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Thread: OTC 4000E Advance reading

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    OTC 4000E Advance reading

    The other day I hooked up my OTC to look at what my advance reading was at WOT/15 PSI BOOST. The reading was zero degrees at 5000 rpm. To me this says it's firing at TDC under those conditions.

    My advance from rpm2 at 5000 rpm is +11.5 and the calculated table for rpm/boost is +20 degrees at 5000 rpm. Advance from map warm full is -7.5 degrees. I dont see how any combination of those three numbers results in 0 degrees advance.

    Does the OTC show true advance? It's certainly reporting everything else correctly.

    I read on a turbo site that 15 degrees advance is what you want...what is the truth. I hope someone knows the answer.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: OTC 4000E Advance reading

    i dont know. MPSciLink shows a slightly different value than what I expect it to be, the OTC shows another value, the calculated advance 3d map shows a different value.

    the only way to really know is to use a timing light somehow while the engine is at load and stationary... perhaps sitting the "frame rails" on sturdy wooden blocks with the wheels off the ground while someone rides the brakes and hammers the car against the brakes to make load/boost while someone else operates a timing light in the engine bay aimed at a degree wheel attached to the crank pulley.

    kinda dangerous but do-able.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    Thanks Brian, why wouldn't that work by looking at the flywheel notch instead?
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: OTC 4000E Advance reading

    Quote Originally Posted by jeff1234 View Post
    Thanks Brian, why wouldn't that work by looking at the flywheel notch instead?
    If you're meaning to do it on your engine stand, I think one would just need a correct reference pointer to show where the notch is degree wise. Do you have a way to put a load on the engine on the stand? That would be necessary too. How did they make engine dynos before the days of the computer?

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    This engine is in my Charger. My flywheel TDC notch is marked with paint to make it easy to see. I imagine that it would show just like when timing the engine normally. I have a friend with a lift so we could definitely get if off the ground for the test. Am I incorrect in my timing assumption.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: OTC 4000E Advance reading

    yeah the flywheel notch would work but it only reads to like 12 or so... in vac, you can have way more timing than that to verify.

    dyno before the computer, hydraulic pump against an orifice, water pump against an orifice, eddy current brake etc, mechanical brake with a strain gauge measuring brake force via resistance changes, etc....

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    My thinking was that with the car up on Jack stands, third or fourth gear and lots of brake input at full advance timing should be in the 0-12 degrees and readable.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: OTC 4000E Advance reading

    i wouldnt rely on regular jack stands. I would probably build a wood structure to sit the front "frame rails", k frame and/or and pinch welds on. and then a couple of straps on either side to heavy structural things to keep the car there.

    With the wheels off and nuts holding the brake rotors on, it would be somewhat safe.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    Actually, my friend Lohnnie has a lift, that's a better idea. Thanks for the caution.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Garrett booster
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    Re: OTC 4000E Advance reading

    I'm writing this based on memory, so take this with a grain of salt, but the LM stores that "advance" value as some kind of calculation intermediate value, not the final result. It's always been in the back of my mind to flow-chart out the LM ignition timing logic and store the final timing value in a different memory location, like take over one from cruise control.

    Jeff C.

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    Jeff, my Charger has a SMEC ecm. Does your memory hold true for that type of control as well. Is it possible that you might have even better info for the SMEC. The problem with mptune, at least for me, is that it feels like we are playing with make believe numbers. I've struggled with the power loss light for a long time at around 4K rpm. I've never been able to totally eliminate it even after following suggestions from the experienced members here. I think if I knew the real timing at that point I could make an educated decision on what to set the timing at to deal with the event. I can't believe that many many others working on these engines haven't had similar experiences. It's like keep moving the numbers around ad infinitum until you luck out or not.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    I just had an idea for consideration. Is it possible that when the OTC 4000 reports zero degrees timing at WOT that it is actually saying that reference timing (12 degrees) is the actual advance at that point?
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Re: OTC 4000E Advance reading

