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Post by valhalla on Nov 5, 2019 0:05:10 GMT 1
I have a slightly strange scenario on the ramps this evening. The code is for the fuel pressure regulator circuit (low) rather than the actual fuel pressure plausibility - I think.
The code is : P0091:62 Fuel pressure control valve circuit low
This can be cleared-down, but reoccurs immediately on cranking to : P0091:72 Fuel pressure control valve circuit low - but note that the code suffix is 72 not 62.
The van is a 2008 Ford Transit Connect with 85k on it, and the symptom is a crank, no start. This happened, apparently, immediately after it was switched-off for 5mins after a decent run. and hasn't run since. It doesn't help that the breakdown recovery services went straight in and cracked injector lines open, so opening a whole pandora's box of issues that make it impossible to diagnose a true instance of rail pressure control problems (air now in rail and/or injectors). So thanks, once again, to some fairly c**p roadside assistance, I'm scratching my head and wondering if this is truly a fuel inlet pressure control solenoid problem, or whether it is something else.
What makes me wonder is: Does this code set on the Delphi/Lynx Fords with a failing inlet pressure solenoid ever? I would expect a P0191 code for a control problem. The solenoid has a resistance on the multimeter of 2.8ohm, so not implausible on the electrical circuit, so I'm wondering if there is a short-to-earth on the wiring to this valve - that is my first port of call tomorrow, if I can get the main engine harness plug apart.
Or is this just a case of replacing the solenoid? Something doesn't quite stack-up with that, though. Why does the code trigger during cranking but not with just the ignition on?
I worry sometimes about the validity of the Ford codes not being exactly correct - in the right ball-park, but not spot-on for a component-level diagnosis.
Cheers for any previous experiences with these valves!!
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Post by valhalla on Nov 6, 2019 23:47:21 GMT 1
I forgot to clarify something above, with regard to the CR hardware. This is a Lynx 1.8 R2PA engine on a 2008MY, so it's running Siemens injectors, but also Siemens CR pump, which of-course makes a difference to the Pressure Control Valve hardware on the back of the pump.
I had a bad time with this engine late this afternoon (first time to look back at the problem) and I'm wondering now whether the code above is just a red herring from the mindless tampering of the breakdown services.
To cut a long story short : The chafing of the harness near the rear lifting bracket for the cylinder head has gone through, but it doesn't directly affect the rail pressure input/output controls, it affects one side of the piezo harness to No_4 injector over the flywheel housing. It's a tiny nick in the individual insulation, only visible by camera close-up, although I was able to detect a continuity with an edge of the multimeter sharp probe. That repaired, and everything else checked and back together, I did a few cranks to see what the outcome was. What I saw was the RPS slowly crawling back up to a low pressure from nothing, after 4cranks (thanks to the mindless meddling), but the battery is utterly cream-crackered despite of my conditioning it a couple of evenings ago. I wondering now if this isn't just a simple case of "dead battery". Only tomorrow will tell.......
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Post by givusaclue on Nov 7, 2019 0:06:44 GMT 1
Hi Valhalla Did you you check the freeze framevdata on eobd before you cleared the fault? rpm would tell you whether it was a fault that occurred cranking or running
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Post by valhalla on Nov 7, 2019 1:41:59 GMT 1
Hi Valhalla Did you you check the freeze framevdata on eobd before you cleared the fault? rpm would tell you whether it was a fault that occurred cranking or running Sadly, no I didn't. The thought-process at the time was to go with the information that the customer had given me when the vehicle was towed in. It had been running fine (albeit like a slug - but I have found the separate reason for that), did a stop for 10mins, short journey, then a second stop at the hardware outlet (he's a joiner by trade) for around 5mins, immediate crank, no-start condition on the van. So my thoughts were "Chances are that any freeze-frame data is going to be 0rpm, 0MPa rail, etc. etc., so let's skip that step to save a bit of time going into the generic EOBD functions on the Autel"
I was more interested in the stench of EaziStart from the induction pipework!! That's never a good sign.....
Two things appear to be going right for the cranking conditions on Live Data: there is a good flag for crank-sync, and there's an indication that the security permission is set correctly.
One flag does not set, right now, and that is the Rail Pressure target for injection-release, but that is no surprise as the rail pressure is too low, albeit it appeared to be recovering a bit this evening after a few tries. Even though the code as-above is being set, there was a continuous control of the Pressure Control Solenoid, which I would have thought would have been 0% if there was a genuine attempt by the PCM to shut that output stage down. Maybe I'll hook the Picoscope to that solenoid tomorrow to have a look externally from the PCM, just to be sure.....
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Post by givusaclue on Nov 7, 2019 10:31:21 GMT 1
the 1.8 can be a cow to bleed up a common problem i've conme accross with the 1.8 is cam sensor & wiring where the cable seems to be cable tied/kinked at the sensor they won't start without that & i think it will cut out if it loses the signal just a thought
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Post by valhalla on Nov 7, 2019 23:43:29 GMT 1
I think I'm going to have to grasp the nettle on this and give it one almighty good bleed tomorrow. At this stage, I have had so much of the FIE apart myself, now, that there cannot be more than 10% fuel in the system!!
