Wiki article summarizing VW TDI emissions cheating so far, click here. Anyone logged in can edit it by clicking the "edit" button on the upper right of the page. It's a reference so please post any comments or questions in the forum. It's a work in progress so feel free to update it!
ALH engine fuel injection pump installation, without removing timing belt
Reinstalling your Volkswagen Jetta, Golf, or New Beetle ALH engine fuel pump (IP), Part 2
Also review ALH timing belt part 3/3 - installation to make sure you understand what you are doing. The article is for premium members only so please join our TDI community.
* Remove all the packaging and plugs sealing the port openings on the replacement injection pump. You may choose to leave the plugs on the injection pump until the various fittings are going to be reinstalled to ensure that inadvertent dirt doesn’t make its way into the fuel connections; just remove them during the reinstallation. Make certain that the injection pump came with four new copper washers. One is already in position behind the return line union. Two will go on either side of the banjo return line. The fourth is for the fuel supply line union (left side where black plug is located).
* Install the injection pump onto the support bracket, hand tighten the rear mounting bolt, and place the connector wires into its wire clip/holder.
* Position the injection pump in the bracket and tighten the front bolts with a 13mm socket to 18 ft-lb (25 Nm) and then tighten the rear bolt with a 13mm socket to 18 ft-lb (25 Nm).
* Remount the injection pump sprocket onto the pump hub and loosely install the three (3) new injection pump sprocket bolts into the injection pump sprocket, positioning the sprocket so that the bolts are in the middle of the elongated holes. Do not tighten the bolts quite yet, but leave them loose.
* Lock the injection pump sprocket using the A4 TDI Pump Pin, making certain that the pin enters the alignment hole toward the top of the injection pump and not to the side of the hole (common mistake). Refer to the earlier pictures. The pump hub nut may have to be rotated slightly with a 22mm wrench to get the A4 TDI Pump Pin inserted completely.
* Ensure that the crankshaft is still at TDC: Recheck that the Nr. 1 cylinder cam lobes are pointing upwards, the brake booster vacuum pump groove in the end of the camshaft where the vacuum pump resides is horizontal and the Universal Cam Locking Plate or equivalent tool is still in place.
* Using the Universal Sprocket Buster Counter-Hold Tool (the green bar shown in an earlier step), hold the camshaft pulley still while loosening the 19mm bolt 2-3 turns. Do NOT remove the bolt at this time, just loosen it a few turns as shown by the white arrow below. Make certain that there is a gap between the washer and camshaft pulley (white arrow).
* Release the camshaft sprocket from the camshaft taper using the Cam Sprocket Puller. After installing the puller, use a 17mm boxed-end wrench to turn the puller bolt clockwise until the camshaft pulley pops off of the tapered end of the camshaft (picture is staged from another step but shows the puller in use).
* Place the timing belt onto the injection pump sprocket and tensioning roller, and thread under the idler roller. The camshaft sprocket may need to be removed (loosen the 19mm bolt all the way) to get the timing belt on. I prefer to remove the camshaft sprocket and inspect for nicks, gouges, or any grease on the taper. The camshaft taper and camshaft sprocket taper should be clean and dry. The timing belt routing is shown below.
* Using a mirror and a light, be sure the tensioning roller retaining tab on the upper left is correctly seated in the hole in the timing belt guard.
Here is a picture from another writeup with the tensioner removed to better illustrate the tab hole. Tighten the 13mm nut loosely finger tight only. The purpose of finger tight only is so that when you tighten the tensioner in a later step, the camshaft and injection pump sprockets can rotate, spreading the tension evenly across the timing belt (the cam lock and injection pump lock should be in place so that although their shafts are locked, their sprockets are be free to rotate). Also below is a picture of the tab not in its slot (pic by rallysmurf). It should not look like this.
Tighten the tensioner by turning it clockwise only, until its notch and raised mark are aligned.
Using a mirror, double check the notch and raised mark positions. Here is a video showing a closeup of the tensioner and a video of the belt. Click the play button (the triangle that points to the right) to view the video. The button to the right of "HQ" will switch the video to full screen. Remember, it's normal for the sprockets to rotate when you tighten the belt (the cam and pump are locked but their sprockets can move). The crankshaft sprocket (shown by the TDC mark on the flywheel) should not move.
* Using the Universal Sprocket Buster Counter-Hold Tool, hold the camshaft pulley still while loosely reinstalling the camshaft sprocket bolt by hand but not yet wrench torqued.
* Make certain the A4 TDI Pump Pin is still in place and centered in its elongated hole.
* Tighten the tensioner lock nut with a 13mm boxed-end wrench to what feels like “Good-and-Tight”, while maintaining the tensioner position with the Compact 3 way Tensioner Wrench. With the engine mount bracket in the way, it is impossible to get a socket and ratchet on the tensioner bolt. This is likely why the Metalnerd Compact 3 way Tensioner Wrench comes with a separate 13mm wrench. It is also why it's recommended to mark the tensioner nut in the Removing Injection Pump Section. Because this is such a critical nut it couldn't hurt to turn it a few degrees past where it was before.
