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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
    So, I'm down to the last bit of annoyance with my EZ-EFI 1.0 system and I'm hoping for a silver bullet.

    Engine is a 366CU Mopar v8. Torker II Single Plane intake. 16 degrees BTDC at idle. 32 degrees all in about 3500rpm. Cam is basic stock 4bbl cam 268/276. Idle set at 800rpm. 13.5 afr at idle. 14.5 afr cruise, 12.7 afr wot.

    Everything is awesome, good cold start, good performance, good cruise, good fuel economy.

    The only problem is on a hot start. The idle surges and sometimes dies on a hot start. If I key on and wait long enough for the O2 sensor to heat up, no problem at all.

    Suggestions?
     
  2. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    I've got the new handheld, what changes would help this?
     
  3. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    OK, I'll try adding a little cranking fuel and see how it goes.
     
  4. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    I've made quite a bit of progress.. Currently at +2 cranking and accel fuel is still zero. I've leaned my idle afr to 13.7 and cruise to 14.8. I'm looking for a little gas mileage and it's still doing well at idle. I've got a little stumble under light accel, I'm going to try +1 accel if the stumble is still there in two days. Cold starts have been amazing compared to last year. I had a dual plane on last winter and it just wouldn't idle cold if the outside temp was less than 25F. This year it doesn't get grumpy until 15F and it's put up with 5F without any coddling.
     
  5. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    I've gone as lean at 14.0 idle but it's too darn cold to play with the throttle blades and it really wanted more throttle blade at 14.0.
     
  6. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    WOT is 12.7, I don't have much to complain about at WOT, no stumbling, etc. I'll put another tenth in it and see if I notice a change. IAC counts on a warm idle in park is 15-18. If I move to 14.0 AFR at idle, it jumps up to 25-30. That amount of IAC count tends to cause stalling at stop lights if it isn't fully warm. Idle count in gear, when fully warm tends to be 45-47. At 14.0 it's closer to 70.
     
  7. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    800rpm idle is very high for this torque converter. I'm only turning over 1500rpm at 35mph. That's the primary load on my IAC.
     
  8. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    I was having a lot of problems keeping it idling when pulling up to stop lights with a 750 rpm idle. By working at 800 I've been able to keep it happier. The IAC starts responding sooner as a coast up to the light. Eventually I'd like to start dropping the idle speed. I've noticed that the longer I run the tune the less likely it is to have an idle dip when pulling up to a light. Realistically I can only train that cold (140F) idle area a couple of times per day and every time I change the idle AFR it needs another day to really learn it.

    As for vacuum leaks, anything is possible. I've done a very through vetting for vac and exhaust leaks:
    1. Replace brake booster, line, and check valve.
    2. Replaced PCV valve, line, and installed a catch can.
    3. Replaced line to fuel regulator.
    4. Replaced line to vacuum gauge on dash.
    5. Got annoyed and replaced every single inch of vacuum line and all fittings. Installed spring clamps on all small diameter lines and new hose clamps on all large diameter lines.
    6. Torker II manifold installed this spring, Mr Gasket O-Ring gaskets
    7. Used brake cleaner with TPS unplugged to check all fittings and gaskets checking for change in idle.

    Exhaust in brand new professionally installed 3" from the stock exhaust manifolds back. Inspected yesterday while doing oil and chassis lube, No soot on any joint. O2 sensor tight in bore Manifold gaskets inspected for any signs of soot.
     
  9. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    This evening, I started the truck and then clamped the line a couple inches off the regulator. I observed fuel pressure slowly rising to the 42PSI static setpoint. I repeated the test, same results. I cut the line, removed the barb fitting, added teflon tape, and re-installed. No change in behavior. Grrr. I'm on hold with FAST to find out if I need to replace the regulator.
     
  10. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Well, the tech didn't consider it a problem. He said that my test is suspect, if the regulator was leaking, I'd have fuel in that vac line, which I did not. I'm ambivalent about that, I'll have to think about how else that vacuum could have reduced. He did have me lower my idle to 600 rpm and the truck did fine on the short test drive. I moved it to 650 because 600 doesn't allow charging at idle with headlights and heater on. A drive across town showed no problems at all. Restart for the drive how was what I'd call a warm start. 105F coolant, 98F IAT. It surged a bit but didn't die. IAC counts out of gear when hot is all the way down at 5, I may have to adjust that.

    So, Idle afr 13.7, Cruise 14.8, WOT 12.7. Idle speed 650rpm, MAP at idle 30, IAC out of gear 005, IAC in gear 19.
     
  11. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    A leak on the threads is certainly possible. I let the truck sleep until this evening. Motorcycle gets much better gas mileage. :) Took it for some short trip stuff this evening. It's certainly touchy with it's current IAC settings. I think tomorrow I'm going to drive it to work and then adjust IAC before the drive home. Then let it run for a day or two before changing anything else. 650rpm charging is borderline. Stopped at a light with the heater on, headlights, and of course brake lights it's barely keeping up. 12.8v at the battery. Idle vac didn't drop that much from 800rpm to 650rpm. I was getting 17" at hot idle at 800rpm, and 650rpm is 15".
     
