Warm up regulator question

[Bitsyncmaster]

I know the workshop manual says exactly what you just typed, my question:

I have done all of these tests with the engine running and got all workshop manual numbers on my gauges.

Is there a reason why to not have the engine running, or is it "because the manual says so" ?

Honestly just asking as I do not know, and I don't want to be leading anyone down the wrong paths inadvertently.

You probably can have the engine running to check primary pressure but it's nice to know you can check the pump pressure accurately if the engine won't run. I have checked a few engines and most have primary pressure on the low side of 68 or 69 PSI. That low reading does not seem to harm anything with a good running engine.

[krs09]

Oh man, I wish I had done a video on how to use them. They are super easy.

So, set them up like I have them in this video:



There is also a picture of this setup in the workshop manual on page D:02:02 with reference points to the handle that you'll set in place to measure control and main fuel preesure (AKA primary pressure).

So, once you open the lil handle at the T-valve, you should read main fuel pressure; this value is the standard pressure that the majority of the fuel system is operating at to open the fuel injectors. Main fuel pressure should be in the neighborhood of 79 psi (about 5.45 bar) - some people report values between 76 to 80 psi. Once you know your main fuel pressure is good, you can turn the handle 90 degs (if I recall correctly) to close it. You are now reading control pressure. Per the workshop manual on D:02:01 subpoint #2, cold control pressure should start at about 1.5 bar (about 22 psi), and it will rise pretty quickly (less than a couple minutes) to 3.5 bar (about 50 psi). As the engine warms up, it should stay at about this value the whole time; you don't need to follow subpoint #3's instructions of disconnecting vacuum hoses (least I didn't have to, Your Mileage May Vary [YMMV from here on]). If you're reading about 50 psi, your WUR should be fine. I had 53 psi on my car with zero issues with the WUR - so a couple psi here and there is ok.

What you DO NOT want to see are wild and/or erratic fluctuations. Of course, you want the values on your gauges to reflect those given in the workshop manual.

Thanks for the post. Just what I needed. My gauge does look a little different, I cant use my banjo bolts it comes with fittings that screw in like the banjo bolts and some of the fitting have rubber o-rings, not sure if that matters. Do you use the gauge with the car running or should you jump the fuel pump? ...Ive gotta pretty far with my d with no prior skill but getting her to run great with a good idle and a good mix will be the death of me.


Just read the other post .. lil late .. thanks guys

[krs09]

You close the gauge valve to read Primary pressure. Most valves that would line up the handle with the valve body. Book says primary pressure should be 70 to 80 PSI. Your engine is not running reading primary pressure, you jumper the RPM relay to just run the fuel pump.

Remove the RPM relay jumper, install the RPM relay, open the gauge valve, start the engine and quickly look at the control pressure. As stated it starts low and quickly climbs to 50 PSI with the cold engine start.

Ok, Followed the steps to the T and this is what I got. With the RPM jumper in the gauge read 69psi steady. So I replaced the jumper with the relay, opened the valve, started the car and the gauge read the same 69psi steady but it didn't start slow, it shot right to 69psi while running. After turning the car off after 5min the gauge dropped to 10psi and after 10min the gauge read 5psi. Thoughts? Sound about right?

[DMCMW Dave]

Ok, Followed the steps to the T and this is what I got. With the RPM jumper in the gauge read 69psi steady. So I replaced the jumper with the relay, opened the valve, started the car and the gauge read the same 69psi steady but it didn't start slow, it shot right to 69psi while running. After turning the car off after 5min the gauge dropped to 10psi and after 10min the gauge read 5psi. Thoughts? Sound about right?

No. It should hold 35 psi or better after you turn it off for at least a half hour, more like an hour.

69 PSI is too high while running with the test valve open, normal is more like 50 (3.5 bar). I think you are chasing two problems: Bad accumulator or check valve in the fuel pump, and a bad (or at least plugged) warmup regulator.

[Bitsyncmaster]

Ok, Followed the steps to the T and this is what I got. With the RPM jumper in the gauge read 69psi steady. So I replaced the jumper with the relay, opened the valve, started the car and the gauge read the same 69psi steady but it didn't start slow, it shot right to 69psi while running. After turning the car off after 5min the gauge dropped to 10psi and after 10min the gauge read 5psi. Thoughts? Sound about right?

Like Dave S said, your WUR is bad but it may just be the inlet screen is plugged. When you shut off the engine, your pressure should immediately drop to about 40 to 45 PSI and hold there for a few hours. That is your rest pressure.

[krs09]

Like Dave S said, your WUR is bad but it may just be the inlet screen is plugged. When you shut off the engine, your pressure should immediately drop to about 40 to 45 PSI and hold there for a few hours. That is your rest pressure.

Damn. Thanks guys. When we rebuilt the engine, we cleaned out the WUR inlets (there was alot of crud built up on the screen) by taking the screens out completely. Ports were totally clean when we put everything back together, I thought it may be bad. Dammit. The Fuel accumulator is responsible for rest pressure no? My accumulator is orginal.

[Cory W]

The Fuel accumulator is responsible for rest pressure no? My accumulator is orginal.

That's one part of it. The original "tall neck" style pumps have an internal check valve that can go bad and leave you with less than 5 minutes of rest pressure. The newer replacements have a replaceable check valve. There's the whole in-tank replacement kit, but that's overkill for the sake of a check valve if everything else is fine imo.

How old is your pump? It may be a good idea to get a pump if you're already ordering, just in case the accumulator replacement doesn't fix things. Part # 110085A through DMC. You will also need Domed Nut 110589 and 2 washers 106977 if you're going from the tall neck pump to this one.

[krs09]

That's one part of it. The original "tall neck" style pumps have an internal check valve that can go bad and leave you with less than 5 minutes of rest pressure. The newer replacements have a replaceable check valve. There's the whole in-tank replacement kit, but that's overkill for the sake of a check valve if everything else is fine imo.

How old is your pump? It may be a good idea to get a pump if you're already ordering, just in case the accumulator replacement doesn't fix things. Part # 110085A through DMC. You will also need Domed Nut 110589 and 2 washers 106977 if you're going from the tall neck pump to this one.

Well the PO replaced the pump before I picked it up. Its about 2yrs old with about 500 miles on it. Where can I find just the check valve? What does it look like? Sorry to be a PITA. Thanks

[Cory W]

Well the PO replaced the pump before I picked it up. Its about 2yrs old with about 500 miles on it. Where can I find just the check valve? What does it look like? Sorry to be a PITA. Thanks

Not likely the check valve then. Still possible though.

This is the check valve on the newer style pump:
checkvalve.jpg

The old style "tall neck" pump:
fuelpumptop1.jpg

And how the newer style pump will look:
fuel-pump-connection-new.jpg

The check valve alone is on the specialtauto site, but it's worth asking whomever you purchase parts from most to get everything in one order.

[Bitsyncmaster]

If you have the original accumulator, replace it. Then if the problem is not fixed look elsewhere but I would bet a lot of money that is the rest pressure problem