newest info
when i replaced coked up iac i cleaned throttle body. horrible plan as it cleans the gunk that was sealing the worn intake/butterfly. look at picture. we shimmed the butterfly vallve so its centered, closes all the way, but theres a mm ALL THE WAY AROUND the butterfly. new TB on order. Not to all, dont clean your tb.
possible solution is to send it to http://www.maxbore.com/ to have it bored, and a new butterfly made.
![Image]()
![Image]()
All material past this line is for historical reference.
OLD
current issue, is idle is around 1100-1300. occasionally holds rpm for a couple seconds after shifting into neutral from gear.
ECU sends both open AND closed signal to iac at same time. iac is new, confirmed working via fsm, and wiring has zero shorts have tested for shorts disconnected from ecu and IAC, have also opened entire loom and subjected to testing.
Also, from start (65f) to warmed up (203-209f), truck only hits open loop maybe once or twice during warmup, and only for a millasecond at that.
ignition advanced is sometimes as high as 35 degrees
odb randomly spazzes out causing multiple resets of scanner tools. multiple ultragauges.
ordered a new ecu. lets cross our fingers.
UPDATE
Still issues. but better?
Ive swapped injectors to see if misfire issue moves. it has not. still cyl5.
When i moved injectors, the idle jumped to 2k. while driving, and i shift into neutral, it would rev to 3k, hold a second, and then back to 2k.
so i put on a new tps, still new iac, and new vacuum line on throttle opener. albeit its a little small so need to up in size. metric vacuum line is hard to find from our suppliers and even autozone. idle is around 1300 cold and 1100 warm. and rarely pulses up. maybe 1500 once in a blue moon. IF i forcefully close the throttle opener it goes to proper 750 idle while warm.
so, i think the misfire issue is separate from the idle issue. going to swap coil packs with a new denso i picked up. and see if that fixes it.
my dash pot foam was solid like a rock, and the caps cracked. so filled with different foam, and going to super glue the cap. its like 60 bucks from toyota, but its so the throttle doesnt slam shut and kill the engine on manual transmission rigs. 22202-62140 is dashpot assembly part number. so im going to try and get a new throttle opener, and properly sized (metric) vacuum line. im unable to find a part number for throttle opener though. so hrm.
Original post:
99 4x4 5vz-fe.
This saga started about three weeks ago. Cel came on for IAC valve. I disassembled completely, cleaned all contaminates and rebuilt with new rtv and IAC seal and TB seal. Except I put tension spring to paint marker mark that Toyo marked with. This resulted in idle at 2k. So I changed it back to stock position. Both times leaving battery unplugged for 20+ min to reset ecu.
That resulted in engine pulsating between 1200rpm and 2000rpm, idle at 2000rpm, and just overall shit engine response. Engine also would maintain rpm for a couple seconds even after being set into neutral.
Since I first touched IAC I was getting cyl 6 misfire, except when I rebuilt second time I'd get cyl 5. Also get general misfire
If it was cold I'd also get any random combination of xyl misfires. And codes only popped up at initial start/warmup.
So, I replaced IAC with a airtex/wells, plugs/wires/MAF/coil on cyl3/5 with denso. Coil on 3 was autozone special so no they are all denso.
Now it idles at 1200, minimal pulsing, minimal rpm throttle lag, but idles at 2000 with ac on.
Originally idles at like 800 with ac off. And maybe 1050 with it on. 1200 was highest ever at idle.
So what's left? Now I might get a general misfire every 100 miles. Vacuum lines are good.
Cam position sensor? Ecu fault? I want to say not injectors as the issue moves between cyl 5 and 6. And lately cause it's running so hard I can smell coolant when I get out. Timing belt/pump/seals were changed 35k miles ago by a Toyota shop. Truck has 225k miles and I'm not ready to let it die.
For reference:
![Image]()
when i replaced coked up iac i cleaned throttle body. horrible plan as it cleans the gunk that was sealing the worn intake/butterfly. look at picture. we shimmed the butterfly vallve so its centered, closes all the way, but theres a mm ALL THE WAY AROUND the butterfly. new TB on order. Not to all, dont clean your tb.
possible solution is to send it to http://www.maxbore.com/ to have it bored, and a new butterfly made.
All material past this line is for historical reference.
OLD
current issue, is idle is around 1100-1300. occasionally holds rpm for a couple seconds after shifting into neutral from gear.
ECU sends both open AND closed signal to iac at same time. iac is new, confirmed working via fsm, and wiring has zero shorts have tested for shorts disconnected from ecu and IAC, have also opened entire loom and subjected to testing.
Also, from start (65f) to warmed up (203-209f), truck only hits open loop maybe once or twice during warmup, and only for a millasecond at that.
ignition advanced is sometimes as high as 35 degrees
odb randomly spazzes out causing multiple resets of scanner tools. multiple ultragauges.
ordered a new ecu. lets cross our fingers.
UPDATE
Still issues. but better?
Ive swapped injectors to see if misfire issue moves. it has not. still cyl5.
When i moved injectors, the idle jumped to 2k. while driving, and i shift into neutral, it would rev to 3k, hold a second, and then back to 2k.
so i put on a new tps, still new iac, and new vacuum line on throttle opener. albeit its a little small so need to up in size. metric vacuum line is hard to find from our suppliers and even autozone. idle is around 1300 cold and 1100 warm. and rarely pulses up. maybe 1500 once in a blue moon. IF i forcefully close the throttle opener it goes to proper 750 idle while warm.
so, i think the misfire issue is separate from the idle issue. going to swap coil packs with a new denso i picked up. and see if that fixes it.
my dash pot foam was solid like a rock, and the caps cracked. so filled with different foam, and going to super glue the cap. its like 60 bucks from toyota, but its so the throttle doesnt slam shut and kill the engine on manual transmission rigs. 22202-62140 is dashpot assembly part number. so im going to try and get a new throttle opener, and properly sized (metric) vacuum line. im unable to find a part number for throttle opener though. so hrm.
Original post:
99 4x4 5vz-fe.
This saga started about three weeks ago. Cel came on for IAC valve. I disassembled completely, cleaned all contaminates and rebuilt with new rtv and IAC seal and TB seal. Except I put tension spring to paint marker mark that Toyo marked with. This resulted in idle at 2k. So I changed it back to stock position. Both times leaving battery unplugged for 20+ min to reset ecu.
That resulted in engine pulsating between 1200rpm and 2000rpm, idle at 2000rpm, and just overall shit engine response. Engine also would maintain rpm for a couple seconds even after being set into neutral.
Since I first touched IAC I was getting cyl 6 misfire, except when I rebuilt second time I'd get cyl 5. Also get general misfire
If it was cold I'd also get any random combination of xyl misfires. And codes only popped up at initial start/warmup.
So, I replaced IAC with a airtex/wells, plugs/wires/MAF/coil on cyl3/5 with denso. Coil on 3 was autozone special so no they are all denso.
Now it idles at 1200, minimal pulsing, minimal rpm throttle lag, but idles at 2000 with ac on.
Originally idles at like 800 with ac off. And maybe 1050 with it on. 1200 was highest ever at idle.
So what's left? Now I might get a general misfire every 100 miles. Vacuum lines are good.
Cam position sensor? Ecu fault? I want to say not injectors as the issue moves between cyl 5 and 6. And lately cause it's running so hard I can smell coolant when I get out. Timing belt/pump/seals were changed 35k miles ago by a Toyota shop. Truck has 225k miles and I'm not ready to let it die.
For reference:
