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My good lady arrive back at lunch time to report that the old faithfull 240 ES 1993 B200 LH 3.1 ( one of the last ) ran very rough after being parked for 10 minutes. Then it cleared and was parked for 2.5 hours and again ran very rough and jerky would not pull but eventually cleared and she drove home the 15 miles. I have tested all sensors, no fault codes and checked all fuses as these are always prone to corrosion. Wnet for a run but car playing up and dose not clear. Suspect fuel pump but it is running anthough the current it takes 3.5 amps at first falls to 1.6 amps after 1 minute, high pressure pump appears noisey but is running. Gave up for today but will have to do pressure checks tomorrow. Anyone any other sugestions what I sould check. I did note that the idle was being controlled although the valve tests Ok resistance wise at 8 ohms and there is a 12v feed. Thanks Guys
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peter if the fuel pump under the car sounds noisy it could be the tank sender unit ,there is a little filter on the end of it (in the tank)and an electric pump in the tank which does go wrong (often a faulty earth),had this once on a 740 of 1990 vintage
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After fuses, the fuel pump relay is always the prime suspect. The soldered joints corrode.
Bypass the relay by jumping fuses 4 to 6 (I think - check in Haynes) so that the pumps run continuously. Then check for running. Disconnect the main pump and listen at the fuel filler for the in-tank pump running. If not, the car will run but the other pump works overtime, and may not cope especially if the tank is low.
Other points might be the fuel pressure regulator on the injector rail. Pull off the small vacuum pipe and sniff for neat petrol - there shouldn't be any.
Check the condition of the wiring on the Crank sensor on top of the bell hosing - notorious for crumbling after about 10 years.
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Update: (Correction meant B200F.) The in tank pump was at fault thus the very noisy cavitating HP pump. After a lot a hassle I replaced the pump and all was well, though I, however whilst checking the ECU codes it flaged a missing Idle Control Valve problem, I checked the connector and discovered a green pin ( mould ) cleaned it up and replaced the connector, cleared the code and ran it again. Same problem but no error codes. It now appears I have lost the return pull down line to the ecu although if you measure the voltage across the pins it measured 11 volts open cct there is no current drive capability or the ECU is not requesting the control thus the tick over is all over the place and strange flat spots when driving. I will check some more today but I'm starting to think there is more to this than meets the eye as this valve is only used at tick over and is closed during normal driving. Any ideas welcome. If anyone has this version i.e. 1991 to 1993 the last made, can anyone tell me the impedance looking back pin the connector to the ecu, it's upper pin in the connector as it is removed. Or does someone have this value as a spec on the ECU. Long shot I think. Thanks, Regards Peter
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Where can I get my hands on a Bosch ECU 0227 400 176 3 531 830 circuit diagram. Who else supplies Fuel Tank Sender Units for Volvos. Regards Peter
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peter look at www.gsfcarparts.com/ and you will find your pump with a bit of searching.
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Although I have this model I'm sorry I can't help with ECU pins and voltage measurement - I've never understood which pins I should be measuring across, or even which shiny box is actually the ECU!
But all the rare troubles I've had, like yours, have in the end been down to corroded connectors, fuses, relay, or peripheral things like the Crank sensor or the Idle Air Valve.
I take it you have cleaned out the IAV? I find it carbons up pretty quickly, as does the Throttle Body and flame trap.
It is easy to clean with a small brush dipped in petrol, and you can activate it a few times direct on a battery to check for free action and proper closing. I know immediately when it is coming due for cleaning because the engine starts to idle at 1000 rpm instead of 800. When really dirty the engine idles erratically at 1500, or sticks at high revs during gear changes.
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Peter,
I'm almost certain that you will have checked this, but;
Are you sure that the throttle position switch or potentiometer (I don't know which is fitted to your car) is sending the correct signals to the ECU? If the throttle cable is sticking, or the switch/sensor is failing, the management system won't engage the idle control as you mention above.
Number_Cruncher
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Thanks guys, been busy today but more tests tomorrow. However the main dealer has confused me by telling me the O227 ecu is the main fueling ecu, it is not the main one is an 0280 000 949 and I may need a replacement or get this one repaired. Regards
Peter
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Check the sytem out after repaint the in tank fuel pump and I am concerned that the O2 sensore is very Slow to react. Although the voltages look good it cycles very slowly like 2 or 3 seconds yo go from 0.1 to 0.9 volts. Is this normal or have I got a sensor problem. Heater works OK. Any ideas welcome. Regards Peter
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Hi Peter,
The cycling frequency for a correctly working lambda sensor is proportional(ish) to engine speed. It is mainly because of the transport lag between injecting fuel and the resulting volume of exhaust gas passing the sensor. The other cause of the cycling is the highly non-linear response of the lambda sensor with respect to changing excess air ratio near to stoichometric.
