1999 V70XC Rough idle and engine stumbling is back! :(

warcraftjunkie · Post by **warcraftjunkie** » 21 Apr 2014, 21:51

Ok, some of you may remember helping me with a problem that I battled with my car for about a year and a half.

https://www.matthewsvolvosite.com/forums ... =1&t=52657
and
https://www.matthewsvolvosite.com/forums ... =1&t=50713

So, the problem is back. Not as bad as it was last time however. I was travelling about 65 mph the other day heading home. I noticed a stumble as I was decelerating and thought hmm.. was that a rough downshift?? I applied the gas and everything seemed to be fine. As I was exiting the freeway the check engine light came on and the RPMs started dropping real low and bouncing back up. I pulled up to the neighborhood just as it stalled out and would not restart. I let it rest for about 2 hours and went back and was able to limp it back into my driveway. I disconnected the battery and reset the light. I hooked it all back up and turned the key on and started the car. It took quite a few seconds to fire up but it eventually did. The Engine light came back on immediately and the car Idled extremely rough; surging RPMs for about 10 seconds before it settled in at about 900RPMs. Once I engaged Reverse the idle took another unstable dip and surge for about 3 seconds before leveling out. Same thing for going into Drive. About 90% of the time the car will stay running at idle, but about 10% of the time it will just die with no stumble. Also after I turn off the car and remove the key, the fan for the radiator will engage and stay running for a few minutes.... even if the car is not up to operating temperature.

I got the car over to OReilly and the code reader there picked up P0236 and P0237. I reset the engine light with the reader in the parking lot and the codes came right back. Those codes are regarding the MAP sensor on the intake tube between the intercooler and the Throttle Body. I believe 0236 is for no signal and P0237 is for signal out of range or low. I replaced the MAP sensor October of 2012 with a Bosch sensor. Could it have failed in only a year and a half of operation? I tested the voltage at the MAP harness and get 5v. Not sure how I can fault test the sensor itself.

Here's what was replaced last time I was dealing with this issue:
Throttle Body with a Xemodex unit
MAP Sensor
MAF sensor (from boneyard)
Front O2 sensor (from boneyard)
Spark Plugs - Bosch Copper Plus.
Coolant Temperature Sensor
Thermostat

Last time this happened, what seemed to correct the issue was pulling all the plugs as well as the ignition coils and giving them a good cleaning. After I put them back in the problems magically vanished for the last 1.5 years. I even replaced the spark plugs with new ones and it still ran like good. I knew at the time it was too good to be true. I never really felt like the car was running like it should be with a fair amount of low end punch from the LPT, and it always had crappy MPG's (17 in the city with my commute being 7 miles each way), but I didn't have to worry about it stalling out making a left turn at a busy intersection or bombing out multiple times in the driveway trying to get it to stay running.

warcraftjunkie · Post by **warcraftjunkie** » 21 Apr 2014, 21:55

Also, if I reset the engine light it comes on immediately next time. If I turn off the car and start it up again, about 10 seconds later the ETM light turns on. If I reset the lights again and start the car the Check Engine light comes back immediately but the ETM light will not turn on until I turn off the car and start it again... 10 seconds later it illuminates. This happens predictably every time.

Post by **abscate** » 22 Apr 2014, 03:39

That's correct for the ETM ( isn't it labelled ETS actually?) light. The unit self tests and if fails, the light comes on. It sounds like your throttle body is bad. Try cleaning or talking to Xmodex...how long is their warranty?

warcraftjunkie · Post by **warcraftjunkie** » 22 Apr 2014, 09:45

I stand corrected on the ETS light.

I guess I'll need to drop the throttle body and see if it's coked up. It's only been on for a little over a year and a half, I wouldn't think it'd be that bad. The symptoms for this came on so suddenly I would think that would have expressed itself for a while as the surface conditions deteriorate.

warcraftjunkie · Post by **warcraftjunkie** » 22 Apr 2014, 21:50

On my way home I stopped to get the codes read again to see if there were any new ones in addition to the P0236 and P0237. I got P0102 and P0121. Those are for MAF and ETM respectively. I let it idle in the driveway while I tugged and pulled on wiring harnesses in the engine bay. It may or not be related but it seemed that if I tugged on the wiring bundle that comes from the fuel injectors and coil packs it almost always caused it to stumble and fail.

The last time I resolved this issue I had just finished up cleaning the coil packs as well as the spark plugs and when I put it all together all the problems went away.

The wiring bundle from the top of the engine (coil packs and injectors) joins up with the wires from the MAF and TCV and disappear into some conduit. The flexible wire covers (not sure what to call them) are brittle and cracked just about EVERYWHERE under the hood. In fact I'd say 50% or more of the wiring is exposed due to it cracking off and falling away.

warcraftjunkie · Post by **warcraftjunkie** » 24 Apr 2014, 09:38

And today it became unsafe to drive.... Couldn't maintain an idle. bumps cause it to failout.

warcraftjunkie · Post by **warcraftjunkie** » 25 Apr 2014, 17:08

Ok, now that it's the weekend it's time pull things apart and look for problems. Since someone suggested I pull the Throttle Body and take a look at it, that's what I'm doing, plus pulling plugs and coils. I also pulled all Turbo hoses.

The Turbo hoses are flexible, but not too soft.

Here's the throttle body... it's a little dirty, but honestly I wouldn't think this would cause idle issues. the throat plate was easy to open and close. Went ahead and gave it a good cleaning since it's off the intake manifold.

warcraftjunkie · Post by **warcraftjunkie** » 25 Apr 2014, 17:24

Next I pulled the 5 coil packs and plugs, starting from passenger side going to driver's side. I also took pictures down each cylinder. As you can see in the pictures the coil packs have hairline cracks in their bodies... some are more than others. The boot on coil pack 1 has a tear near the collar.

Would those cracks be enough to be causing erratic idle much like a failing ETM? How about Cylinder1 and 5 how they are much cleaner than 2-4?

warcraftjunkie · Post by **warcraftjunkie** » 26 Apr 2014, 10:04

So, any thoughts about those cracks on my coil packs? Could they be giving me symptoms of a failing ETM... no codes for misfires thus far.

SpeedyPete · Post by **SpeedyPete** » 26 Apr 2014, 11:57

Hello: Junki as an electrician of 40 plus years any time I see cracks or tracking on insulators I replace them. So that being said I would start with cleaning the coils and all surrounding areas and associated parts. Double check your insulating boots and replace your plugs. You might get lucky for awhile but eventually you probably will have to replace the coil packs and or the insulating boots. You are dealing with the possibility of high voltage double tracking. In other words the path of electrical current is not fully going to ground thru your plugs (Spark) but also simultaneously slightly bleeding off on another path ( dirt,oil to block). I had this on my Mercedes awhile back. Good luck with this I think you are looking at having to spend some $$$ here. Clean everything first, check results, then proceed to spend on new parts as necessary. Regards, SpeedyPete