'01 Idle Stumble/Surges

[cham]

Hey guys,
I've been sorting some smaller stuff with the V70 (2.4 N/A Auto) lately and finally decided to maybe tackle this running issue that's plagued the vehicle for a while. You guessed it, the classic Idle/running issues most likely related to the ETM.

Currently there are no codes, only alert messages for the "Gear Selector Reduced Function" and "Alarm System Service Required". The alarm error only pops up when unlocking the car and with the door open briefly after. I'm in the process of sorting this one.

It experiences that stumble when coming to a stop at a light and the rpms like to drop and then recover. Doesn't stall but there have been times where it seems close. Pulling off from a light it also feels like there is a struggle for a moment/delay. When driving it's less of a problem but there are times where it surges a little and feels like the trans is kicking down or just hunting for a moment. From what I've read these are all classic symptoms. Now first I should mention the PCV system has never been replaced to my knowledge, and it's an '01 with 150k miles. Likely that is contributing as I've heard it can distort MAF readings when clogged. I'll be checking the spark plug tube holes to see if they are filled with oil at all meaning positive pressure is pushing oil out past the tube seals which is common for clogged PCV. On that note it likely needs spark plugs in the near future as well. Last thing I forgot to mention, I'll get a voltage low alert if I have the headlights on without the car running for only a few minutes sometimes. Guessing battery needs replacement but could this be causing the running issues I'm experiencing?

The ETM itself is a white label dated '01 week 4 (01W040603) and part number 8644345 which is not even the 346 updated part let alone 347. I've been eyeing some junkyard cars that I'd like to know if those in the know could chime in if its worth a look. There are a couple 2002 S60s with the Magneti marelli ETMs. Both are 2.4 N/A Autos. I'm going off photos as the yard is quite a ways out. If I look, I'll grab mileage and VINs etc. Based on my research on Volvo Parts, the Magneti ETM used on my vehicle was used on S60s with the same engine. The most updated version is Part#: 36050564.

The biggest problem it sounds like I'll face is getting one with the right programming. I've seen a lot of posts from @precopster and he mentions in one that the N/As specifically had more programs than the Turbos. He mentioned something like a 1 in 5 chance you get the same one. The problem being it sounds like during the "recall" for these ETMs some dealers opted just to reprogram them instead of replacing. I imagine that is what happened to this vehicle at some point in its life as I'm pretty certain the 2001 week 4 date means it's original. I guess this makes things more complicated? I had also heard they would reprogram them to suppress DTCs or errors? Anyways, I wanted to cover my bases; feel free to tell me if I'm missing any vital information to help diagnose. Thanks for following along with me!

[abscate]

First of all, you need a solid battery in the ETM cars first them to run, so pony up the $150 and put thst to bed. It has to have 12.5 volts at rest, not 12.2

The software update from Volvo did just extend error range tolerance so they wouldn’t have to replace throttle bodies on warranty. The best solution today, covered in the ETM Room below, isthe newest version of body available on eBay for about $150

Here is the thread on low battery voltage on the CANBUS cars, 1999 years and on

viewtopic.php?t=92161&hilit=Low+bus+voltage

[Vova585]

I believe you are starting at the wrong end here. You are concentrated on throtle body without first addressing basic maintenance which is well overdue likely given 150k. Spark plugs, fuel and air filter, clean MAF, perform "glove test" for PCV system-it is more reliable than looking for oil in the spark plug wells, drain/refill of the transmission oil, timing belt. If you are determined to try ETM, there is no point to buy used unit. It will need to be programmed to the car which likely will be PITA to find person who will be able to do it(volvo dealer will only work with brand new unit). I would recommend to remove ETM and send it to xemodex for repair/diagnostic. They will change system to brushless potentiometer design and it will be plug and play when returned to you. It is not a cheap service, but I have 150k on mine rebuilt unit from them with no issues. While you are waiting for service of your etc you can adress PCV system, belts, baterry, filters.....

[cham]

Hey abscate thanks for chiming in!
So the battery isn't even a couple years old and after removing it from the car it tested 12.2V. I charged her back up and threw it on the car. The cold idle after starting the car hung longer at a higher RPM before settling to its final idle speed (more likely a result of reset fuel trims). Usually it only holds like 1200-1400 RPM for 15 seconds at most then settles. The fuel trims reset and that changed driving characteristics slightly but the surging/stumble at idle after warmed up is still there. I'll be getting the battery tested just to make sure it is the issue otherwise I'm assuming alternator is going.

I found the ETM Room, good stuff I'll check it out. As far as a replacement body for $150 on ebay, is this an aftermarket version of the newest Volvo "36050564"? Or are you talking about a used Volvo unit "36050564"?

[cham]

I believe you are starting at the wrong end here. You are concentrated on throtle body without first addressing basic maintenance which is well overdue likely given 150k. Spark plugs, fuel and air filter, clean MAF, perform "glove test" for PCV system-it is more reliable than looking for oil in the spark plug wells, drain/refill of the transmission oil, timing belt.

