1997 volvo 850 loses engine pressure. replaced fuel pump. car stops moving forward in gear but will idle forward if no pressure on gas pedal.

SYMPTOM 1: ROUGH IDLE IN THE COLD

The engine will not idle smoothly, or it stalls during idle when the engine is cold. When the engine is cold and you take your foot off the gas pedal, the engine runs very rough and may even stall. When you run the engine at higher speeds, it seems to run fine, or at least it runs more smoothly.
Possible causes:

1. If you have a carburetor, you may have a bad accelerator pump or power circuit.
   The Fix: Replace accelerator pump or replace the carburetor.
2. There may be a vacuum leak.
   The Fix: Check and replace the vacuum lines as required.
3. There may be some type of ignition problem.
   The Fix: Check and replace the distributor cap, rotor, ignition wires, and spark plugs.
4. The ignition timing may be set wrong.
   The Fix: Adjust the ignition timing.
5. There may be a fault in the computerized engine control system.
   The Fix: Check engine control systems with a scan tool. Test the circuits and repair or replace components as required.

1. The EGR valve may be bad.
   The Fix: Replace the EGR valve.
2. The engine may have mechanical problems.
   The Fix: Check the compression to determine the engine's condition.
3. Idle speed is set incorrectly.
   The Fix: Set idle speed to the car's original settings.
4. The fuel injectors may be dirty.
   The Fix: Clean or replace the fuel injectors.

SYMPTOM 2: ROUGH IDLE WITH WARM ENGINE

The engine will not idle smoothly, or it stalls during idle when the engine is warm. When the engine is warm or hot and you take your foot off the gas pedal, the engine runs very rough and may even stall. When you run the engine at higher speeds, it seems to run fine.
Possible causes:

1. If you have a carburetor, you may have a bad accelerator pump or power circuit.
   The Fix: Replace accelerator pump or replace the carburetor.
2. There may be a vacuum leak.
   The Fix: Check and replace vacuum lines as required.
3. The fuel pressure regulator may be operating at too low a pressure.
   The Fix: Check the fuel pressure with a fuel pressure gauge. Replace fuel pressure regulator. (This is not really a do-it-yourself kind of job.)
4. Idle speed set incorrectly.
   The Fix: Set idle speed to specs.
5. There may be some type of ignition problem.
   The Fix: Check and replace distributor cap, rotor, ignition wires and spark plugs.
6. There may be a fault in the computerized engine control system.
   The Fix: Check engine control systems with a scan tool. Test circuits and repair or replace components as required. (This is not really a do-it-yourself kind of job.)
7. The EGR valve may be bad.
   The Fix: Replace EGR valve.

1. The engine may have mechanical problems.
   The Fix: Check compression to determine engine condition.
2. The fuel injectors may be dirty.
   The Fix: Clean or replace fuel injectors.

SYMPTOM 3: FAST IDLING

The engine idles too fast. After the engine has run long enough to become warm, the idle speed does not come down to normal. You really notice it when you come to a stop and must have to push ******* the brake pedal to keep the car from moving.
Possible causes:

1. If you have a carburetor, you may have a bad accelerator pump or power circuit.
   The Fix: Replace the accelerator pump or replace the carburetor.
2. The engine may be overheating.
   The Fix: Check and repair the cooling system.
3. The fuel pressure regulator may be operating at too low a pressure.
   The Fix: Check fuel pressure with a fuel pressure gauge. Replace fuel pressure regulator. (This is not really a do-it-yourself kind of job.)

1. The ignition timing may be set wrong.
   The Fix: Adjust the ignition timing.
2. There may be some type of ignition problem.
   The Fix: Check and replace the distributor cap, rotor, ignition wires and spark plugs.
3. There may be a fault in the computerized engine control system.
   The Fix: Check the engine control systems with a scan tool. Test the circuits and repair or replace the components as required.
4. There may be a vacuum leak.
   The Fix: Check and replace vacuum lines as required.
5. You have a bad idle speed control unit.
   The Fix: Replace the idle speed control unit.
6. The alternator may not be working properly.
   The Fix: Replace the alternator.

