I've got a 1994 Vauxhall Astra 1.7DTL with a Bosch VE rotary pump, and for want of a better term it kangaroos. It does it as you accelerate, or as the engine becomes under load. This is not an uncommon problem on these models, but to try to cure it I've changed the injectors twice, fuel injector pipes, engine mountings, cleaned the EGR valve many times and blocked it off, cleaned the inlet manifold thoroughly, adjusted the fuel screw on the pump (½ turn max, and every subsequent adjustment has been within that ½ turn), used Millers fuel additive, checked and double checked pump timing with a dial gauge (0.8mm ± 0.1mm BTDC), and I still can't cure it. Some days it isn't too bad, others it's terrible, but it's always worse when the engine is under heavy load, and especially when it's cold. I always worry when it comes to MOT smoke test time too.
The compressions with checked about four years ago, and they were about 300psi on 1, 2 & 3, with No.4 slightly lower on about 280psi. I can't see this being enough to make a significant difference, and it always starts well from cold anyway.
I'm convinced it's to do with transfer pressure in the pump, but at 202,000 miles it's not really worth spending £400 to get the pump overhauled, especially if there's no guarantee it'll cure it. And in any case I'd de-coke the head at the same time if I did decide to have the pump done.
I'd be grateful for any suggestions other than scrap it.....
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It might be worth looking at the fuel filter.
Sometimes these filters were supplied with extra, superfluous, o-ring seals - particularly the small one in the middle, near the thread. I can't remember which cars needed the extra seal, and which didn't, but if you got it the wrong way round, running problems, and difficulty bleeding the system were the result.
If this doesn't help, it might be worth using a length of clear fuel pipe to make sure that you aren't getting bubble of air in the fuel - most older diesels run very erratically with air entrained within their fuel.
I don't know how you would check your idea about the transfer pressure being wrong - is there an obvious port on the pump to connect a pressure gauge to? (again from memory, I don't think there is?)
Number_Cruncher
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NC I change the fuel filter every 12 months but you are right about the centre O ring. I remember from my days of working in a Vauxhall dealer that a bulletin said we were to leave it out, but if I recall that was on older 16D and 16DA naturally aspirated engines.
I'm not totally sure whether it should be used on a 1.7DTL but I always do fit it on mine. Maybe next time I'll remove it and see what happens.
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Just spoke to a friend of mine who also worked in a Vauxhall dealer. He left in 2003, I left in 1995. He reminded me that the inner seal should be removed on all these variants, as it prevents the outer seal from sealing properly and the filter draws air as a result.
I changed my filter about 6 weeks ago, and I can't undo it without damaging it. So I think I'll invest in a new one.......
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Check the fuel return pipes : often crack and let in air: will be worst when system is cold as bubbles will have formed overnight.
madf
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I got a new fuel filter and fitted it without the centre O ring seal. I drove it up a hill in 4th gear until the engine laboured like mad and I was down to about 20mph and it was not doing it. Before it would've been hopping anout like a jack rabbit.
If it's not cured then it's definitely much better.....
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>>If it's not cured then it's definitely much better.....
Excellent!
Over the years, I wonder how many people have paid out for expensive fixes to these cars, like new injector pumps, when only a simple o-ring in the wrong place is the fault?
Or, perhaps the better question is why do these filters continue to be supplied with a seal isn't needed, and which will make the car run badly?
Number_Cruncher
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What annoys me is that if it had been a customers car in the workshop I'd have probably binned it without even thinking about it, but because it was my own I was slightly more conscientious........
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