Slant Six Forum :: 85 D150 ESA / Lean Burn / Ignition questions

What the heck is that?

I've recently acquired a non-running 1985 Dodge D150 with a slant 6 that I'm trying to get running. It's my first carburated vehicle and the vacuum lines, emissions and ignition system are confusing me.

I'd like to remove the EGR system and the air pump

but keep the vapor canister and PCV system.

Unfortunately, the weber only has one vacuum line and I have no clue if I can tee it off enough to provide vacuum to the vapor canister, the PCV system, and the ignition system.

My 85 slant does not have a vacuum advance distributor.

a box labeled "ESA" on the routing diagram. Is this the lean burn computer?

I have many vacuum questions I'll save for another post, but this may be related to the ESA. I have three vacuum lines running to the fender on the passenger side, close to the firewall, that run into something that's connected to the wiring harness. What the heck is that?

I'm not sure if the one vacuum source on the weber 38/38 DGES is a ported vacuum or a manifold vacuum signal.

Thanks for the welcome to the board. I'm having fun working on an old truck. I found this link in your book suggestions very helpful < http://u225.torque.net/haynes_instructions.html >.

How do I add a large-bore vacuum tap the the plenum of the intake manifold?

is the plenum the part of the manifold under the carburetor but before the runners?

Clifford sold it to me (my first mistake) and the support they gave me was suspect.

Regarding the EGR delay timer, can I remove the timer and the hard vacuum lines that run to it?

Do I need to cover the remaining connectors?

I'm sold on the HEI upgrade, thanks for the link and the time put into the original article. However, I'd like to know more about how it works compared to the lean burn system.

If my lean burn distributor doesn't have the mechanical vacuum advance needed for the HEI upgrade, how does the lean burn system advance the timing? Does it read off of some data table using engine load (vacuum signal) and engine speed?

Also, if the weber doesn't have a ported vacuum source, can I retard the timing at idle (assuming I've installed a vacuum advance distributor)?

I'd like to remove the EGR system and the air pump?

You may also want to do the fuel line mod.

Author:	NOVA_Slant [ Mon May 04, 2009 4:37 pm ]
Post subject:	85 D150 ESA / Lean Burn / Ignition questions
I've recently acquired a non-running 1985 Dodge D150 with a slant 6 that I'm trying to get running. It's my first carburated vehicle and the vacuum lines, emissions and ignition system are confusing me. I have a new weber 38 /38 that I'm going to use to replace the stock carb, and I found a clifford intake and exhaust manifold on ebay for a decent price I'm going to use also. I'd like to remove the EGR system and the air pump, but keep the vapor canister and PCV system. Unfortunately, the weber only has one vacuum line and I have no clue if I can tee it off enough to provide vacuum to the vapor canister, the PCV system, and the ignition system. Ignition System My 85 slant does not have a vacuum advance distributor. Instead, it looks like a vacuum line is running to the driver's side fender, to a box labeled "ESA" on the routing diagram. Is this the lean burn computer? My distributor has a small electrical connector running to/from it (pick-up coil?). Does this provide the ESA with the engine speed? I haven't opened up the wire loom, but I'm guessing the ESA took vacuum and engine speed information to electronically advance my timing. My stock carburetor did not have electrical connections to it, and the exhaust had no oxygen sensor in it when I removed it. What other sensors should feed into the ESA? I have many vacuum questions I'll save for another post, but this may be related to the ESA. I have three vacuum lines running to the fender on the passenger side, close to the firewall, that run into something that's connected to the wiring harness. What the heck is that?

Author:	Ed Mullen [ Mon May 04, 2009 4:44 pm ]
Post subject:
Quote: What the heck is that? It's the "computer." Almost everyone here will tell you to get rid of it and your distributor and switch to EI or HEI ignition and an electronic distributor with a vacuum advance.

Author:	SlantSixDan [ Mon May 04, 2009 5:01 pm ]
Post subject:	Re: 85 D150 ESA / Lean Burn / Ignition questions
Quote: I've recently acquired a non-running 1985 Dodge D150 with a slant 6 that I'm trying to get running. It's my first carburated vehicle and the vacuum lines, emissions and ignition system are confusing me. Welcome on the board. Get these three books as quickly as you can. Quote: I'd like to remove the EGR system and the air pump Easy enough... Quote: but keep the vapor canister and PCV system. Smart thinking. Quote: Unfortunately, the weber only has one vacuum line and I have no clue if I can tee it off enough to provide vacuum to the vapor canister, the PCV system, and the ignition system. No. You'll need to add a large-bore vacuum tap to the plenum area of the intake manifold (the existing tap on the rearmost runner won't do the job) for the PCV and the vapor canister. Plumb in the vapor can as described here. The distributor vacuum spark advance requires a ported vacuum signal (no vacuum with throttle plates closed at idle), not a manifold vacuum signal. Quote: My 85 slant does not have a vacuum advance distributor. But it will when you dump the Lean Burn. See also HEI upgrade. Quote: a box labeled "ESA" on the routing diagram. Is this the lean burn computer? Yes. Quote: I have many vacuum questions I'll save for another post, but this may be related to the ESA. I have three vacuum lines running to the fender on the passenger side, close to the firewall, that run into something that's connected to the wiring harness. What the heck is that? EGR delay timer.

Author:	Reed [ Mon May 04, 2009 5:03 pm ]
Post subject:
You might also want to read this article.