If such were cheaply available, with a linear sensor, and reduced transport lag, it would be possible to design a continuous controller that didn't cycle from rich to weak in order to average out at stoichiometric.
However, back to your original question, 2 to 3 seconds sounds too slow even at tick over. It *may* be worth pulling the lambda sensor out to see if it has become gummed up with soot or exhaust deposits. The extra time taken for the the exhaust gas to diffuse through a layer of crud is potentially responsible for slowing the closed loop's cycling frequency.
Number_Cruncher
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My problem with the 240 1993 B200F was, as you may recall my good lady reporting that the car was a little unwell. After checking for error cades, all clear and a test run decided that the primary fuel pump was very noisey. This turned out to be the intank pump electrical fault where the lead through goes through the top plate. fixed that got all back together and fired it up. It appeared to have no idle control so started to suspect the valve or the ECU. the connector on the valve has had water in it but it all cleaned up but still not running properly. Checked ECU output to discover it was not talking. Removed ECU and tested the output drivers ( I have an electronics backgound ) and could find no fault. Replaced unit and low and behold Idle valve signals puls with modulated but engine not really happy, Lambda sensor responding slowly and biased toward running weak.. Shut it down and powered up just the fuel pumps, I can here the noise made by the pressure regulator and suspected air in the system but checked all pressures against the haynes manual ? and the HP test caused a minor leak from the filter output banjo. So decided to strip pump and replace filter whilst I was at it. The LP pipe onto the pump was corroded with a layer of paste type aluminium oxide on it and very easy to remove, and thought 'brill' there is my problem it's sucking in air. Serviced whole unit new filter pressure checked at 100 PSI ( Air ) and refitted today. Ran intank pump and bled air no leaks so ran main pump for 10 mins no leaks but pressure regulator sounds very similair.. closed off return pipe and shut pump down so system holding 80 odd psi to do final leak check whilst I write this email. Perhaps Cliff could have a listen to his Torslanda fuel pressure regulator and tell me what his sounds like. To run the pumps with the engine off you will need to link fuses 4 and 6 with the ignition off and the pumps will run up. Thanks Peter
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Hi Peter,
Is there a swirl pot in the tank on your car?
Sometimes, the return line feeds fuel into a swirl pot from which the pump draws its fuel. If the section of pipe from the return connection of the tank to the swirl pot becomes detatched or perishes, you can get funny behaviour, drawing air, especially when the tank is low(ish) on fuel.
This fault affected some mkII SRi Cavaliers, but I haven't heard of it again since, or on other cars.
Number_Cruncher
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No there is no swirl pot it's just a straight pipe 2 inch above the filter pick up. Thanks Peter
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peter ,did you actualy take the tank sender unit out and check the o ring and clean the gauze filter? problems here are sometimes intermitent and a floater on the gauze filter can allow fuel through but sometimes not enough.
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Thanks defender, Yes I have had the sender unit out and inspected and tested. It is all very clean and a sweet sounding pump. The filter is not contaminated and I have backwashed it to make sure. More tests today now that the exterior pump has been tested and the filter replaced. Regards Peter
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The plot thickens, It appears that the in tank pump is pulling in air and feeding the main pump with a lot of bubbles. Firing up the tank pump only and bleeding it out of the pipe just bebofe the main pump vis a clear length of pipe and there are the stream of bubbles the tank is about 3/8 full and I assume the pump is fairly well immersed at that so it is out with pump agin to see where the air is getting in. It can not out side the sender unit as that would be under pressure and would leak. Regards Peter
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I have a Volvo 240 SE 1993 and after lots os tests and faults I have discovered that the in tank fuel pump is only delivering 1.7 to 2 PSi. My haynes manual for this car suggest the 4 to 5 PSI is required form 1986 onward. This low pressure (Balnked ) leads to air being drawn in via the releif apetures behind the power connectors so the fault only shows with 1/4 or less fuel in the tank.
Can anyone help be and confirm that the pressure for a 1993 B200F Jetronic LH 2.4 should be 4 to 5 PSI and can anyone give me a Bosch partmenuber. Europarts say it is a 441 660 081, 138-9721, ORB MP 721 pump but suggest it is for 1984 onwards which is a 2 to 3 PSi Pump.