*Using a mirror, ensure that the notch and the raised mark are aligned on the tensioner as shown in the video and not moved from tightening the nut.
* Ensure that everything is still at TDC and that the A4 TDI Pump Pin is still in place.
* Using the Universal Sprocket Buster Counter-Hold Tool, hold the camshaft pulley still while reinstalling the camshaft sprocket bolt with a 19mm socket to 33 ft-lb (45 Nm). Some have recommended increasing the torque by about 20%, which means 40 ft-lb (54 Nm). See 1000q: ALH timing belt part 3 for a further explanation.
* Tighten the three (3) bolts on the injection pump sprocket bolts with a 13mm socket just enough to hold the sprocket. Then tighten them to 18 ftlb (25 Nm).
* Remove the Universal Cam Locking Plate and A4 TDI Pump Pin.
* Using the Universal Sprocket Buster Counter-Hold Tool (used on the camshaft) or the 19mm crankshaft bolt (on the lower part of the engine, not the camshaft), rotate the camshaft CLOCKWISE for two complete rotations. Compression should be felt during the rotation, which will go away if everything is timed correctly. If the compression does not go away and/or it feels like a valve is being hit then carefully turn it back and re-check all the TDC setting and bolts for correct torque setting. If for some reason the transmission was placed into gear, place the shifter into neutral.
*Once the two manual rotations are completed, the Cylinder Nr. 1 should be at TDC with the lobes in the up position. Recheck all the TDC marks.
* Reconnect the harness connector for the injection pump wiring, and slip the connector into its retaining bracket.
* Reinstall the three (3) bolts for the vacuum pump with a 13mm deep socket and/or 13mm offset box wrench to 15 ft-lb (20 Nm). Remember to include the vaccum pump seal.
* Reinstall the valve cover with a long 5mm Allen socket to 7 ft-lb (10 Nm). In my case, I had to reconnect the Oil By-Pass filter line to the valve cover.
* Reinstall the vacuum line support bracket with a ¼-inch drive 10mm deep socket or 10mm offset box wrench underneath the vacuum pump, and then the vacuum line.
* Reinstall the three coolant glow plug wires in front of the vacuum pump.
* Reinstall the upper timing belt guard, five (5) clips.
* Reinstall the EGR and hoses or race pipe and upper intake hoses if removed.
* Reinstall the fuel lines (2, 1, 4, 3) by tightening to the lines marked at the beginning of this modification with a 17mm open-end wrench, making sure they are adequately tight.
* Pull the rubber plug from the injection pump fuel supply inlet. Install the fuel supply line connector on the top of the injection pump with a 17mm deep socket to 18 ft-lb (25 Nm), using one of the new copper washers.
* Install the banjo return fuel line and cap nut onto the injection pump with a 17mm socket to 18 ft-lb (25 Nm), using three (3) new copper washers; one between the injection pump and the union, and one each on both sides of the banjo return fuel line.
* Reinstall the braided return fuel line from Injector Nr. 4 to the injection pump, including placing it back on the plastic clip attached to the vacuum reservoir bracket.
* Reinstall the two fuel line clips with a 10mm socket.
* Reinstall the vacuum reservoir ball and CCV system.
* Reinstall the fuel supply line and remove its hose clamp.
* Prime the injection pump by drawing diesel fuel using a hand operated vacuum pump (e.g., Mityvac Model 04000). At first, there will not be much vacuum pressure, but keep pumping. Air bubbles will be seen in the clear fuel supply line, but then they will go away. As soon as the vacuum pump holds pressure, you should see a little diesel fuel exiting the return line.
* Reinstall the fuel return line and remove its hose clamp.
* Crack loose the nut on top of Injector Nr. 3, wrapped a shop towel around it, cranked the engine a few seconds until some fuel comes out, and then retightened the nut. Repeated on Injector Nr. 2. This will additionally center the timing belt on the pulleys and allow the tensioner to remove any slack.
* Start the engine. It should take only a few seconds of cranking the engine before it starts. The engine will likely cough and shudder a little but then quickly settle to a nice idle.
If the engine will not start even after priming the fuel line, recheck TDC and check if you missed something.
* Check to make sure there are no fuel leaks. Also, if the thermostat was changed then be sure there are no coolant leaks and the level of coolant is correct.
* Reinstall the skid plate or belly pan, and lower the car off of the jack stands. Re-check the coolant level if the thermostat was changed.
