Project OMG: Stopping the leak

Now with video! See lower down.

There was a bonus this morning, when the seal kit for the Omega arrived earlier than expected. To recap, the Omega had a declared fuel leak when I got it, which I just about managed to stem for an MOT, but which very much still needed doing. Leaks from these Bosch diesel injector pumps seem very common – to the point that you can’t help thinking there must have been a better way…

Having already removed the inlet manifold, it didn’t take long to pull the pump to bits. I first marked the sides, as positioning is very important (as I’d soon find out!). I’d already smashed a 7mm socket onto the anti-tamper screw, and cracked that off, so it really was just a simple case of undoing four bolts, removing the lid, then undoing three more to get the next level off. I used plenty of blue rags to catch the diesel that spills during this operation, and I’d thoroughly degreased the pump and surrounding area. Cleanliness is good!

The new seals were fitted – one of the old ones just fell out, and the other didn’t need much coaxing. The new ones simply push in. I put the pump back together, but didn’t fully tighten the base screws. These need to be left for fine-tuning. In short, if this part of the pump is not exactly where it needs to be, the fuelling will be out. At best, the car will run poorly. At worst, the car won’t run at all.

It was at this stage that I discovered that the battery was flat. It just about had enough juice to illuminate the dash lights, but not enough to turn the engine. Unfortunately for me, the car was parked in a manner that left it impossible to get a car in front of it. The 2CV (just because it was there) was just able to pull the Omega backwards, so I could then squeeze the Honda S-MX in to provide some much-needed charge.

My black, Japanese jump pack.

My black, Japanese jump pack.

Incidentally, the tiny li-ion jump pack I have was not even remotely interested in starting a high-compression, 2.5-litre turbo diesel engine. Nor was my ancient Halfords lead acid jump pack, though that hasn’t been that keen on starting a 2CV engine lately…

The Honda hurled volts at the Omega, and it then burst very noisily into life – on account of having no inlet manifold fitted, and also the EGR pipe venting to atmosphere in the engine bay. It sounded awful, not settling to an even idle. As the pump filled up with fuel again (replacing what was lost), the revs suddenly rose alarmingly. I quickly turned off. This is a real danger, so never walk away from the car if starting it in these conditions. Keep your hand on the key!

I then slackened off the lower pump bolts, and gave it a few taps forward using a wooden hammer handle. Don’t hit the pump with the metal part of the hammer, or you’ll damage it. I tried starting it again. Uneven and awful. Off again and a further tweak. Now it seemed to run nicely. Brilliant! I then set about tightening the bolts and refitting the inlet manifold. I missed a key stage here, which we’ll get to in a minute!

Refitting the manifold was a right faff, as it’s very easy to lose the nuts that hold it in place. Six are easily accessible above the manifold. The other six require you to get them in place where your hands can’t reach. I lost two and had to remove the manifold again. Stuffing a bit of rag in the socket helped keep the nuts in place until they were seated. I wish I’d thought of that earlier…

I also wish I’d taken more photos, but time was very much being munched away. I needed to crack on.

With the engine back together again, I fired it up. Oh dear. It was lumpy, prone to surging and chucked out loads of soot. This didn’t look right at all. The problem is, you need to keep the engine running while you tighten down those pump bolts, as even that slight movement can disrupt the fuelling. I was going to have to pull that sodding manifold off again.

With the pump now accessible once more, I loosened the bolts and started the engine. Still lumpy, so at least I knew the problem wasn’t manifold related. I tapped the pump forward, it was still bad. I kept going (we’re talking very small movements here) and bingo! Suddenly it began running sweetly again. I left the engine running this time, and tightened the bolts. That upset it again, so I backed them off once more and nudged the upper pump section forward a little more. Tightening it this time made no difference to the running. Success!

Back on with the manifold and, despite my best efforts, I still managed to lose a manifold nut. Like my old XM, this is one of those annoying bloody cars where if you drop something, the chances of it reaching the ground are pretty much nil. I couldn’t find it but thankfully, a 13mm-headed nut with washer was a fine replacement. Reaching the rear-most nuts is a particular challenge, that left me ‘planking’ atop the engine. I’m glad no-one saw me.

With it all back together once more, I could hook up the jump leads AGAIN and bask in the cheering warble of six happy cylinders. A test drive revealed that all was well, and no longer was there a hideous stench of diesel every time I stopped. The test drive was about four miles, and I left the car running to hopefully recharge the battery. That’s two batteries out of four on the fleet that are far from happy, and both are on cars that were off the road for over 18 months…

Fixed! No leak, smooth running. Phew!

Fixed! No leak, smooth running. Phew!

It’s all very pleasing, and leaves me looking forward to cracking on with other jobs. This poor car really is overdue a service, and I’d still like to sort out the unchanged rear spring. It is rather overdue a wash too. I’m sure that’ll remind me of how big it is!

A video of today’s adventure will be forthcoming. EDIT – and is now here!

One thought on “Project OMG: Stopping the leak

  1. Very wary of diesels, I had a Orion once which was fitted with the wrong pump and it struggled to drive up any sort of hill due to timing. But I feel your pain on having to fit and then remove and then refit various parts, hopefully now you will be able to crack on with the other minor job’s without the stench of diesel.

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