Help Needed: 1HDFT Injection Pump install, Timing Gears, BDC vs TDC

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Because I’ve removed an injection pump on a 1HZ before, and changed timing belt and such a few times… I failed to review the factory manual before removing the injection pump on my 1HDFT.

Instead of setting the motor to BDC, I set it to TDC. I marked the timing belt to gear relationship, and I scribed the IP to timing case relationship. What I FAILED to do, was mark the Injection pump drive gear to idler gear relationship. How would I fail to do that? It might have been, oh shiny object. Ask me about my dog. A tree. A rock. Hi.

Anyway, as you might guess, the timing marks on the idler gear were off. Like… way off. So I couldn’t use them. I used the timing marks on the timing belt to mock it all up and I thought had reverse-engineered into where the IP-drive gear and idler gear should be. But the truck runs like poop. I bled and bled and bled the lines, got it sorta running… but it just runs terrible. Barel starts, won't idle, smokes, etc.

So, I read the manual, and realized I should have had it at BDC, which (I thought) explains why the timing marks on the idler gear and the IP drive gear were so far off.
So before tearing back into it, this time, I set the timing marks at BDC. Now the timing case cover is off, and I can see the gears. And it all seems cussed up. It looks like it’s off by 5 degrees or so!
Question 1: have I already bent my valves?
Question 2: can I just turn the crank a couple notches and align everything up and call it good?

Photo 1: shows crank gear bottom left, idler gear in middle, IP drive gear upper right. Timing marks are circled in red.
Photo 2: close up of injection pump gear and idler gear
photo 3: close up of crank gear and idler gear.

photo 3.webp


photo 2.webp


photo 1.webp
 
What's weird... is that if I were to rotate the crank so that the timing mark is pointing at the idler gear... I'd still have to unbolt the idler gear and place it back in correctly.
In other words, I think the idler gear wasn't in the right place anyway.
 
Id toss er back together proper and then before you flash it up, pull the valve cover and look for broken/cracked tappets, and cam caps. I doubt you bent any valves, since they are perpindicular to the piston crown.... tends to break valve train parts instead.
 
Hey Brian, those match marks between the various gears will only match up on assembly and then every umteenthtrillionth rotation after.
Did you rotate the motor while the injection pump was out? (you should not have been able to since the cam would lock up)
If you put your own match marks back together you should be pretty close, the teenytinyest (I know, yet another very technical word in my post) adjustment in pump rotation makes a huge difference in injection timing and engine idle. If you are even running at all that means you are very close, I would say just advance the pump a little bit (tilt top towards engine block) and see if it smooths out.

If you really want to be certain you can pull the cam (easy to do with how far you are in), pull the timing idler gear (easy to do with how far you are in), pull the crank gear (not as easy to do, but easy enough) and reset all the marks.
That's probably more work than it's worth as long as you put it back together with your match marks lined up. You can give it a rotation and make sure the factory marks on the two timing pulleys are exactly aligned and then concentrate on dialing in the pump timing by rotating it a little bit.
 
Wait, did you not take the front case cover off the first time you changed the pump?
It would be very hard to get the injection pump drive gear to skip a tooth with the front case on (as in, I'm not sure there would even be enough room for it to clear the other gears at all?)

The FSM lists the procedure for swapping injection pumps and taking the front cover off does not have to be part of the program (therefore no mark on the gears to worry about)

Also, it's recommended to use BTC rather than TDC for service work since at TDC the cam can spring back and ding the valves on the #1 and #6 cylinder, or you can inadvertently rotate the cam a little and ding them yourself. You can take it apart at any mark you feel like, just so long as it goes back together on the same marks.

I'm thinking your timing is just a tiny bit off. (a whole tooth or more would be a HUGE amount off, engine would not run)
 
Guys, thanks for your help
Kevin, why would the factory marks not line up after millions of rotations?? It's not like the gear was jumping teeth. The way the manual reads they should line up if you set the timing marks to BDC.
My whole problem is I did not mark the idler gear.
Oh wait I can't move the crank timing gear... I can only turn the crank. I mean the crank timing gear can only go on in one position. The idler gear can be removed and reset in place. But if/when I do that the timing marks will only line up on the idler gear/IP gear interface.
I would need to turn the crank a tiny bit to get it all back to where it is supposed to be.
 
And yes I did take off the timing case. It was cracked and needed to be welded.
The whole problem was removing the IP gear and not marking it. Then realizing the factory marks were way off (because I was at tdc instead of BDC) and guessing where the gear should go.
 