Thanks Guys Regards Peter
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What do you mean by the pressure regulator? The thing on the end of the injector rail works on inlet vaccum, and releases surplus fuel down the return pipe when vacuum is high - eg overrun, or idling, but ups the pressure when the throttle is opened. I can't see how you can test it with just the pumps running - surely it needs the engine running before it does anything, and you can't hear anything then because of the engine noise. I understand the only fault it can develop is a perforated diaphram, causing neat petrol to be drawn into the inlet.
There is the accumulator cum filter canister, underneath next to the main pump. I think that just smooths out the supply by ensuring a reservoir of pressure/fuel.
I don't see how the in-tank pump alone can be drawing air, because it is under the surface of the fuel.
A common source of air being drawn in by the main pump is minute rust perforation of the steel pipe at the top of the tank unit, just before the rubber supply pipe joins on. I fixed mine by cleaning off all the rust and dirt, and sealing the whole of the metal pipework with epoxy resin. It is almost impossible to get the rubber pipes off to withdraw the in-tank unit without damaging the probably rusty/fragile steel pipes.
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Cliff,
All the regulator does is keep the *difference* in pressure between the fuel in the rail and the air/vacuum in the manifold constant. This allows the amount of fuel injected to be, as near as possible, proportional to the duration of the injector pulse.
Without the engine running, the regulator will be working in exactly the same state as wide open throttle with the engine running, i.e., the highest of the range of allowable fuel pressures in the rail.
Peter,
I think you may be onto something having seen the bubbles in the fuel line. Does your car run OK when the tank is full?
Number_Cruncher
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There is always fuel returning to the tank as the incoming pressure is 80 psi plus but th rail pressure is 42-44 and is backed off by the high vacuum by 0.5 bar to reduce emmissions. I have run the in tank pump only via the bleed valve infront of the HP pump and there is no doubt air are being pulled in. On inspection the in tank pump is at fault as it can only raise 1.7 to 2 psi and although the current drawn is about right the current pulses indicate it is a 6 pole rotor and 2 of them are pulling only 55% of the others so I assume the pump is passed it.
The air gets in via the breather slots behind the electrical connections on the in tank pump. it just so happens that the fuel levle, very carefully measured, is just below the top of the pump and the holes are exposed. If I fill the tank tomorrow I think the car will return to normal but I intend to change the in tank pump and acheive the 4 to 5 PSI and avoid main pump starvation when the tank goes below about 25%.
This fault has been crazy and so much hard work for something so simple.
I'll let you know the outcome after I fit a new pump. That's if Europarts can supply the right pump for a late year Volvo. As a result of all this Hassle and thinking the ECU was not controlling the tick over, I ahve managed to purchase on the net both the Fuel and the ignition ECU for £33.50 a great back up have as these cars become rarer. If you think you have an ECU type problem talk to me because I have become the expert down to the last 10mv and 10ma, every connection, current reading, fuel flow and pressure. It's nice to have the gear and the time. But what a drag particularly when the local Volvo agents do not know their Fuel ECU form their Ignition ECU part numbers or cost..
Regards Peter
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Hi Peter,
While the irregular current draw isn't a good sign for the in tank motor, is it possible that the low pressure output is caused by a sticking pressure relief valve? There is usually some sprung valve to prevent the build up of excessive pressure.
Number_Cruncher
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Not Fixed. I picked up a new in tank pump today and after checking all the numbers I established it to be the right one. Removed sender unit and installed new pump. Checked everything over again and fitted unit to tank. fitted hoses and powered up the pumps, all secure no leaks so back to the front of the car and I can still hear air in the regulator valve. Car ran but lumpy at lower revs. when to the fuel station and filled her up as I had pumped a lot of fuel out doing flow tests. Drove 6 miles and although better it still is not right and I can still hear air bubbles going through the pressure regulator Now the main fuel filter has been changed and there may still be a bit of air in there but where can this air be getting in. The pump and rubber pipe connection are now completely submerged all the pipe fittings are clean and leak proof I'm Stumped Any Ideas welcome. Regards Peter
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Hi Peter,
Sorry to hear that your Volvo's fault isn't history!
Does the fuel have air in it straight away, as soon as you start, or does it only develop after the engine has been run? How is the fuel tank vented?
Years ago, I did see a fault, albeit not on a Volvo, where the fuel tank vent was blocked, and the fuel tank partially collapsed onto the in tank pump's pick up. Thankfully, the tank had collapsed far enough to kink the pipework, which is how I spotted what had happened, because from the outside of the tank, it wasn't obvious.
