what's needed to test fuel pressure?

[electrofelix]

'93 318IS M42

Similar to the thread http://www.m42club.com/forums/showthread.php?t=10405 I have a problem where I basically need to press the gas pedal when starting until the car warms up a little otherwise it dies.

Acquired an MT2500 snap-on scanner recently so I should be able to get some live readings from the oxygen and coolant sensors, don't know about the AFM temp sensor though. Since the car run's well once warm, don't think it's ICV related, and have fixed all vacuum leaks as well.


So the only part I won't be able to test is the fuel pressure.

No Schrader valve on the fuel rail for the M42, so I assume will have to put something together and hook it up in between fuel filter and rail or pump and filter to test if the pump is providing enough pressure in the system or if the filter managed to get clogged (<3000miles done since replacement).

Plenty of kits out there, but no idea as to what's actually required to be in the kit to be able to do this. Assume some people here have either put together one that's suitable of have bought a kit that has the necessary fittings. Suggestions?

[doitover]

I probably shouldn't answer, my car has had the fuel line rerouted a bit and it may not reflect what you have. I'm pretty sure that when I checked mine all I had to do was remove a line from a fitting, add a short piece to the fitting and then connect the gauge to a T spliced between the hoses. It wouldn't be real convenient but you could do that either at the fuel pump or on one side of the fuel filter.

Also, I'm pretty sure that what you describe sounds like it is the ICV or a leak.
Since you are pretty sure that it isn't a leak it is likely to be the ICV.

[electrofelix]

Once warm the butterfly valve in the throttle body can be let go fully closed and car will idle fine, so I've assumed that this means the ICV must be doing it's job otherwise the engine would still die.

If the ICV was sticking I should be seeing an idle bounce. I do see one overshoot on braking and releasing the clutch into neutral quickly from a high rpm (~2500). But since it only occurs when a fast change occurs to the system I figure that it's unlikely that the ICV is the culprit.

Of course if someone can suggest a way in which the ICV could cause this without sticking randomly at other times, it would help me get my head around the idea.

[electrofelix]

Going to try testing the whole lot, fuel and vacuum lines.

Would the following be suitable?
Draper DVG1
http://www.paddystoolstore.ie/DVG1
http://www.draper.co.uk/catalogue/Pagesource-EU/p89.pdf

Or should I be going with something a little more heavy duty
http://cgi.ebay.ie/ws/eBayISAPI.dll?ViewItem&item=360227823042&ssPageName=STRK:MEWAX:IT

One advantage that I noticed with the draper tool is that it appears possible to check vacuum hoses with it as well. That would allow me to make sure that not only the hoses (which are relative new) are ok, but also all the other components in the vacuum system are working correctly.

Only concern with it would be whether the connectors are strong enough?

[flyinglizard]

The ebay one will work , the rest are for vac and carb fuel systems. ( under 10#)

The M42 has a low pressure setup, with lines running from the frame rail to the injector rail. Any fuel pressure test kit should have enough stuff to check at the "IN" line on the frame to engine hose.  The pressure reg runs to the low side line, so check the other, Sorry I foreget if it is the black one or the chrome one. I think the chrome.    Crank the engine and see how long it takes to show 40# ( check for book value)or so. I think that most of these are set for 40#ish. Corvette, Mustang , most of the Bosch license stuff  i s about the same. (37)
  Any that have the hose clamps at joints are "low" pressure.
 After the engine starts, the pressure should drop a couple of pounds. If you see a large needle bounce at idle, one injector may be hanging.  The engine usually will also bounce.
 The real hot start test, is residual pressure. Shut down and watch the pressure . It should stay about 25-30#(check Book for actual BMW value)  for about 20 min .    If it dumps to zero real fast you have a check valve leak. If it dumps slow, maybe an injector, maybe regulator. ETC.
 A stethscope can often hear any  leak that drops the # value in less than 5 min.MM