92 740 lack of power and stalling

Skribb · Post by **Skribb** » 04 Dec 2010, 16:19

just recently bought this thing and was told the fuel pump and pressure regulator had been replaced but for some reason it has almost no power unless floored and stall out when its put into any gear unless you double foot the pedals as it will try stalling when the gas is pushed to take off normally....it attempts to stall at any stop or slowing down to turn aswell and after driving it will idle irradically when put in park ranging from 900 rpms up to 2500 rpsm and stay high then suddenly drop and stall or bounce back up...its non turbo with the regina fuel/ignition system so please dont tell me it has 2 pumps i know it only has one atleast but im out of ideas with it asto the problem i replaced the inline filter and noticed the valve to check the fuel pressure but i have not been able to find what it is suppose to be to try and isolate the problem if anyone has any ideas or knows the issue i will greatly appreciate it even just the normal fuel pressure this is the first volvo i have owned had all chevy and oldsmobile till now so im at a loss

Retired MVS Contributor · Post by **Retired MVS Contributor** » 04 Dec 2010, 19:02

You asked me not to tell you it has 2 pumps, so I won't...The non-pump in the tank has a filter sock on it which I think might be clogged...

Skribb · Post by **Skribb** » 04 Dec 2010, 21:58

i only ask because it has only one pump i have been through the lines front to back and all it has underneath is the inline filter and lines are still factory the only pump in the whole system is in-tank i worked on a 740 turbo years ago with the bosch 2 pump system so about the only thing i know volvo wise is the difference in fuel systems and that the coil is square and on drivers inner fender not round and near firewall if this thing was General Motors i could gut it to bare chassis and put it all back together but its not so im lost i hadnt thought to check the filter on the pump though that will be my next thing to do thanks

Post by **billofdurham** » 05 Dec 2010, 12:10

Welcome to Matthew's Volvo Site.

The Regina system usually does have only one pump in the tank. However, some do have two and conversely some of the Bosch systems have only one.

You say the pump has been replaced recently. So I say has it been replaced with the Regina pump? This is a common mistake. The in-tank pump for the Bosch system is low pressure and the Regina pump is high pressure. The Volvo part number for the Regina pump is 3507736.

Bill.

Skribb · Post by **Skribb** » 05 Dec 2010, 13:39

thanks for the welcome bill,

the previous owner said his neighbor is a volvo tech and did it but who knows how reliable that info is the pump i have from its number is3507436 not sure if its a different brand or wrong all together i have no idea what the pressure is supposed to be normally have looked but cant find an answer its running 40psi currently with the stalling and lack of power i was suspecting the map sensor but no idea where its located chevy was easy to spot this is like brain surgery to me lol.

Post by **billofdurham** » 05 Dec 2010, 15:26

3507436 is the Bosch in-tank priming pump.

The following is from Brickboard:

The Regina fuel injection system uses air pressure and temperature in the intake system to compute the air mass moving into the engine. The MAP pressure sensor is located on the driver's strut tower support. It is connected to the intake manifold through a hose and takes a reading of intake pressure. The sensor is piezo-electric and changes a voltage input to an output signal proportional to manifold pressure. The system calibrates atmospheric pressure when the engine is started and under full load conditions. To test, turn ignition "on" and test the back of the sensor connector or the pins on the back of the ECU connector (do not disconnect with the ignition "on"):
Connector A or pin 6 is ground
Connector C is the constant voltage input from pin 7 on the ECU and should read 5 volts to ground
Connector B is the variable output signal from the pressure sensor to pin 11 on the ECU. Connect a hand vacuum pump to B or 11, apply vacuum, and read the signal. Voltage should drop from 5 volts to a lower number. If it does not drop, replace the sensor.
Problems may also occur in the sensor, the vacuum tube leading to it, the connector, or the wiring leads.

OEM and Replacement Parts. If you cannot find an OEM replacement MAP sensor (Volvo 1378162), look at a parts store for an identical unit for a GM car using the same part (an early 90's GM 3.1 V6, ie. 1990 Chevy Celebrity w/ 3.1): Delco# 213-185; Standard Motor Products AS5; GP Sorensen; Echlin.

Bill.

Skribb · Post by **Skribb** » 06 Dec 2010, 14:36

resolved the problem bad MAP sensor and plugged IAC runs like a champ thanks for all replies