Author:	NOVA_Slant [ Mon May 04, 2009 6:51 pm ]
Post subject:
Thanks for the welcome to the board. I'm having fun working on an old truck. I found this link in your book suggestions very helpful < http://u225.torque.net/haynes_instructions.html >. Vacuum questions: How do I add a large-bore vacuum tap the the plenum of the intake manifold? On the stock and clifford manifolds, is the plenum the part of the manifold under the carburetor but before the runners? I'm not sure if the one vacuum source on the weber 38/38 DGES is a ported vacuum or a manifold vacuum signal. I can't find much information on this carburetor. Clifford sold it to me (my first mistake) and the support they gave me was suspect. Regarding the EGR delay timer, can I remove the timer and the hard vacuum lines that run to it? Do I need to cover the remaining connectors? Ignition questions: I'm sold on the HEI upgrade, thanks for the link and the time put into the original article. However, I'd like to know more about how it works compared to the lean burn system. I cut my teeth on a '92 1.6L Honda engine that spins to 8400rpm and makes 170hp stock; I'm more familiar with an ECU that controls fuel and ignition maps for two different camshaft profiles. If my lean burn distributor doesn't have the mechanical vacuum advance needed for the HEI upgrade, how does the lean burn system advance the timing? Does it read off of some data table using engine load (vacuum signal) and engine speed? Also, if the weber doesn't have a ported vacuum source, can I retard the timing at idle (assuming I've installed a vacuum advance distributor)? Thanks!

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Author:	Ed Mullen [ Tue May 05, 2009 6:03 am ]
Post subject:
Quote: I'm not sure if the one vacuum source on the weber 38/38 DGES is a ported vacuum or a manifold vacuum signal. Can you see/tell if the inside of the port is above or below the throttle plate when closed? (above: 'ported', below:'manifold').

Author:	SlantSixDan [ Tue May 05, 2009 9:40 am ]
Post subject:
Quote: Thanks for the welcome to the board. I'm having fun working on an old truck. I found this link in your book suggestions very helpful < http://u225.torque.net/haynes_instructions.html >. Oh, good. Those are important instructions. Quote: How do I add a large-bore vacuum tap the the plenum of the intake manifold? Drill, then tap, then install a pipe thread to hose barb fitting made out of brass. Quote: is the plenum the part of the manifold under the carburetor but before the runners? Yes. Quote: Clifford sold it to me (my first mistake) and the support they gave me was suspect. Typical Clifford. See here, here, and many others. Quote: Regarding the EGR delay timer, can I remove the timer and the hard vacuum lines that run to it? If you will not be using EGR, then yes, you can remove all components of the EGR system. Quote: Do I need to cover the remaining connectors? The electrical connectors can just hang free. Be sure to remove or securely cap any vacuum lines you won't be using. Quote: I'm sold on the HEI upgrade, thanks for the link and the time put into the original article. However, I'd like to know more about how it works compared to the lean burn system. Oh, that's easy. HEI (or Chrysler electronic ignition, or any of many other ignition systems down to and including a basic pre-1972 points/condenser system) works reliably and allows good performance, drivability, and economy (PDE). Lean Burn doesn't. Quote: If my lean burn distributor doesn't have the mechanical vacuum advance needed for the HEI upgrade, how does the lean burn system advance the timing? Does it read off of some data table using engine load (vacuum signal) and engine speed? Yup, that's exactly what it does. Certainly an innovative idea for its time, and obviously the principles would be used for many years onward, but the (fixed) calibration of this particular system doesn't give good PDE, and the hardware of which this system is built is a product of its time: PRIMITIVE! Quote: Also, if the weber doesn't have a ported vacuum source, can I retard the timing at idle (assuming I've installed a vacuum advance distributor)? I'm not sure how the one follows from the other in your mind, or perhaps I misunderstand what you're asking. Retarded base timing really spoils PDE. You'll need to figure out a way to have (or approximate) ported vacuum to the vacuum advance or you'll be giving up a good deal of PDE. If you find your carburetor has no ported vacuum source, you can approximate it by installing a closed-throttle switch, either NC or NO. This switch would be tripped when the throttle is at idle position. You'd use it to control a vacuum solenoid connected to manifold vacuum, with a restrictor orifice in the line between the solenoid and the distributor. Vacuum solenoids are easily found all over any wrecking yard; they're used extensively in '90s vehicles. You'd want a venting vacuum solenoid which will drop the downstream line (from solenoid to distributor) to atmospheric pressure when power is not applied, not a holding vacuum solenoid (which would seal off the line to the distributor, thus retaining its vacuum). You may also want to do the fuel line mod.

Author:	otherroutes [ Wed May 06, 2009 6:48 am ]
Post subject:	Re: 85 D150 ESA / Lean Burn / Ignition questions
Quote: I'd like to remove the EGR system and the air pump? From what I've gathered from the immense knowledge on this forum, plus my own experience - IF you have catalytic converters in your exhaust then either: (a) don't remove the air pump as you'll melt and block your exhaust; or (b) plan and budget to remove the cats too. Having driven with blocked cats and paid for a new exhaust without cats (since a previous owner removed the air pump) I can assure you that a blocked exhaust damages your performance way more than the air pump. The air pump is probably kinder to your bank balance too.

Author:	Ed Mullen [ Wed May 06, 2009 9:46 am ]
Post subject:
Quote: You may also want to do the fuel line mod. Isn't the fuel filter already behind the alternator by 1985?

Author:	tlrol [ Wed May 06, 2009 7:17 pm ]
Post subject:	Tell us about the performance of the Weber 38/38
When you make the swap let us know how it goes. I have a Weber 32/36 and I think a 38/38 is in my future...I would like to hear of other people's expriences with the 38/38...

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