I'm planning a full lean-burn removal on my 87 B150. Apart from installing EI, I also want to keep the emissions systems in place, just take the lean-burn controlled solenoid valves out of the loop, and remove the module.

I'm looking to convert to a Holley 1920 (presently running either a 6145 or 1945--I think the former is more likely.)

The only vacuum device in my van that an older /6 vehicle would have is the upstream/downstream smog pump valve. I'd consider leaving the solenoid and work it from a switch on the dash. It gets it's direct vacuum from the manifold, not the carb.

If anyone has a vacuum diagram scan of a pre-lean burn engine, it would be greatly appreciated, and helpful in figuring how to set up the EGR.

The lean burn module reads a sensor in the intake manifold and operates a solenoid between the vacuum amplifier and the EGR valve. I'm guessing that in earlier setups, there was just a temp valve in the hole in the manifold that cut vacuum to the valve in the same way. If I'm correct, the part number for that temp valve would also be helpful.

Take a look at:

http://www.slantsix.org/forum/viewtopic ... ram#141151

CJ

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Part of Tyrde-Browne Racing

cool. thanks.

Looks like I'd have to add a bunch of parts to set up the EGR like that, and there'd still be a solenoid valve in the loop.

Maybe I should entertain designing my own circuit to go between the sensor and the solenoid (to do what the module does for the EGR system, but to adjustable parameters) and leave the vacuum routing as/is.

I assume the sensor in the intake manifold either has variable resistance to ground or switched continuity to ground. Either way I need to detect the appropriate temp, have that trigger a timer, have the timer power a relay that powers the solenoid, have the relay actuating start another timer that cuts power to the relay and resets the first timer. (so it detects warm up, waits a while, opens the EGR valve, closes the valve a minute later and restarts the process in an infinite loop.)

this might help its for a d150 truck though probably quite alike
By illldeca1 at 2008-07-27

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87 d150 2bbl carb 225
79 f250 300 v8
97 cavalier z24
83 f150 straight 6
89 f450 diseal 4x4 dually 5sp

Trying to make the emission control system work without really understanding the function and interrelationships of each and every component could easily have you chasing your tail, spending a lot of money and effort, and winding up with a vehicle that doesn't run right and/or makes other problems. There is no solenoid necessary in the EGR system, but you will need temperature-sensing vacuum switches (known as "ported vacuum switches"). What-all else you'll need depends on which exact carburetor you wind up using. A '73+ Mopar carburetor with a venturi vacuum tap will allow you to set up the system along factory lines, with a vacuum amplifier (vacuum relay) looking at the venturi vacuum signal to control manifold vacuum to the EGR valve. It is also possible to set up a working EGR control system with a carburetor not equipped with a venturi vacuum tap; see "Poor man's EGR" on this page. Your truck already has a charcoal canister, so you needn't shop that; a very good cross reference for the various-temperature ported vacuum switches is here.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

that is the exact vacuum diagram of my van. (thanks for posting it).

I know I don't "need" a solenoid, I just have one. I also have a sensor for the EGR in the intake manifold. Both are interconnected via the module. I am simply entertaining the idea of taking the module out of the loop.

The module in my van really only controls three things: EGR, ignition timing and upstream/downstream smog pump air.

The smog pump influences nothing tangible except emissions, which are only of concern to me when I go through inspection. Realistically upstream/downstream thing need only ever be on whichever is appropriate for going-to-inspection conditions (idling for a half hour at operating temp to get the cat as hot as possible)--I'm guessing the downstream air would be good for that.

The ignition is going to be a vac-advance distributer and an EI unit--module out of the loop entirely.

The EGR is the only thing left to attend to. I had assumed it only really needed a vacuum switch, but I saw on the first diagram up there that there was a timer and a solenoid in that setup, which gave me the idea that perhaps a delay after temp is reached may have some benefit (and may be a function of the module/solenoid).

Building a circuit the replace the module to control the EGR solenoid would cost me more in postage, than anything else (two timer ICs, and a handful of caps and resistors from Mouser.com won't exceed $4).

I can monitor all input/output of the module under driving conditions easily enough and infer what conditions precipitate the solenoid opening.

I'm reluctant to beleive that the silly lean burn module is executing much rocket science when it's only input is two temperature sensors and a vacuum line, and only output is the timing advance, cutting off the EGR and deciding which of two tubes it pumps air into the exhaust with.

I may just go with a vacuum switch (that's where I was leaning originally, and assumed was the pre-late 70's EPA nonsense setup) but if pissing away $12 (assuming I went through 2 failed prototypes before figuring it out) lets me toss the module with no mechanical work beyond swapping distributers, it's worth it--even to fail. (If it works, I'm sure some other person in the same boat wouldn't mind having the schematic).

