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High pressure fuel supply pump timing issue

Hello guys,
After some unfortunate events my Nissan Primera 2.2 DI (2002 yr.) bent one valve (while tying to start a car) and broke a camshaft. I took off the cylinder head and took it to the shop to do full repairs (regrinding, changing valve, washing etc.). Today I was preparing to assemble everything back together and while reading workshop manual, I noticed, that my fuel pump sprocket punched mark is not aligned with marked primary chain link. I think this sprocket could have skipped some links. So I definitely can time the crankshaft with camshafts, but i’m not so sure if fuel pump needs to be in exact alignment with crankshaft? As i understand in common rail engines, injection is timed via injectors and ECU, thus fuel pump is just constantly holding required pressure? I know I could align sprockets by stripping primary chain, but it’s just so much of additional work. I’m adding a primary and secondary chain alignment scheme, maybe it will be clearer.


I really don’t want to assemble everything only to have injection, fuel pressure faults, so please, can anyone give me some insight?
Thank you, and sorry for my english, I’m not a native speaker :slight_smile:

There is an alignment mark for a reason.

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I can’t speak to your specific issue, no experience. But I could imagine the fuel pump on direct injection engines needs to be timed to the crankshaft. So the fuel pressure will pulse at its highest pressure near the top of the compression stroke.

Alignment mark might could just be a guide for correct instalation of chain. There needs to be no slack on the tension side, thus alignment mark helps for that.
As for pressure pulses, I think there is constant pressure in fuel rail rail, and there is just one exit for fuel from pump, so it can’t be timed with specific cylinder intake stroke.
Sill waiting for other opinions.
Have a good day!

Yes, if nothing else aligning the chain links to the pulley marks sets the proper tension on the chain.

I’m not familiar with your engine but the “pump- distributor” type fuel pump on my 2002 Jetta TDI (has a separate fuel line going from pump to each injector, not a common rail system) requires the pump to be synchronized to the crank via the timing belt. Check the shop manual for your car or a forum specifically for your model.

Also, bad things will happen if you don’t get the cam timing just right so after you believe everything is properly aligned you may want to turn the engine through two complete revolutions manually (use a wrench on the vibration damper nut, turning in the engine’s running direction) to confirm there is no valve to piston interference. Don’t turn the engine backwards for this test because of potential problems from reversing the slack in the timing chain.

@Matas_Sapalas - What caused all this damage in the first place. Just replacing the damaged parts may not solve your problem.

@texases Secondary timing chain have skipped some teeth because of some iresponsible untightening of vacuum pump sprecket on far side of the engine. This was not noted, and we tried to start a car, so we damaged one valve.

@ken2116 Thanks for your answer. Good point about turning engine over by hand, I will definitely time the camshafts with crankshaft. Im just not so sure if fuel pump needs to be in specific position. Manual is no help, unfortunately. There is just a tip to check chain alingment, but not in fuel pump chapter.

from what I see, fuel pump sprocket has to be put in alignment before you install the camshaft timing components

did you disassemble only the top part (camshaft chain) and kept fuel pump sprocket as it is?

as you told yourself, it may have skipped few teeth, so it needs to be readjusted to match marks

while there, check if chain or shoes or tensioner need replacement - at 17 years old it may be worn to the point you want to replace them too

The fuel pumps that I have found in views of your engine have 4 independent pressure outlets and so it must be in time. There is actually a timing light to adjust injector timing on such systems.

I’m familiar only with my own car, the 2002 VW Jetta TDI where the pump is timed to the crank (and cam) and delivers timed shots individually to each of the injectors. That being said, you’ll need to determine whether the timing of pulses is determined by your pump or by some other way. Your’s may be different, but you still need to be sure.

See if you can get a look at the official service manual published by the vehicle’s manufacturer - a dealership should have it and if you ask nicely the service manager or a mechanic may let you take a look at it, or answer your specific question directly. Next in line would be a competent independent mechanic familiar with your engine. I found assembly drawings and specs for my injector pump with the help of one of the users forums on tdiclub.com - dedicated to VW and Audi diesels. Look for online forums devoted to your vehicle or, absent that, to diesel vehicles in general. If no luck with those, consider posting your questions to tdiclub.com as someone there may know how to help you.

There’s enough potential expense riding on your having accurately timed the cam, and perhaps the pump, that it might warrant the relatively small expense of paying a competent mechanic to check your work before you start the engine, one might even be willing to come to your car.

Best wishes,

Ken

@Rod_Knox Hi, 2.2 93 kw YD engine has this kind of fuel pump, with only one high pressure outlet via injection tube. that’s why I’m guessing it doesn’t need alignment, it just keeps high pressure in fuel rail.
image

@thegreendrag0n Hi, Yes, only top part was disassembled, fuel sprocket was untouched. Well, it’s kind of hard to believe that primary chain have skipped 9 links during the piston-valve contact, and even if it did, and fuel pump does not have to be timed, I could just time camshafts and she would be good to go. But you got the point, it would be wiser to check primary chain. I’m planing to keep the car for 1-2 years max, so these additional hours to strip oil pan, sprockets, pulleys, tensioners, chain case will be pain in the a** :slight_smile: I’ll give it a good thought this evening.
P.S. one more thing that gives me doubt about this pump sprocket alignment mark: I have same engine in my garage (for parts) and when I took upper chain case off, I saw that this chain is also not aligned, and this motor was running just fine.

well, then you answered your own question.
if another engine has timing marks the same, then the diagram is wrong.
my limited experience on timing chain replacement (Nissan VQ40DE engine, not yours), is that Nissan own shop repair manual has errors in how marks on harmonic balancer align to cover marks, I had to review what otehr people on YouTube doing to see it was obvious error in OEM diagram for my vehicle year.
what I also found at a time (measuring how close pistons are to the top, BBQ bamboo skewers came handy), that both “recommended/wrong mark” and “real alignment mark” would not result in valves damage if chain is removed

I’m guessing you will find out.

If there is an alignment mark on the housing that aligns with the mark on the sprocket that is all you need.

The colored links are aligned during assembly but will not match the alignment marks again after turning the engine 2 revolutions, the number of rollers in the chain do not match the number of teeth in the sprockets.

For example there may be 24 teeth in the crank sprocket and 48 teeth in the pump sprocket but 111 teeth in the chain. Because of this the rollers in the chain are not in contact with the same tooth in the sprocket for each revolution to prevent a wear pattern from developing.

If you rotate the engine by hand for 10 minutes you may see the links align eventually.

Hello everyone,
After waiting so long for parts, yesterday I assembled the car and after long towing to bleed fuel system (priming pump didn’t do it’s job) she is up and running. Big thanks to @Nevada_545 who mentioned this, should I say, obvious point about chain alignment. Shame on me I haven’t realized it earlier, then again, it was first time I did cylinder head replacement, so I had a lot of other things to worry about :smiley: Just like you told, I just rotated the crankshaft, and after dozen of turns marks eventually aligned.
Have a good day.

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Thanks for letting us know