You should now fine tune the injection timing with a Ross Tech VCDS (used to be called VAG-COM). If you don't have a VCDS but the engine starts, just try to find someone later who has it and use their VCDS to check and fine tune the timing. The purpose of the locking pin on the injection pump is to ensure that the car will start and is set to the approximate correct timing. Fine tuning the injection timing will make sure that you are maximizing power, starting, and economy. If nothing else, it's a good idea to make sure that injection pump timing is set within the normal boundaries of the graph. Some screenshots from rocketeer928.
Caution: when the engine is running, make sure any bolts/tools/fingers are clear of all belts or radiator fans. The moving belts or fan can easily rip off your hand or fingers if they get caught in the belts or fan! See the TOS Agreement for the full legal disclaimer.
Start the car and check engine oil pressure, any abnormal sounds, etc. Assuming the car is running OK, rev the engine at about 2,500 rpm until the coolant temperature gauge is sitting straight up (ideally at least 85°C or 185°F). You could also go for a drive until the engine is heated up. A warm engine is required to check the timing.
Adjusting fuel injection pump timing on VW Jetta TDI
Leave the engine running at idle. Connect the VCDS cable to the car’s OBD2 port and to your Windows PC. Start up the VCDS software and you'll see the screen below. Click “Select” (circled).
After VCDS has established a connection with the ECU, click "Basic Settings - 04". You could also click “Meas. Blocks – 08” , then Engine Measuring Block 000 and click “Go!”. Then click the “Switch to Basic Settings” button.
Click the “TDI Timing” button. A graph like the ones below will appear and the glowplug light on the instrument panel will flash. If the graph can't show up or you don't have a genuine VCDS, look at measuring block 000 (shown below).
If you use data block 000, note block 2 (timing) and 9 (fuel temperature not coolant temp). When block 9 is reading 110 (this is why you must let the car warm up), then block 2 should show 70. The values may not correspond to C or F. It may be an internal value that the ECU translates into temperature. To be sure, go to "advanced measurement blocks" and check off which values you want to see, there you can see the actual temperature. Refer to the service manual for the injection timing graph if you can't see the graph through VCDS.
From the drop down menu in the lower right corner, select either “1.9l R4 TDI AGR/AHF/AHL Golf/Jetta (pre 04/1999)” or “1.9l R4 TDI AGR/AHF/AHL/ASV Golf/Jetta (post 03/1999)”, depending on the year of your car.
The horizontal and vertical yellow lines apex is where the timing is set. Below is the position that the timing happened to land on. Below the blue line is retarded and above the green line is advanced. An acceptable range is between the lower red and upper green diagonal lines.
If there are no yellow lines, timing is very retarded. If there's only a vertical yellow line timing is too advanced (pictured below).
To adjust injection pump timing you must physically adjust the injection pump. Adjusting the injection pump will change block 2 (the horizontal line if you're looking at the chart). Always keep the injection pump timing within the boundaries of the timing chart on VCDS. Slightly advanced timing (above the center line) will result in slightly higher EGT and slightly more engine stress but better fuel economy, power, and easier cold starts. Slightly advanced timing is preferable to slightly retarded timing although anywhere within the boundaries of the lines on the chart is considered acceptable.
The picture shows timing that is considered acceptable.
To adjust injection pump timing, first shut off the engine. Take off the upper timing belt cover.
Slightly loosen the 3x 13mm injection pump sprocket bolts. Only loosen them enough so that the sprocket can slide under their pressure - if you loosen them fully, the injection pump may move independently of the sprocket due to pressure from the belt and internal forces. A tip is to loosen them one at a time and then tighten it just barely with a ratchet. If you loosen them all too much, the sprocket is too free to move and timing may go from way retarded to way advanced.
Then use a wrench to gently nudge the 22mm center nut that is connected to the injection pump shaft. Rotating the nut counterclockwise will decrease the block 2 value and retard timing, clockwise will increase block 2 value and advance injection timing. Refer to your service manual for the exact graph of the injection pump timing envelope for your car. Do not apply too much pressure to the center injection pump sprocket nut because it's not designed to be removed and you don't want to loosen it! Then torque the 3x 13 bolts to their final torque of 18 ft lbs
Note that the service manual says to rotate the injection pump shaft/nut clockwise to advance timing, counterclockwise to retard timing. Remember that when you move the pulley or shaft in one direction, the relative motion of the shaft is in the other direction.
Recheck timing by following the earlier steps. Obviously, when you are adjusting the 3 bolts or injection pump pulley, the engine must be off!
It took rocketeer928 three adjustments to get the timing slightly advanced, as he prefers it (pic from rocketeer928). Reinstall the upper timing belt cover when satisfied.
* Reinstall the upper engine cover with a 10-mm socket, or push it back on if you’ve retrofitted it with the pop off cover.
* You may need to clear some engine and other fault codes with VCDS after all is finished. Make certain that any fault codes were created while replacing the injection pump, and that you don’t some unrelated problem.
That’s it. Drive and enjoy!