Pig rich and popping

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  1. #1

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    Pig rich and popping

    Looking for some help and direction here.
    Just got done with a rebuild and my 7mgte is popping and running rich once warm. Plugs are an hour old and badly carbon fouled.
    550cc injectors, Lexus afm, etc. tested for leaks and found a couple. Ohm Tested and set tps, ohm tested afm per fsm, tested cold start timer, coolant temp sensor, idle control.... I’m still leaning towards a possible afm but I just don’t know. Any ideas for my next step? Afm is the only thing I don’t have an extra of or I would have just tried it. Thanks

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    Maybe worth noting, no HAC sensor. Never had one. Car had a popping rich issue before rebuild with same afm and injectors but also had low compression so did the rebuild. Problem persists but is worse than before. Here’s a pic of the plug with less than an hour run time.
    Also (more things keep popping in my head) walbro 255 pump and bypassed J tube.
    Attached Images
    Last edited by Gebular; 04-01-2019 at 06:18 PM.

  4. #3
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    have you tried checking to see if its thrown any codes (jumping diag connector pins and watching check engine light flashes)

    do you have a functioning oxygen sensor ... the stock ecu will need that so it understands how to trim the injectors / run at stoich during part throttle

    do you have a wideband 02 to see whats going on ?

    there is some info on tricking the stock ecu HAC input so it does not throw a code here :

    http://www.fadingworld.com/CRE/Autom...d%20Codes.html
    Last edited by madisonMK3; 04-01-2019 at 06:20 PM.
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    Yes initially I got an HAC sensor code and throttle sensor code. Once I set the tps that one went away. My o2 sensor is stock but I would love to go wideband soon. I do have a spare I could try that. And thanks for that info on the HAC code!
    I’ve also set the timing a couple times since I set the tps. First time was 10 degrees and second time was 12 degrees because I thought advancing it might help a little but it didn’t
    Last edited by Gebular; 04-01-2019 at 06:32 PM.

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    My walbro seems louder than normal or maybe I’m just tuned into everything. Is it possible the fuel pressure regulator went bad or the fuel return line is collapsed or clogged? When I had the rich condition before I always though it was from that restrictive j-tube so I bypassed it during the rebuild hoping it would fix my problem. There’s so much fuel that I’m sure it’s geting passed the rings right now so need to figure this one out. It can also be tough to start cold but the rich popping stuff doesn’t start until it runs for a couple minutes

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    Would love some advice guys. I’m getting really concerned I’m washing the cylinders with fuel and don’t want to do in the new engine. Today I’m going to check and bypass vsv, test fuel pressure, blow through return line and see if it’s clogged. I might even bypass the cold start injector. but if I use the cold start injector port on the rail to test pressure and it runs better, I’ll probably know if I need to or not. Any other bits of advice is more than welcome.
    I’m also putting in my spare o2 today as Madison suggested
    Last edited by Gebular; 04-02-2019 at 09:47 AM.

  9. #7
    90T 3p141592654's Avatar
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    It would seem you are not running closed loop. I would check for cross counting on the O2 sensor. Also, install the HAC sensor.

    http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=119

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    Quote Originally Posted by 3p141592654 View Post
    It would seem you are not running closed loop. I would check for cross counting on the O2 sensor. Also, install the HAC sensor.

    http://www.cygnusx1.net/Supra/Librar...spx?S=FI&P=119
    Thanks for that I will check for sure. A couple updates though, I checked the vsv per fsm and it failed everything and smelt like there was gas in it. I also retro fitted my old snap on fuel pressure tester to the cold injector spot in the rail and my fuel pressure is too high. Here’s what I got-
    Static 38 psi seems ok
    Running vacuum unhooked 42 psi
    Running vacuum hooked up 34 psi

    I also watched the bleed off and it held over 30 lbs for over 15 minutes. It’s arill at 12psi and I shit it off a half hour ago so that seems good. Gonna check the return line and move on.
    Besides a plugged fuel return, what could cause the extra pressure? I’ve read that even 2psi can cause problems and I’m 4 over

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    Fuel return had a lot of restriction so I got my hopes up and blew it out but it’s still not doing great. Maybe a little better? Still need to test the o2 or just get a wideband coming. Need an HAC sensor and I guess a AFPR to turn back my pressure. Here’s a video of it running. Phone audio sucks but you’ll get the idea. Also there definitely has in the oil. Has me concerned

    https://m.youtube.com/watch?feature=...&v=iw8ITlj8l9o
    Last edited by Gebular; 04-02-2019 at 05:08 PM.

  12. #10
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    man looking at that video its really hard to say. could be the video but that is a very loud misfire, almost sounds mechanical (hollow knocking) through the phone.

    saw the ffim and am wondering what turbo you are running

    any yes get that wideband 02 I don't understand how there is a ffim and no wideband / electronics in there to tune it


    you had the vac line off the regulator I assume, so its not spraying out there (fuel reg diaphram failure)
    are all plugs fouled the same ?

    did you check the 02 with it running (like the tsrm shows) ?

