Tech Forum : Control pressure problem or user error?

Excello	Posted Friday, Jun 8th 10:25pm [Edit] [Quote] [IMS] [View car]
Junior Member Post nr. 1 Viginia, USA 1982 323i	Greetings Everyone, As this is my first post (and a long one too ), I want to start off by saying Thank you to everyone who has ever contributed to the wealth of good information here . I have had a great affection for the e21 cars for many years and finally found a 1982 323i locally on Craigslist with no rust and only 60 000 miles on it. However when I bought the car about ten months ago, the car had been sitting for the past 10 years and had “some fuel system issues”. I had to replace many of the parts in the fuel system and just the other day put the fuel tanks back in after giving them a good cleaning (what a mess!). However, the problem I’m having is driving me crazy. With guidance from the factory manual, I can not get the control pressure within specs . I have run the usual fuel system diagnostics on the car (something I have never done before) and have now come to the conclusion that I must be doing something wrong or I have a faulty CIS injection tester (doubtful). When I run the system pressure test the reading is about 70 psi with the fuel pump still running (with the diode relay and fuel pump relay removed and jumping the 87 connector from the pump). As soon as I disconnect the pump, the pressure drops to 30psi. I then proceed to test the cold control pressure, by opening the valve on the tester to let fuel pass to the warm-up regulator. I do the same thing as I did before by running the fuel pump. The result is identical: pressure goes up to 70 psi and as soon as I de-activate the pump the pressure drops to 30 psi. Does this mean that my cold control pressure is 30psi or 70? Either way it’s off the charts, since it should only be about 15 or 16 psi according to my charts. I have replaced the WUR three times now with some used units that worked prior, and with identical results every time. And there does not seam to be any blockage in any of the return lines (released the banjo fittings on the return lines to see if the pressure dropped, but nothing happened).I also ran a flow test which gave me about. 900 ml in 30 seconds, which really should be more like 750 ml, but I don’t know if that would be a problem? Last night, out of desperation I even replaced the fuel distributor (found one for $75.00 on eBay), and the results were the same as before. Currently the car starts up but dies right away, this could of course be related to the something else, but I really need to figure out what is going on with the darn cold control pressure, or what I am doing wrong, since the symptoms of too high values could be a car starting (off the cold start valve I guess) and dying right away. Any ideas would be appreciated? Thanks. --Nils New and replaced parts: New fuel pump New Diode relay New Fuel Filter New Fuel pressure Accumulator New Fuel sending unit. Cleaned out fuel tanks. New Aux air valve (the new kind without the electrical connector) Replaced Cold start valve (used) Injectors are spraying nicely after replacing two of them

imaradiostar	Posted Saturday, Jun 9th 5:49pm [Edit] [Quote] [IMS] [View car]
Member Post nr. 1055 Nashville, TN 81 323i, 82 525i, 85 524td, 90 535i	I bought a porsche fuel distributor on ebay and it did this- swapped back to my 323i FD and the problem went away. I don't suppose you have access to another FD? You could use one from a Volvo 260 if you can get your hands on one. jamie

Excello	Posted Sunday, Jun 10th 10:51pm [Edit] [Quote] [IMS] [View car]
Junior Member Post nr. 2 Viginia, USA 1982 323i	I don't think there is anything wrong with the fuel distributor(s). I'm wondering if perhaps the fuel pump is pumping too hard (but then wouldn't the system pressure be off as well?). Another thing I'm wondering, is why none of the three WURs I have tried are responding to temerature changes? Cheers --Nils