MPS, Rebuilding the MPS Options

[Superhawk996]

Aren’t other guys in CA running 123’s?

Regardless - worn dizzy bushings or not - that doesn’t account for the no start issue.

[Superhawk996]

Also with respect to the dizzy vs timing

Yes - start over from scratch. Assume nothing.

Find TDC on cyl #1 compression stroke. Install dizzy properly. Verify rotor position per Haynes / factory manual. Verify plug wires in proper order.

[fiacra]

If only I didn't live in California I would buy a 123 .

I'm not aware of any reason you can't run a 123 on your car here in California. If you are thinking it is because of the smog check, I don't think that's the case. You can correct me if you're aware of some part of the regulations that I'm not remembering. In any case, I wouldn't try switching out to the 123 until you have solved your current issue.

I don't have much to add to the advice your received so far from people with more experience than me, but do be sure to carefully check your distributor cap for a hidden crack. I couldn't tell from the picture if there was any streaking on the cap. There is some wear around the rim of the distributor cap that I can see in your picture (at 12 o'clock in the pic) that makes me a bit suspicious that the cap was moving around.

[Ron914]

As far as putting a 123 in my California car I was told in order to pass the California smog test the car had to have all the original factory equipment that it was sold with . The biggest issue is I do not have a catalyst on my car but because my car was not sold in California I should be exempt , we will find out when I take it in for the test . I had a 73 VW bug that we rebuilt to a 1835 and when I went to get my smog test I was failed (even though the car was well below the carb standards ) because I did not have the original equipment it was sold with ,like the vacuum advance distributor ,oil bath air cleaner , something else I don't remember ,oh it was the carburetor .I had to put the old solex ,air cleaner and distributor on the car and go to a BAR station where after testing the car was now putting out more than the standard allowed but because it had all the original. equipment on it they gave me a waiver . I remember the guy doing the test was really pissed off because as he said he did not have the authority to open and inspect the motor and he knew it had a cam in it still but had to give me the waiver . I guess I can do some more investigation on the 123 but I just don't want to do anything that might cause me to fail and would hate to have to remove e it every two years for the test . I don't even want to install the Bursch I got for my car because I have the original muffler with the Cat delete pipe and plater on my air cleaner still .

[Ron914]

First on the to do list

MPS is leaking down too fast. Something not right. Did you use a light coat of grease on the gasket. Did you assemble the gasket / diaphragm in the order indicated? 1st time i did one it didn’t seal properly - didn’t grease the gasket to see what happens - it leaked.

It should be holding vacuum much longer than it is.

The other stand out is the ECU trigger points. They alternate as you rotate the engine. Did you only check them in only one position?

Whether or not I go back to Pertronix would depend on which you have. The newer version 2 & 3 supposedly has a protection built into them to prevent the ignition on burnout problem of the originals. So if I had an original - stay points. If you have one of the later 2 or 3’s I’d be fine to change back. The main downside of Pertronix is it just isn’t as easy to see it work but if you’re getting spark at the plugs - good enough.

FWIW - check spark visually. The timing light method can fool you if you have soot fouled or plugs. Just because the timing light flashes doesn’t not guarantee a spark has jumped the gap. Your plugs are looking janky but i don’t think they are the root cause of your problem. They have been too rich due to the CHT resistor and the fact that your MPS isn’t working properly.

I greased the paper gasket and installed it first then the diaphragm ,and next the retainer ring I did not gob a lot of grease on the gasket but covered both sides well and used wheel bearing grease as was suggested in lieu Haylomar .I removed the original rubber gasket ( it was more square than the supplied round one) that was on the electronic side and replaced it with the one supplied .
I can always open it back up and check if that does not sound correct just to double check .
I also can change the plugs with a new set I have .
I have already taken out the points and reinstalled the Pertronix , here is the box it came in .

