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Matt
Matt, Engineer
Category: Volvo
Satisfied Customers: 20605
Experience:  Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
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Problem starting Volvo 5.7

Customer Question

Problem starting Volvo 5.7
Submitted: 19 days ago.
Category: Volvo
Expert:  Matt replied 16 days ago.

Hello

I'd check that you're getting full power to the glow-plugs, they pull a lot of current so take care when checking but see if the relay is clicking when the ignition is turned on first and also check the fuse if this is OK check to see if the engine earth strap is also OK. If the engine has the alternative heater element in the inlet then check the power supply to that too.

If the plugs haven't been changed in the last 20K then they may have to be replaced.

You can test the glow-plugs with a multimeter by measuring the resistance across the plug ( between the power connection and the body) it should be around 4-8ohms if its tending to infinity / open circuit the plug is faulty or by using a clip on current clamp, either on the supply wire to glow plugs or onto engine earth, with glow plug light on you should see 15-20amps for each glow plug fitted, 4 cylinders would be approximately 60-80amps.

Also its worth checking that the electric pump that feeds the main fuel pump is working correctly, it should run for a few seconds then switch off when you first turn the ignition on. If the connections to this are corroded or damaged then the pump could stop at any time. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse, ideallymeasure the voltage at the pump and check its getting 12V

Also if its not injecting at all then check the connections to the crankshaft sensor, unplug it and check for corroded contacts and broken wiring, and consider fitting a new sensor - do the same for the cam position sensor

If the EGR valve is stuck open then this too can effect starting so try disconnecting it to see if this helps or changes anything

Could also be an injector leaking fuel back through the overspill pipe, so not getting enough fuel pressure to tell ECU to fire the injectors, this is trickier to find and you’ll need the garage to do a ‘run back’ test to identify which one is the issue

Lastly it’s also worth considering fitting a new fuel filter as if only slightly blocked this can lower fuel supply pressure and choke the main pump, the pump will be more sensitive to this when its cold as diesel thickens considerably with low temperatures.

Customer: replied 16 days ago.
Matt, I have gas Volvo Penta 2009 5.7 GIJ 300. My issue is that the starboard engine will not start unless I give it a little forward throttle. Once it starts and the throttle is still forward the engine will hunt between 600 and 1500 rpm for about 8 minutes then smooths out. I then ran the engine for two at 2800 rpm. Once I start docking and going in and out of reverse the engine cut off and I would have to redo the start process.
Customer: replied 16 days ago.
I was having the hunting problem for several boat cruises, then I had a complete head job because the mechanic said I had bad lifters. He replaced the lifter, push rods, manifold, risers, and valves reseated. Once that was complete that's when the starting problem got worse. He said my fuel pump was excessively hot and I confirmed that by checking the other engine fuel pump temp. I replaced the fuel pump. Same start problem after the fuel pump change. The mechanic then said that at least one fuel injector was sticking open. I had them cleaned and flow checked. The shop said none of the injectors were leaking. Two had bad spray patterns and flowed at 62 after cleaning all units were flowing at 67. Same start problem after the injectors were re-installed.
Customer: replied 16 days ago.
I then starting swapping parts from the port to starboard engine and re-started the engine checking for improvement. The first component was the pressure switch/sensor on the fuel rail. The second was the Throttle Positions Sensor. The aft sensor next to the intake. No change. The last item is an idle control (?) the fwd sensor next to the intake (see picture). I have the same problem on the starboard engine and the port engine still starts right up. This is my current status.
Expert:  Matt replied 16 days ago.

OK thanks for the extra information

as its a gasoline then not much of my previous advice applies but it would still be worthwhile to replace the fuel filter as if blocked then this can overload the fuel pump and make it run hot

it would also be wise to measure the fuel pressure to see if this is an issue or not

I'd also do a compression test across all cylinders as they should all be within 10-15 psi of each other as this will show up if the recent engine work was successfull

Customer: replied 16 days ago.
Matt, I had the same problem before replacing the fuel pump assy which comes with a new fuel filter. I had compression test before the head job. I will recheck the fuel rail pressure. I also was told to pull the injectors again then hook them to the rail and see if any leaks once i turn the key on.
Expert:  Matt replied 16 days ago.

Hello

was the compression rechecked post head job?

as I'm wondering if it was low before and its not been resolved with the head rework then you may have worn rings?

If you do the measurement dry and then squirt a little engine oil into each cylinder and repeat the measurement

if the pressure shoots up then you have an issue with piston sealing

Expert:  Matt replied 10 days ago.

Hi

do you still need help?

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