Hi Brian,
I emailed you back, but here it is too:


Kevin is right, the timing marks will only fully align every 243 rotations (or a few up or down). This id due to the differences in teeth on all the gears.
So do not worry about that.
If you did not rotate the engine while the pump was out, you should just be able to put the pump back in in a single position (due to the key on the main shaft).

Here is what I'd suggest: Put the pump in, put the timing gear cover on, and then manually rotate the engine AFTER you put the timing belt on. The marks on the cam-belt gear and on the pump-belt gear should match after every full roatation (actually it is 2 to 1, but you'll see that). Only if these marks don't match is your timing off severely.

Does that make sense?

To adjust the plunger stroke (equaling to timing of the pump), you would need to follow the manual, with the dial indicator in the center hole between the injector line connectors on the pump.

Let me know if that makes sense, I can go in more detail,

Cheers,
jan
 
If you turn the crank pulley to the TDC mark, do all the other TDC marks line up?

I'll go to the manual to put the procedure together to fix this, but it'll take me a little.

cheers,
jan
 
OK, here is how to fix that.
Kevin, please check if you agree.

With the pump on and the t-belt on, set the marks to BDC (top mark on cam and IP belt gear).
Take the belt off, take the timing cover off, take thew idler gear off.
Now you can reinstall the idler gear correctly. The marks should be pretty close already. turn the IP shaft and crank accordingly to make them align perfectly.
Once done, install the timing gear cover and belt drive gears.
Then reset the IP to BDC, and install the belt.
The cam belt gear should still be at BDC.
To check, rotate the crank clockwise to TDC, and all the marks should align at TDC.

Should be easy.

To heck the pump stroke you can get a relatively cheap tool from ebay, such as this:
http://www.ebay.com/itm/VW-Audi-Bos..._Automotive_Tools&hash=item3cd9675e4a&vxp=mtr

Does that make sense?
cheers,
jan
 
OK, yes... this is what I had in my head. I set it all to BDC before dismantling. The IP is really already there... I just need to remove the idler gear, turn the crank about 2 teeth clockwise, and re-install.

Should be easy. Right?

I hope I didn't smack the valves being off 2 teeth.

Guys, thanks for your help. Really appreciate it. I'll most likely tackle this tomorrow or Saturday.
 
That sounds pretty good Jan. Since the motor has already been turned over in its current configuration any damage that may or may not happen has already been done.
The crank gear timing marks should be pointing the right direction every time it's at BDC (I think?) and then you can reset the others from there. If the engine was running it HAS to be very close. Also, with the block at BDC the cam can be rotated if needed without risking hitting the valves. Everything will match back up.

The injection pump keyway should be at about 11 o'clock from the front of the engine during assembly. I only mention that since the pump shaft would be very hard to turn when not mounted to the engine.
 
kevinmrowland said:
That sounds pretty good Jan. Since the motor has already been turned over in its current configuration any damage that may or may not happen has already been done.
The crank gear timing marks should be pointing the right direction every time it's at BDC (I think?) and then you can reset the others from there. If the engine was running it HAS to be very close. Also, with the block at BDC the cam can be rotated if needed without risking hitting the valves. Everything will match back up.

The injection pump keyway should be at about 11 o'clock from the front of the engine during assembly. I only mention that since the pump shaft would be very hard to turn when not mounted to the engine.
Click to expand...

Yes, my pump guy has a special tool for that that fits the keyed shaft of Denso/Bosch pumps.
J
 
OK, so the idler gear was removed. the crank was turned clockwise about 5 degrees. The idler gear was reinstalled.
Now crank to idler, and idler to IP-gear are have their marks lined up.
And the cam is still set to BDC.
Plan is to re-assemble, put timing belt on, turn crank by hand clockwise to double check the marks stay lined up. Then drive to mexico.

Cam_Gear.webp


IP_Gear.webp


crank.webp
 
Outstanding plan.
Turn it by hand and if all the 3 TDC marks line up you are golden.
When and where are you going to mex? I'll be there over christmas…
cheers,
jan
 
Success!
And suck it did. My head wasn't in this and I kept having to redo stuff. Explains how I got here in the first place. Nearly forgot keyway for main crank. Nearly forgot to tighten fan clutch bolts and main IP gear bolt. And main ground cable.
Honestly. I'm normally a good mechanic!
Anyway, thanks to all you guys for being patient and answering my questions. Once you start to doubt yourself, it's hard to move forward.

Jan, probably headed down in January to La Ventana.
 
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