knever3 Posted February 26, 2022 Share Posted February 26, 2022 I have had a rough idle with a misfire the last month and am looking for direction. I have a renix stroker with 99 intake and bored throttle body. Of course this cold start sounded normal, but I didn't let it run long to warm up. My wideband O2 sensor is going bad again. I replaced it once already so kind of mad about paying another $100 just to measure A/F ratio while driving. My TPS looks suspicious and my fuel trims look off. Let me know what you think of the short video. Ok don't know how to post a video, so I will post a link. Sent from my SM-G960U1 using Tapatalk Link to comment Share on other sites More sharing options...
Ωhm Posted February 27, 2022 Share Posted February 27, 2022 1 hour ago, knever3 said: My TPS looks suspicious and my fuel trims look off. Concur, TPS values do seem low, as for the ST/LT fuel trim, let vehicle get up to normal operating temperature first. Link to comment Share on other sites More sharing options...
zomeizter Posted February 27, 2022 Share Posted February 27, 2022 I see unstable idling there that maybe caused by an intake/vacuum leak, ST fuel trim sorta confirms, do things get better once at operating temp? Link to comment Share on other sites More sharing options...
knever3 Posted February 28, 2022 Author Share Posted February 28, 2022 This is after it warmed up. The blue display is my dead wideband O2 so pay no attention. The TPS still isn't right and I've tried to adjust it a few times and can't get the proper voltages. I have that janky Hesco renix to new style adapter and if you notice it looks like it's sticking so the idle won't come down. Should have gone OBD1 Sent from my SM-G960U1 using Tapatalk Link to comment Share on other sites More sharing options...
MiNi Beast Posted February 28, 2022 Share Posted February 28, 2022 I'm awaiting another tps to show up from Amazon to replace mine for the 1st time this year. think it was 4 times I swapped the tps out. Swap it out and carry an extra one. Link to comment Share on other sites More sharing options...
Ωhm Posted February 28, 2022 Share Posted February 28, 2022 It does seem like you have two different TPS(V)(%) settings. Sticking/binding somewhere. Your ST fuel trim is bouncing above and below 128. Normal. LT fuel trim (141) is high, but your INJ PW=4.1mS is low, so I’m going to assume it just the type of injectors you’re running with. All of this is within the range of authority for the ECU. Link to comment Share on other sites More sharing options...
cruiser54 Posted February 28, 2022 Share Posted February 28, 2022 What's going wrong with your wideband? Just the O2 sensor or the unit itself? Link to comment Share on other sites More sharing options...
knever3 Posted February 28, 2022 Author Share Posted February 28, 2022 What's going wrong with your wideband? Just the O2 sensor or the unit itself? I believe so, the last time it went full lean like it shows I replaced the O2 sensor and it worked for a year or so. I called zeitronics and talked with the tech and verified and bought it from them again. I thought about buying a REM to put above my display to get more info instead of using the MT2500 at times. I don't know if it's getting water in it or what.Sent from my SM-G960U1 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted February 28, 2022 Share Posted February 28, 2022 So, you have an oxygen sensor for the factory setup and a separate one for your wideband? Link to comment Share on other sites More sharing options...
knever3 Posted February 28, 2022 Author Share Posted February 28, 2022 Correct Sent from my SM-G960U1 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted February 28, 2022 Share Posted February 28, 2022 MAP sensor shows quite low vacuum. Link to comment Share on other sites More sharing options...
knever3 Posted March 1, 2022 Author Share Posted March 1, 2022 Hmm, well I ordered another TPS and will clearance the Hesco adapter if this new one binds. I'll check into the Map sensor vacuum as well, thanks for the tips guys! Link to comment Share on other sites More sharing options...
knever3 Posted March 14, 2022 Author Share Posted March 14, 2022 I measured the ground from B to battery ground and got 0.4 ohms. Perfect I measured the reference voltage from A to B and got 4.863V. Between B and C my Output voltage was .827 Volts. So 4.863x0.17 is 0.826V. Perfect so I didn't change or adjust the TPS. I still can't figure out why my MAP vacuum is low. It has a rubber line from the intake to the MAP. It doesn't have a leak so now what? It idles better in warmer weather for sure.Sent from my SM-G960U1 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted March 15, 2022 Share Posted March 15, 2022 I'm very suspicious of the MAP reading. What did Tip 5 reveal? Might check the ground at the MAP itself anyway, Also, if the hose from MAP to throttle body doesn't "cascade" and has low spots, that can cause issues. Link to comment Share on other sites More sharing options...
Ωhm Posted March 15, 2022 Share Posted March 15, 2022 I wonder why your INJ_PW time is low (4.3_4.9mS), yet LTFT is adding time to INJ_PW. Are you running with factory injectors? Link to comment Share on other sites More sharing options...
knever3 Posted March 18, 2022 Author Share Posted March 18, 2022 I have 21lb/hr injectors if I remember correctly. I tried 24lb Ford injectors and that was too much. It would pull fuel all the time and run super rich. I have a '95 fuel rail and FPR as well. 99 intake BBS 62mm throttle body. Bored .60 over 4.2 crank 4.0 rods. I measured the ground circuit to battery and got 0.4ohms. The voltage was 5.02V with ignition on. I replaced the vacuum line with Cruisers elbows and line from the port under the throttle body this time. No change in voltage on the mt2500. I measured the engine vacuum with a analog gauge and it read 18". So do I just have a bad map sensor?Sent from my SM-G960U1 using Tapatalk Link to comment Share on other sites More sharing options...
Ωhm Posted March 18, 2022 Share Posted March 18, 2022 3 hours ago, knever3 said: So do I just have a bad map sensor? Your MAP sensor looks good on this recording. On a previous recording MAN VAC showed 20+”Hg @ idle. 18.4”Hg @ idle is typical MAN VAC, verified with your analog gauge. On 3/15/2022 at 9:23 AM, cruiser54 said: Also, if the hose from MAP to throttle body doesn't "cascade" and has low spots, that can cause issues. That new MAP line routing has a dip in it at the MAP sensor itself. You might not want that elbow there. Link to comment Share on other sites More sharing options...
zaconrad Posted March 26, 2022 Share Posted March 26, 2022 Have you checked the iac valve? That would be my guess. Link to comment Share on other sites More sharing options...
knever3 Posted March 29, 2022 Author Share Posted March 29, 2022 What is my MAP supposed to read anyway? I would expect it to read the same as manifold vacuum since that is what it uses to forward the value to the computer to determine length pulse to the injectors. I just did the mileage calculation not using my remote start and I went 200 miles on a tank of gas with 18.4 gallons, that equates to 11.9MPG! That sucks, especially with gas at $4.69 for premium. I had the Fuelly App on my phone and I thought it used to be somewhere around 14.7MPG, not that makes much of a difference. Link to comment Share on other sites More sharing options...
Ωhm Posted March 29, 2022 Share Posted March 29, 2022 6 hours ago, knever3 said: What is my MAP supposed to read anyway? Manifold Absolute Pressure (MAP) Both BARO_PRES and MAP values are displayed using a absolute scale since that what the MAP sensor deals in. MAN_VAC value is calculated and displayed using a gauge scale, same as a vacuum gauge one would carry in their toolbox. MT2500/DRB/REM uses the following formula to display MAN_VAC: (BARO_PRES)-(MAP)=MAN_VAC. Link to comment Share on other sites More sharing options...
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