pressure regulator shims

[emptynoid]

anyone have a good link for pressure regulator shims? I thought I found some on eBay but they don't ship to US. I'd like to lower my system pressure to see if the car runs better right now I'm at 74-ish with my warm pressure at 54psi

[320iAman]

On the pressure regulator valve there are two shims, remove the small one-small thin washer- the control pressure will drop little. FAQ's has lots of answers to questions.

Randy

[emptynoid]

Hi Randy, thank you but do you know where I can pick up some shims I only have one and can’t seem to find them online?


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[epmedia]

I did a google search 'k-jet pressure regulator shims' and came up with a few results. Here's one of the results:

May want to contact them to ensure the dimensions are correct?
DeloreanGo

[320iAman]

Adding more shims will increase system pressure. take out the shim you have in there now and then test system pressure it will drop.

From FAQ's--Your sizes .1 and .5mm the two on the pressure regulator

Adjusting System Pressure
System pressure can be adjusted by adding or removing shims under the spring in the pressure regulator assembly. This can be used to bring system pressure back in to specification, or "tune" the fuel system outside of it's original operating parameters. For instance, raising system pressure above stock levels can increase the total flow capacity of the fuel distributor (note that higher system pressure WILL reduce fuel pump flow rate and may cause other problems). Note that adding shims will not raise system pressure to specification if the fuel pump is simply too weak.

Adding shims will raise system pressure, while removing shims will lower system pressure. Shims were supplied in 2 thicknesses which raise system pressure in the following increments:

.1mm - .85 psi
.5mm - 4.3 psi

What Robert has found there will work and so will this one from Germany select normal if you have the later type.

s-l1600c.jpg

https://www.ebay.com/itm/18444554966...sAAOSw6LRgSihQ

Randy

[mxl556]

Thank you Randy for posting a link. Related question- why would system pressure be 78PSI, but cold and warm pressures are within spec (28psy at 85F and 50psi hot)?

[cgifool]

WUR controls the "control pressure" (which is what you're measuring cold and warm). You'll want to re-check and probably re-adjust the WUR after changing the system pressure.

[emptynoid]

My search cam up with the same links which lead me to posting this thread, I wasn’t completely sure they were right, and I thought there would be a BelMetric reference.

I can’t get my warm pressure lower than 53-54 so I was thinking to lower my system pressure which is at 74 would help, I tried removing the existing shim and it did go up to 86 I think, I did not try it shim less, maybe the shim that’s there is incorrect, my caliber battery died so I didn’t take any measurements

Thank you

[320iAman]

Thank you Randy for posting a link. Related question- why would system pressure be 78PSI, but cold and warm pressures are within spec (28psy at 85F and 50psi hot)?

Could be the system pressure control valve piston is stuck wont slide back to where it should be ,using too large of shims would do this as well.

Randy

[mxl556]

it is OK to remove the pressure regulator and check (remove) shims, or I need some replacement washers/o-rings if I were to touch it?

Thanks!

[mxl556]

Could be the system pressure control valve piston is stuck wont slide back to where it should be ,using too large of shims would do this as well.

Randy

Hi Randy, are you talking about the pressure regulator on the side of FD that has shims and o-rings or the piston on the bottom of the FD?

Thanks,
Max

[320iAman]

Hi Randy, are you talking about the pressure regulator on the side of FD that has shims and o-rings or the piston on the bottom of the FD?

Thanks,
Max

Yes, its alright to open it up and check what you have there, probably have to fish out the little piston, you don't have to replace shims, there is 2 a smaller one and a larger one in thickness, the larger one is usually in the back and smaller one in front, check the o-rings are round and not flat on the front surface.

Randy

[mxl556]

thank you Randy, I ordered the kit above and will check it out when it arrives. For now I am replacing the accumulator and rechecking the pressures, will see how new accumulator affects everything.

[320iAman]

Sure, The accumulator smooths out the pulses of fuel from the fuel pump and when the engine is turned off keeps fuel up in the feed line to the fuel distributor for easier warm start ups as the diaphragm is closed. The check valve on the fuel pump keeps fuel in the gas metal line from the fuel pump to the accumulator for easier start warm starts as well.


Randy

[mxl556]

Interestingly, I replaced the accumulator and all the pressures are back in spec. My system pressure came down from 78 to 68psi. Cold and hot pressure stayed about the same - 28psi at 80F and 50psi hot. So somehow, bad accumulator was messing up system pressure. By the way, new accumulator (007) is smaller than the original (021) but using the piece of the old serpentine alternator belt made it fit in the bracket. I kept the original rubber ring as well.

[emptynoid]

that's interesting...... i still have an old accumulator on the car and it holds pressure pretty good so I've kind of ruled it out but now that has me thinking. Did you replace it because it wasn't holding pressure or just because.

[320iAman]

It seems the new accumulator created more back pressure keeping the psi down.

Randy

[mxl556]

that's interesting...... i still have an old accumulator on the car and it holds pressure pretty good so I've kind of ruled it out but now that has me thinking. Did you replace it because it wasn't holding pressure or just because.

I had a hard time starting the engine after parked for an hour or two and it also had some drivability problems, uneven idle and slight miss at cruising speed (lean missfire). Also, semi warm engine started and died right away sometimes. A lot of it probably had to do with too high of a system fuel pressure.
Accumulator was shot- when I tested the residual pressure, it dropped from ~30psi to 10 in about 10 minutes, in 20 minutes pressure was zero. Now it takes about 2.5 hours to have pressure drop to spec'd 22psi after 20 minutes.