SYMPTOM 4: STALLING UPON STOPPING

Car stalls when stopped quickly. You are driving along and everything is just fine ... until you let off the gas pedal and apply the brakes. The engine starts shaking and may even stall. Not a good thing to happen because you lose power steering when the engine dies and could risk an accident.
Possible causes:

1. There may be a serious vacuum leak.
   The Fix: Check and replace the vacuum lines as required.
2. There may be a fault in the computerized engine control system.
   The Fix: Check the engine control systems with a scan tool. Test the circuits and repair or replace the components as required. (This is not really a do-it-yourself kind of job.)
3. Broken linkage.
   The Fix: Repair or replace the linkage as required.

Idling issues can be very frustrating, but with some patient troubleshooting, you'll have a real chance at figuring it out. Remember to always check your engine idle with the air conditioning and defroster turned off, as both of these systems are designed to change the idle when they are on due to the air conditioning system's demands on the engine.

It can be low fuel pressure issue or clogged fuel pump.Or its engine related issues,---------------
Check the help link mentioned below to troubleshoot the problem :------

Engine stalls when gas is given?

http://technoanswers.blogspot.in/2012/01/engine-stalls-when-gas-is-given.html

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Car stalls when MAF sensor is connected?

http://technoanswers.blogspot.in/2012/01/car-stalls-when-maf-sensor-is-connected.html

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Car Engine Stalls While Driving?

http://schematicsdiagram.blogspot.com/2011/12/car-engine-stalls-while-driving.html

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Car stalls and throws white smoke from exhaust?

http://repairhelpcenter.blogspot.com/2012/01/car-stalls-and-throws-white-smoke-from.html

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Stalls And Dies At Stop Sign?

http://www.howtobyme.blogspot.com/2012/07/stalls-and-dies-at-stop-sign.html

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GMC Sonoma Stalls and idles low

http://technoanswers.blogspot.com/2012/10/gmc-sonoma-stalls-and-idles-low.html

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Nissan Pathfinder stalls and bucks on Acceleration?

http://technoanswers.blogspot.in/2012/02/nissan-pathfinder-stalls-and-bucks-on.html

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1992 Chevrolet stalls and shutdown?

http://schematicsdiagram.blogspot.in/2012/04/1992-chevrolet-stalls-and-shutdown.html

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Stumbling and stalling at idle after engine rebuild?

http://schematicsdiagram.blogspot.in/2012/03/stumbling-and-stalling-at-idle-after.html

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1990 mazda 323 stalls and quit running?

http://technoanswers.blogspot.in/2012/02/1990-mazda-323-stalls-and-quit-running.html

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2000 Toyota Camry: Idling and Stalling Problem?

http://whatisbyme.blogspot.in/2012/05/2000-toyota-camry-idling-and-stalling.html

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1995 Toyota Corolla: Stalls, Sputters and Pops Through Intake Manifold?

http://whatisbyme.blogspot.in/2012/05/1995-toyota-corolla-stalls-sputters-and.html

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1999 Toyota Camry: Erratic stalling and high engine RPM at idle?

http://whatisbyme.blogspot.in/2012/05/1999-toyota-camry-erratic-stalling-and.html

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Dodge Dakota stalls, stumbles at idle. Has low fuel flow and runs hot?

http://schematicsdiagram.blogspot.in/2012/03/dodge-dakota-stallsstumbles-at-idlehas.html

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1994 Toyota 4Runner: Stalls and Stops While Driving?

http://whatisbyme.blogspot.in/2012/05/1994-toyota-4runner-stalls-and-stops.html

---------------

1997 Toyota Camry: Erratic Idle and Intermittent engine stalling?

http://technoanswers.blogspot.in/2012/04/1997-toyota-camry-erratic-idle-and.html

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Ford Maverick: No Idle and Stalling issues?

http://schematicsdiagram.blogspot.in/2012/04/ford-maverick-no-idle-and-stalling.html

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These details will help.
Thanks.

sounds like the regulator is not doing it's job, but you say starving? Is the engine running lean or rich? Is there black smoke coming out the exhaust? I'm thinking high pressure would normally cause a rich condition.

pull off the fuse box cover under the hood. held down with 4 T25 screws. Replace the red relay.

