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Surging idle hot start EZ-EFI 1.0

Discussion in 'FAST Support Forum' started by gremlinmt, Oct 21, 2018.

  1. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Those rear throttle blades can pick up a little carbon and hang. "Blipping" them manually against the slack in the linkage can usually clear that away and allow you to notice when they start fully closing again. Backfiring is a prime candidate that causes this.

    You need an adjustable canister with a diaphragm that can be adjusted using an Allen wrench. This will give more control over timing advance at vacuum and engine loading. Ported vacuum should be connected to the canister. I would just disconnect and plug the vacuum to the canister for now. 16 initial with a 12 degree distributor gives 28 degrees of timing - good enough for now at 3500 all-in slope, just not as economical for gas mileage with a properly set vacuum advance. I would have just bought a MSD distributor. They come with the slope already set to 4000. You pretty much only swap in an adjustable canister and just work at getting the vacuum advance right, and just use the black advance bushing that comes with it.

    It's been a long time since I had a Chrysler product. I had a new '69 Road Runner I liked, but the new '70 'Cuda I had was a lemon - something was always broken on it. That 'Cuda turned me away from them, and I never bought another Chrysler product. I wish I still had the Road Runner with it's big wedge engine, but I really hated that Hemi 'Cuda. Both of them would be worth a fortune today, but I sold them for almost nothing back in the day. People didn't care so much for them then. I had my 'Cuda for sale on a car lot for months and it didn't sell. I pulled it when people started stealing the emblems off the body. It took two years to sell it. Both were 4-spd pistol grip shifter cars with only about 20,000 miles on each of them.
     
  2. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Yesterday was the first backfire I'd seen since the week I put the engine in. The throttle blades aren't as clean as I'd like, a lot of miles on a dual plane manifold. This vac canister is adjustable for when the advance starts coming in, but not for total advance. It also tends to come in rather quickly. Swapping it out should be trivial. The reason I haven't bought an MSD is purely price. There are only two options for a vac advance distributor for Chrysler, the ready to run to the tune of $440, or the ecurve at almost $470. All the other Chrysler options don't have provisions for vac advance. I purchased a new Spectre distributor at $100, the same as my old one. It comes with a lifetime warranty. I just need to take the core back to get my money back on it. I honestly think I killed it myself. If was running fine until I put my grubby little in there. I probably mangled a wire or got some shmoo on the pickup.
     
  3. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Its got a miss this morning right around 1200rpm under load. I'll be opening it back up this weekend to install new alternator. I'll pull plugs while I'm in there. I'm going to pull the vac canister out of the circuit before the drive home tonight. See if the miss changes.
     
  4. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    I wish you had already removed the vacuum as I mentioned earlier. It's likely you are getting too much combined vacuum and/or mechanical timing @1200 - which not only will foul the new plugs, but will also make any readings of them difficult.
     
  5. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Added a new throttle return spring and disconnected the vac canister before the drive home. It seemed to be better. New alternator showed today. I'll be installing it this weekend along with solving some voltage drop issues in the wiring harness.
     
  6. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    You've mentioned the MSD E-curve distributor and upgrading to a different ECU. I have to say the E-curve sounds like it may be a great option for an upgrade as it offers different vacuum strategies and electronic timing advance control (and slope). I really feel the E-curve would be the best and more economical option - rather than upgrading to EZ EFI 2.0 or Sportsman for their timing controls. However, I am really not familiar with the actual performance of the E-curve.

    Despite MSD says the MSD 8534 Pro Billet only works with 6 series up ignition boxes, it will work fine with your engine - even a stock Chrysler CD ignition box. The reason is the module will be connected directly to your FAST EZ EFI ECU. FAST even carries a direct wiring adapter for this. You would just change to the included black advance distributor bushing, keeping initial at 16-18 degrees. This would give you 34-36 total mechanical advance degrees with Slope already set correctly from the factory. You would then replace the MSD canister with a Crane adjustable vacuum advance to correctly supply the needed vacuum advance curve. The Crane part is just a standard GM hex key adjustable canister. The needed vacuum curve adjustment will allow vacuum timing to drop more quickly under load, but allow more timing under no or low load engine operation for better mileage. Now that Holley has bought MSD, I'm sure this option is no longer made clear. But, the results using this MSD Pro Billet style are definitely positive.

    https://documents.holley.com/8534.pdf

    https://www.holley.com/products/ignition/distributors/chrysler/parts/8534
     
  7. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    The problem is, they don't make an MSD probillet with a vac canister for the mopar small block. Maybe they used to, but they don't any more. I don't know if there is some way to add it on? The e-curve takes a lot of guess work out of the process, but it also takes a lot of cash out of your pocket. :) The instructions seem somewhat vague for the ecurve. I assume that it's like installing a dual sync distributor where you stab it in at full advance and the electronics retard the timing as needed.

