Alternator issue

Post by **jmmxc** » 18 Dec 2011, 11:46

This is getting insane!!! Even if it's the ecu somehow causing this problem I can't even get the thing out and if I do swap the one from the other car is will have to be programmed.

It looks to me that you have touched so far on the most possible causes for your problem but the ECU itself.
I would concentrate on finding a way testing the ECU inputs/outputs that control the Fuel Injection system before giving up.
jmmxc

99_xc70 · Post by **99_xc70** » 18 Dec 2011, 12:29

I would love to but the ecu has to be removed with some magic tool. I want to remove it and test for resistance in cylinder 1 and 2 injector clip right to the ecu pin. I can't see it having a broken wire somewhere due to the fact that I have power and ground at the clip by checking with my noid light. I have 12v with the key on and the noid light flashes with on both connectors with the engine running.

What does the cam sensor and crank sensor do? I read that the crank control some of the cylinders and the cam sensor controls the others? Since it is a 5 cylinder engine?

Post by **Pauloil** » 18 Dec 2011, 13:58

99_xc70 wrote:I did do a voltage drop test and got 0.4v from the B+ on the alternator and 0.2v from the alternator case to the battery negative post. I cleaned the connections first and then did the test. The connections are good it just the alternator is not charging under load. I just want to know if the alternator is not charging properly will that mess with the ecu and cam sensor/crank sensor causing ignition timing problems?

the B+ cable goes to the fusebox, be sure to check it under load at 2K rpm. sounds like your red starter cable is bad and that should be the first thing you replace. you prob need to clean your grounds as well

Post by **jblackburn** » 18 Dec 2011, 17:10

Crank controls firing and cam controls injectors.

The ECU on a 1998 just pops out with a couple clips.

99_xc70 · Post by **99_xc70** » 18 Dec 2011, 18:38

I have a 99 and I don't think it just pops out, I wish. Either way I still would have to tow the car to the nearest volvo dealer and have it reprogrammed if I did swap ecu's with my other car. I will have a new alternator tomorrow and I also grabbed the crank sensor and coils from my other car to see if it makes a difference.

I cleaned and checked all connections right from the positive and negative leads from the battery. Every connections has be sanded and cleaned. No green scale anywhere, there was none to begin with. This car is super clean and that's why I want to get this running other than the other one. I have two 99 v70xc, ones green and the other is black. The black ones is the one giving me trouble. I bought it not running(broken fuel pump and burned out starter). Now it starts and runs but misfiring on 2 cylinders.

I will have an update tomorrow with the new alternator, coils and crank sensor installed. Well alternator first and re-test the charging system.

Post by **Pauloil** » 18 Dec 2011, 20:20

ipdusa has a generic starter cable for our mutual car-- might be good for your new alt. I thought I needed a new alt on my XC, but putting in new B+ cable(from batt. to fusebox) got the volts back up!

Post by **jmmxc** » 19 Dec 2011, 13:14

Oh...one more thing: Since you mentioned unusually high ripple, have you checked the voltage regulator to determine whether it properly maintain the alternator voltage to within 12~14 at idle and high rev (about 2K rpm)?
This can be a quick swap to make to verify any improvement.

Just another thought.

99_xc70 · Post by **99_xc70** » 19 Dec 2011, 13:41

I checked all diodes and they are reading properly. I think it is the voltage regulator that is the problem. My other running v70 has the battery light on because the alternator is not charging, so I can't take that one!! I going out now to get my alternator tested.

Also when I replaced the starter could I have damaged the crank sensor pickup? Where is the pick up at? On the flywheel?

99_xc70 · Post by **99_xc70** » 20 Dec 2011, 14:18

Alright so an update I guess. Replaced alternator with a good used one. Re-tested charging system and it is now working properly. I still have a misfire on cylinder 1 and 2. Just for fun a replaced coils 1 and 2 and the crank sensor from my other car and still didn't help anything.

I removed the ecu to see if any junk was in the pins or connector, didn't see any problems. I have spark, fuel and compression in all cylinders, just my ignition timing is messed up. 3,4 and 5 cylinders are working properly. If i unplug injector 1 or 2 the rpm comes up a bit and it almost runs better, not when I unplugged it almost stalls like 3,4 and 5. So where are all the grounds at on this car? What about a vacuum leak? My idle is dead on 900rpm and does not fluctuate at all. If anyone live close to me they could have a pretty mint black v70xc for free!!

Post by **BEJinFbk** » 20 Dec 2011, 14:27

When's the last time you replaced the plugs in this car?
And what kind are they?

Alternator issue

Re: Alternator issue