Is this a fuel problem? 1984 Volvo 244 b23f m46

Dustin240 · Post by **Dustin240** » 06 May 2017, 13:39

1984 volvo 244 b23f m46
Okay so im new to the forums and i need help i would usually never ask for help but im stumped on this my 84' volvo 244dl does not want to run on start up it shutters/jumps and sometimes stalls i try to solve the promblem by giving it a little throttle and the pedal just goes to the floor with no reaction like the throttle cable isnt even connected but once i let it run in that horible manner for about 5-6 minutes until warm idle will stablize and throttle response comes back and im off for a drive, FPR checks out MAF clean long before this issue, TB cleaned, pumps and relay seem to be okay, i just dont know. Help please

93Regina · Post by **93Regina** » 08 May 2017, 20:33

Dustin240 wrote: ↑06 May 2017, 13:391984 Volvo 244 b23f m46...does not want to run on start up it shutters/jumps and sometimes stalls....5-6 minutes until warm idle will stablize and throttle response comes back and im off for a drive,

Generally, this suggests there is not enough fuel entering cylinders, or too much air entering cylinders.

This might suggest your IAC is stuck open, maybe too many air leaks (intake mainifold, injector o-rings shot, tubing sucking air, or clamps not secured, etc.

So, pull the vacuum hose off of Fuel Pressure Regulator, and start it cold, and see what happens.

Dustin240 · Post by **Dustin240** » 09 May 2017, 13:11

same results

93Regina · Post by **93Regina** » 09 May 2017, 21:59

Dustin240 wrote: ↑09 May 2017, 13:11same results

Possible reasons:

1. Lower fuel pressure...due to pump(s) or FPR bypassing

2. Vacuum line sucking air...or maybe brake-booster's bladder is busted (so, unplug its line at intake, and plug intake hole there)

dougburgy · Post by **dougburgy** » 15 May 2017, 14:19

Just shade tree mechanic here....but I'd say if you had serious vacuum issue or low fuel pump pressures (pre or main) you would have issues all the time, not just at start up and warm up. At least some issues when you "go for a drive". Do these have an inline fuel pump check valve? If not, while sitting you might be going down to zero psi in fuel rail. Then...you have to wait for pre and main pumps to do the job of getting fuel back up to pressure for injectors to function properly, etc.

Also, how's basic tune up state? new plugs? new wires? New cap and rotor? Things inside the dist cap nice and clean/dry?

lummert · Post by **lummert** » 15 May 2017, 15:15

dougburgy wrote: ↑15 May 2017, 14:19 Just shade tree mechanic here....but I'd say if you had serious vacuum issue or low fuel pump pressures (pre or main) you would have issues all the time, not just at start up and warm up. At least some issues when you "go for a drive". Do these have an inline fuel pump check valve? If not, while sitting you might be going down to zero psi in fuel rail. Then...you have to wait for pre and main pumps to do the job of getting fuel back up to pressure for injectors to function properly, etc.

Also, how's basic tune up state? new plugs? new wires? New cap and rotor? Things inside the dist cap nice and clean/dry?

Low fuel pressure caused at least one stall on cold start up on my 1988 Volvo 760 Turbo wagon. I was experimenting with a 2.5 bar BMW fuel pressure regulator.

93Regina · Post by **93Regina** » 15 May 2017, 20:07

dougburgy wrote: ↑15 May 2017, 14:19....but I'd say if you had serious vacuum issue or low fuel pump pressures (pre or main) you would have issues all the time

Open Loop and Closed Loop are two different states...in Closed Loop operation, ECU can compensate within its design parameters.

At startup, cold, symptoms suggest extra air, or low fuel pressure..."does not want to run on start up it shutters/jumps and sometimes stalls....5-6 minutes until warm idle will stablize and throttle response comes back and im off for a drive," which suggests it runs better in Closed Loop.

dougburgy · Post by **dougburgy** » 15 May 2017, 20:41

Makes sense. If when cold these are in open loop and ecm looking for info mainly from maf, coolant temps, etc...extra air from someplace else sounds like it could really mess with fuel/air ratio. But enough to keep if from starting, jumping, stalling? Must be a nice size leak. Does sound like lack of fuel...and he said fuel pumps seemed to be OK. That is why I was thinking starving due to something else in fuel system like clogged up fuel filter, bad post-pump check valve (allowing pressure in rail to bottom out), etc. Please let us know what you find out.

93Regina · Post by **93Regina** » 15 May 2017, 22:51

dougburgy wrote: ↑15 May 2017, 20:41Does sound like lack of fuel...

Also, the thermostatic flapper valve, if still intact, will stick in "heat mode" when defective, so, as engine warms, the air density decreases, which means less fuel would be required, but AMM should detect this, until it is destroyed.

Without specific tests being performed, these threads can go round, and round.

Btw OP, I've got a LH 2.2 AMM and ECU (Auto), and even Chrysler Box

dougburgy · Post by **dougburgy** » 15 May 2017, 23:40

and round and round

But....good to throw things at them to look at and research further. PO gutted my thermo flapper before I got my 242. Doesn't bother me a bit. I'm in Oregon, so pretty mild. Plus car is garaged. Those can stick open, or closed, depending on when wax plunger thingy goes bunk...causing some very odd symptoms (and possible damage from overheating, etc)