Crank crank crank crank crank vroom

[gone postal]

My '91 takes awhile to start. My brother's RENIX actually starts faster by several seconds!! I'm going to guess that it's the fuel check valve and heard of a BMW part to patch it or I've heard of others using valves from a boating store (just skeptical of it holding up to gas, but woudl try if I found one and was assured it would work - need to know the line diameter though and is there a certain pressure it should hold?). Anyway, tried the search, but "fuel valve" only came up w/ two things and neither were right. Does anyone know of this, have a part # to something and a link to buy online (plenty of boat shops in town, but no Bimmer dealers).

[themud]

Ya know this is funny I had the same problem on my 95 it took forever to start then one day my starter just took a dump on me(after about 2 years of wacking it), the hard starting had gone on for longer than that..I replaced it and the damn thing fires up right away now??? My guess is it has something to do with the cps sensor and if the flywheel isnt spinning fast enough it wont send the signal to the sensor for fuel...just my 2 cents..
themud

[Tom R.]

Another member here had a long crank problem on his '89 XJ that was resolved by replacing the camshaft position sensor in the distributor. I assume the HO motor has the same sensor...? The other usual cuprit is the CPS.

[Jonnyjpr]

Yea, i have a 91 too. It takes quite a few turns before it gets goin.

[Elfwizard1975]

My 91 also does that, I think mine has to do with Fuel pressure. There is enough fuel pressure to run and start, BUT it is not what the book says it should be. It actually loses pressure when it sits.

[Powerman]

I have a 2000 with the same problem. It got progressively worse. My starter is good. My battery needs replacing. I read about it being the check valve in the pump and it all makes sence to me. I haven't felt like spending the money or time to replace my pump for the minor problem. If there is another cause I should investigate I'm all ears. If there is an easy inline fix for this I would be happy to hear about it.

[Speed_racer]

Have hte same problem, new starter too, although a cracked flexplate.

Im changing my flexplate, and starter (lifetime replacement) tonight, well see where that goes, if no luck, next step is MSD

[gone postal]

Well, didn't know that the CPS could cause this too. It doesn't seem like the starter is weak, so I'll rule that out. I really don't think it's the CPS though b/c it starts considerably faster if it was just recently run. After sitting overnight, it takes awhile, but if I drive to a store, when I go to leave, it will start almost right away.

Anyone know the size of the fuel line? I want to go to a boat store to try and find a check valve tonight.

[Elfwizard1975]

I don't think its the CPS, It seems like fuel pressure to me. Loses pressure as it sits. Just like mine does. Test the Fuel pressure at the rail after it sits awhile, push in the schrader valve it should squirt out big time, if it dribbles thats your problem.

[Powerman]

Exactly, same thing for me. Running around doing errands it starts immediatly. After it sits it takes a while. I was thinking about this. If you put a inline check valve in somewhere, the line would still drain back to the pump wouldn't it? My point is if the line was empty up to the check, and full to the ejectors, the engine would start but then quite when the "bubble" got there. Does that make sense? I'm still open to fixes.

[1985xjlaredo]

My 88 takes forever nomatter how long it sits Cranks 6-7 times that I can tell and then vroom starts up. New Battery Good Alt, Good spark, New Plugs and wires. It does seem that the starter is spinning kinda slow.

[Powerman]

So does anyone know of a easy fix to a worn out check valve in the fuel pump?

[Speed_racer]

My 88 takes forever nomatter how long it sits Cranks 6-7 times that I can tell and then vroom starts up. New Battery Good Alt, Good spark, New Plugs and wires. It does seem that the starter is spinning kinda slow.

If for whatever reason you have a base model, they use a smaller amp alternator, i upgraded mine to the one in the laredo models, and believe it or not, it did make a difference.

