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Surging idle hot start EZ-EFI 1.0

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

  1. 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.
     
  2. 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.
     
  3. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Today was a day off because I worked last Sunday. Started the day by taking the truck to drop the kids off at school. Truck ran well. 25F outside. I must have been out late because the engine was still at 36F when I crawled into it. Warm starts are still a problem. Whenever IAT is more than about 60F more than actual temp due to heat soak it wants surge and usually die. Because I had time today, I did a lot of short drives where the engine was fully warm so I could replicate the issue. I keep pushing the cranking fuel up when the start temp is above 125F and the cold start enrichment up when it's below 125F. If seems to be getting better. I'm +2 on cold start and +4 on Cranking right now. It's still surging but not dying as often.

    Also did a freeway blast this morning. 2500rpm at 65mph. That was at 14" of vac. Pulled plugs 1 and 3 when I got home. Plugs were in very good condition with no fouling. Looking at the log book, they have about 400 miles on them. Ceramics were cleaned with a poorly defined line at the bend on the ground strap. Threads were discolored to the second thread so I assume heat range is good. No signs of detonation.

    Driving about feels pretty good. I'm still getting used to the return springs. Pedal feels heavy but I suppose that's not a bad thing when looking for fuel economy. :) Throttle is responsive and doesn't bog down.

    This spring I installed a catch canister between my PCV valve and throttle body. It always amazes me just how nasty the stuff coming out of the crank case is. Mostly water but with a nasty scum of oil and what feels like parafin. Glad to capture it and throw it away instead of sticking it into my engine. I've included a picture.
    20190111_113126.jpg
     
  4. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    I'm just happy I collect it instead of shoving it down the intake. That's about 400 miles of collection. My commute is short enough that it's just reaching full operating temp as I'm pulling into the parking garage on a 20F morning with no warm up. I like to plug it in and that helps a lot with reaching operating temperature sooner.
     
  5. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Well, boring drive today. Engine started up easy at 42F, warmed up quickly, drove well, idled beautifully at 650rpm. New alternator shows at least 13.2v on EZ-EFI display and 14.0v on my battery monitor. Restart at 109F engine temp and 95F intake temp had no drama, just settled down and idled nicely.

    I've gone through every wire and connector between the battery and the EZ system, it tends to read 0.7v low which is better than the 1.0v low before going through everything. It's got a brand new starter relay and all old wires and connectors have been replaced by weatherpack connectors. I'm leaning towards ignoring it. I may stab a multimeter lead into the back side of the ecu connector just to verify but i think the reading is just plain wrong.

    I did some full throttle pulls at highway speed. Full pedal travel registers 95% on the throttle readout so I'll calibrate that in the morning before first start.
     
  6. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Even with heater, lights, radio, ham radio, cell charger. Actual battery voltage runs 13.8, handheld reads 13.2. I think you are right, ignore handheld reading. New alternator is running 2.88 pulley ratio. Not the ideal 3.1 but as close as I'm going to get with this engine. I'm currently running 13.5 AFR at idle. Any leaner tends to surge when hot idling. Not sure if there is a good reason to go leaner. Cold starts are so much better with the current distributor curve that I'm willing to leave it alone.
     
  7. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Another boring day. Weather is supposed to take a turn for the worse this week so I bundled up and took the motorcycle. I like to be able to say I rode the motorcycle every month, in Montana. :D Drove the truck to Scouts. With the advance set correctly it takes a lot longer to warm up when driving. Only reach 171F pulling into the lot at the church, maybe a 2 mile drive. Truck started beautifully after the meeting. No hickups, easy idle, and warm enough so it didn't need any correction factor.

    What do you do when your truck just runs right? :)
     
  8. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Holy Hanna it's cold up here. Today we never got above zero. Engine really didn't want to start this morning despite being on the block heater for 2 hours. It did start and idled up ok.

    I drove it a lot today because it didn't want it to freeze and I didn't want to take the 2wd panel van out on powdered snow being rapidly pounded into ice. With extended idling I was seeing a very slow surge. Engine would idle up to 800, correct, go down to 700, the stabilize at 750. It would do this every 20 seconds or so.

    I tryed putting another point of fuel in but for some reason my handheld will not accept 13.4 or 13.6. You can have 13.3, 13.5, or 13.7. Whatever. Set it to 13.3 and it has settled out.

    Tomorrow it gets an extra hour on the block heater before work. It's supposed to be -10F in the morning. I do know that if intake temp is less than zero once engine reaches operating temp, it'll throw an error. Hopefully the block heater and engine heat will warm things up enough to keep me out of limp mode.
     
    Last edited: Feb 4, 2019
  9. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    If it's normal it's stupid. If I change the settings and go look again it should be whatever I set it to. I thought maybe it wanted a power cycle so I changed it to 13.4 and left it for a week. When I came back it still said 13.5. This surge wasn't during cold operation. Engine was fully warmed and idling in park while I went into a local wholesaler. Engine temp was 192, intake air temp 7. I consider the cold start pretty normal. Even Mobil 1 10w30 is pretty sluggish at 0F. :)
     
  10. madmike

    madmike New Member

    Joined:
    Apr 15, 2014
    Location:
    Los Angeles
    If anyone still has trouble with their hot start idle surge. i think I found the problem. If you are running HEI with vacuum advance and EGR this will solve your problems. The throttle body has two types of vaccum; Ported and Manifold. Ported operates only when throttle is opening and manifold is continuous at idle. The Ported nipple located front passenger, is below the plates making it a manifold vacuum, not port vacuum. if you send your throttle body to FAST they will correct it. Car ran great but always an embarrassment with a hot start. Took me 5 years to figure this one out....
     
  11. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Lots of people still have problems with it. That was not my problem although it's related. My engine likes manifold vac at idle. This lets me start the vehicle easy with 14 degrees initial, but as soon as it starts, vac advance kicks in and I'm at 29 degrees. This works well for me. I've tried it on a Chevy and it didn't work at all. You couldn't get the blades closed far enough to get to a reasonable idle.

    Andy over on the Facebook EZ-EFI group moved his air temp sensor to the air cleaner. Less heat soak, less problems for him.
     

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