Thanks for the list of vacuum switches. I'll be falling back upon it if/when I lose patience.

SlantSixDan, the link above is for ignition. Is this the intended link to the "Poor man's EGR"?

http://www.allpar.com/fix/EGR.html

Looking over the article it says that you want manifold vacuum to the distributor vacuum advance when below 150 degrees F. Does this sound correct?

I can see where having manifold vac to the dizzy when the engine is running too hot @ idle to help bring up engine speed fixed fan for cooling, but why is manifold vac to the vacuum advance when cold good?

OK, I can see how the manifold vacuum would work better on a cold vehicle according to this...

http://en.wikipedia.org/wiki/Ignition_timing

"On some vehicles, a temperature sensing switch will apply manifold vacuum to the vacuum advance system when the engine is hot or cold, and ported vacuum at normal operating temperature. This is a version of emissions control; the ported vacuum allowed carburetor adjustments for a leaner idle mixture. At high engine temperature, the increased advance raised engine speed to allow the cooling system to operate more efficiently. At low temperature the advance allowed the enriched warm-up mixture to burn more completely, providing better cold-engine running."

It looks like I already have the proper temperature ported vacuum switch from the factory on my radiator for EGR control but if I wanted to get the distributor to run on manifold vacuum during cold startup or when hotter than normal I would need a 3 way temperature ported vacuum switch mounted on the engine somewhere.

This link is great if I need to investigate myself
http://www.drbob.tqhosting.com/tech/cto.html, however does anyone have a valid part number for a 3 way valve that accepts manifold and ported vacuum and gates them properly for distributor vacuum control based on coolant temp that fits on the engine block? Is there even an extra place on the block to mount that 3 way temperature ported vacuum switch into coolant?

http://www.bwdbrand.com/web_app/Main/Page.aspx?ID=77

The thermal vacuum switch (second from the top) shown in the link above is what I'm talking about to control distributor vacuum. Ignore that in the link it mentions EGR to the middle port.

So is anyone running anything like this for the distributor vacuum on their slant?

Okay: What exactly do you have in mind when you say you want to keep the emissions system in place? What is the goal here, exactly?
What are you hoping to achieve?
Why? Again, what's the goal? And will you be running a catalytic converter?
There are many different configurations. Your request is too generic, and while you have had some replies with diagrams, you are likely to cause yourself unwanted aggravation if you try to make your truck conform to pieces and sections of random vacuum diagrams.
No, the earlier systems didn't use a manifold temp sensor. They controlled whether the EGR was active or not by sensing coolant temperature. Depending on the configuration, the sensor is in the cylinder head or in the radiator top tank.

It's very likely you can wind up with a configuration that meets your goals, but it'll be a lot easier to offer suggestions if you state those goals in clear detail.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

No. Ported vacuum is better. On a cold engine, the throttle is held partway open by the fast idle cam, so the distributor sees vacuum.
Remember, anyone can edit Wikipedia. There is a huge amount of crap in the automotive articles, and there is no good reason to rework the distributor vacuum control to incorporate a ported vacuum switch as you have in mind.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

That sounds resonable Dan given that I did not take into account the bump up in idle speed's effect on the distributor vacuum advance. My 1920's high idle screw was stripped out when I got the car and I have no high idle at this time. I'm looking for a new 1920.

How about the EGR question that I posed regarding having the EGR share the same vacuum line as my vapor purge valve? Would that line using a delay valve work OK for EGR control Dan?

No. If you want to keep EGR, why not put it together the way the factory did before the advent of Lean Burn — hockey puck shaped "vacuum amplifier" taking a venturi vacuum signal from a carb so equipped and sending manifold vacuum via coolant temp ported vacuum switch to EGR valve?

Still waiting to learn your exact goals, but it seems like one of them is passing NJ emission tests, is that so? What else?
Still depends on exactly what you hope to achieve.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Ed Mullen posted on this about a year ago and he was from NJ. I don't think he needs help on it anymore.

I hope to achieve some knowledge on how to properly hook up an EGR. Wouldn't a properly working EGR reduce NOX emission and allow me to run more timing with less chance of ping at light cruise at operating temp?

The ported vacuum that you mention. Is that different from the vacuum for the distributor. I have an EGR ported vacuum connection on my carb but I now have a plug over it. Does the vacuum signal from this EGR port in the 1920 differ from the ported vacuum connection signal that is used for distributor advance pre amplifier?

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74 Dodge Charger 225 factory A/C auto 1920 carb stock exhaust.

Mods;
HEI, MSD B3, Magnecor 8 mm, ZFR5N, .060 rotor, CH410X cap, new 3874814 dist, fuel mod, valves hot .010 & .020, all new hoses, JP chain, brake hoses and fluid.