Well my old problem is back on my 740 turbo. It feels like a surge when I press on the gas pedal at times. So I put on these new parts, Both fuel pumps new, used intercooler dealer wanted $1000 for a new one. So one week after putting on the new in tank fuel pump the problem is back. It comes out of nowhere the problem I can be driving fine then out of nowhere the car will surge. but if I turn off the car it turns right on and its ok. Also if I don't turn off the car and if I press down on the gas the car will turn off. So does anyone what can the problem be? FPR? it also has new cap/rotor/wires but not plugs.

 

What do you mean by 'surge'?

 

like when i press down on the gas at certain times fuel doesnt want to go through. the car will not go past 2k rpm

 

I can't remember from your previous posts but did you ever check the car for codes? I ask because I'm having a hard time narrowing this surging problem down to electrical or a fuel problem. On one hand your problem sounds like vapor lock or fuel starvation, but then again it doesn't because you say it will run fine after you shut it off and start it back up. Have you changed any other parts then what you listed? If you have no codes I would look deeply into the fuel system for a blockage or a leaking fuel pressure regulator, have you investigated those items?

Dale

 

I offer some ideas to look into if nothing else...
Evaluate the condidtion of the air mass meter and the connector to the meter's integrity. With that make sure there are no leaks in the air intake assembly, and in regards with leaks, check for vacuum leaks. Evaluate the condidtion of the engine grounds, close to that check the ignition switch and the fuel pump relay. Last will be to check knock sensor and if there are codes or not stored in self-diagnostic tool in the engine compartment. If there are codes, well there you go, could be ECU failure. Hope all goes well.

 

I do have a cel light on, but I am pretty sure its cause of the speedometer. Speedometer doesn't work. But I can check at autozone thanks.

 

I don't think autozone checks OBD1 vehicles. You can check them yourself, do you know how? If not go to this thread https://volvoforums.com/m_49285/mpage_2/tm.htmand it tells you how to do it then let us know what codes you have. Your speedometer signal code (311) will not turn on the CEL. At least it didn't on mine when I pulled that boneheaded stunt of starting my car with no instrument cluster...

 

I just tryed to get the codes and it didnt work. all it did was flicker in port2 when i put the car to on. I didnt start the car.

 

Hmmmm, I'm not sure what the problem is. You should be able to get the codes with the line plugged into port 2 and 6. Make sure the socket and the plug aren't corroded and that there is a positive connection when you put it into the port. It should work kruspe, give it another try with clean connections and only hold the button down for 1 to 2 seconds.

 

I didnt hold down the button just pressed it. And I am pretty sure I am the only person to test it this way on my 740. Cause its very clean. Its dark now, tomorrow I will do what you said and hopefully it will work thanks.

 

Well I just came back from the car and it still didn't work. I held down the button for 1second, then 3seconds same thing. I even put it in hole 2/6/5 still nothing. I am about to take an axe to this damn car!

 

Hopefully tech will chime in here but I can't think of a thing that would cause your OBD1 to not work. Well one such thing does come to mind and that's a faulty ECU, but I don't know if these ECU's go bad occasionally or not. We could certainly start shotgunning the problems but it sure would be nice to have at least a little direction as to what the ECU is faulting. I would wait to see what tech has to say before you go any further with this in case he thinks your ECU is at fault too.

 

You probably got it already, but for peace of mind...

To check to see if codes are stored in the diagnotic unit, since no MIL codes regester as present on dash,
do as follows:
-ignition switch(driver's car key in ignition hole and turned to "on") to "ON"
-place plug in socket 2 for fuel injection system and/or socket 6 for ignition system
-press the button, no more than a few second, one second ought to do it
-watch for the LED light, the blinking of this light will indicate fault codes(MIL)
-if there is no fault code in the particular system you are checking the LED will flash once, then a brief pause, flash again to another pause of the same length of time, then flash a third time. This code of "1-1-1" indicates there are no faults stored. The number of flashes per interval will indicate the number for an MIL code...one flash = 1, two flashes = 2, three = 3. This means you should see a first light-up of the LED, if it flases once that's a 1, then a two second or so pause then another flash should occur, followed by another pause and the third should show up. [One flash -pause- one flash -pause- one flash] = 1-1-1...[Three flashes -pause- one flash -pause- one flash] = 3-1-1...[One flash -pause- two flashes -pause- one flash] = 1-2-1.

That should be sufficient in extended notations via text to properly evaluate the faults. Hope it helps.

 

tried it again and it still doesnt work. I heled down the button, pressed it still no dice.

 

How new is the Mass flow sensor?
How new is the fuel pressure regulator?

Try removing the engine computer and leaving it unplugged for a few minutes and reconnect and try to read codes.

 

I dont know about the mass airflow sensor nor the fuel pressure regualtor. What tools would I need to remove the ecm?

 

You will need a T-25 maybe a T-30.
It is located under the dash under the kick panel on the passenger side.

 

well i just got back from the car. I pulled the maf out and started the car, it started up then died right out. plugged it back in restarted it and was fine. the fuel pressure regulator looks orginal but the hose that goes from the throttle body to fuel pressure regulator looks not that old. Took the car around the block drove fine, but it has done that in the past as well, but it was also warmer this afternoon.

 

I was reading when you disconnect the maf and start the car and if it doesn't idle then the maf is working. Well that happened yesterday so since thats working, maybe its either the fuel pressure regulator or the ecm?

 

If the mass flow is bad and you disconnect and it runs it is bad.
It should run with it unplugged either way.