  12. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    I'm going to try this lower idle for a while. I like how little it's loading the torque converter. It really improves the driving manners. I've had a 700 rpm idle in the past, it was ok, but even after weeks of driving, it would stall under hard decel. It's like it was pushing hard enough that the iac couldn't quite keep it going, but the start of the iac opening just started a little too late. We will see, it's got a giant battery in it and a 90amp alternator, it's can idle in discharge for some time before it becomes an issue. I'll keep an eye on my key on voltage, make sure it's getting a full charge during my short hops around the city.
     
  13. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Today's updates. Reset the IAC to run right about 18 at idle in park, this gives me like 28 in gear which is pretty awesome. Good performance on the way home in stop and go traffic. No stalling or even much dip in the idle. I also moved to a 13.5 afr at idle. It was surging a bit at warm idle in park.

    My alternator pulley ratio was way underdriven at 2.33. I don't know who chose a 7 inch crank pulley for this engine (well before I bought it), but it's small. It seems like factory should have been closer to 8, of course I can't find any stock diameter pulleys. Both TuffStuff and Powermaster make pulleys that will get my ratio between 3 and 3.1 I ordered the 2.25 inch pulley that will bring me to 3.1 ratio. This will give me 200 more rpm at idle than I had when my idle was 800. This being a truck, my rev limiter is set at 4500rpm (cast crank) and even at highway speed I don't exceed 3000rpm. That leaves me at 9300rpm on the alternator, well under the recommended limit of 18000rpm.
     
  14. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Beautiful day so went out and played with the truck for a bit. 13.8 appears to be the sweet spot for idle. Good strong vacuum, even down at 600rpm. Pulled a spark plug from each side. I've attached pictures. I don't really have enough experience to see anything useful in these pictures.
    20181215_101115.jpg 20181215_100308.jpg
     
  15. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    It's a stock curve, I believe 1 heavy and 1 light spring. I've got a limiter plate in it so I could start with extra at idle without going over the top. Should put the curve all in by like 3500rpm, I'll check it with a timing light a little later. There is no WOT on those plugs, it was some extended idling and light throttle around town for the past couple days. No anti-seize. It appears that my passenger side valve cover has developed a drip. I'll have to pull it and clean it. Plugs are probably at least three years old. Platinum autolights.
     
  16. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Given that it's been at least three years since I did plugs, probably a decade or more since I did wires, and 6 years on the cap and rotor, I pulled the trigger on all three. If the weather holds, I'll have time to do them before Christmas. I went with Denso 3031 copper plugs, heavy duty cap and rotor and 7mm OEM wires from United. From what I've read, Platinum plugs run hotter. The Denso 3031 are stock range. Denso 3066 would be one range cold. Typed all that for reference....
     
  17. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    I've had good luck with stock plug wires in this truck. It's not a high compression motor and it's only a streetfire MSD unit so not nearly as hot as the big 6A units. The higher resistance plug wires keeps the EMI and RFI down. I'd consider going to an 8mm Streetfire wire only if it's as good at suppressing noise as the carbon core wires. I use this truck when I'm doing ham radio stuff as well, I'm not interested in a bunch of electrical noise.
     
  18. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    All right, you convinced me. Ordered up a set of blue streak 8.5mm wires. Supposedly the 8.5mm wire is 170ohm per foot, spiral core wire. They've got a 9mm wire that is listed at 15ohm per foot but no EMI protection.

    Checked advance curve, it's coming all in about 2800rpm. I can't find any documentation that says it should be slower. Coming in by 4k doesn't make any sense at all to me. This motor never gets to 4k. If I had an advance curve coming all in by 4k I'd realistically be limiting my total advance to 25-27 degrees because the distributor would never spin fast enough to get there.
     
    Last edited: Dec 17, 2018
  19. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Well, I called the Mopar guys at FBO Systems and chatted about timing on the 360. He recommended all in around 3500 given my vehicle weight and engine combo. In theory a mopar distributor has one of the spring posts on an eccentric, so if you want a little slower curve, just turn it and it'll tighten up the spring. My dizzy may or may not be an actual mopar dizzy so I will see when I open it up. I went ahead and ordered a spring kit, he said 2 mediums out of his kit should give me a 3500-3800 all in.

    While I'm keen on having good fuel mileage, I also want an engine that will actually pull my vehicle down the road.

    In other news, the alternator pulley still hasn't shipped. If it doesn't ship by end of day, I'll order from another source and cancel the first one.
     
  20. gremlinmt

    gremlinmt Member

    Joined:
    Mar 13, 2013
    Spec for the motor is .035 plug gap, for engines up to 9:1 compression, MSD recommends .050. Do you have an opinion? Plugs and wires will probably be here before Christmas, spring kit and time to get into a garage to pull the distributor won't be until after Christmas.
     

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