    As long as I'm basically in a holding pattern on timing. I've got another question. If I used my advance plate to lock out my distributor, could it be used as the timing input for a sportsman ecu?
     
  8. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    The hunt for an adjustable vacuum advance has come up empty. The Summit can is listed for their billeted distributor line.

    I know my old vac can is 10 degrees that I can pull in anywhere from 7-20 inches of vacuum. The new vac can is 15 degrees with a similar adjustment range.

    This leaves me some options:
    I could use manifold vacuum, retard initial and aim for 16-18 degrees at idle.
    I could use ported, retard timing enough so it will cruise nicely with the vac advance.
    I could not use vac advance at all but that might cost me a lot of mpg.
    I could swap canisters to get it down to 10 degrees vacuum advance.
    There is some talk that you can shim the vacuum advance arm and limit timing that way. I'll have to look at that. A lot of trial and error.

    Come tax season, I could pull the trigger on something from MSD. I'm tired of spending money but this is probably the easiest option.
     
  9. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Any locked out distributor works with EZ EFI 2.0 or Sportsman. Both of these ECUs use the same wiring harness.

    Check with Holley. The old instructions claim the 8534 distributor has a lockout plate that can be replaced with a vacuum canister.
    Of course, no telling what Holley has done now that they have acquired Accel, Mallory, and MSD.

    If you work with an adjustable canister, you may be able to get it right - if you start out using a setting that lowers the canister advance movement under vacuum. That 1200 RPM point indicates the vacuum advance is coming on too early - not that the total canister advance is necessarily too great. Use the ported vacuum to delay vacuum. Your engine should easily tolerate 10-12 degrees of vacuum advance.

    Keep the initial at 16-18 degrees with the total mechanical at 34-36. Ten degrees of vacuum advance will have you at 44-46. Which is within spec. - if the slope is correct.
     
    Last edited: Jan 2, 2019
  10. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Ok, I'll add another degree of timing, bring it up to 17 degrees. Set the vac advance to come in as late as possible, preferably with the 10 degree can. If we are going to be staying below 18, should I move the limit plate to 14 degrees? That'll probably actually slow the mechanical curve down a bit more.
     
  11. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Leave the degree plate at 12.
     
  12. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    It's been a long weekend. New alternator is in, I've got a nice steady 14.5 volts at idle. There is a voltage drop or no true reading on the handheld. It consistently lags behind 0.5 volts. But that still leaves it at 13.5v at idle. Much better than the 12.1v or less I was seeing. While we were at it, we went through all the old stock white plastic connectors and upgraded them to weatherpack connectors. We also replaced the start relay and all it's connectors. They were original to the truck and somewhat loose. Everything is tight and ship shape.

    On the timing side, nothing is quite so easy. Any time the vac cannister is hooked up, spark breaks up, it misses, stutters, and backfires out the exhaust. I tried retarding the timing all the way to 5 degrees BTDC and advancing all the way to 22 BTDC. It doesn't matter, as soon as the vac can is hooked up, everything goes to hell. This is super frustrating because it clearly needs more timing at light throttle. Intermittent miss and backfire is the rule.

    All of these issues are manifesting on the new distributor, even though the vac cannister tested good (held vacuum, advanced the plate, responded to adjustments in spring tension. I pulled the one off the old distributor and did it all again. I even used a mighty vac to run the vacuum advance by hand. No improvement.

    IMO this leaves me with one possible issue. I don't want to influence anybody. I'm working tomorrow so no fixing is possible until late day, if at all. If you've go the answer, please tell me.
     
  13. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Do a fairly long warm engine handheld video, with the initial at 18 degrees, and let's see if I can spot something with canister disconnected. Hold the throttle steady at a few different RPMs to 2000 RPM. I assume the problem begins above idle speeds with the canister connected. Be sure to do the video of the handheld close up.
     
  14. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    I'll take rotor phasing for $!000 Alex. So while I was in the shower thinking about what could possibly be wrong when I plugged in vacuum advance, I decided that my symptoms matched two possible problems: 1. late spark, backfire out the exhaust is usually caused by spark when the exhaust port is open. 2. Spark arcing to the wrong terminal in the cap. ie. rotor phasing.

