Modern fuel pressure regulator substitute?

[raygreenwood]

Yes....I DID chime in....that it was about time you adjusted the MPS.

But as I have stated maybe a thousand times now.....its the VERY LAST thing you do,.....and not until all other things have been checked. That includes fuel pressure and system leak down.

You have had these ongoing narratives for years now with adjusting problems.

In these threads....I ALWAYS....ALWAYS.... go down the FULL list.....have you checked EVEYTHING for vacuum leaks?....have you checked fuel pressure and leak down and fuel volume?...have you checked voltage?....have you checked all 23 connectors?...have you checked the ground?....have you checked and adjusted the TVS?....have you checked all sensors (TS-1 and 2 and MPS for resistance and vacuum)?

We keep getting from "you...yep they are all good or seem good"....



The problem we keep finding is that the last check or replacement YOU made of X, Y or Z part.......was YEARS AGO!

That does not count at all.

I was glad I asked three posts back. You say you have a new fuel pump. When did you install it? 4.5 years ago? That pump is not new....even if it has "0" miles.

The fact that you run low miles...is irrelevant to whether a part with low miles is good.

When we ask in one of your threads if you have checked EVERYTHING....we mean HAVE YOU CHECKED IT NOW...not years ago. Anything you did to the engine YEARS AGO....is meaningless and worthless in teh scheme of problem diagnostics.

So we told you its about damn time you adjusted the MPS....and now we find out you have been having a leak down issue with fuel pressure....which would NEGATE the need for adjusting the MPS.

Guess what...once you fix the leaking FPR....you will need to adjust the MPS AGAIN...to put it back where it was so as not to run rich.

Sorry...not trying to be pointy at all. Glad to help anytime.....but you have a history of this and I have bitched about it before.

I will say it again.....With D-jet...nothing is NEW or certain.....or even correct...unless you have checked it NOW.

The MPS does not change with time unless it gets a defect like a leak in the seal, diaphragm or o-ring. The coil can change...if it or its wires get corroded....but short of finding it in a junkyard or submerged in a bucket....or not driven in 20 years in the Pacific Northwest.....thats rare.

So when we said...yeah...its about time you adjust the damn MPS....I would say you led us down the primrose path....because you obviously missed testing your fuel pressure leak down....which is a REQUIREMENT!

How were we supposed to know you skipped that or did it a decade ago?

No worries...now you know! Ray

[blues90]

[KTPhil]

Just a side note... I had a pump/regulator issue years ago after the car sat for 6-7 years. It stank rich in the exhaust! I didn't rush to change the MPS... I checked pressure, and it was only about 22 lbs or so. So it was running lean, even though it had unburned gas in the exhaust. It combusted so poorly it was sending unburned fuel through the exhaust. I adjusted/replaced the pressure regulator (I can't remember which, it was about 12 years ago or so), and it ran well, with no MPS adjustment needed at that time.

[blues90]

[Tram]

Something I am wondering... on these E systems there was a service bulletin about soldering in a resistor to the TS2. The test was if the car started/ ran optimally with TS1 (air temp) disconnected. I have this in my archives somewhere but damned if I can find it. I can't remember the value of the resistor off the top of my melon but I bet our Ray of sunshine knows.

It's easy to solder up your resistor to male/ female spades and use it as a jumper between the sensor and the connector.
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[blues90]

[blues90]

My new FPR arrived today so I'll see what that does once i install it . It just comes in a box with no caps on the two ports. Hope the temp here drops it's real hot out side.

I thought about this. I was going to check to see what the original FPR reads now then decided to just install the new one rather than deal with replacing the FPR with a pressurized system. Then check the system pressure with a gauge and see if it holds pressure like it should without clamping any lines and if it does leak down then clamp return to see if the NOT SO OLD 2 port pump holds pressure and if so pressurize again clamp the pressure side before the gauge and see if the new FPR holds. Plus clamping both sides just to see if the lnjectors and CSV hold which they did last time I checked.

I could clamp both sides of the old FPR to install the new one which basically one needs to do either way since fuel will pore out of the ring even if there is no pressure.

I checked and found the MPS coils both read proper and no short to ground and it holds vacuum for hours on end. I checked and found no other vacuum leaks or external fuel leaks. There is only the vacuum lines one to the MPS and one to the auto trans modulator and one to the PCV and one to the dist vacuum advance which I bought a spare dist just for the trigger points and vacuum can , well the can works yet does not hold vacuum so as I have for years I plug the line and live without it. It did have better response with it yet since this engine when I rebuilt it has flat top pistons it pinged when hot so I can't time it at 5BTDC since the compression is higher. I also replaced all the runner boots and injector seals and head gaskets the proper ones for a FI engine and they don't leak. In fact when I did all of this at the end of 2019 and fired it up it didn't change the hunting I had , I still had to unplug the TS1 then decided to adjust the MPS to match what the unplugged TS1 did.

It might be better once I know the fuel pressure is holding and stable yet since this can leaks a bit it just adds a vacuum leak , not a huge one but still a leak none the less.

[blues90]

Is there any reason while checking the MPS for a vacuum leak with a vacuum pump @ 15 inches of vacuum would hurt the MPS?

For some odd reason last time I drove it ran fine other than the fuel leak down which I'm going to fix. This time since I checked the MPS vacuum it has flat spots on acceleration , I even unplugged TS1 and it made a bit of difference but not like before.

Checked the TPS and it's fine , can't find any vacuum leaks any where.

All I did was pull vacuum on the MPS. I know the engine at idle pulls more than 15 inches if I place a vacuum gauge teed into the MPS line. It used to be steady now of course it is not , it doesn't hunt or miss fire it just does not accelerate smoothly at all. It used to do this with no load never while driving it.

