Starting Problems After Pressure Valve Replacement.

Good evening, fellow enthusiasts!

I'm having the following problem:
This afternoon, I replaced the equal pressure valves on my 1Z engine with new ones (from an AFN engine), and now it won't start.
Vehicle:
1 Series BMW, 1994, with a new engine (replacement engine).
but old fuel injection pump, approximately 200,000 km.
Nozzles (0.216) are approximately 15,000 km old.
I wanted to replace the pressure relief valves because I was experiencing very strong idle fluctuations/jerking, even though I had a new engine. Otherwise, the engine had normal performance and always started perfectly.

Here's what I've already tried:
+) I reconnected the old GDV sensors, and when I start the system without the HD cables connected, the GDV sensors don't produce any output.
+) If I install the new GDV modules, something will happen, but even if I install the HD cables, it still doesn't start.
To avoid airlock problems, I connected the pump to a diesel supply.
I've already checked the parking brake.

Since the engine was running before and I haven't changed anything other than the pressure relief valves, I'm currently at a loss as to what's wrong.

Please provide possible solutions or a fault analysis!
Sure, here's the translation:

'Thank you in advance!!'

greetings
Wolfgang.

P.S.: If possible, please respond today - I have to go back to work tomorrow!! If anyone from your customer service hotline is still available, please send me a private message!

Hello NVE!

Have you loosened the cover nuts on the nozzles and checked if diesel fuel is leaking out when the engine is running?
Does your starter motor run smoothly, or is the battery perhaps almost completely discharged (connect it to a charger!)?
Are there any air bubbles visible in the pump suction line (from the filter to the ESP)?

Did you install new seals (copper washers) between the pump head and the GDVs?
Were the cylinder head bolts tightened with the correct torque?

Did you ensure the utmost cleanliness in the fuel injection system area?

If your 1Z engine is misfiring, it could be due to the very large 0.216 injectors. What fuel injection quantity does the MWB 1 display with VAG-COM when the engine is warm?

Regards,
Alex.

Hello Alex!

Thank you for your quick sympathy!!

Okay, I loosened the banjo bolts and waited for the diesel to come out. The starter motor is working well and is already connected to a charger. I don't see any air bubbles, as I have the pump connected to a drip line for bleeding.

The gaskets are new, but I didn't pay attention to the tightening torque. What is the correct tightening torque for the cylinder head bolts?

Yes, I made sure to keep things clean.

In my opinion, the jerking wasn't related to the injectors; it was more of an uneven running. I got rid of the typical jerking problems (acceleration jerking) by adjusting the injection quantity using VAG-Com (5 mg/stroke). However, I still have this very uneven idle, as if one cylinder isn't working. That's why I suspected a faulty glow plug unit (GDV).

The strange thing is that I can't get either the old or the new one to work, even though I haven't changed anything else.

Best regards.
Wolfgang.

Hello NVE!

Okay, so if diesel is coming out of the injector nozzles' pre-injection valves, then at least the pump is working. Then, it should eventually start, even with one or more faulty glow plugs.

Have you had the 0.216 injectors installed for a while? Did you check the injection timing after the modification? The 0.216 injectors have an opening pressure of 220 bar, which significantly shifts the (unregulated) injection start (default setting) towards a later timing. Your starting problems might be caused by this!
If the injection start time was already close to the late limit and your modifications to the ignition timing might have shifted it even slightly further towards the late side, then the engine will naturally not start.

By the way, your pump setting still seems way too high. Having 5mg/h at idle with 0.216 injectors will likely cause a significant increase in engine misfires.

Here's another very simple approach: Have you checked the coolant temperature sensor? It might suddenly start working if you simply disconnect the sensor's cable!

Good luck!

Regards,
Alex.

Hello Alex!

I also thought that if the pump was running, it should eventually start working, but it doesn't.
'My suspicion was also that it was related to the start of injection, which is why I also checked the timing belt setting - everything seemed fine (one cylinder at TDC - the dowel pin for the crankshaft position sensor slides in). Today, I also moved the belt one tooth later (which would result in an earlier start of injection), but without success.'
I also tried the thing with the temperature sensor (pre-heating it for a long time), but nothing happened.

Okay, let's go back to the fuel injectors: I noticed that the ones in my 1Z pump were different from the new ones from AFN. First, they have different part numbers (165 - 170). Second, the spring protrusion (the end of the injectors that connects to the pump head) on my old injectors was much longer and had a tighter preload.

It's also questionable: Why doesn't the diesel fuel reach the upper mounting nuts when I reinstall the old fuel injectors?

What might have changed when I first removed the GDVs?

greetings
Wolfgang.

Hello Wolfgang!

Are the pump heads the same for the 1Z and AFN engines?
If the structure and geometry of AFN and 1Z-GDVs differ as fundamentally as you have described, then I would certainly start to wonder if it makes sense!