Not quite sure about the trigger points ( I only verified they were plugged in correctly on the dizzy and the conection to the ECU was good . I would say I checked them in one position How do I properly check them ?
How do I test the plugs properly ( I am new to this stuff so walk me through what I should do ) .
It's getting late so I will have to get back to the car tomorrow . I will wait for any new suggestions or comments .

[Ron914]

If only I didn't live in California I would buy a 123 .

I'm not aware of any reason you can't run a 123 on your car here in California. If you are thinking it is because of the smog check, I don't think that's the case. You can correct me if you're aware of some part of the regulations that I'm not remembering. In any case, I wouldn't try switching out to the 123 until you have solved your current issue.

I don't have much to add to the advice your received so far from people with more experience than me, but do be sure to carefully check your distributor cap for a hidden crack. I couldn't tell from the picture if there was any streaking on the cap. There is some wear around the rim of the distributor cap that I can see in your picture (at 12 o'clock in the pic) that makes me a bit suspicious that the cap was moving around.

The cap is brand new that wear was on the cap when I took it out of the box ,I assumed it was cleaned up during assembly that way . It was securely snapped into place .

[Superhawk996]

I would open the MPS back up. I can post time lapse video of my MPS if necessary. It doesn’t leak down. I may have reused the OEM rubber seal - can’t remember for sure. I know from experience experience they leak if not assembled properly.

I wouldn’t worry about changing the plugs yet. Get it running better 1st. I’m old school - the way to test plugs is remove them, hook to spark plug wire, use insulated gloves or tools, hold metal part of the plug to the engine / ground, cranks the engine and watch for a bright, hot blue/white spark. Intermittent, weak yellow spark is bad news. Spark not jumping cleanly from the center electrode to the ground electrode is bad news. Seeing the spark as it jumps the gap gives you a lot of information. SAFETY NOTE: don’t do this right in the vicinity of the cylinder bore where fuel vapor may be. Fan housing is a good ground and a safe distance from cylinder opening. Better yet - disable fuel pump while doing this by pulling the pump relay.

With respect to the ECU trigger points - just rotate the engine about 1 revolution and verify both sets of trigger points are working. They alternate. One set open, once set closed. The more important thing is to be sure your electrical spade connectors from the wiring are right on the trigger points and making good contact. I doubt anything in the points themselves has changed from when it was runnning last.

Check your FI grounds.

That Pertronix box looks old, shop worn, annd doesn’t indicate igniter 2 or 3 so I’m going to assume that’s an original subject to burn out and flaky operation if ignition left on. Personally, I would stick with points for now while troubleshooting. The original Pertronix is a deeply flawed design in my opinion given that it can be damaged by leaving the ignition on. It’s a black box - you can’t see or measure what’s going on inside.

If you do the visual spark plug test and have a good strong spark with the Pertronix in place - then leave it. Just be aware of its flaws and keep the ignition off while you are doing other troubleshooting lest it go bad in the middle of the troubleshooting and cause more confusion.

[emerygt350]

I agree with hawk. The first time I rebuilt mine it leaked as well, just didn't get it back together right (I think I forgot the gasket or put it in the wrong place? Can't remember). After I put it back together right it held vacuum forever.

[Ron914]

I would open the MPS back up. I can post time lapse video of my MPS if necessary. It doesn’t leak down. I may have reused the OEM rubber seal - can’t remember for sure. I know from experience experience they leak if not assembled properly.

I wouldn’t worry about changing the plugs yet. Get it running better 1st. I’m old school - the way to test plugs is remove them, hook to spark plug wire, use insulated gloves or tools, hold metal part of the plug to the engine / ground, cranks the engine and watch for a bright, hot blue/white spark. Intermittent, weak yellow spark is bad news. Spark not jumping cleanly from the center electrode to the ground electrode is bad news. Seeing the spark as it jumps the gap gives you a lot of information. SAFETY NOTE: don’t do this right in the vicinity of the cylinder bore where fuel vapor may be. Fan housing is a good ground and a safe distance from cylinder opening. Better yet - disable fuel pump while doing this by pulling the pump relay.

