I have a 1990 240 wagon with 108k on the odometer, I'd guestimate 122k actual miles as the odometer broke sometime last year. I've owned the car for about a month, replacing the odometer gears a high priority when the weather allows.

Whenever I start it in the morning it'll spark instantly but then stall unless if I give it a bit of gas. Once the cars running its just fine, idles a little odd with a light "groan" with light rpm sparks, but the car never stalls nor hesitates. Has a slight "bog" if you tap the gas.

I've replaced a faulty Fuel Pressure regulator, cleaned the MAF a little, tested for engine codes (both ports result 1-1-1), ran some Techron, and tested the fuel pumps. Primary pump buzzes to life, trying to find a way to test the inner pump.

I still need to clean the IAC, inspect the injectors, inspect the TPS timing, and Throttle body, cold weathers being a bit of a burden though.

My question is where do I start? Should I fiddle with the IAC first? The TPS? What fuse links to the inner pump?

Or should I just trade it for a less "quirky" 940?

 

to test the 240 fuel tank pump, remove the fuel tank fuse (I believe its fuse 4 on a late model), and use an alligator clip jumper wire to connect the left side of the clock fuse (fuse 8) to the RIGHT side of the missing fuse 4, with the car turned off, this powers the in-tank pump. open the gas cap and you should hear it humming.

if you REALLY want to test it, jack the car up, disconnect the fuel line that runs from teh gas tank to the main fuel pump, and stick it into a fuel-safe bucket or jug, and do the same jumper trick, and gas should come out at a steady rate.

 

I would start by cleaning both the IAC and the throttle body. While you have it out, check the IAC to ensure it opens and closes properly and does not stick. Then properly adjust the Throttle Position Switch.

Regarding how to check the in-tank pump, check out this link:

In the Tank - 240 Volvo Tank Pump and Sender

I really doubt that the in-tank pump would cause any of the symptoms you describe but it is worth checking out just to keep your main pump healthy.

 

I thank both of you for the swift advice on the fuel pump

To me it seems like theres some slack in the accelerator pedal, certainly needs the linkage tightened up. When the cars cold it idles a bit low so I think that something else may be out of adjustment.

My father has a nice garage so when I can I'll spend a good weekend cleaning up everything and adjusting everything back to factory specs.

Replacing the fuel regulator has helped stabilize the idle a bit, I just hope that I haven't harmed anything driving the car like this.

 

first, make sure the idle switch on the side of the throttle body is engaging when the throttle is at idle, and disengaging as soon as the throttle moves more than a hair.

2nd, make sure there are NO air leaks in the intake path between the MAF and the intake manifold, including any and all vacuum hoses.

3rd, clean the throttle body and idle air controller valve.. while removing the idle air controller for this cleaning, inspect its two hoses, if either is a bit cracked or crunchy, replace them both.

4th, the ignition system should be in good baseline condition (good spark plugs at the correct gap, quality spark plug wires (Bougicord makes the ONLY good spark plug and coil wire sets for these cars), good distributor cap and rotor.

finally,there's an idle adjustment procedure... you fully warm up the motor, switch off all extra accessories (fan on 0, no AC, no stereo, no lights), and unplug the idle air controller's electrical connection, restart the car, and it should idle at 500-600RPM, there's a screw on the throttle body you adjust for this. then when you plug the IAC back in, the idle should be strong and stable at 700-750rpm, adding a load to the engine, like putting the car in gear, the idle might dip for a blink but should pick back up to 700rpm. a cold engine should idle higher, like 900-1000 rpm until it starts to warm up, then drop to 700.

after disconnecting the idle air controller and doing this adjustment, the LH2.4 system will probably throw a 'check engine' fault, display and clear any error codes on the OBD diag box to clean this up.

 

I don't think its engaging, the idle switch definitely needs to be adjusted along with the throttle cable.

Between the airbox and MAF one of the plastic pipes was cracked from installing a new air filter, I plan on getting a new pipe next junkyard trip. The cars had trouble starting before the new air filter.

Plugs, rotor and wires are fresh, I believe we used Bosch but I cant recall atm. Batterys brand new.