  13. #11

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    Quote Originally Posted by madisonMK3 View Post
    man looking at that video its really hard to say. could be the video but that is a very loud misfire, almost sounds mechanical (hollow knocking) through the phone.

    saw the ffim and am wondering what turbo you are running

    any yes get that wideband 02 I don't understand how there is a ffim and no wideband / electronics in there to tune it


    you had the vac line off the regulator I assume, so its not spraying out there (fuel reg diaphram failure)
    are all plugs fouled the same ?

    did you check the 02 with it running (like the tsrm shows) ?
    The phone audio is garbage. I listened to the video and I see what you mean and when you’re here it’s definitely an exhaust pop. Like Unburnt fuel hitting the manifold and igniting. Last time I started it, it backfired on start up.
    Stock turbo. My analog meter is toast so I’m waiting on my buddy to come with his high dollar diagnostic probe. Tried it with my digital meter but it wasn’t fast enough to measure “bounces”.
    All the plugs are fouled the same and I have new ones coming because these ones can’t be working great anymore. The regulator doesn’t obviously shoot gas but like it said, it smelt like gas inside the vsv pressure up solenoid so it certainly could be leaking very little under vacuum?
    Could you recomend a wideband setup?
    Would the apsx wideband kit be acceptable? Looks like it has a simulation wire I can run to the ecu
    Last edited by Gebular; 04-03-2019 at 10:00 AM.

  14. #12

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    I think I’ve decided on the aem wideband because no need to calibrate it all the time. I’m going to stop running it for now out of fear of washing the cylinders and bearings with gas. I’ll still do the o2 test when my buddy can make it out. Also need to get an AFPR so I can turn my pressure back.

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    I don't know anything about aem, I have an Innova lc-1 --has worked great for years / on my 3rd sensor as they foul up if you run leaded race gas. it uses a common wb sensor that is like $40 on amazon.

    calibration is easy, hold a button for 30 seconds. honestly I would assume they all wear somewhat (wb o2 sensors) and calibration only helps (I don't see that as a feature). i put a new wb sensor in every 2 years anyway, its cheep insurance.

    what I like about the lc1 is 2x programmable outputs and a serial connection (+software) that lets you update firmware on the device / program outputs / log o2 on your pc during a pull

    the programmable outputs are important imho, I use one of the outputs to drive the stock cars ECU (WB simulates a narrow band signal)
    other output feeds my maft-pro computer a true WB scale (I datalog with maft pro, the 02 only log is somewhat worthless as it has no other data points ie:rpm / boost ) **I should note you have to give the toyota ECU the 02 signal AND a load across the 02 heater circuit. I run an LED resistor across the heater circuit to trick my car and prevent throwing an 02 code with this setup

    it is critical the stock ecu gets 02 info to adjust the fuel trims / understand where stoich is during cruise / part throttle

    but super duper uber piggy rich, gas exploding in manifolds... (I imagine its reeking of gas by the car correct) makes me wonder if its something else...ecu jacked and holding injectors open / etc
    Last edited by madisonMK3; 04-03-2019 at 01:31 PM.

  16. #14

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    Yeah I kind of feared something like a fried ecu. Would the resistor pack cause any problems like this? And yes the gas smell is overwhelming lol.
    Also, I can leave my stock sensor and just put the wideband down lower right? Let the stock one take care of the ecu

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    I just wanted to follow up on this in case anyone searches. There’s so many unresolved threads out there. I installed an adjustable fuel pressure regulator, lowered my fuel pressure, installed an aem 30-0300 wideband, and a new denso factory o2. When I first started it, the computer took a bit to relearn and it was running worse than ever and had me stressed out but I went ahead and let it warm up, took it on a short drive and it is running great now. I still have a very slight intermittent pop at idle but I understand tons of these engines out there do this and with a straight 3” exhaust, it makes it more pronounced. Gonna try a few things to get rid of that but overall it’s running really nice and I’m very happy. I think just the new denso o2 would have solved most of this even tho the original one wasn’t “technically” bad. It was fouled and confusing the computer. But I’m happy to have control over my fuel pressure and at least some control over afr in open loop.

  18. #16
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    good to hear man!
    now that you have o2 working, the toyota tccs ecu has a way to tell you info on its "learned fuel trim"

    if you google tccs vf trim there is good info out there. basically the car takes its base injector map (aka best guess map) and compares it to actual data from the o2 / real injector pulse width to achieve stoich. the difference between the two is called the "trim". you want to set your static fuel pressure so that the car is making as little adjustment ( injector trim) as you can, under idle/light throttle. also your lex AFM screw will influence the injector trim at idle. its a balance between that screw and base FP

    if your vf is always pegged at 0v or 5v the cars ecu will assume something is wrong because its fuel trim is excessive.

    one thing I have learned is the cars ECU is much more predictable (keeps its tune consistent under high load open loop maps) if its injector trim is reasonable (minimal, under 10% adjustment).


    if the trim is over 10% the ecu pulls timing and uses very pig rich open loop (high load) maps bc the car assumes there is an issue due to excessive inj trim

    now you need a SAFC / piggy back tuner to really get the most out of your setup. the stock ECU is prob going whaaaayyyyy pig rich in boost (like 550 / lex should). that safc will allow you to tell the ecu "less airflow" under boost and lean it out to get more power
    Last edited by madisonMK3; 04-23-2019 at 06:40 AM.

