Slow start XJ - bought BMW part - where to install??

I found a few threads that referenced a BMW part which is basically a check valve and a rubber hose, but it was cheap, so I figured what the hell. Does anyone have any pics of this installed on their XJ? I haven't been under mine in awhile, but I was thinking of putting it after the fuel filter so that there wasn't a chance of clogging, etc, but not sure if the room is there. Any ideas or pics? TIA.

bump - I know people have done this - even saw a pic once a long time ago, but can't find it and can't remember exactly where/how it was installed...h

Nothin' I've ever heard of.................:dunno:

Yeah, I have absolutely no idea what you are talking about! No offense, but the first time this thread came up, I thought it was joke!

Is this the check valve to keep pressure in the fuel system? I remember reading something about it a while back.

Maybe someone else will remember.

Close to the gas tank. You will need a mini tube cutter from the plumbing section of the hardware store. Be carefull not to get any metal chips in the fuel line. Use care and safety precautions as a small amount of gasoline will flow out.
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Whats the BMW part number? I've been looking for it for my long cranking 90'.

I would think that the check valve should go in line somewhere between the tank and the filter.

Ok, I'm interested, what is this supposed to accomplish?

By putting a check valve in the fuel line it makes it so fuel won't drain out of the line, always keeping fuel in the lines all the way to the engine.

http://www.naxja.org/search =bmw+check+valve
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I got the BMW check valve (P/N 16 14 9 068 988) from BMA Parts ( 1-888-262-3911 ) about 12 months ago. The cost was under $ 20.00 delivered.

Tim - Thanks a lot. Approx. how much pipe did you cut out? Didn't know if you just fed the pipe into the rubber hose so that you didn't cut out any and to ensure that it was a solid seal or if you cut out 6" or so. I plan on doing this tomorrow since my fishing trip got cancelled.

Postal,
I cut out a section of the pipe so that I had about 1.5 inches of metal pipe to put into each end of the rubber tube.

so why exactly does a BMW come with these check valves but a jeep doesnt. Is germany that mountainous and hilly ?

shouldnt the system be pressurized from the intitial turning the key? i hear the pump going for a few secs.

jayuu said:

shouldnt the system be pressurized from the intitial turning the key? i hear the pump going for a few secs.

Click to expand...

Mine's a '91, so it might be different, but my pump runs for a couple of seconds when turning the switch to the "on" position. I noticed that I can cycle the key and get the pump to run for two times, -but never any more than twice. When I do cycle the key twice and let the pump run twice, my crank times are greatly reduced.

That leads me to believe that this check valve may very well reduce crank time.

The question is, -will it cause the injectors to weep?

ratman572 said:

Mine's a '91, so it might be different, but my pump runs for a couple of seconds when turning the switch to the "on" position. I noticed that I can cycle the key and get the pump to run for two times, -but never any more than twice. When I do cycle the key twice and let the pump run twice, my crank times are greatly reduced.

That leads me to believe that this check valve may very well reduce crank time.

The question is, -will it cause the injectors to weep?

Click to expand...

I'm wondering the same thing about the injectors. Anybody? I also found this thread on jeepforum..

http://www.jeepsunlimited.com/forums/showthread.php?t=640146&highlight=long+crank

Having done some searching and reading you will find that the fuel pressure check valve on the 1997-2001 is prone to failure. It is part of the fuel pump assembly located in the gas tank and is non-serviceable. There are 3 fixes for long cranking times caused by pressure bleed down: 1) turn the key off and on a few time to build pressure. You can do this forever and it costs nothing. 2) install a check valve of one type or another in the fuel line. 3) Replace the fuel pump assembly which is $200.-300. plus labor or your time.

1996 and before may be be similar, but I don't know.

Your fuel system should keep some pressure for days or weeks at a time. The normal reading should be listed in your Factory Service Manual. If you have the valve on the fuel rail you can take a reading or estimate the pressure by relieving some pressure just after shutting down the motor. Compare the first reading to one taken after 12 - 24 hours of sitting. Long cranking times and rough running for up to one minute are normal symptoms of pressure loss. A CEL code is even possible. In warmer temperatures the loss of pressure can also allow the gas to vaporize in the fuel rail from heat soak causing vapor lock which will also lead to longer crank times and hard starting.

Weeping injectors can cause a loss of fuel pressure also and hard staring. Injectors usually fail due to age, not normal fuel line pressures. Injectors can be tested to see if they are still functioning properly.

BMW had the same problem with their check valve and they created the service kit with a check valve, hose, and clamps. It is easy to buy, cheap, and the supplied hose is the correct size for XJ's.

Yeah, Tim summed it up. My '91 too an extremely long time to start - 5-6 seconds of solid cranking. Cycling the key multiple times didn't seem to help - only cranking for about 2 secs, then stopping and then cranking again and it'd usually start after another second or so. The stock check valve is part of the fuel pump and I'm cheap for my $600 wheelin' rig. This part is around $4 + shipping.

Tim - hadn't been under my vehicle in a few months, but when I got under there, our systems must be different. The line from my tank to my filter is rubber and would've been ideal to just put the check valve there, but it was larger than the rubber line that came w/ the valve, so I was afraid I wouldn't get a good seal on the valve. I ended up adding it on the steel line about 8" after the fuel filter and it's a great fit. Still allowed the line to snap in the grommets that run along the frame (line runs up front along w/ the brake line and two other steel lines).

Like I said, before it would take 5-6secs and I lost pressure almost immediately - w/in 5min. for sure. I installed this, changed front diff. fluid and trans. fluid, cleaned up, ate dinner, showered, etc and went to start the ole XJ - took 2secs. Not instant like a new vehicle, but not bad for a 16yr old 167k beast.

Someone told me that the ecm will not allow the engine to start until oil psi has reached a certain level. As clearances increase with age/mileage, cranking will take longer because it takes long to build up oil pressure. I know for a fact this is true with some vehicles, but what about jeeps?

privatejoker said:

Someone told me that the ecm will not allow the engine to start until oil psi has reached a certain level. As clearances increase with age/mileage, cranking will take longer because it takes long to build up oil pressure. I know for a fact this is true with some vehicles, but what about jeeps?

Click to expand...

Drove my '91 with 5 psi oil pressure for 4 months. If there's a failsafe, it doesn't work.