[xjpheonix]

your crank possition sensor is located on the block at the trans bellhousing on the drivers side up high
as your engine spins it sends signals to the computer telling it when to fire the 1st cylender... if its not reading right it could very easily fiz this problem...there is a hole in your theory about the "check valve"
when you turn your key to the "on" possition it "loads up" your whole fuel system... there for if you were to leave your key in the on possition for 5 seconds before cranking you would have your regulated pressure at the injectors ready to go
try that and see if it starts right a way
if not i would say crank possition sensor is the culprit

[XJVenom]

your crank possition sensor is located on the block at the trans bellhousing on the drivers side up high
as your engine spins it sends signals to the computer telling it when to fire the 1st cylender... if its not reading right it could very easily fiz this problem...there is a hole in your theory about the "check valve"
when you turn your key to the "on" possition it "loads up" your whole fuel system... there for if you were to leave your key in the on possition for 5 seconds before cranking you would have your regulated pressure at the injectors ready to go
try that and see if it starts right a way
if not i would say crank possition sensor is the culprit


Correct me if I'm wrong, but I thought the check valve is designed to maintain the fuel pressure while the pump is off. If this is correct, then there is no "hole" in his theory because after the 5 seconds in the "on" position, the pressure would drop very rapidly if the check valve was dead (or dying). This would basically negate the whole purpose of the pump initialy powering on before starting the engine anyway, wouldn't it?

[xjpheonix]

the pump pumps gas to the injecters .. while the pump is running for that 2 seconds it fills the whole system with fuel
the gas wont run back past the pump while its running and i also dont belive its going to run back to the tank that fast through the impellor of the fuel pump... if it sits for a long while then does it ya i would say check valve,,,
but not that fast
the cps is like 50 bucks and it is an easy remove and replace

[sjx40250]

Pre-91's crank longer. My 90 always cranked longer than I thought it should. Got in the habit of turning the key and waiting for the fuel pump to quit running then cranked.

My 92 started taking a longer time to start a couple of months ago. I was surprised! Taking the approach like my 90 didn't make a difference. What did was leting the starter crank once or twice, turning it off, then starting it and it was really fast. Two weeks ago it fixed itself and now it is back to normal!

BTW: When I put new injectors in my 90, it started like my 92! I was amazed! I have owned it since new and it never started that fast.

[gone postal]

Well, I'll do a fuel pressure check b/c I'm still leaning that way. The hole that I find w/ the CPS is that it's consistent. Why would it start faster after just running opposed to the long cranks after sitting awhile? I find it starts fastest if I let it turn over 2 or 3 times, stop and then crank till start. I think that it loads the fuel and then has enough pressure to start. If the pressure turns out fine, then I'll replace the CPS. Isn't that a troublesome part anyway? Probably wouldn't hurt to replace it b/c I have no idea how old it is...

[doubledoors]

Why replace the cps if it's not broken? The fuel injection system/rail does take 4-5 seconds to pressurize. I always turn the key, wait for pressurization, and then crank, crank, crank, vroom.
If your problem has gotten noticeably worse, and all your other tune-up parts such as the plugs, cap, rotor and wires are good, I would suggest running a can of injector cleaner through the system. Oftentimes on these older XJ's the air intake is gummed up and benefits greatly from a full, professionally done, intake cleaning.
I own a 87 4.0 XJ, and work as the service manager for a shop north of San Francisco
that services, among other cars, all manners of Jeeps and 4X4 vehicles.
Let us know how it turns out.
Best of luck

[gone postal]

I guess I'll buy a fuel pressure guage - don't really want to spend the $$ on it b/c not sure how much I'll use it. Someone earlier mentioned that the system should have enough pressure to "spray" fuel if you pushed the valve. For how long should it hold that much pressure? If I wait 2 or 4 or 6 hours after I shut it off?

All "tune-up" parts are new - plugs, wires, rotor, filters and ran fuel injection cleaner. I also used SeaFoam for the combustion chamber and also added some to the oil, so the whole engine should be "relatively" clean (considering it has 166k miles on it). I've only had it 5 months and it's been like this for as long as I remember. The day I bought it I don't remember it taking this long - almost seems like it started after the tune-up, but i don't see how any of that could affect this. It could also be my imagination too b/c I only had it for like 3 days before the tune-up and I only drove it on/off a trailer, so not too much time for this issue to stand out.