Hi!

Sounds to me like the engine in fact is getting gas when idleing, but not getting enough air. Therefore my 2 cents are on you IACV (Idle Air Controller Valve). It's a small steel cylinder suspended in a rubber piece on the front of your throttle body, and its job is to supply the engine with air when idleing. This is a necessity since the throttle body valve is closed when the gas pedal isn't pressed. Take out the IACV and clean it thoroughly, also make sure that the air going from it is not hindered by any gunk or deposits on its way to the intake manifold.
(You could have someone hold their hand on the IACV when you take your foot of the gas pedal. If nothing happens it's probably dead or stuck. If something does happen there is still a chance that the air is hindered somewhere).

Good luck, let us know if this didn't help!

your fuel pump needs replace my friends vo does this to

Hey Jruthesq

The 850 is equipped with an Idle Air Control Valve (IACV) which supplies the engine with air when idleing (a necessity since the main throttle body valve is completely closed when no throttle is applied, thus the engine would lack air without the IACV when idleing). The IACV is suspended in a rubber mount on the front of the throttle body itself, and is easily removed and inspected/cleaned. If it's dead a good cleaning usually gets it going again. Also make sure that the air from the IACV is unhindered on its way from the IACV to the throttle body (it's actually common for the holes in the throttle body to be gunked up so bad by hardened carbon deposits that one sometimes needs a nail or even a drill to open it up again).

Just thought I'd mention this since you said that the gas needs to be feathered for the engine to start. When you press down on the gas the main valve in the throttle body opens up, closing the IACV and supplying the engine with enough air.

Oh and if your fuel pump relay is a green one marked 103 you should replace it with the new and improved red one. The relay is located under the fuse box cover under the hood. Remove the 4 torx srews holding the cover in place and you'll see the relays under there.

Good luck mate!

Hi!

You meant a 2.4 litre engine, right?

Check:
- Fault codes from the diagnostics system.
- Fuel pump relay, located under the fuse box cover under the hood. If it's a green one labeled 103 it might be the culprit and should be replaced with the new and improved red one.
- The fuel pump itself, measure voltage to the fuel pump and make sure it's getting sufficient power. Can you hear the pump working when turning on ignition?
- Fuel filter might be clogged up. Located under car, by the right rear wheel.
- Unaccounted air entering through vacuum hoses. Spray them with start gas while the engine is idleing, if engine revs up you've found a leak.
- Throttle body might be in need of cleaning, probably a good idea anyway as it usually gives the engine a tad better performance.
- Mass airflow sensor might need replacement or cleaning of connector.
- If idle is rough check idle control valve.
- Make sure all plugs are firing, engine might be missing one cylinder, causing it to vibrate depending on engine RPM.
- Check that coil is ok.

Your problem doesn't sound like a camshaft/crankshaft position sensor, but you never know. Have the codes read, that'll probably help alot!

Well, that should give you some idea as to where to start checking...
Good luck mate!

Have you changed the fuel pump yet?I had the same exact problem.I replaced my fuel pump with an AUTOZONE PIECE OF JUNK fuel pump.That pump lasted almost 2 days.The second day i had it the truck didnt want to start but it did and it ran like ****,and when i put it in gear it ran as long as I didnt touch that gas pedal.You could go get a fuel pressure test or just replace it,your call.You might want to check your filter too but im sure its the pump.Good luck

I am a volvo tech and your problem is fuel pressure ralated and i had same problem in 1995 850 turbo and the fuel pump was the problem and a used one is around 35.00