jschaefer7406 Posted May 29, 2013 Report Share Posted May 29, 2013 Hello all, Being it's been warming up here lately, been using the A/C more in my '00 S70 AWD. Noticed that the car surges when the compressor cycles, almost like the throttle is overcompensating for the increased load. Surge can be noticeably felt on the highway and can also be seen on the boost gauge. I'm not talking about the normal vacuum change of 2" or so when the compressor cycles, I'm talking about a more harsh reaction. Car is tuned (16T & blues), but has been since '09 and never had this issue before. That in mind, I don't think it's related... Not sure if it's related, but I'm still experiencing the vacuum oscillation from my previous thread as well: Thoughts? Have tried a spare MAF, tried searching for vacuum leaks with carb cleaner, etc. ETM was replaced in August with a new Volvo unit, not sure what else to try . Thanks in advance, Joe Link to comment Share on other sites More sharing options...
rbodor3 Posted May 30, 2013 Report Share Posted May 30, 2013 You used another new Volvo ETM, not the xemodex unit? Still could be the ETM. Sounds to me like the ETM or MAF. You noted the MAF was a "spare" - I assume you don't keep NIB MAFs lying around, which means this "spare" was used. Can you validate it works correctly? Link to comment Share on other sites More sharing options...
jschaefer7406 Posted May 30, 2013 Author Report Share Posted May 30, 2013 You used another new Volvo ETM, not the xemodex unit? Still could be the ETM. Sounds to me like the ETM or MAF. You noted the MAF was a "spare" - I assume you don't keep NIB MAFs lying around, which means this "spare" was used. Can you validate it works correctly? Thanks for the response. Yes, Volvo ETM right from the dealer. I got too good of a deal to pass up on the OEM unit, may do Xemodex next time around . The vacuum oscillation occurred with the good used ETM as well (was dated 2010), so it'd be hard to imagine all 3 ETMs had the same issue (including a new one). Not saying its impossible, just lower on my list. As far as the MAF, it was a used unit bought from a SS member who parted a '00. Could be bad as well, may try swapping the air box lid from the Wife's old XC and see if it acts the same way. Thanks, Joe Link to comment Share on other sites More sharing options...
burnout8488 Posted May 30, 2013 Report Share Posted May 30, 2013 There is a little vacuum hose on the very left of the intake manifold (where the banjo bolt connects underneath) that slips on to a hard plastic PCV line. I always forget about it, have you verified it is connected? It's the only non-obvious vacuum line that isn't very accessible Link to comment Share on other sites More sharing options...
Kevin. Posted May 30, 2013 Report Share Posted May 30, 2013 I have this issue with a non ETM car......interested to see what the dealio is Link to comment Share on other sites More sharing options...
jschaefer7406 Posted May 30, 2013 Author Report Share Posted May 30, 2013 There is a little vacuum hose on the very left of the intake manifold (where the banjo bolt connects underneath) that slips on to a hard plastic PCV line. I always forget about it, have you verified it is connected? It's the only non-obvious vacuum line that isn't very accessible Have looked with an inspection mirror as well as I can see, but haven't pulled the intake or anything. Also have verified PCV health, have good vacuum in the system @ idle... Though about swapping the intake gasket (since its cheap and easy), but the manifold has never been off so THEORETICALLY it shouldn't be leaking, right? Good info, keep 'em coming Joe Link to comment Share on other sites More sharing options...
burnout8488 Posted May 30, 2013 Report Share Posted May 30, 2013 Every time your posts get bumped I keep brainstorming new things! Hopefully a solution comes to the surface soon... When you did the carb cleaner test I assume you sprayed right at the intake gasket mating area? Would make no sense that it would start leaking but I suppose stranger things have happened... Link to comment Share on other sites More sharing options...
jschaefer7406 Posted May 30, 2013 Author Report Share Posted May 30, 2013 Yeah, sprayed everywhere between the intake and head... Seems to have a slight exhaust leak, as I saw a good bit of smoke when I Seafomed the car back in December. Technically, I guess an exhaust leak could mess with the front O2 readings and cause issue, but it seems far fetched. ME7 is so finicky with O2 readings that I'd suspect a code if that were the issue, but who knows Joe Link to comment Share on other sites More sharing options...
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