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wacko's Avatar
 
Join Date: Oct 2012
Location: Chilliwack BC, Canada
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Quote:
this however sounds like a timing issue not a fuel issue ..



I hate to even bring this up but are you sure you timed your cams right ?
I am pretty sure☺️
I did check it a few times to make sure.

I am definitely losing fuel pressure as it doesn't build up like normal when I lift the sensor plate

Old 12-30-2014, 08:22 AM
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i used the 16 plastic whater bottles for my 930.

if you unplug the connector to the AFM and turn the key on (pump running) nothing should come out of the injectors.
for your car to backfire like it is one or more injectors would have to be leaking a LOT. once it fired the first time that would clean out any gas in there then it should fire up. it may run bad. usually a miss or pop due to one cylinder getting more fuel,

pull the plug wires off and put them on one at a time. make sure you are putting them on in the direction of rotation of the dist. 1,6,2,4,3,5.

lift the sensor plate when starting. i think you are either too lean or its a plug wire issue.
if it is a too much fuel issue what about the CSV. you dont have it wired so it is on all the time?
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86 930 94kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
03 BMW 330CI 220K:: [__] RUNNING: [__] NOT RUNNING:
01 suburban 330K:: [__] RUNNING: [__] NOT RUNNING:
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Old 12-30-2014, 08:39 AM
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What do you mean: "doesn't build up as usual"?

If you lift and they start flowing, do they flow continuously? If you let the plate go, do they drain down, or stop quickly?

If you raise the plate does it take a while for flow to get to the injectors?
Old 12-30-2014, 08:41 AM
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i was going to add how long has it been sitting?
could the plunger be sticking inside the fuel head.
with the pump on, you should feel a lot of resistance as soon as you lift the plate. if there is any free movoement then the plunger is stuck. (this would mean all the injectors are dumping fuel when the pump is on).

i have to quote VFR

What do you mean: "doesn't build up as usual"?
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86 930 94kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
03 BMW 330CI 220K:: [__] RUNNING: [__] NOT RUNNING:
01 suburban 330K:: [__] RUNNING: [__] NOT RUNNING:
RACE CAR:: sold
Old 12-30-2014, 08:47 AM
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Other things to check is air leaks. The rubber bits do get old and lose flexibility.

I found when I removed the CIS, the intakes moved a lot. Maybe the rubber sleeves are leaking? The injector sleeves also have an oring that get hard as a rock.

All the vacuum lines, air handling pipes and manifolds are potential leaks. The idle speed adjustment screw is really an air bypass.

If you sort out the fuel side, the next area is to check the air side of the equation.
Old 12-30-2014, 08:59 AM
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Normally when you lift the sensor plate you can feel the pressure build quickly and it becomes almost difficult to hold up. That is not happening. I can easily hold up the plate with some but very little resistance.
Old 12-30-2014, 08:59 AM
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Sounds like either the fuel manifold is binding, or your pump capacity is low.

Plugged filter? You'll get pressure, but not enough flow rate to sustain pressure.
Old 12-30-2014, 09:02 AM
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I am loosing a lot of fuel. I put my fuel pressure tester on between the wur and the Fuel Distributor with the shut off on the wur side of the gauge. With the shut off closed it builds and hold pressure. With the shut off open it dumps fuel into my engine.

Would this eliminate the plunger being stuck?

Does this suggest cold start valve?
Old 12-30-2014, 09:09 AM
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Just looked over your recent posts. Wow you do that rebuild fast! So that probably eliminates old fuel sitting around.

Still, your fuel distributor could be starved for fuel based on your observations.
Old 12-30-2014, 09:10 AM
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Where is the fuel going?
Old 12-30-2014, 09:21 AM
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If the plunger was stuck partially open, the fuel distributor wouldn't know why, It would just flow.
Old 12-30-2014, 09:26 AM
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i think what you have been feeling is the control pressure rising as the WUR heats up which increases resistance on the sensor plate.....no?

do the fuel pressure test with the connector off the AFM. do not lift the sensor plate to do the test.

do the fuel pressure test again.
system pressure, valve closed should be about 4.8bar
control pressure:
cold- depends on outside temp but i dont think it should be below .8 with the engine off.
warm- connector plugged into WUR and heated up
with vacuum to WUR 3.2-3.6bar
no vacuum to WUR (IE engine off)- 2.7-3.1bar

if you can pull a vacuum onthe WUR while testing that is a big help. you should see about a .8bar difference with and without vac.

with a low contol pressure the resistance will be low on the sensor plate. the important thing is do you feel the resistance as soon as you lift the plate.