I'll follow those instructions, hopefully this weekend I'll have a tachometer for this. Again thank you for the help, I'll let you guys know what happens once everything's sorted out.

 

ok, if the plastic pipe is cracked, don't even bother to do anything else until its replaced... intake air leaks raise hell with low RPM performance.

 

oh, and re: tachometer, if you have a digital volt meter that has a 'frequency' ("Hz") setting, hook it up to ignition coil pin 1 and ground... the coil fires twice per turn of the engine, so take the frequency in Hz and multiply by 30 to get RPM. 23 or 24Hz would be about 700 RPM... 20Hz would be 600RPM.

 

If anyones selling that pipe I'll buy it, anything less than the crazy ebay prices.

I need to get better about not cracking them when I'm replacing air filters.

 

wait, I misread... if its the airpipe between the filter and MAF thats no big deal. its the one between the MAF and the intake manifold thats critical.

 

Alright, I'll just tape the broken one up then for now.

 

I dug up a spare pipe for between the airbox and MAF, I'll probably replace it when I get around to taking off the TB.

 

Seems like when its getting to be a bit more stubborn each try, outside temp doesn't make a difference.

It sparks and starts immediately for a second but then sputters out, as far as I can tell whatever triggers the car to idle isn't triggering, so I have to keep a light foot on the gas to keep it going.

When it stalls I can hear a "mechanical gasp" of sorts, sometimes the engine will make a small shake. Once the cars idling though it will run all day. After driving it for a bit and shutting it off to go shopping it'll stall unless I give it gas, engine temp makes no difference. Though fussing seems to get it going!

With the new Fuel Pressure Relay the idles smoothed out a bit, less weird groaning. Been doing some country drives to clean out the carbon so it'll drive and idle terrific once I get it going.

I took a look at the outside of the TB and its pretty gunky at the back, probably a dark cave in there, hopefully this weekend I can get everything cleaned up.

I hope all of ya have a Merry Christmas!

 

I've got most of the hoses removed, should I disconnect the battery before I remove the electric bits?

Also, before doing any work, I put the computer into DTM 3 and got a code for 1-2-1, it wasn't reading from the AMM.

One of the hoses that goes to a tiny nipple on the TB has a small hole in it too, I'll take care of these after I've cleaned up the IAC and TB.

EDIT: The throttle is adjusted properly, barely moving it with my hand causes a loud click.

 

Just adjusted the throttle a tiny bit, sprayed the Throttle Body a bit (need to get a new gasket before removing it), sorted out one of the tiny hoses that goes to a "nipple" on the TB, and cleaned out the IAC quite a bit.

Initially the car still wouldn't idle, a few small adjustments of the throttle and replugging the AMM in seemed to help it, runs much smoother now. Hopefully it will start up right tomorrow.

I did read somewhere that a defective speedometer signal could cause the ECU to not idle the car, and the plug or something behind my speedometer needs sorting out, only works when its hot.

Could a failing speedometer cause the car to not idle at start-up?

 

speedometer is not connected to the fuel injection or ignition computer on LH cars. idle is entirely a function of the idle switch in the throttle body, and the timing pulses coming from the crank position sensor.

 

Thats good, if it bugs up again I'll have to see if theres a way to troubleshoot the CPS.

 

inspect the wire to it. thats what usually goes bad, not the CPS sensor itself. its hidden between the head and the firewall, stuck into the top of the bell housing, so its hard to see.

out of the car, it looks like this,

 

The speedometer signal is used by the ECU on LH2.4 systems and it DOES affect the idle. However, symptoms are not a rough idle. Instead you may get stalling when coming to a stop. This is very easy to diagnose as it throws a 3-1-1 code.

 

I haven't got either of those so I guess the speedometer or the speedometer sensor are sending signals.

Theres a cable above the throttle cable which you can adjust with your hand, I'm trying to figure out what exactly it is. Tightening it makes the car start instantly but the idle surges briefly, calms down after a little gas. Loosening it just makes the car stall when I try to start it up.

I may have an air leak somewhere causing that surge, once the cars driving it never surges nor does anything abnormal.

As far as the CPS wire goes I'll poke around and get a good look at it, when I got the car the engine bay was pretty filthy so that CPS wire could be dirty.