    Quote Originally Posted by jeff1234 View Post
    I just had an idea for consideration. Is it possible that when the OTC 4000 reports zero degrees timing at WOT that it is actually saying that reference timing (12 degrees) is the actual advance at that point?
    no. that is an arbitrary number that is only used to set the distributor timing.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    I disagree, not trying to be antagonistic but arbitrary is not the correct word because the definition is the opposite of the inferred meaning. However reference number/point is accurate. When we unplug the coolant temp sensor it put the ecm in limp-in mode making it possible to properly time the engine. Once that is accomplished we then reset the power loss light by plugging the sensor back in and restarting the engine. Now, if I understand the basics, the ecm handles the timing based on numerous factors. In my tune at 4000 rpm, wot, 15 psi I should be at 35.5 degrees by adding the advance from rpm2 and the number from the calculated tables together. So why the otc displays 0 degrees I don't know. Using part throttle, no boost, the otc displays increasing advance numbers. Regardless of what the otc says, is that amount of timing to much or to little relative to knock in your opinion. I do hear clicks when I see the power loss lamp but know of nothing that is loose or vibrating. This has gone on for a long time as you know and has done so on both 782 heads I have used. I have about 90% fuel on the pef table at that rpm. I have cleaned my engine grounds and all connections to the smec and pm.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Re: OTC 4000E Advance reading

    fine. its a reference number used only to set the distributor position so that the calculated timing values are what the engine experiences. it has nothing to do with the advance the ECU calculates when in normal operation.

    if you are adding the value from AdvanceFromRPM2 and AdvanceFromMapWarmFull and getting 35degrees at 4000rpm and 15psi, thats alot of timing..... too much timing. especially if you are getting CEL illumination from knock.

    I'm at 18.5 degrees at those same RPM and boost values on a 2.5 with a G head and 93 octane. the 99CalculatedTables - FullThrottleTotalTiming calculated table says 15.0deg for those RPM and Boost points but it takes MAPMUL into account and im not sure it should as MAPMUL is supposed to only be in effect when the spark advance is below zero.

    Which is why im not sure what the actual advance is..... because MPScandroid/MPScilink shows one value, the FullThrottleTotalTiming graph shows another value, the OTC shows another value (and it updates wicked slow) etc.

    I suppose I could make a cal with all the timing values set to 10 degrees (mapmul set to 1, adaptive retard disabled like in the MP cals etc) so that it could be checked with a timing light on the trans hole with the car jacked up. then the OTC could be checked against the tables etc. and if i did it for my car, I could verify the MPScilink and MPScan and MPScandroid to see what they show for timing.

    we'll see if i get time. im in winter-is-coming-prep-mode right now.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    Brian, I recently tried a different tuning strategy, that is, I downloaded from TM the file T-SMEC_25_MTX_A131_MP.TPL. I loaded my tune and that one onto MPtune and changed all of the settings in my tune except peftbl to the be same as 131. This was an effort to start over with a good peftbl but get back to what should be a good starting point. I went through each tune item by item and verified that the were the same. Perhaps the old tune settings are a part of the problem but as I recall the only changes I made concerned things I had changed. The two tunes were a mirror image.
    Yesterday I was reading an executive summary that Morris had sent me. He stated in one paragraph that the calculated tables were wrong and he was going to change them. I wrote an email to him asking for verification of the changes and if they had happened and I'm waiting for a reply.
    I looked at mapmul in 99 caltbl and they appear to be the same. Table 2 is blank but has the following after it.... (the abbreviation, int and inside a box, the number 1) Is that the multiple?
    It wasn't my intent to get you to do a tune as you described, but rather I'm just trying to find a way to figure out just what is happening and I keep finding that no piece of info correlates with any other one which makes it impossible to make a change that fixes this for good.
    If you did the tune as you described it would certainly be information that everyone could benefit from.
    I wonder what would show up in your mptune if you were to load the file I listed into mptune on your device if it would show the same +20 in most of the boxes after boost. If it showed different numbers, for example negative numbers then maybe the problem is in my setup. At least it would be a short cut that wouldn't take much time.
    Thanks
    Last edited by jeff1234; 09-15-2023 at 02:30 PM.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Authorized Vendor Turbo Mopar Vendor jeff1234's Avatar
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    Re: OTC 4000E Advance reading

    I sent an email to OTC to find out if the 4000E modifies it's display of information coming from the ecm. The following is a copy of the body of that response. So, the tool is reporting what the SMEC is telling it.
    (No it does not modify anything, it reports what the computer is showing, or in this case the vehicle might not support this PID. Not sure any tool will give you this reading, would have to try a different tool or a timing light.)
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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