Ok so I have a problem with a 86 740 GLE i picked up for Four Hundred dollars. Body is Clean and so is interior. So I bought it. It wouldn't run when i first bought it. The people I bought it from said they put 2K into it trying to figure it out. first thing I checked was the Fuel Pump Relay. That was it Ran great. Now I am haveing this problem when i leave a full stop or let the idle drop back to regular when i hit the gas again, light or hard, it acts like it looses all fuel pressure then it comes back. Just the other day it wouldn't start at all. So I started going over the possible problems Fuel Pumps weren't working so i Pop my Old relay in which is open now and manuely close the circuit got nothing so I checked the Fuse it had gotten so hot in the past that the plastic on the fuse had melted to the block so when i pulled it out the metal prongs of the fuse where still in the block (this is when i found out the fuse had melted). dug out the old plastic and stuck a new fuse in pumps worked but weren't pumping. Replaced the Main Fuel Pump (when i had the line off i turn the pumps on and internal pump was pumping fine. about a gallon in a minute or less.) Runs now but still have the problem with the seem to be the momentary lose of fuel to the injectors. Checked with a few Mechanic friends and found out there are no DTC's with this thing all symptom diagnostics looked further told me to check TPS, O2, Injector Control Unit and Air Flow Meter. Sorry the story is so long but wanted to give all the info i could. any help would be a great help.


James

 

Are all of the regular maintainance items up to date, plugs, plug and coil wires, distributor cap and rotor, cleaning of throttle body and idle air control valve, fuel filter, air filter, battery maintainance etc?

 

umm the coil is new the wires are new the filter i'm not sure about. Had clean gas comming out both ends when i did the fuel pump. Throttle body probably not, idle air? where is that? air filter went looking for one tonight thinking Wal-Mart might have one(ya right). Battery is fine cranked it over alot trying to get the fuel pumps workling again no problems there. I did have to fix the vaccum line to the brake booster hose was cracked and check valve was sticking. The only other thing i forgot to say was that the check engine light comes on for about 2 minutes then shuts off. sometimes if i leave it sitting at idle for to long it's like the main fuel pump stops working it will idle but when i hit the gas it tries to stall but stay running. wish i had a video or sound track of what it does Might help you understand a bit more. :shrug: i'm trying to get the thing working ok so i can let my fiance drive it. Thanks for the reply. I'm glad to see this forum is Active.



James

 

It needs to have the throttle body and idle air control valve removed and cleaned, and flame trap service if it has not been done. The way the pvc systems are set up on these cars, the throttle plate and IAC's gum up, and drivability problems will ensue. While you are in there, check the plastic air intake tube that attaches to the throttle body for pinholes and splits. Any extra air entering after the AMM will also cause problems. Check one of the previous post, and it will explain where the IAC is, and how to clean. A good auto parts store that stocks import parts, like NAPA, should have an air filter.

 

I really appricate all the Info and suggestions. cleaned the Throttle body on the car. didn't think to take it off. I also used full strength Carb Cleaner. [&:] it still runs fine till it stalls or, like what happened tonight, sputteres. went to one of your other posts and find a link to a website called Volvo Owner Club? anyway they had FAQ's in there and came accross one about the FPR same symptoms i'm having just mine aren't as bad. i'm going to do the test tomorrow and see what I come up with.

Two quick questions as well. There is a screw on the bottom side of the throttle body that is adjustable by hand. I'm wondering what it is and it's purpose. the other thing is it seems like I can't get the car to idle at 1200 rpm (sound confuseing) what i mean is it either idles or even when i put the slightest pressure on the gas peddle the RPM's jump to 1600. Is this a problem?

Again thanks for the help so far. It did need the throttle body service...

 

Usually when an FPR goes bad, it will run rich, belch black smoke etc. The black screw is for initial base line idle adjustment, when the IAC is out of the circuit. Will not do any good to mess with it until the other problems are sorted out. Sounds like the thing is sucking major air somewhere ( vacuum leak, bad intake manifold gasket, stuck IAC), or the throttle position sensor is mis-adjusted/bad, or both. It should idle at around 750.

 

It was the FPR did the test and nothing was getting by it. so i pulled the one off my 91 GTI and stuck it on the volvo. it's running great now.
The other stuff could still be off i'm not sure. need to find out how to check or if I have to take it to a Forgein Mech. or the dealership.