Z22yh high pressure fuel pump repair

This is a step by step guide to repairing your high pressure fuel pump ONLY IF THE THREE PUMP SEALS ARE OK!!! I had the usual fuel pressure problems with the P1191 etc codes, so decided to strip my pump to see what had actually failed.

The issue with the pumps is over time the oil they are pre filled with at the factory seeps through the oil seal into the engine, thus losing the hydraulic action of the actuators inside the pump, and in turn loss of high pressure fuel delivery. The fill port for this has a steel ball bearing pressed over it, suggesting that they are a sealed unit, BUT, by stripping the pump down you can get this bearing out and refill the pump with automatic transmission fluid! Note if you strip your pump and the seals are perished/split, THIS REPAIR WILL NOT WORK, but if your seals are ok, you've put off spending £300 for a while 🙂

Here's how you do it:

Make sure engine is cold

Step 1:
Disconnect battery negative lead ( you may or may not need you car pass to reactive radio etc afterwards, I did not have to on a 03 signum elite).

Step 2:
Unscrew the black cap on the fuel pump, then place a piece of old rag under the needle valve. Now using a thin flat bladed screwdriver, push the needle in to depressurize the fuel pump. A small amount of fuel will be expelled onto the rag.

Step 3:
Using a flat bladed screwdriver, carefully loosen the clip and push the hose off the pump fitting. Keeps the clips safe.

Step 4:
Unscrew the nut on the other fuel pump fitting using a 17mm open ended spanner.

Step 5:
Remove both fuel fittings on the pump using a 13mm spanner. Put them somewhere clean and safe.

Step 6:
Using a small ratchet with 8mm socket, remove the 3 bolts from the fuel pump housing, then gently withdraw the pump.

Step 7:
Using a T30 torx bit, undo the 3 pins holding the pump together. You may have to use a thin flat blade screwdriver to separate the housings. Get a piece of cardboard to lay out the internals of the pump.

Step 8:
Once separated, you should be able to see if there is any oil present, more than likely its gone into the engine. Pull out the actuator plate, this is the part that has three piston rods on that press onto the seals to operate them, be carefull with it as it easily falls apart so take note of how it looks just in case.

Step 9:
Now it's time to see if your seals have gone. The plate underneath the actuator plate you have just removed houses the seals, to get this out, tap the pump housing down onto a piece of plywood and it will drop out. When this falls out the 3 springs go in the fuel ports may come out to, remeber these go spring down into the port, metal dome up mating to the seal for reassemly! Now you can check if your seals are ok if they show signs of wear or splits, STOP NOW, it's new pump time unfortunately 🙁 BUT if they appear ok, put the plate and seals somewhere clean and safe and continue.

Step 10:
If they didn't fall out, take out the 3 springs from the fuel ports, and place them somewhere clean and safe.

Step 11:
Now you need a piece of 3mm bar and a g clamp to get the ball bearing out of the fill port, I used a cut down 3mm drill bit using the chuck end not the cutting end as that will break! Place the 3mm bar into the hole underneath the ball bearing, and using your g clamp, wind down onto it to push the ball bearing out, note, as you get near to it coming out, put a 12mm nut over the hole the ball bearing is going to come out off, and continue with the g clamping.

Step 12:
Now the bearing is out, you can,
A) Drill and tap the hole to m12 to accept a bolt to make any future work easier.
B) Leave as is, and knock the ball bearing back in later.

Step 13:
Meticulously clean all parts and reassemble pump.

Step 14:
Using the ATF fluid, slowly top up the pump through the fill hole you made by knocking the ball bearing out, literally use a bottle cap and fill, turning the pump hex end over by hand as you do to draw the fluid into the pump, do this until it draws no more fluid into the pump.

Step 15:
Put cam seal in front of fuel pump and reattach to the pump to the engine, gently rotating it until the hex end engages into its camshaft housing then fit the 3 bolts.

Step 16:
Knock ball bearing back into fill whole gently until seated or, if you did this, put your m12 pin in using a copper washer.

Step 17:
Put all fuel fittings back onto pump.

Step 18:
Tighten metal fuel pipe back onto pump with 17mm spanner. Then push the other pipe back on making sure the clips lock.

Step 19:
Reconnect battery, check your work over and start the car DO NOT DRIVE STRAIGHT AWAY LET IT TICKOVER FOR A WHILE, you may get a spanner light, just let the car Idle for a while till it goes off.

All being well your car should now be back to full power as you have extended the life of your pump and put off spending £££ for a while 🙂

Best of luck, yayo 😉