if you are lifting the plate a lot pull the injectors and put them in bottles.

you should just do what i said earlier and be done with the fuel side of this problem:
with the injectors in bottles:
let the WUR heat up and check warm control pressures (WCP).

check the plunger in the fuel head by lifting the sensor plate from 0 all the way to max.
(you can also check fuel volume for WOT this way.)


lift the sensor plate and hold it open about 3-5mm for 5 minutes or so so you can compare the injectors for fuel volume. this is for a good idle.

check each injector for spray pattern

check each one for leakage with pump on and sensor plate down. if they all leak the mixture is too rich. (if you are not sure about the fuel mixture adjust it CW until they start to spray then CCW until they stop).

once you do this you can eliminate the CIS.
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86 930 94kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
03 BMW 330CI 220K:: [__] RUNNING: [__] NOT RUNNING:
01 suburban 330K:: [__] RUNNING: [__] NOT RUNNING:
RACE CAR:: sold
Old 12-30-2014, 09:40 AM
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The fuel seems to be running into the cylinders 1,2,3 it is running out the open exhaust port on cylinder 2
Old 12-30-2014, 09:47 AM
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Quote:
i think what you have been feeling is the control pressure rising as the WUR heats up which increases resistance on the sensor plate.....no?



do the fuel pressure test with the connector off the AFM. do not lift the sensor plate to do the test.



do the fuel pressure test again.

system pressure, valve closed should be about 4.8bar

control pressure:

cold- depends on outside temp but i dont think it should be below .8 with the engine off.

warm- connector plugged into WUR and heated up

with vacuum to WUR 3.2-3.6bar

no vacuum to WUR (IE engine off)- 2.7-3.1bar



if you can pull a vacuum onthe WUR while testing that is a big help. you should see about a .8bar difference with and without vac.



with a low contol pressure the resistance will be low on the sensor plate. the important thing is do you feel the resistance as soon as you lift the plate.



if you are lifting the plate a lot pull the injectors and put them in bottles.



you should just do what i said earlier and be done with the fuel side of this problem:

with the injectors in bottles:

let the WUR heat up and check warm control pressures (WCP).



check the plunger in the fuel head by lifting the sensor plate from 0 all the way to max.

(you can also check fuel volume for WOT this way.)





lift the sensor plate and hold it open about 3-5mm for 5 minutes or so so you can compare the injectors for fuel volume. this is for a good idle.



check each injector for spray pattern



check each one for leakage with pump on and sensor plate down. if they all leak the mixture is too rich. (if you are not sure about the fuel mixture adjust it CW until they start to spray then CCW until they stop).



once you do this you can eliminate the CIS.
Will the wur heat up without the engine running?
Old 12-30-2014, 09:50 AM
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I think you need to isolate some parts from the problem. From what you posted it could be injector related.

If it were me, I'd pull all the injectors and test them individually for opening pressure. Just to make sure that is not the problem, or a subtle addition to the problem (red herring).

Once you know the injectors are working properly and can only open when the desired pressure is reached, then you can eliminate them as being a problem.
Old 12-30-2014, 10:05 AM
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Ok. I'm at work now but will check them tonight.

Thanks for all the feedback
Old 12-30-2014, 10:07 AM
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If your CIS was working properly prior to rebuild, and you didn't do anything to it but remove and replace, then chances are the components are fine...

What happened to me on my first engine start attempt was the connection at the big plug at the front of the motor near the left side of the engine bay was loose and the frequency valve was not running... this will cause the car to not and or barely run.

When you lift the sensor plate, do you hear the frequency valve buzzing? It should be very distinct buzzing over the injectors squealing.

Regards,
Brian Petry
Springboro, OH
Old 12-30-2014, 10:10 AM
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The cis was working well before engine drop however I may have damaged one of the injectors removing it from the injector sleeve.

I think the frequency valve is buzzing, I will double check that as well tonight.
Old 12-30-2014, 10:19 AM
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Are you sure you have enought gas in tank. the rear same level as the front.
Old 12-30-2014, 04:50 PM
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CIS troubleshooting..........

Quote:
Originally Posted by wacko View Post
The fuel seems to be running into the cylinders 1,2,3 it is running out the open exhaust port on cylinder 2
Is this happening with fuel pump running and air flow sensor sitting down? The fuel injectors should not be delivering any fuel to the cylinder/s during a FP test run until the FD plunger is lifted. Could you elaborate when the above condition occurs? Not sure what you have been doing for the test. Thanks.

Tony

Old 12-30-2014, 06:48 PM
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