I didn't have a lot of time on this this afternoon, but what I managed to do was get a decent battery onto the van, in a decent charged state. So having achieved "square_1", I then re-logged another crank with the system as it was last night. This time, no indications of rail pressure at all. Hmmm.
I inserted my CR pressure transducer into the HP line from bomb to No_1 injector, and confirmed on a subsequent few cranks that there really is not any pressure to measure - despite the LP system being left alone up to this point. So the external transducer backs-up the Rail Pressure Sensor, both effectively zero, which is a step in the right direction.
At this stage, I'm getting cold in the workshop....I have been working most of the day outside on a recalcitrant tractor, with incontinent front-loader hydraulics, and my arms are soaked in diesel from that job. Hmmm. So I have a brighter idea. "Why not just give up at this stage?" Then a not-so-bright idea, "Why not take my perfectly good Focus 1.8 Lynx with identical FIE, and start swapping components?". Not quite as daft as it sounds; the PCV at the HP outlet on the Focus is very accessible at the moment, and this is the component that ought to be flagging the code above (circuit low), so even if my measure of 2.8ohm on the pins of the original is OK, it would prove whether or not the code is set once the PCV is driven by the PCM under cranking conditions.
It made not one difference. That could be good. It means either the code is being set incorrectly (likely), the PCM has an issue closer to its multiway plug in the under-dash harness (possible), or the PCM drive-stage itself is duff (just about possible). I know that no issues exist underbonnet on the PCV circuit, so my thoughts about PicoScope'ing the PCV, VCV, and RPS during a cranking condition now make more sense than ever. A job for tomorrow morning, I think, before anything else turns-up......
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remmington
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Post by remmington on Nov 8, 2019 7:51:28 GMT 1
I agree with your "charge the battery and have a bleeding session".
If you have no rail pressure when cranking.
You may not have any diesel in the system?
You may not be getting any pump pressure - physical pump failure?
You may have an injector robbing the rail pressure?
Because the recovery services have done you "no favours" - spilling fuel.
And you are in for a bleeding session - I would wanna be checking the filter for metal - you are gonna have to remove the filter to fill it with fuel anyway.
+1 for Giveusaclue remark for these are a "pig to bleed" - I have suffered non starts after servicing and fuel filter changes. I also may have reduced the service life on several starter motors in my time.
Is this the one which has a spider shaped rail? Or does it have straight rail with a burst disc/return pipe on one end like a transit? Not sure I have worked on with a Siemens system.
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Post by givusaclue on Nov 8, 2019 10:18:08 GMT 1
assuming it doesn't have an intank lift pump, i use an inline compound guage to confirm the lp side of the fuel pump functions (vaccuum), then can't you bleed the pump, fit a dummy actuator & confirm the integrity of the pump before trying to move on to the delivery side of things?then it's narrows it down to a problem with pressure regulation be it electrical or injectors leaking the pressure back one caveat: i don't remove the compound guage once i've esatblished it's got low pressure until i've got high pressure so as not to undo all my good work bleeding the damn thing until i've identified the root cause i'm in a rut at the minute with failing siemens injectors & trying to extract a semi drilled butchered glowplug on a merc v6 an inch down from the surface that someone else started, just hope the thread repair insert can bridge the "oval entry wound" i love these kind of jobs, not! looks like i'll be getting the spark eroder out remmington , too hard to drill
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remmington
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Post by remmington on Nov 8, 2019 12:36:47 GMT 1
assuming it doesn't have an intank lift pump, i use an inline compound guage to confirm the lp side of the fuel pump functions (vaccuum), then can't you bleed the pump, fit a dummy actuator & confirm the integrity of the pump before trying to move on to the delivery side of things?then it's narrows it down to a problem with pressure regulation be it electrical or injectors leaking the pressure back one caveat: i don't remove the compound guage once i've esatblished it's got low pressure until i've got high pressure so as not to undo all my good work bleeding the damn thing until i've identified the root cause i'm in a rut at the minute with failing siemens injectors & trying to extract a semi drilled butchered glowplug on a merc v6 an inch down from the surface that someone else started, just hope the thread repair insert can bridge the "oval entry wound" i love these kind of jobs, not! looks like i'll be getting the spark eroder out remmington , too hard to drillBitch...
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Post by valhalla on Nov 8, 2019 22:38:55 GMT 1
He had to get the "spark eroder" in sometime around now.....
Yes, I hate these damn things - way back was when I had a Focus 1.8 Lynx that cost me a whole night to re-bleed following a service at the last slot in the day. I could well be cracking-out all the bits and pieces I made for that. The trouble is, Ford were used to using no lift pump on these when they went over to Siemens, and the Germans would have made the eyes of the Ford senior management light-up like cash-registers as soon as they mentioned that their pumps "do not require a lift pump under normal circumstances". Hence the worst-designed LP fuel systems this side of the world...... Experience of Siemens pumps on LR engines (fitted with LP pumps as well.....) are that they are utterly unbleedable once they get air past the volume control valve (VCV), and have to be removed for bleeding; lots of pump shaft-speed to purge air.
