ETM problem, S70 stutters at park and idle
 

Hi everyone, can someone please check there 2000 S70, engine on and listen to the etm is it supposed to be buzzing constantly at the built in tps mine is not, I checked my V70 and its buzzing, humming noise the reason im asking is that i get a slight stutter at park and idle rpm drops to 600 and jumps back to 900 stays for a while then again at a stop light very annoying on the S70 the V70 runs great no problems. Im in the process of going thru my coils. Spark plugs have been changed gap at 0.028 used bosch what the manual calls out had oem Volvo plugs in it changed to bosch i did not feel the difference. I also did a fuse test #2 per the Xemodex flow chart and it checked fine.

Thanks for any help

I don't hear any buzzing. I suspect that would mean something is slightly loose and vibrating.

I don't believe .028 is the correct gap. I didn't look it up but when I replaced the plugs they were pre-gapped and if memory serves, not adjustable. But that could be the kind of plugs I used. Like I said, I don't recall the details.

I have a similar issue when stoping, when the gas pedal is released. The rpm's drop like it wants to stall and then goes back to a normal idle. From what I have read it's likely a dirly MAF sensor. It runs ok for now and i'd like a break from fixing it for a little while. As it is it's getting new rear brakes and front brake hoses this weekend (both lines are cracked). Maybe rear hoses too, depending on what i see.

Hi Kwatt, thanks for the response I originaly put in oem volvo plugs which gap is preset i then replaced them with bosch 7955 that calls out on the volvo manual with a 0.028 gap thinking that was my problem. Im in the process of checking the etm, maf, timing marks, and talking to the guys at xemodex to see if my etm is going out. The buzzing on the etm is coming from my V70 which is running great on the S70 i have no buzzing i think that is going out cant spend to much on it right know not working.

Did you ever find out more about that buzzing noise? My car is doing the same thing now. Here's the thread in case it has some helpful information:

https://volvoforums.com/forum/volvo-...s-64943/page2/

Hi Cactuslegs, sorry for the late reply. Ive seen your video and the noise it's the same as both of my cars 1999 V70 and 2000 S70, there was no problem with my etm it was coils so i replaced all of them the car run fine no more stutter.

Glad to hear you're running good again! I ended up changing the MAF and I think that solved most of my problems, although every now and then it doesn't want to start for me. It's weird that the ETM makes those noises even though it is working fine. I wonder what it's doing, lol.

I had talked with xemodex about the etm and that noise is a process it goes through the noise i was refering to was when the engine is on, it was making a buzzing noise on my 1999 V70 which is running fine on my 2000 S70 no buzzing noise which now its running fine. It seems its coming from the built in throttle position sensor. On your starting issue have you checked the fuel pump relay and check your battery cables at all ends make sure there not loose. I had a starting issue on my V70 it was the fuel pump relay.

I have not checked the fuel pump relay, but I think it's okay as when I turn the key, I can hear the pump working for a couple seconds, and I've checked the schrader valve at the fuel rail and it spewed out, so I have pressure. The battery terminals are tight as well. The starter engages every time, just wont crank sometimes, it's weird. I've found that if I turn the key to the on position, then let it sit for a few seconds before attempting to crank it, it will start on the first try. Maybe my fuel pressure regulator is going bad? Since it has to be allowed time to build up pressure maybe? I don't know... lol

Cactuslegs - the relay issue can be intermittent. sometimes the contacts get pitted and fail intermittently. Lots of reasons can cause intermittent failure. Generally, its a high load relay and high load relays tend to do better when replaced on occasion.


You said something interesting... "The starter engages every time, just wont crank sometimes". Are you saying you hear the starter *click* but it won't turn over? Or it turns over and won't start? The fact you say you say you turn the ignition on for a few seconds and it starts every time makes me believe you have a fuel delivery issue.

Thanks for the reply kwatt. That's good to know about relays, I didn't know. I though they were more like fuses, and if they were good, they were good. The engine turns over every time, but sometimes does not start. Sorry for the confusion. I agree with you, it does seem fuel related. I'll probably go ahead and replace the fuel pump relay and the pressure regulator just to see what happens.

I would shy away from messing with the pressure regulator unless it tests to fail. You can easily test it with a fuel pressure tester. The shroeder valve is on the fuel rail. Take off the cap, start the engine and check the pressure. I think its supposed to be around 40 psi - someone wrote it here once.