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Discussion Starter #1
Hello, I've read quite a few threads on this issue and done a bit of diags and work on my 307 but can't seem to put my finger on the issue here are the details:

Regardles of morning cold start or with warm engine, it struggles to start. The issue is that the hard starting is not not consistent. Some days it's worse then others. Sometimes it can go on a long 15 second crank without firing - it feels as if it's fireing on only one cylinder but the other three do not catch on. When it's in this mode it's easier to give it a few short cranks and then it fires. Sometimes it can actually be worse to start when engine is hot.

Battery is brand new 80Ah and so is starter. I estimate that the engine spins smoothly around 400 rpm during cranking.

Tests carried out:

Compression test with cold engine. 32 bar on all four cylinders. Note: 1 glowplug is blown but cannot replace as tip snapped and stuck in cylinder head. For this cylinder i removed the injector to carry out the compression test.

PP200 live data shows rail pressure at 298 bar during cranking. Difference between fuel pressure measure and fuel pressure recommendation 6 bars. Diesel pressure regulator OCR 17%.

When the engine starts it runs fairly smoothly and with good power.

One thing i noticed during driving with live data monitor is that the "difference between fuel pressure" value varies quite a bit even under constant load.

One other thing, it's got some problem with the fuel additive tank and has some related DTCs in the engine ECU which are as follows:
- Permanent fault. Additive system. Fault: fuel additive accuracy
- Permanent fault. Additive quantity. Fuel additive ECU
- Permanent fault. Additive quantity. Fuel additive low level reached

Any tips of where i should look/check would be welcome.
 

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Discussion Starter #2
Forgot to mention that i replaced the diesel filter and before hooking on the line to the HP pump I ran the tank pump a few times in part to prime the filter up, but also observe the flow and I can confirm that there is quite a healty diesel gush coming out of the hose.
 

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I would do a leak off test, and see if any injector stands out, I would in this case be looking for one with low leak off. Symptoms point to a injector possibly sticking open hence excess diesel white smoke, when it sticks fuel rail pressure drops stopping correct injection on others and poor starting
 

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I agree sounds like injector issue although your fluid may need a refill and reset if your DPF is still present or it will get clogged also it is best to have all 4 glowplugs working to allow DPF to regen 3 will be ok but loose 1 more and it wont regen.

DPF related issues wont make it hard to start but will affect it running
 

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Discussion Starter #5
Thanks Windy and Reliable. As it happens I had ordered a leak-off test kit which I'm waiting to arrive sometime this week, and I'm planning to carry out the test this weekend. I will post the findings.

Regards Reliable's comments about the additive: I have actually topped up the additive tank but could not get the ECU to reset. Based on the fault codes stored which I posted I assumed that something's faulty with the additive system. But maybe i'm doing the reset procedure incorrectly? If you know of a good thread or document with clear step by step on how to re-fill and re-set I would be most gratefull.

About the regen: I tried carrying out a forced regen yesterday, but after going through the whole process the end verdict by PP2000 was that the regen failed. Any ideas why that would happen? I'm sure that the heaters were doing their work in loading the engine and the temperature gauge went well above the 90 deg. point, but in the end it appears that the regen was unsuccessful. I'm reluctant to try and remove the stuck heater by drilling through the tip lest any of the debris falls into the cylinder and gets lodged between the piston and the side wall and cause big scratches to the cylinder wall? I'm more inclined to fit some kind of current monitoring device to the heater supply rail so that I notice immediately the minute one of the remaining three blows up and have it replaced before it cokes itself in.
 

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Discussion Starter #6
Update: I've carried out the leak-off test this morning and all four barrels filled roughly the same amount after 3 minutes of engine idleing so I'm confident that the injectors must be in reasonable condition. The mileage on the vehicle is only 90K after all.

Drawing up on my experience as an engineer, due to the intermittent nature of this concern only two check items at this moment come to mind. One is valve timing, the other is potential fault with crank position or camshaft position sensor/s. I've seen some issues in the past with hall effect sensors where they can become intermittent at slow cutting speed but output a better signal at a higher speed, however I'm still a bit sceptical that the engine ECU does not pick up on this intermittance and store a related DTC. Anybody has experience with cambelt timing issues on this type of engine? Could it be possible that timing could be out by 1 notch and still allow for the engine to run fairly smoothly with good power and no clashing of valves with piston?

There's one other thing I noticed when I try to read live data with PP2000, I get a warning message saying: "Incorrect matching of the ECU (Incorrect engine, system or vehicle). In spite of this incorrect matching of the ECU, do you wish to continue the diagnostics procedure?" I'm not sure why it's giving such message and how to rectify it. Any comments on this would be welcome. Thanks.
 

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