Number_Cruncher
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The air is in the fuel straight away and the tank vent is clear. Due to the air in the fuel the engine is a littlee rough at tickover and the idle control valve is not in control and the Lambda sensor is showing a lean mixture. No fault codes. She often bulks on acceleration after a slowing down, junctions, islands and the like I guess due to accummalated air in the gallery. Starts ok. When the top of the pump was exposed I could understand how air could be pulled in if the pressure was low but now I am at a loss. The Haynes manual quote 4 to 5 PSI blanked for this pump and even the new one only produces 2.5 PSI blanked. If any one has another source of pressure figure for this model then please reveal as I am at a loss right now. Thanks Peter
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You have disturbed the tank sender unit twice, I think, once to inspect the old pump, and now to install the new.
Are you absolutely sure the steel pipework on the outside of the assembly unit is sound? As I said, this area gets full of road dirt and is a perfect trap for damp, so the pipes are very prone to rust. Dislodging them, as in withdrawing the assembly or pulling the rubber connections off, can easily exacerbate a pinhole leak in the rust, which lets air get drawn in.
You could try running an entirely separate intake pipe from the main fuel pump to a gravity fed petrol can higher up. If the problem persisted you would know it had nothing to do with anything in the tank. But if the car then ran properly you would have substantially narrowed down the fault location.
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Thanks Cliff. I'm not going to investigate further today but I will chack with Volvo about the correct pressure for this model. I have checked all pipes and run the intank pump only thus no flow and maximum pressure for 10 minutes or so and checked all pipes and joints and no fuel leaks but the air is getting in somewhere.I ran the pump (Old) and the sender unit in a deep bowl of fuel for 15 mins and took several pressure feeding and this would have shown up any leaks then. I'm going to do a direct feed to the HP pump to isolate the pipework as you suggested. If I partially restrict the flow rate in the return pipe I expected less air to be drawn in as the in tank pump could meet the reduced demand but alas it does not appear to make a lot of difference. Very Strange. Regards Peter
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Update. New intank pump fitted and all reconnected with remain connection at main HP pump and new Filter. Fired it up and it is still lumpy lack tickover control. So put clear plastic pipe in line with feed to main pump and no air being pulled in so all is well there. connected return pipe at the rear of the pressure regulator to a container and the the flow rate is 1 ltr in 30 seconds. That's both pumps running no engine. Manifold pressure is 48 psi ( spec 41 to 44) max vacuum 45 Blank pressure 107 psi ( spec 70 to 92 ) holding pressure 90 PSI ( spec (80 ) Pessure at 20 mins 24 psi ( Spec 14.5 psi. ) Now I was concerned that the pressure regulator makes a nois to its selve and thought air may me passing through it but inserted a secontd regulator in the return pipe and would it up to 50 psi and the noise moved to the extra reg and the main one was silent and ther are bubbles in the return fuel after the second reg.
Set up a test in the garage with clean fuel at 75 psi and a reg and sure enough vapour bubbles form after a regulator due the pressure drop so I am now happy that the fuel system is all up and running but to be sure I ran the main pump on a direct feed from a container with 10 psi fuel and the the situation is identical.
The car still does not run particularly well with lack of idle control and lumpy operation and does not like picking up after an over-run. Remember this fault was originally cuased by the electrically failed in tank pump which is all now fixed and I am not quite sure where to look next. No ECU error codes. no air leaks that I can find but do note she runs fine when the engine is cold. Check all sensors, temps, crank sensor, throttle switches, knock sensor, ignition waveforms and Lambda the latter is still a bit slow and indicates a lean mixture. So any ideas guys where I should look this has cost me so much time but just alludes me. Regards and Thanks Peter
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From cold, until the first switch of the lambda sensor from reading weak to rich, the car will be running open loop. This open loop running period may last quite a while. After the first switch of lambda sensor voltage, the ECU will try and switch into closed loop operation with the tell-tale pulsing of the lambda signal, which should switch lean/rich/lean at about 1Hz at tick-over.
If the engine runs OK until the lambda sensor begins switching, then you know that the fault is something that is hindering the correct closed loop operation rather than a general fault which would affect open loop operation too.
Is your lambda sensor heated? Is the heater drawing any current? Does the injector duration change significantly between the open loop phase of running and during closed loop running?
Number_Cruncher
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Thanks for that number cruncher I will take a look when it stops raining. Regards
Peter
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