3B

 

Yep checked that connection already.

 

OK, I replaced the battery today because the old battery would not hold above 12.2v. The problem is still present but is significantly reduced both in how frequent the problem is and how severe stumble is. It still only happens with the power windows, turn signals, headlamps, and wipers. It dosen't happen with any other load, cooling fans come on it runs fine, same with A/C, heater, radio etc.

I'm at a loss now, I don't have the money to take it to a shop for diagnosis, do the headlamps and power window circuits share a common wiring harness. Does anybody on here have access to the factory wiring diagrams for the power windows, and lighting systems?

Thanks again for the help, I refuse to give up.

Scott

 

I will see what I can dig up tomorrow.
You might have to bump this post to remind me.

 

I can't claim much knowledge of Volvo electrics but I do know something about low level control circuits. I sounds to me like it is not a question of absolute load but more likely a spurious signal getting into the engine management circuits. I would look for a misplaced ground or signal wire from one of the functions that causes the stall. If a ground is lifted or poor, the circuit might be grounding through the engine management box or a poor connection might be sending a spike through the system. In my experience, unless there is frank component failure, this type of problem usually reflects a poor ground.

Pretorien

 

Wow sounds like somebody who knows what he is talking about. When I see words like "spurious signal" I have no idea what you are talking about, but I'm impressed. I understand enough to know you should be looking for a bad ground though.

 

Finally. Fixed. At least for the moment all problems are gone. After removing the airbox assembly I did a voltage drop test between every visible ground wire and the bolt that attaches it to the frame. I found a ground just below the coil that had a difference of 2v between the wire and the chassis. After removing the bolt and cleaning the contact point and reattaching the ground wire I put it all back together and so far the problem has not resurfaced.

Thanks for all the help.
Scott