However, I can only imagine that the pump head was damaged if someone forcibly screwed in longer or larger-diameter valves (which, as you obviously didn't do).

If you only screw in the pressure sensors (GDVs) into the pump head and omit the injector lines, will fuel leak out on the pump head side when starting the engine?
If that's not the case, then either your turnout has a problem with its mechanism or the derailment device is stuck.

Finally, I have one more highly unlikely explanation: If the threaded connection of the GDVs and the thread on the side of the injection lines are the same, then it is, of course, possible to screw them in the wrong way. But I don't believe any designer would make such a mistake, and I trust that you have enough technical understanding to screw the valve in the correct direction .
Otherwise, the check valves would always remain closed if installed incorrectly, and no diesel fuel would reach the injectors.

Regards,
Alex.

donalexo wrote:

In the event that the threaded connection of the glow plugs and the thread on the side of the injector lines are the same, then it is, of course, possible to screw them in the wrong way.

No, they are not the same, and they look very different on both sides. Even my grandmother would be able to screw them in the right way .

By the way, about half a year ago, I also had my GDV (Gasdruckventil) in my 1Z replaced by one from AFN. Although the AFN valves look a little different, they fit perfectly and work great in the 1Z .
It wasn't a problem to bleed the lines afterwards.

It's not likely to be related to the GDV values.

/Jan

Good morning!

Thank you for your responses! Yesterday, I continued trying to adjust the start time of the injection and experimenting, but without success.

I'm still wondering what changes might have occurred by removing the fuel pressure regulators (GDVs) from the fuel pump setup, and why fuel isn't being pumped when I reinstall my old GDVs.

No, they are not the same, and they look very different on both sides. Even my grandmother would be able to screw them in the right way .
I see it that way too!

By the way, I also had my GDV (Gas Discharge Valve) in my 1Z replaced about six months ago by AFN parts. Although the AFN valves look a bit different, they fit perfectly and work great in the 1Z.
It wasn't a problem to bleed the lines afterwards.
Okay, that sounds promising. Has the injection timing changed for you?

If you only screw the fuel injectors into the pump head and omit the fuel injection lines, will fuel leak out on the pump head side when starting the engine?
'When I installed the new screws, fuel started leaking out, but with the old ones, strangely, it didn't.'

Best regards.
Wolfgang.

Hello NVE,

I would start by continuing to test the existing GDVs. At least you know that they used to work.

Furthermore, it's possible that you're experiencing a different issue with the ESP, unrelated to the swap you performed. While unlikely, it's not impossible. One thing that immediately comes to mind is a broken cable. You might have damaged it during the installation, and now it's no longer working.

It might be worth checking the voltage at the fuel injector. If that's okay, you could use an oscilloscope to check the feedback voltage of the MSW (Motor System Wiring). If everything seems fine there, then I think the next step is to check if any diesel is being drawn in at all (is there any fuel coming out of the return line?) and whether it's at least reaching a somewhat acceptable RPM.

If you can answer all of these questions positively, then I don't know how you did it, but you managed to break the pump.

EDIT: Finally, the parking brake itself might be defective or stuck. You could try removing it and reinstalling it without the internal components. The motor should still be able to be switched off via the MSW (Motorsteuergerät - Engine Control Unit), but it's best to prepare for it to stop working.

Regards,
Guste.

@NVE
No, the start of injection hasn't changed.

"Did you perhaps drop any copper rings during the process? Apparently, some are supposed to be placed in the holes of the manifold, in front of the GDV valves. I didn't replace them myself, and I didn't see them. It's easy to imagine that the valves might not open properly if those rings are missing, because they seem to be slightly pre-tensioned, as I could see when I was replacing them."

/Jan

Hi everyone - I finally found the bug!

After I couldn't find any faults on the mechanical side of the pump, and fuel was also reaching the fittings, I moved on to the electrical side. After checking the shut-off valve again, I checked the remaining wires, and I immediately found a broken wire right at the pump connector.

I must have damaged a cable while removing the control valves. In any case, wire number 1 in the pump cable was loose in the pump connector, which is why it wasn't making a good connection.

Thank you for your help and the good tips!

Best regards.
Wolfgang.

NVE wrote:

In any case, wire 1 of the pump cable was loosely connected in the pump connector and therefore did not have a good connection.

Is line 1 one of the RWG cables?
If there's a problem reported from that system, it should, in my opinion, also trigger the warning light even when the engine is not running... Have you noticed anything like that?

Hello Ulf,

That also surprised me. The only possible explanation might be that there was some kind of connection, but it was repeatedly interrupted by the restarts... or something like that.
'I haven't seen the warning light come on or blink even once. But it does work, because it lights up during the preheating process!'

best regards
Wolfgang.