Cold start problems

Waveruiner · Post by **Waveruiner** » 15 Feb 2012, 11:19

Hello to all on the forum. My name is Dave and I live in North West of England (UK). I've owned my V70 SE Auto (170bhp, 106,000 miles)) for 5 years and love it, but it's not loving me back at the moment! It runs on LPG and unleaded, and I've had the LPG system checked and even disconnected to see if the fault was with that. The problem only manifests itself when the temp is below 10C, and 2 main Volvo dealers and a specialist fuel injection tech can't find the reason. The problem is that it will not start after standing overnight unless I pull the fuel pump fuse before trying to start it, crank it over, then insert the fuse whilst it's still cranking. I have a fault code which translates to "02 sensor Bank1 Sensor1", and the ECL has been on for the past 6 weeks. In the past 2 weeks I have changed the cylinder head gasket, re-seated all the valves, replaced the cambelt and tensioner, replaced the cam and crank position sensors and both pre and post Cat 02 sensors. I replaced the ECT sensor, and cleaned the Bosch ETM as well, and fitted a new alternator. I am seeing only 80psi across all 5 cylinders when cranking, but 150psi as soon as it has started and I've shut off and re-tested. Fuel pressure is 45psi at the rail when cranking, and 48psi when started. it gives all the symptoms of overfueling, but nobody can understand why! Obviously the low compression is a worry, but it goes right up as soon as it's started, so what could be causing that across all 5 cylinders. Once it's started in the morning, it will start on the buttton even after sitting 6 or 7 hours at freezing point, but leave it overnight, and it won't start! I checked the fuel pump relay and that was fine. If you've any suggestions, no matter how off-the-wall they may be, let me know! Thank's and regards, Dave.

Post by **regent** » 16 Feb 2012, 18:58

Dave,
Here is what I'd like to ask:

1.This may sound like a dumb question that you've already gone through, but have you checked the VVT?
2. Possible fuel pressure regulator misbehaviour?
3.The Compression Test: Isn't it supposed to be carried out at WOT with plugs removed? How did you perform it?
Thanks

Post by **fazool** » 16 Feb 2012, 21:25

I had only skimmed your post and my first thought was "flooding" or as you called it "overfueling"

If you get the engine cranking THEN provide fuel (via the fuel pump relay) it can start. If fuel is provided right from the beginning it floods and can't start.

Thats what it sounds like. The changing compression sounds like a VVT problem, no ?

Post by **regent** » 17 Feb 2012, 08:42

My 2 cents Re: FLOODING

Be weary of possible hydraulic shock when flooding is excessive (if that's what's happening). Very undesirable prognosis!

Waveruiner · Post by **Waveruiner** » 17 Feb 2012, 09:22

Thank's guys for your replies. The VVT checked out OK, and the compression test was done as you suggested (WOT, plugs out). A local Electrical specialist has fitted a resisitor into the electrical system today to fool the ECU into thinking it's warmer than it really is, and it fired up straight away! Obviously, If it thinks it's warmer, it provides less fuel on start-up. Apparently it's also a known BMW Series5 fault, and he's done this as a factory recall mod when he worked for BMW a few years back. The theory he had about low compression values is that the amount of fuel it was injecting in was washing the oil off the bores, so giving the low compression, hence affecting all 5 cylinders, which does make sense. I'll do a cold compression check when it's stood overnight and report back if it's improved. Again, thank's for the thoughts guys, and I am going to re-check the VVT and solenoid just in case.

Post by **regent** » 17 Feb 2012, 15:37

Did you mention that you had replaced the Engine Coolant T-Sensor? If the added resistor fixes the problem, then it is either the signal from the ECT or the calibration (the code that tells the ECU how to interpret the signal).

Excessive fuel washing the oil down to the sump means that your oil is already diluted with fuel and not so good. I would not wait for the gasoline to evaporate from the oil.
Please make sure you change it!
Cheers!

kendash2000 · Post by **kendash2000** » 30 Dec 2013, 07:13

My Volvo experienced this problem. Temp gauge was at 1/4 (normal 1/2 when warm) at 30 degrees F. Car would crank and fire after cranking multiple times (got worse over time). When started, idle leveled out and ran well. Started up normally when warmed up. After a week, got worse and when car was warmed up, Temp gauge went to just below hot. Ordered coolant temp sensor from FCP (Part # FAE 9186486) and it works perfectly.