[blues90]

I connected the pressure gauge primed the system and had 28 PSI , running is was 30 PSI. Now I have the pressure side clamped off to see how long it takes for the FPR to leak down. After 30 minutes I released the clamp on the pressure side and it dropped 2 psi which seems normal. Now I have it clamped to check the FPR. In 30 minutes it dropped 2 psi.

The odd part is the only way it would run smooth is if I adjusted the MPS another 1/4 turn CCW so now that makes it 3/4 turn yet any time I connect TS1 it runs worse , before it didn't and TS1 at shut down was 157 ohm. TS2 was 1950 ohm. I even backed the MPS back to it's original starting point and connected TS1 and it ran lousy , before this made it run better. The other odd deal is if i unplug the MPS it still ran then if I plugged the MPS port on the IAD because it was a vacuum leak it went back to running lousy. I always thought they would not run with the MPS unplugged.

That makes no sense since both temps sensors read what they always did.

My hope is the FPR is the issue.

[blues90]

With the pressure side clamped off in 2 hours it dropped from 28 psi to 20 psi. I loosened the pressure side clamp dropped 1/2 PSI. I'll check it in 24 hours and if it's down to 0 I'll replace the FPR.

By the way this morning after 24 hours when I removed the fuel gauge test port screw no fuel at all came out so there was no pressure at all.

[KTPhil]

Once it is running, with 28-30 psi, the leak down no longer matters, as far as mixture (MPS) adjustment goes.

So I'l post my further comments (not regarding the regulator) on your other thread:

https://www.thesamba.com/vw/forum/viewtopic.php?t=...;start=100

[blues90]

[blues90]

[blues90]

Went out there 24 ours later had 4 psi on the fuel gauge. still had the pressure side clamped off , loosen the clamp didn't drop at all so the fuel pump is holding just fine.

TS1 was 244 ohm / TS2 was 2290 ohm around 75 degrees F.

Next was the insane battle of replacing the FPR had the right side jacked up with a stand under the beam. clamped off the fuel lines under the car and above both sides of the FPR plus still kept the pressure side clamped.

Let me tell you at 73 years old working on the floor on cardboard with crap falling in my face and a slight bit of fuel dripping out of the old FPR and grease and filth on the auto diff took me hours to wash that off.

Once I was done with that fight and getting the FPR nut tight mine still had the rubber washer tossed it. Trimmed off a bit of fuel line on the outlet of the FPR so I knew it was good. Primed it with the primer switch had 29 PSI.

Then I go to start it and it would crank but not start if it did catch it popped out the exhaust sometimes then quit.

Then I just thought what the. Thing is I ran it yet adjusted the replacement MPS a bit richer but this was after I put the gauge on and it started after lots of priming .

Long story short I connected the NOS MPS and it fired right up . The gauge read 29 PSI , no air in the lines , running it read 31 PSI , Right after shut down it read 29 PSI and now it sits with the gauge on to see how long the system holds pressure.

Note in order for it to run smooth I was back to unplugging TS1 just like before now that works again. I have no idea what failed in the MPS I had adjusted , All I did was check for a vacuum leak and it went south. Maybe some day I'll remove the 4 rivets , maybe. the coils read fine , it holds vacuum all I can think of is maybe one of the two aneroid cells failed and maybe this was why it was started out of the blue cause driving issues.

No idea why I still have to disconnect TS1. It's fine connected when cold yet not long after start up maybe 20 minutes I can hear the engine begin to hunt with an unsteady idle so for now I'll live with it.

At least the NOS MPS was never screwed with and is much much newer than the one I was using which I took off a 72 parts car in 1986. I used that one on this car for a long time and it ran fine as long as TS1 was unplugged just like now.

I cannot find any vacuum leaks anywhere and like I said before even after replacing every single line and hose and seal and gasket at the end of 2019 it ran just the same as long as I unplugged TS1. This is why I used the old MPS and decide to adjust it and it did work fine.

I didn't bother setting the pressure to 30 PSI this new FPR has a small hex screw to adjust rather than the 10 mm nut and 31 PSI is within range. I'd rather it runs a bit rich than lean.

I'm done adjusting MPS units. What ever it is it's not a vacuum leak. Sure due to engine wear a slight MPS adjustment might do it , I just do NOT what to go there.

I was freaked out when it would not start today , good thing I had the NOS MPS.

I did make a 200 ohm ballast resister in case the one in my heap fails and a 90 ohm just to see if that helps with the hot soak 30 minute start up low idle condition.

[Tram]

Try plugging off the vacuum line from your AAR to the manifold when it starts hunting at idle. Hunting at idle means it's lean.
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[blues90]

[blues90]

I went down and checked the fuel pressure gauge after it sat for 23 hours. The gauge read 2 PSI . I primed the system read with the primer switch and it read 28 PSI so I clamped off both the pressure side and before the FPR and it dropped from 28 PSI to 26 PSI in 14 minutes yet seemed to hold after.

Brought a sample of the oil from the dip stick in a sealed pill bottle so my wife could smell it said it smelled like oil and I checked the oil level it was not higher and felt like 40 weight oil which I have in it.

I did notice when I primed it it did not take nearly as long for all the air bubbles I hear running into the tank . usually it takes a minute this time it took seconds.

I just want to be sure it's not injectors.

[Bobnotch]

[blues90]

[blues90]

So far it's been 3 hours and 15 minutes and clamping the pressure and FPR inlet the pressure gauge still shows 26 PSI . I can usually smell gasoline pretty well and put my nose right at the oil filler dip stick out and can't smell anything . oil I can't smell never had a great sense of smell but I can smell gas I can still smell what dribbled on the tin when I removed the old FPR.