The definitive guide to fixing SC400 hesitation issues
10-27-12, 01:27 PM
#61
Got confused. My throttle body only has the TPS, which is what had 4 terminals. I can't seem to find the ISC valve on my throttle body. Based on pics, it's supposed to be just to the right of the TPS on the throttle body. My 1UZ w/o Trac control, only has the TPS, but no ISC? Is ISC on all SC400's?
01-18-13, 09:31 PM
#62
Driver School Candidate
Going thru troubleshooting for acceleration hesitation & I'm checking resistance of ISC valve as indicated in 1st posting. The ISC has only 4 terminals, yet they discuss testing B1-S1 & S3 and B2-S2 & S4. Does that mean B1 & S1 are same terminal & B2 & S2 are same?
If so, how do I do next steps of applying 12V to B1 & B2 & repeatedly ground S1-S2-S3-S4-S1 in sequence? If I have 12V on B1 & B2, I don't think I should be then grounding the same terminals S1 & S2. I must be missing something here. Can someone that's done this before clarify this for me. Thanks.
If so, how do I do next steps of applying 12V to B1 & B2 & repeatedly ground S1-S2-S3-S4-S1 in sequence? If I have 12V on B1 & B2, I don't think I should be then grounding the same terminals S1 & S2. I must be missing something here. Can someone that's done this before clarify this for me. Thanks.
01-28-13, 02:52 AM
#64
Driver School Candidate
Vibrant, hopefully some one reading this post will have a manual for your specific model. The iac shown earlier in this thread I believe only fits the V-8 engine on ls400 and sister models. I'm sorry I don't have a manual for your model Lexus.
01-28-13, 06:10 AM
#66
Pole Position
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Thank you to durps for linking me to this thread. I had changed the fuel filter, changed plug wires, and did the ECU delete mod and still had problems. He linked me here and poof it was the TPS's didnt get them dialed in but placing them near center was a huge improvement. Up next bushings
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03-02-13, 09:15 AM
#70
Driver School Candidate
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Thank you!
Brad I just wanted to say thank you for posting your thread on the hesitation issue. I had been chaseing that issue for over 4 months and your advice was spot on to diagnose my problem with the fuel pump ECU. I jumped the unit as you showed and behold It fixed the problem. Once more Thak you!
09-10-13, 09:52 PM
#71
Intermediate
Ok, hereīs a video of mine. Today I cleaned the IACV, thatīs why it didnīt idle, but that loss at 2k I have no idea what it is. If I unplugged the MAF its still the same.
Story of my car. Is a SC400 with a 1UZ-FE engine with a turbo in it. The turbo broke and bleed all oil through the intake. I cleaned up the throttle body, check TPS and is working and resulted in a broken MAF. Car runs good but have this ~2k RPM problem which I canīt figure out what is causing it.
09-12-13, 11:36 PM
#73
Intermediate
Thanks!! You provided 3 links and in only one seems to be a fix :/
My car idles fine, I have no problem idling, is when I slightly depress the accelerator that, around 2k, bounces.
Pay attention before suggesting links that you didnīt even read
My car idles fine, I have no problem idling, is when I slightly depress the accelerator that, around 2k, bounces.
Pay attention before suggesting links that you didnīt even read