With respect to the ECU trigger points - just rotate the engine about 1 revolution and verify both sets of trigger points are working. They alternate. One set open, once set closed. The more important thing is to be sure your electrical spade connectors from the wiring are right on the trigger points and making good contact. I doubt anything in the points themselves has changed from when it was runnning last.

Check your FI grounds.

That Pertronix box looks old, shop worn, annd doesn’t indicate igniter 2 or 3 so I’m going to assume that’s an original subject to burn out and flaky operation if ignition left on. Personally, I would stick with points for now while troubleshooting. The original Pertronix is a deeply flawed design in my opinion given that it can be damaged by leaving the ignition on. It’s a black box - you can’t see or measure what’s going on inside.

If you do the visual spark plug test and have a good strong spark with the Pertronix in place - then leave it. Just be aware of its flaws and keep the ignition off while you are doing other troubleshooting lest it go bad in the middle of the troubleshooting and cause more confusion.

I appreciate your information . I figured that was how I should test the plugs but wanted confirmation . Good idea about the fuel pump ,don't want to start a fire . I unfortunately already put the Pertronix back in . Because of what I read I jump to turn off the ignition while I am in the engine bay if motors shuts off while I am messing around so I will be careful. I do carry a set of points/condenser/feeler gauge in my cars tool bag just incase,
I will recheck the trigger points I did verify the markings on the wires go to the correct terminals on the dizzy and good connection is being made . I need to reconnect the ECU and reinstall in its location today before anymore testing ,I also will use the old plugs ,I really did not want to put my new plugs in just yet until I get this problem figured out . I will need to order a new set for my tool bag .I will need to find someone to crank the motor over for me so I can test the plugs , I do not have one of those remote starter switches but that sure would make this easier because I usually only have myself for these things . I was thinking of opening up the MPS later today ( I really didn't expect to see so much leak down after replacing the diaphragm . I am almost 99% certain I replaced everything correctly in order . Paper gasket went in first then diaphragm then metal ring . The only suspect to me was using the new round rubber gasket over the old square edged gasket .The small ring was replaced on the big screw as shown in the diagram. Should I reapply more bearing grease to the paper gasket? I wouldn't think the settings I took and used for reassembly would cause a leak ? I will update this post as soon as I can get to these new things to do .

[fiacra]

Ron got that Pertronix from me, and yes it is older. It sat in a box on my shelf for at least 10 years.... If it is a worry for you Ron I'm happy to refund your money and you can simply trash the Pertronix.

I went down the rabbit hole and I think you are correct about the 123 and the smog check. Of course everything depends upon who is doing the inspection. I believe the 123 would fall under the category of performance distributors, and these would require that the company submit it to the CARB for certification that it does not make the car run dirtier than the OE distributor. An exemption would then be issued. I couldn't find any documentation of this having been done.

[Superhawk996]

Remote stater switch is about $15 and priceless in operation - eliminates the need for that helper.

Yeah - maybe a bit more grease on the paper gasket. But no means should it be slobbed all over but a dry gasket will leak. Tried it. It definitely leaked.

I also put a touch of silicone grease on the o-ring. I don’t recall that being in the directions but that’s what I do with almost any o-ring.

[Superhawk996]

https://www.youtube.com/watch?v=Z0n2aTFRMiI?si=W8rg02X2Kwp4r_54


I cut this off at 1/2 hour simply because it doesn’t move.

Keep going on it until you get a good seal on the MPS

[rjames]

There is an art (and likely some luck) in getting the MPS to fully seal, even when you put things back together correctly. One thing that I've had good luck with is tightening each of the screws (or nuts/bolts) that replaced the rivets a little at a time before moving to the opposite one, similarly to how you would tighten lug nuts so that you tighten the whole thing down as evenly as possible.