    I know I didn't have severely retarded timing. I also knew that the timing light got erratic when I plugged in the vac advance. Some research shows that while the mechanical advance on a mopar distributor takes place on the shaft and is therefore not subject to rotor phasing, the vac advance happens by moving the pickup, which is effected by rotor phasing. I took my old cap and drilled a hole at the #1 terminal. Pulled the distributor and checked phasing at rest. It was right in the middle of the terminal. When I pulled in full vac advance, my rotor was mostly passed the terminal. I pulled the reluctor and moved it until the at rest was just behind the terminal and the full advance was just in front of the terminal. All of a sudden my vac can works like it should. No problems anywhere in the rev range. No pinging on light throttle. Spec shows that vac advance should be starting to come in around 7 inches of vacuum. Once I'd verified operation I checked mine, it's coming in around 13 inches with the adjustment all the way at the stop. It feels like it should come in a little sooner. I'll buy another vac canister to slip in there and start around 7, see how it tolerates it.

    no advance.jpg full advance.jpg adjustment.jpg
     
  15. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    Yep. I wish you had checked the phasing earlier. I'm sure you've got the problem that was causing everything to barf solved now. Now you should be able to find your best settings. Get the timing all squared away first and then see how lean you can go. You may need t go a tenth richer with the WOT as you lean the idle and cruise A/F a tenth at a time. Go slow and take your time. You know the drill. Sorry I didn't mention the phasing earlier.
     
  16. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Yeah, the old distributor that had the failed pickup was phased properly. Who would expect a part out of the box to be so poorly phased that it wouldn't work? Of course I picked up a new canister from the parts house just now. It's supposed to start coming in about 7". This one is all done at 7" and is actually starting before I can even see it on the gauge. *sigh* you'd think they'd take a little more care with this stuff.
     
  17. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    You have to wonder about what country these things come from today. Most new over-the-counter parts now are from all over the world today - with very questionable quality. I keep up a very nice '95 Buick Le Sabre, with 68,000 miles, my uncle left to my mother when he passed in 2007. She's in her late 90's and doesn't drive now, but I've had to replace almost every electrical switch and module under the hood of it since then to keep it running - she just doesn't want to sell it because it belonged to her brother. To get good parts from the local auto parts, I've had to replace some of them 3-4 times in a row just to find one new part that actually worked or worked correctly. It's hard to find the factory AC Delco parts, and they are usually expensive when I can find them, but I learned long ago it's just not worth the time trying to use anything else. It's far worse today than it was in the 60's and 70's when Chinese suppliers were faking brand name parts with substandard materials - and labeling them "Made in USA", Delco, Ford, and Autolite.

    Lol, I just had to put a new computer and a new e-prom in that Buick a year back. Tomorrow I have a NOS Delco ignition module coming for it through "FleaBay" - the best one the local auto parts had for sale didn't work. Because of that, I had to check all the wiring and sensors - which were still good. At times, I think it might be a good thing if it just burned itself up. The last time I drove it, I just barely got back home - then I had to replace the fuel pump. For a dark red car, it must have a hidden coat of lemon yellow primer.
     
  18. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Dropped in new vacuum advance this evening. Comes in at 7 inches, full advance about 10 inches. Paranoia is high, I checked phasing with new can, just in case the arm is slightly longer or some other ridiculous problem. The stamp on the arm says it pulls in 11 degrees, timing light says 15. Quick test drive, no pinging at part throttle. I'll run it for a while see how it does. Currently at 16 initial, 34 all in, two heavy springs. I should have checked when that comes in again, but I just didn't have it in me. Last time I checked with both heavy springs it was all in about 3500rpm but that was with advance plate at 12 degrees.

    Long term, I've found a company that will build up a nice billet distributor to spec for under $300 delivered. Once I get timing exactly correct, I'll order one up and put this timing issue to bed for my lifetime.
     
  19. A A

    A A Well-Known Member

    Joined:
    Jun 22, 2014
    I guess you've gotten the timing about as close as you can with what you have to work with. Your engine may tolerate these settings at 9:1.
    16 initial + 18 total mechanical + 15 vacuum = 49 degrees total timing. As long as you have no valve ping, detonation, or pre-ignition, on hard acceleration - you may be fine. If good, you can try leaning A/F. As I said earlier, WOT may need to be richened as far as 12.5 as you lean the idle and cruise A/F. Only lean a tenth at a time - then evaluate the plug ceramic.

    New distributor sounds like a good plan.
     
  20. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Well it would only have that much if I was cruising at 85+ mph. Even there, I doubt I'd see that much timing. It takes a fair bit of muscle to move 6800lbs of 4wd drivetrain and brick-like lines down the highway at that speed. Thing turns over less than 2800rpm at interstate speeds and it hardly ever gets on the interstate. Apparently I can take timing out of the vacuum can by shimming the stop. .003 per degree. Anyway, it's been quiet at cruise up to 65mph. The highway is *Banned**Banned**Banned**Banned* icy right now so I'm not willing to stuff it in the passing lane and get crazy. I'm going to dial idle down to 13.5 AFR and see if it cures my hot idle start surge. That'll tell me which direction I'll need to go with cranking fuel.
     

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