Hello, I am new to this forum. I’ve enjoyed and found many enlightening posts with great information in the short time I’ve been using the site. Years ago I owed a P1800 w/electric OD. Was an awesome car. I think it had 230,000 miles on it when I sold it, still ran great. Currently I have a 2001 s60 with 173,000 miles, that I inherited from my niece. I have resolved several problems after reading many of your previous posts. But now I am not sure where to go with the current problem. The engine has a replacement Xenodex ETM. It starts fine idles perfectly but when placed in gear it will not rev above 1000 rpm until it has warmed up. After that it will accelerate very slowly in sporadic spurts, once you get rpm above ~ 2000 rpm it starts to rev more rapidly. I have a code reader that is specific to Volvo and can monitor engine parameters. Once car
is up to highway speed cruise control will maintain speed on most fairly level roads, hills cause serious downshifts and engine revving to maintain speed. I have monitored O2 sensor,
MAF, Manifold vacuum, timing advance, knock timing retard, and injector time. O2 reads .73v @ idle, .02-.05v all other rpm’s (way lean). Checked fuel pressure ~ 50psi steady (gauge reading no sensor model), timing is all over the
place -5 deg to 36 deg coasting down hill. Retard 0 to 20 deg. The most confusing though is injection time, most of the time when cruising it registers 0 us(micro seconds) but under hard acceleration it jumps from 0 to 10,000 us (10 milliseconds) for a second or two then back to
0 then back and all over between 7,500, 9300. But never stays always constant. I removed the ECM and checked for broken solder joints none noted. I’ve checked throttle position desired vs actual and they appear to correspond. MAF and manifold pressure register as expected. Any guidance you can provide would be greatly appreciated. To dated
I’ve replaced plugs, one bad coil pack, resolved one major vacuum leak(disconnected hose causing stalling and starting issues). Such a nice car but the acceleration issue is major hazard when crossing roads or entering highway from a crossroad. Thanks for any help. Ed

 

How old is the ETM? I have heard of the xemodex ones going bad. And I believe they have a great warranty. Give them a call.

Another place to look would be the engine temp sensor in the thermostat housing. On a personal car I replaced one on just a guess out of frustration - I had no data to show it was bad but it fixed the poor running when cold! (I hate swapping parts, that's just not how I fix cars, for I can't justify charging for uneeded parts to a customer) If you replace it I would suggest using only a volvo or the OEM part.

 

Thanks I will look into both suggestions. Much appreciated. I’ll let you know what I find.