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3g stumble

775 Views 27 Replies 3 Participants Last post by  93celicaconv
Running this down the pike again.
'91 GT, 5sfe. Get up to 3000rpm and stumbles, will not go any higher although red line is 6200.
Timing is spot on, new dizzy, new igniter, new coil, fuel pressure is right on specs, new fuel filter, throttle body is shiny clean. EGR is clean, new vacuum hoses, new VSV. Only "modification" is the charcoal canister was removed and vented to air.
Car drives and run perfect except for the RPM limiting.
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OK, did some grocery gettin' this morning. Especially looked at the tach on start-up. Yup, for a brief moment it was 1000 rpm, this is just turning the key, no gas pedal. After maybe 2 seconds it settled to around the 700 mark and after a minute or so down to around 650. No hiccups and the run went well. did not stumble around 3000rpm. Not saying the problem is fixed but I'm happy with the results so far. Idled smooth. Very might have been that aftermarket igniter with a combination of re-installing evap and everything put back to factory.
Thanks to you and '93 conv.:)
Looks like you are almost there. Your warm idle speed on your engine is 700 +/- 50 RPM. You are on the low edge of normal (if you trust your instrument cluster tachometer). If you want to make an adjustment on your engine's idle speed, this thread from is a good one on how to to that. It has some other items in it, but the process of adjusting idle speed to get it on target is all there.

- Idle drops after warm up 1990 celica gt 2.2
Picked up an OEM boneyard unit off ebay. Guy said it works and takes returns.
Being and old guy I wanted one with cassette and cd.
The original pigtails are there. Been a while since I opened it up but I'm not doing that until I get OEM unit.
Again want to thank you for all the help and info on the stumble. Happier than a clam now that there are no run ability issues. This pic is when I replaced the ECU two years ago.
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From the picture, looks like you have the larger single pigtail connector for the radio head unit. Assuming the exposed wiring (not wrapped) is how the OP spliced in with the aftermarket head unit. Hope all that wiring is in good shape. A head unit with 2 smaller wiring harness connectors will not work on this setup. Hopefully the unit you got is for a single large wiring harness connector.
I'll make it work. Wires are all color coded; I think I can handle that:whistle:. Probably have to do some soldering splicing.
Or get the correct radio made for that wiring harness connector. It's up to you. Let me know if you want me to look at my inventory.
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Got the radio and it was truley plug and play. All the pigtails were not cut by the PO. Easy Peasy.
I think this thread is finished.
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