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  1. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    Well in this case it is an upgrade (in terms of reliability and life span) as the Bosch sensor I am using is a Planer style vs the OEM thimble style. Pretty common mod for the OBD1 and SC'd guys, check it out here: O2 Sensor Replacement - 1994 FZJ80
  2. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    Check the scoping work done on the previous page @bicycleagent003, specifically the last post on that page. The 02 sensors are singing perfectly and the problem was traced back to the IAC.
  3. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    I fixed the IAC valve, the internal washers had degraded to the point where the valve would get jammed in the closed position. Digging through my spares box I was able to get a solution that worked. So now the valve is back in service and working great. I'll update the post in a couple of...
  4. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    No, I think it is the IAC valve, it's not responsive, I've got a new one coming. But I figured I'd get some practice in with my new Picoscope toy.
  5. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    O2 Sensors look good
  6. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    IAC (ISC) signal testing. Again the signals sent to the ISC valve are present and working. In this test I expect to see S1-S4 pulse to ground, and all do. ISC 1 Blue ISC 3 Yellow ISC 2 Red ISC 4 Blue
  7. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    Not yet, I will this afternoon
  8. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    I don’t have ac. I just used the A/C port on the ECU to trigger an idle up. So it’s an easy way to see if the ECU is sending signals out to the ISC, which it is.
  9. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    Yea so this takes some explaining. I don’t have A/c in this rig, and I wanted to add an idle bump up for when the air compressor is turned on to help the alternator get to an rpm where it can produce more. I read that when the A/C is switched on the ECU sees this and will bump up the...
  10. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    So I scoped S3 from the ISC Valve and I switched on my Air Pump circuit several times, which as stated previously triggers the ECU to bump up the idle via the AC input port. And in the scope, we can clearly see that the signal is being sent out to the ISC. I also checked continuity from the...
  11. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    So I took the IAC valve off to clean it and I ran the FSM's test on it as detailed below. The B1 --> S, S3 checked out ok at 26 Ω. The B2--> S2, S4 came in at 49 Ω, the test temp was about 72° F, so close enough. Well, I didn't think much about it and cleaned the rest of the valve and...
  12. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    This is great info, I’m just rereading everything and realized I missed some important statements you made regarding how these circuits operate. I’ll for sure try moving the AFM flapper next time to rule it out. Check off the low hanging fruit. Also can you share your spreadsheet? And what...
  13. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    Thanks @elripster that would explain why the capacitor is in that circuit, to help smooth things out.
  14. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    THanks, it's not a problem that is leaving me stranded, it's just annoying. I wish that I could find a schematic of the OBD1 1FZ-Fe ECU's circuits so I could trace the logic, the 96 FSM gives almost enough of this to be helpful but that didn't exist in the 93-94 fsm.. These rigs were built...
  15. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    I really have a hard time believing it's the AFM since I recently ohm'd it, but I'll put it on the list to check. I guess reading the Diagnostic code section regarding the AFM there is a possibility of it not triggering a CEL yet still causing the issue. So the 96 FSM gives some more insight...
  16. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    If I had more information on which sensors the ECU is evaluating to determine when to trigger the FPR I could narrow down my search for the delayed acceleration issue. But this is all the FSM gives me Both banks tie in after the cats, I mean I can scope the O2 sensors and determine the A/F...
  17. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    Wide band? which bank do you suggest monitoring? easy enough to unplug and clean, I'll do that tonight.
  18. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    So I feel like I've done a terrible job describing the issues, so let me break them down separately. Sluggish 1st Acceleration When I pull away from my house in the morning (first drive of the day) I lean into the gas and the engine is underpowered, then I lean in even further and suddenly it...
  19. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    It's been happening for a while. It's intermittent which makes it harder to track. I think the surging idle and the delayed triggering of the FPR are related but they may not be. Upon cold startup, the engine will idle fine for a minute but as it gets warmed up it will begin surging and the...
  20. SmokingRocks

    Odd Acceleration Issue & Occasional Pulsing Idle

    Thanks for the feedback, the Pico is certainly a step up from my homemade scope that I plugged into my iPad. I'm loving the pico. And yea, I was thinking of checking the TPS, Coolant Temp Sensor, RPM Signal from the distributor and basically all the sensors the ECU is looking at to control...
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