I could not bleed this car earlier today, and it "just did not feel right". The bleed bulb in my kit was telling me that there was no flow, and the air was not purging. After a short lunch and lots of tea, I fired-up the garage-control software, and lo-and-behold, somewhere at the back of the shelves with my service filters stock, there ought to be a filter for this van. In the end, I found it, and that went on this evening.
The bleeding is still not great, but it feels better. I have checked, and there is fuel in the rail as far as the pressure-transducer T-piece in my kit, which is a good sign - something is getting through. But.....still no real pressure on cranking, even when the whole process is speeded with a "bit of sniff" straight into the intake. So I really do need to get the PCV back-probed alongside the VCV, and make sure the solenoids are being cranked open properly. After that, it comes down to money....
...which leads me to the next problem on this engine. The head gasket has gone. Not big-time, or enough to stop it from starting, but enough to leave the coolant circuit pressurized with gas after a few cranking measurements. So I have had a chat with the owner this evening, and given him the worst-case scenario, which is that he has bought yet another duff van this year. That makes two lemons in a row for him now, which I really feel sorry for the chap, as he is paying-off the finance on both, in parallel.....
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Post by valhalla on Nov 8, 2019 22:48:30 GMT 1
You may not be getting any pump pressure - physical pump failure? You may have an injector robbing the rail pressure? Because the recovery services have done you "no favours" - spilling fuel. And you are in for a bleeding session - I would wanna be checking the filter for metal - you are gonna have to remove the filter to fill it with fuel anyway. Is this the one which has a spider shaped rail? Or does it have straight rail with a burst disc/return pipe on one end like a transit? Not sure I have worked on with a Siemens system. My worry now, assuming the PCV and VCV are getting proper signals, is that the CR pump is genuinely knackered. The old filter was sighted-down through the stubs (no debris) but I will definitely slice it open tomorrow, as I want to see how gelled-up it is. Even if the CR pump has not disintegrated, it may well have struggled to pull fuel past a blocked-up element.
Injector_4 might be in trouble, but that would be easier to see if the engine was running. This was the cylinder that had a slight chafe on the injector harness near the rear of the head. I could dead-head it with the pressure measurement gear, and perhaps I may well try that if all else fails tomorrow.
This still has the spider rail, or "bomb" as it was known in certain circles (appropriately, as it turned-out), which I think was a straight carry-over from the Delphi system? It looks the same in the pictures that ETIS lists.
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remmington
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Post by remmington on Nov 9, 2019 0:10:19 GMT 1
Your quote "I could dead-head it with the pressure measurement gear" I have a Facom 1750 bar gauge for this job Not used it much thou - truth is - mostly you can trust the pressure readings on live data - if the voltages look right? Made my mind up a year ago - not to keep buying expensive diesel test kit.
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Post by valhalla on Nov 9, 2019 22:47:49 GMT 1
Your quote "I could dead-head it with the pressure measurement gear" I have a Facom 1750 bar gauge for this job Not used it much thou - truth is - mostly you can trust the pressure readings on live data - if the voltages look right? Made my mind up a year ago - not to keep buying expensive diesel test kit. I use a Laser bit of kit - nice flexi hoses to intercept the fuel itself, and decent long leads to hold the readout display whilst cranking the engine over.
To be frank, yes, I too feel that this is tied-up capital that could have been better spent. I use it far too little to be worthwhile. However, I don't tend to trust rail pressure sensors - that comes from having too much hard experience with BMW M47D and M47R engines with the rubbish rail sensor on the end of the rail, which I feel is far too fragile for its own good in this application from Bosch. That was why I bought the Laser tool, as it gives me a second-chance at working-out what has gone wrong. It is also very good for dead-head connections.....
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Post by valhalla on Nov 9, 2019 22:57:53 GMT 1
And indeed, the misery of this van just goes on. I had a short while this afternoon, around other things, to get the PicoScope onto the VCV and PCV.
There's no rail pressure, because there's no solenoid drive, either PCV or VCV. As they are fed by a common supply line (black/blue, I believe), then it would tally that the PCM is either not connected on that line (unlikely, I feel) or that the power supply has gone dulally on that common supply (quite likely, I suspect), but I will not know until I get the right/front wheel and liner out of the way, just to get to the PCM. It has taken me a while this evening to work-out that the PCM is cleverly positioned there, as I have been scratching my head for a while this afternoon..... So I had just taken everything of instrumentation back off, and put the engine-bay back together as far as I dare.
The van is out in the long-term car-park for the remainder of the weekend, as I have other fish to fry on my own beloved vehicles tomorrow......
I explained to the hapless owner of this F*** that there is little point planning-in a head-gasket renewal if the thing does not start and run. Add a new battery and an "elephant's trunk" to the shopping list, and it's getting 50/50 as to scrap it or not.
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Post by givusaclue on Nov 11, 2019 0:21:21 GMT 1
I may have a pcm for one of those, you can program it in with the gear you out have if required
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