Injector jammed open??

[white]

Bear with me, a couple of years ago my 350i started suffering what felt like severe fuel starvation and it's been stuck in the garage since. Recently got a pressure guage from work, connected it to the pipe-work and energised the fuel pump by moving the air flap. Pressure reaches a healthy 37psi but then drops to 10psi in 10 seconds dead, so somethings leaking! Put the guage directly onto the pump hose and it held it's pressure well, so non-return valve is ok. Next changed the regulator for a "known good used one" from a specialist but pressure drop still the same.
First question, is there a way of testing the regulator without swapping it for a new one, before I begin stripping plenum, ram-housing, rails, etc to remove the injectors?
Assuming an injector is stuck open, is it more likely to need just cleaning, or changing for a new one (cars done 50k).
Finally, I have some ultrasonic baths here at work. If I do have to remove the injectors I might as well clean them all anyway - anyone know a good solvent to use in the bath to help clean them?
Cheers
Trevor

[GreenV8S]

I don't see the point in testing the regulator for leaks, in normal use it only has to apply a restriction it doesn't have any need to seal. Given the small amount of work involved I suggest you pull the injectors out. If you feel inclined you could blow them through and see whether any of them are obviously keaking, but at that age it would probably be well worth getting them cleaned anyway. I think the going rate is of the order of £15 per injector. If you're in a position to do this yourself so much the better.

[badredwedge]

If you have an injector stuck open have you got a pot full of fuel ?? (and a sump for that matter ?? )

[leorest]

white said:

...anyone know a good solvent to use in the bath to help clean them?

I have a small utrasonic tank in the garage and would also be interested in which solvent to use. I was thinking of a cup of petrol with a high concentration of injector cleaner, the stuff you buy and stick in the fuel tank. Is this a stupid idea? Probably
Leo

[dickymint]

I don't suppose you connectd the gauge to the cold start injector pipe? if so it would drop after 10 seconds because of the thermotime switch. Just a thought.

Edited to say - stuck injectors can often be sorted by hitting them firmly and repeatedly with a screwdriver!!! (trick learnt from wedg1e).

>> Edited by dickymint on Saturday 10th September 13:08

[wedg1e]

Thread revisit...

I've got a couple of dismantled injectors here that seem to have rust on the internal parts. Now I'd have thought that they'd be stainless but it appears not (or at least not the best quality). So a normal ultrasonic tank solution (ie water-based) is probably not a good plan, especially if you were going to leave the injectors on a shelf for a while afterwards.

As to whether injector cleaner would work, well, you'd imagine so! Thing is, there's a fine mesh filter in the inlet stub that catches particles; whilst injector cleaner might shift any stray particles that get through, I doubt it would shift rust.

Given the number of injection setups that appear on Ebay, I'd say buy a spare set of injectors, flow test them all along with those already on the car and pick the best matching set. If you get stuck I have one or two spares that I could bear to part with...

[anonymous-user]

Get a webber 500... then you will have no more EFI worries!

[white]

Thanks for the ebay tip Ian - not sure why I didn't think of this because I'm on ebay every day!
Regarding the injectors, I removed the whole set-up complete and energised the fuel-pump -- and no leaking injectors! Still I removed them anyway and put them in an ultrasonic with a mixture of petrol and injector cleaner for a few days.
So to be honest I'm scratching my head. Injectors seem ok, fuel pump seems to hold it's pressure, so what's going on. Cars been off the road a very long time now and I can understand why people move over to carbs!
Believe it or not I took it to a specialist last year to find out what was wrong with it, only for the !$&* to right itself (until I got it back home)when it was on their rolling road so they couldn't find the fault, though they did say pressure looked low until that point.
@#*%!@@
Thanks for the reply by the way...

[Gerry Attrick]

Decon 90 is the cleaner the industry uses. Separate the bits and stick them in for about an hour. It will shift almost anything.

[rev-erend]

Normal trick is to try someone else's bits that work..

Try the ECU first .. if it runs sweet : then you know you have found it.