As for the 4-5 seconds, I can wait 15 seconds w/ no improvement. I've even cycled the key on/off 3 or 4 times to no avail. The only thing that seems to start faster is either doing a few cranks, stop and then re-crank or if I restart w/in 15-20 minutes of last running. If that sounds like a CPS, then I'll replace. If not, I'd like to add a check valve, but I don't know the BMW part # or the fuel line diameter (looked in Haynes manual and didn't see the specs for that).

[xjpheonix]

hey i am not saying for sure its the cps... all i am saying is a check valve would let fuel run back but the pump pressurizes the system befor e you start it that is why there is a relay on the fuel pump to load the fuel rail...
if you turn the key and wait till its loaded does it still start the same as if you dont let it load
from what i have read the answer was yes
so you turn it over a few times then stop then start again and it fires right up?
wouldnt the cps read those first cranks also and know where the engine is at that time
and i think the fuel pump has the check valve in it i am not sure on your year
so all i was tryin to do was give another point of view good luck

[gone postal]

if you turn the key and wait till its loaded does it still start the same as if you dont let it load

yes - still takes long

so you turn it over a few times then stop then start again and it fires right up?

not right away, but definetely faster than if I didn't

wouldnt the cps read those first cranks also and know where the engine is at that time
and i think the fuel pump has the check valve in it i am not sure on your year
so all i was tryin to do was give another point of view good luck

Not too familiar w/ the CPS and it's functioning. I guess it would read the first few cranks - maybe it "resets" it or repositions itself properly from those first few cranks and lets it crank faster the second time. I do believe the check valve is internal on the fuel pump which is why I wanted to add an external one by the fuel filter. Sounds a lot easier than dropping the tank and replacing a fuel pump. Of course I don't want to cut my fuel line and mess with it if I don't have to.

[xjpheonix]

if your going to replace the fuel pump i have found it easier to cut a nice sqare hole right above it and then seal it back up good so the fumes dont get in ..
so if you let the system load it takes the same amount of thime as if you dont .? right? so in my head i am thinkin " ok fuel has to be at the injectors by now because i have let the system laod" if it still hardstarts then i would approach it from a different angle... the next thought would by what tells the engine to fire and when? that is my thinking
let me know what you find out

[4xBob]

I had this in a file (sorry I don't know the author):
"Fuel Check Valve Source
The BMW fuel check valve part number 16 14 9 068 988 fits between the filter and the fuel rail since its connections match this section of fuel hose. I installed one a couple days ago and it works fine. The unit comes with about a foot of 8mmx13mm fuel line, hose clamps, insulation and plastic nut covers for $3-5. It is necessary to make room for the valve, but that is not hard. Call a dealer and order one, or it may be in stock."

[1985xjlaredo]

If for whatever reason you have a base model, they use a smaller amp alternator, i upgraded mine to the one in the laredo models, and believe it or not, it did make a difference.
Nope got 2 Laredo's 1 is an 85 though.

[1985xjlaredo]

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BMW Fuel Pressure Check Valve pn
I had this in a file (sorry I don't know the author):
"Fuel Check Valve Source
The BMW fuel check valve part number 16 14 9 068 988 fits between the filter and the fuel rail since its connections match this section of fuel hose. I installed one a couple days ago and it works fine. The unit comes with about a foot of 8mmx13mm fuel line, hose clamps, insulation and plastic nut covers for $3-5. It is necessary to make room for the valve, but that is not hard. Call a dealer and order one, or it may be in stock."
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HOw the hell did this thread get mixed up in to the vroom vroom thread?

[XJVenom]

I had this in a file (sorry I don't know the author):
"Fuel Check Valve Source
The BMW fuel check valve part number 16 14 9 068 988 fits between the filter and the fuel rail since its connections match this section of fuel hose. I installed one a couple days ago and it works fine. The unit comes with about a foot of 8mmx13mm fuel line, hose clamps, insulation and plastic nut covers for $3-5. It is necessary to make room for the valve, but that is not hard. Call a dealer and order one, or it may be in stock."


Thanks 4xBob! I was looking all over the forums for info on this check valve. I'll order is ASAP and give it a try. Thanks again for the information.

[xjpheonix]

you try anything yet?
please let us all know what it turns out to be and good luck'