1993 940 Turbo - Issues accelerating beyond 40mph

[krs0305]

Hi,

My 1993 Volvo 940 Turbo wagon has suddenly begun to have some issues when accelerating on the freeway. It has approximately 219,000 miles on it and as far as I can tell has been cared for regularly. (I am the fourth owner and bought it one year ago). I put in a new battery last fall. Please note that I am not a regular driver... I put about 8,000 miles on my car this year and pretty much only use it on the weekends or for short trips around the city during the week.

So... my issue is that a couple weeks ago when we were getting on the freeway, it was having trouble getting up beyond 40mph. While trying to get it to go faster, we would press lightly on the gas, and the RPM gauge would go up to 3500-4000 while still going at 40mph. Then after about 5 minutes of driving at 40mph (with emergency lights on), it would suddenly 'kick in' to the higher gear and cruise at 60-70mph no problem. It did this twice -- on the way to our destination and on our way back (the car was parked for about 2 hours inbetween). Both times after we had the initial issue of it being stuck at 40mph and then kicking into higher gear, after we got to 60-70mph it had no problem again.

Then this happened again last week. So I took it to the auto mechanic (one that I have had a good experience with before) and explained what happened, and suggested (pulled out of my , really) that they look at the timing belt and starter solenoid boxes as well as any transmission issues.

So then the auto mechanic called me up and said all they could figure out was wrong with it was the transmission fluids were low and coolant also. They topped off the transmission fluids and coolant. I felt pretty silly... paying $100 for that 'diagnosis' but whatever.

However, the problem still remains. We have tried to drive the car a few different times and it still has the same issue... once we get on the freeway and try to accelerate we are stuck at 40mph or so with the RPM going up to 3500-4000, have to turn on the emergency lights, and then 5 minutes later the car will suddenly kick into gear and we can drive at 60-70mph no problem from then on. We never have this issue when the car is 'warm' (like after we have just gotten off the freeway and filled up gas and then gotten back on the freeway), but we will have this issue when we start the car again after it's been parked for a few hours or more.

Anyway I plan to take the car back to the mechanic and have them do more tests on it to try to diagnose it.

Does anyone here have experience with this kind of issue and have an idea of what it could possibly be? I am thinking it is not really safe to just accept the car is like this and do the whole 40mph for 5 minutes, turn on the emergency lights, then wait for it to decide it wants to kick into 60-70mph.

Thanks a lot. As you can probably tell I am not very experienced with car repair and issues so any advice is appreciated.

[lummert]

Sounds like a boost leak. Check all the hoses and hose connections between the turbo and the throttle body for leaks.

[shegarty]

Could also be a stuck overdrive relay or solenoid which will not let it shift into the higher overdrive gear. The relay is an easily replaceable plug in part. The solenoid can be modified fairly easily with a dremel or you can purchase a kit from iPD. Both fixes are easily searchable on the forums.

[lummert]

Before I learned my 1988 760 Turbo w/AW71 had an overdrive I was driving without the overdrive. I noticed that the rpm's were a bit high and the one time that I drove on the interstate doing 65 mph the engine rpm's were kind of high. I probably drove without overdrive for just about a year. Then I installed an IPD overdrive bypass plate.

The overdrive doesn't come in until about 35-40 mph even when at operating temp. Have you tried driving faster than 40 mph to get it to shift into overdrive?