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    Quote Originally Posted by madisonMK3 View Post
    good to hear man!
    now that you have o2 working, the toyota tccs ecu has a way to tell you info on its "learned fuel trim"

    if you google tccs vf trim there is good info out there. basically the car takes its base injector map (aka best guess map) and compares it to actual data from the o2 / real injector pulse width to achieve stoich. the difference between the two is called the "trim". you want to set your static fuel pressure so that the car is making as little adjustment ( injector trim) as you can, under idle/light throttle. also your lex AFM screw will influence the injector trim at idle. its a balance between that screw and base FP

    if your vf is always pegged at 0v or 5v the cars ecu will assume something is wrong because its fuel trim is excessive.

    one thing I have learned is the cars ECU is much more predictable (keeps its tune consistent under high load open loop maps) if its injector trim is reasonable (minimal, under 10% adjustment).


    if the trim is over 10% the ecu pulls timing and uses very pig rich open loop (high load) maps bc the car assumes there is an issue due to excessive inj trim

    now you need a SAFC / piggy back tuner to really get the most out of your setup. the stock ECU is prob going whaaaayyyyy pig rich in boost (like 550 / lex should). that safc will allow you to tell the ecu "less airflow" under boost and lean it out to get more power
    Great info! Thank you so much for that. I’ll be checking into to that today to see where I’m at. I have a pretty bad discrepancy between my new fpr gauge and my old snap-on pressure gauge. I don’t know which one to trust so I might try a third to see what it reads. The snap on is 20 years old or better. And yes I’m very rich under boost right now just like you said. I finally got my HAC sensor in the mail yesterday. It was lost in the mail for over a week. Ohm tested good and I installed it last night. Going to do some more tooling today. Thanks for all your help!

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    Have you set your base ignition timing at the CPS? What is it? Having the CPS a tooth off can screw up a lot of things and still run.
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    Quote Originally Posted by Wreckless View Post
    Have you set your base ignition timing at the CPS? What is it? Having the CPS a tooth off can screw up a lot of things and still run.
    Hi Wreckless thanks for the reply. Yes I set timing with the engine at full temp and idle was 700. It’s @ 10 degrees. The engine is running really good now compared to before. Only a slight intermittent “pop” once it’s warm and idling. When it’s cold in open loop it’s smooth as silk

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    I tested the vf circuit idling and it was 2.23 volts then a weird thing happened. The idle all of the sudden jumped up 100 rpms and the vf circuit started reading 0v. I think it may have went into closed loop at that moment but I don’t know for sure. So when that happens, the ecu is pulling as much fuel as it can in attempt to lean it out, right? Trying to figure this out. HAC sensor is in now. Just reset the ecu as well and have no codes anymore. I’m gonna go warm it up and test again

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    Last edited by madisonMK3; 04-23-2019 at 05:32 PM.

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    Quote Originally Posted by Gebular View Post
    ...and the vf circuit started reading 0v. I think it may have went into closed loop at that moment but I don’t know for sure. So when that happens, the ecu is pulling as much fuel as it can in attempt to lean it out, right? ....
    they go into closed loop very quick after startup. even when the car is ice cold, from what i can tell. I can see this on my wideband (innova, takes maybe 15 seconds to heat up itself before it reads) how the ecu grabs hold and keeps it bouncing around stoich ...aka crossing over 14.6-14.9 quickly. your oem narrow band only reads stoich so the car has to find it and maintain it. your wideband sees much more depth / range but will show the car running in closed loop

    as I understand 0v is the car saying "Im sending a smaller pulse width, leaner than my "best guess" map" and 0v = 2 steps lean

    turning down fuel pressure OR allowing less metered air in through the meter (backing out AFM body screw) will balance things out. possibly some lex/550 masters can chime in as I run no AFM at all since my tuning device, maft pro, uses a map sensor + IAT to generate the Afm signal.

    keep in mind VF changes are not so instant. its learned value so there is some delay. you can try idling the car and turning fuel pressure down 5 psi and monitoring vf for a bit. lower pressure will help that piggy rich wot as well

    I am maxing out 440's w like 50psi base pressure (42 at idle) and tricking my cars ECU to guess rich, 1 step ~ typically 3.5v vf. the cars ecu will also use its vf learned value to build / influence its WOT fuel maps. im able to hit 15 psi on 440's and still be rich in spots w no fuel cut.

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