[Ron914]

There is an art (and likely some luck) in getting the MPS to fully seal, even when you put things back together correctly. One thing that I've had good luck with is tightening each of the screws (or nuts/bolts) that replaced the rivets a little at a time before moving to the opposite one, similarly to how you would tighten lug nuts so that you tighten the whole thing down as evenly as possible.

I checked the trigger points and they are switching between 12 &21 ,12&22 with good continuity back to the ECU . I lightly rubbed grease on both sides of the paper gasket so I will take it all apart again and reddit .I did tighten the screws opposite of each other like lug nuts but I will just have to open it and try it again ,I will add silicone to the large ring , to get to the little one I will have to redo the adjustments . Not sure if I want to mess with that but if still leaking I will redo everything .Is the fuel pump relay the large rectangle silver one ? Still waiting on neighbor to test the plugs . I think I read somewhere what is needed and how to connect a remote starter ,this would be handy .

[Ron914]

Ron got that Pertronix from me, and yes it is older. It sat in a box on my shelf for at least 10 years.... If it is a worry for you Ron I'm happy to refund your money and you can simply trash the Pertronix.

I went down the rabbit hole and I think you are correct about the 123 and the smog check. Of course everything depends upon who is doing the inspection. I believe the 123 would fall under the category of performance distributors, and these would require that the company submit it to the CARB for certification that it does not make the car run dirtier than the OE distributor. An exemption would then be issued. I couldn't find any documentation of this having been done.

It's not a problem fiacra ,
I don't want any money back . Everything with this car is a learning experience for me . I will just be extra diligent when outside of the car tuning it . If I was to eventually pass a smog test I could then install the 123 but would have to remove it every two years or find a guy as everyone tells me that looks the other way . Hopefully Jay Leno's law passes and I won't have to worry about the smog check any more . I know there is a lot of controversy about that law . I could also buy a newer version of the Pertronix if I wanted to but I would rather put that money into a 123 but first order is to get my car sorted out and pass the smog test .I want to drive my car to my first WCR in June .

[SVG223]

Good luck with this, my MPS is leaking too, watching and learning. (IMG:style_emoticons/default/popcorn[1].gif)

[JeffBowlsby]

Just a heads up, there are other places the MPS cases may leak besides the gasketed locations. If vacuum loss still occurs investigate/repair these also. Methods I have used:

-Case to outer plastic 4-pole harness connector interface. Run a line of superglue around this joint.
-Check valve at internal port, back of case. Not much to repair here, but replace the check valve if you have a donor MPS case.
-Center-most adjustable screw (inner screw) to outer screw at the center of the diaphragm fixture. Add a small dollop of grease over the slotted screw head to seal the threads, grease will get sucked into the threaded joint if there is a vacuum leak.
-Joint interface between the pleated diaphragm and its center threaded pressed on fixture. Run a line of superglue around this joint.

[JeffBowlsby]

dbl dbl.

[fiacra]

If I was to eventually pass a smog test I could then install the 123 but would have to remove it every two years or find a guy as everyone tells me that looks the other way .

I wouldn't advise you do that. Unfortunately those people are out there, and I'm sure you could find a shop that would do it, but I'd like to think you are a more ethical person than that. I know you can do this the right way.

The "large rectangular box" on the relay board is the voltage regulator. Here's a link to a picture of the relay board with the relays labeled.

http://www.914world.com/specs/SirAndyCarbFuelPumpRelay.php

And here's a link to a video explaining the relay board.

https://www.youtube.com/watch?v=YLgQxpNHzIU

A remote starter switch is cheap, easy to get, easy to use, and invaluable when adjusting the valves.

[Ron914]

[quote name='SVG223' post='3205335' date='May 13 2025, 05:18 PM']
Good luck with this, my MPS is leaking too, watching and learning. (IMG:style_emoticons/default/popcorn[1].gif)