Hi everyone. I am having some trouble again. I have an 86 740 turbo w/automatic and every once in awhile it seems like the car just will not accelerate properly. Its almost like the engine does not want to accelerate past 2000-2500 RPM. It is wierd because the turbo spools up and is really working itself hard trying to move the car. It can barely even make it up hills and it just stumbles all over the place. The other day it got really bad and sitting at a red light, I turned it off. When I started it back up it ran fine, like there was no problem at all. I took it to a shop once before and they said they wanted to change both fuel pumps for the small price of $1,350.00. Needless to say I walked because the car started to run fine again and they were scam artists. I have newer plugs, clean t.b., new air filter, etc.. Basically it is well tuned. It has only 166k miles on it so I do not know where to start. I imagine it is something in the electric. Please help if possible. Thanks ahead of time, Joe.

Hello,

Not sure if you are still having the acceleration problems but here goes.
I had the same problem with my car. I looked everywhere, replaced quite a few parts, brought it to three "volvo mechanics" and continued for months to not be able to solve the problem. I took off the hose that runs from my AMM hose to my PVC valve and it was full of crud! Cleaned it out with a coat hanger and some carb spray and I had my old car back again! It was a happy day!

Best of luck...

Regards,

Anastasia
1986 740 Turbo Wagon 380,000 miles (still original turbo... it can last longer then you may think...)

Thinking about your situation again... check the small hose coupling on the right side of the intercooler that is attached to the long mettle pipe. The underside of this hose will at some point go and will cause a bog down "acceleration hesitation up hills" problem.

Best Regards,

Anastasia
1986 740Turbo Wagon 380,000 miles

Hi-

I have the exact, same problem on my 91 740. If you do a search for "hesistation" in the FAQs and the RWD boards, you will find that we are not alone. Unfortunatly, there are a myriad of things that could be causing the problem: IAC valve, FPR, blocked up cat, timing belt jumped a tooth, fuel pump, and, of course, the ECU.

I'd have a good volvo shop start with the cheaper answers.

I'm just about to put in a new fuel pump and I will post if that's the answer to the problem. Really, though, I'm just in denial about the ECU.

If it's any help, I've found that my hesistation isn't quite as severe if I go easy on the throttle the first few times I accelerate in the morning. I haven't had any problems hill-climbing, though.

BTW- $1300 for fuel pumps seems insanely high. I'd get a 2nd opinion.

good luck
mp

A few things I would check out would be the cat converter-if it is coming apart internally-you would get symptoms similar to as you describe. You should also check the timing belt-to see if it has jumped a tooth. Just a few ideas for you to check out before shelling out money to a shop-good luck

Does it do this with a full tank of fuel? Check on exactly when it does this, the more details the easier it is to track down. If it does it only when the car has less than half a tank and it gets worse the lower amount of fuel you have in the pre pump (in tank fuel pump) is my suspiscion. These little pumps fail and really are only there to pull the fuel from the bottom of the tank, when the tank is full the fuel itself (with gravity's help) pushes it out enough for the car to work fine. Also check to make sure there are no leaks in the sending unti coming from the fuel tank. A pin prick hole could cause these symtpons as well. The metal lines going into the unti rust and unless you tap on them you may not be able to find the leak. Check to see if there's any rust on them. In the trunk (or hatch of a wagon) under the carpet on the drivers side there is a small metal panel with a few screws in it take these out and you will be able to see the sending unit. Use a sealed light as if there is a leak there will be gas fumes in that area. You can also check by pulling the fuse for the pre pump and see if this makes a difference, if there is no difference in how the car runs with the fuse out and it only does it when there's less fuel in the car it could be your pre pump. Soemtimes the strainer on the pick up tube i the gas tank also gets clogged and this could cause it as well but it would more likely happen all the time.