I've already done basic stuff like clean MAF, air filter, trans was drain-filled 15k ago and timing belt along with water pump was already done at the same time. I'll try the glove test but I've heard the PCV box can fail a couple ways especially if it has the diaphragm version on the N/A model, which mine unfortunately has. Sometimes it can fail in a way that still pulls vacuum at the oil cap, not sure but I'll try it anyways.

[Vova585]

I am not familiar with all possible variations of ETMs. I thought MAgneto was using a potentiometer which was "brush riding on the contact" over time metal brushes were "eating" through the contact plate coating and thus resulting in incorrect result to the ECU. Unfortunately the only way is to open the unit and see. Plus the ECM needs to be coded to the ECU, thus I questioned purchase of the used unit. In terms of PCV system for 2.4 N/A i would invest $90 to replace it and eliminate the variable. It appears that it is far less of the headache in comparison to 2.4T. (Word of advice do not by IPDs "home" stuff. My hoses disintegrated after 1 year and I had a pleasure to do this job again but this time with genuine parts.)

[abscate]

A used latest iteration throttle body is the way to go. A good buyer will list what car it came from. Try to match your purchase to your car flavo(u)r

NA
Low pressure turbo XC GLT
High pressure turbo T5 R

The latest ETM is non-contact and seems to be universal software

[cham]

Bit of an update here.
So I've run through a few of the recommendations with not much effect. New factory fuel filter, replaced battery under warranty. I ended up tracking down a couple shorted bulb sockets causing electrical gremlins. No improvement on idle.

The glove tests were an interesting one. I did it twice. First time the engine was warm but hadn't been driven much and it passed with flying colors. Decided to try again a day later and took it on a drive first, and it passed again with flying colors. But when I decided to rev the engine while in Park, it did actually very slightly start to inflate. I've also read somewhere on here the NAs can still pull vacuum with a failing PCV diaphragm. Regardless, looks like its in need of replacement in the near future. I plan to replace spark plugs but am still deciding on brand, the factory OEM 3-prong plugs worry me, I'm leaning NGK I think.

So final thing to note is I started looking into the air intake thermostat only seen on NAs. It supposedly is for emissions and efficiency, but essentially with a cold engine it diverts air from a separate intake tube that runs past the back of the engine, into the airbox. Helps warm up the car quicker. Well it failed fully closed and only allowing hot air in all the time.

I've since fixed it, propping the cold side open with a bolt as we are getting into the warmer months, it wont matter until winter comes around again. Engine actually feels like it has some extra power restored now, and runs as whole better. The stumbling when coming to a stop light has been improved. Still always does it when switching to park but I'm really surprised. Some of the P80 850/V70 posts seem to suggest when this happens, it's a MAF killer due to the heat. Could have contributed to my current issues. It still idles at 750RPM in Park, pretty sure it should actually be 850RPM.

I wanted to ask, kind of separate topic but what temp is the electric fan supposed to come on at? I've read maybe anywhere from 220F-230F but that sounds high to me. Isn't that temp starting to get into the too hot territory?

[DavidE7]

There was a recall for the 2001 electric radiator fans:
https://www.tsbsearch.com/Volvo/SMB-26-141

There are also problems with the voltage regulator for the alternator but it is replaceable with the updated design (only worth doing separately if the bearings are still smooth):
https://www.fcpeuro.com/Volvo-parts/V70 ... =6&d=58&v=

Those were two of the early repairs I did for the 2001 V70s. I have replaced the PCV hoses and box on both V70s at least once.

I need to learn how you tested the air intake pneumatic switch. Did you just pull the corrugated aluminum hose off the intake after the engine was warmed up?

I have the XeMODeX ETMs on both of the 2001 V70s my kids use. Keeping the ETM clean on the inside helps it operate smoothly.

[cham]

Nice call with the alternator regulator, I hadn't heard about this defect yet, I'll look into it. Fortunately I checked my fan module a while ago and its part number is not of the affected ones. I'm just curious how they function and how to know if it's functioning correctly.

So was it really plug and play with your XeMODeX ETMs, no re-programming? Did you also replace the MAF sensor as well like they recommend?


Yeah so the intake thermostat valve moves with both temp and vacuum. I'm not exactly sure which performs which role but I am pretty certain the thermostat does most of the movement for the flap/valve. Essentially the best way to test is to wait for a warmer day so your intake temp into the airbox is going to be naturally warmer, and then warm up the engine. Drive it around until it is nice and hot so there is no question it should be opened up to the cold side. Make sure the airbox/valve vacuum lines are hooked up correctly and that there are no obvious leaks. Put the car in Park and keep the engine running. Remove the intake hose that connects the front grill intake to the airbox. There you will get a nice view of how much that flap/valve is opened.

Especially if its a hot summer day and the flap is barely open, its a safe bet its likely failed. I also had the benefit of seeing a bunch of grime/dust pooled up in front of the flap indicating it hadn't been open from its closed position in a long time. Not to mention my air filter always stayed very clean since air was only coming from behind the engine instead of the front grill.