unstable idle.....

got home from work today, and the car was doing this..... (you dont have to watch all of it to get the idea....)

https://youtu.be/sKPJb4TUq2Q

so air filter box n tube off....

https://farm8.staticflickr.com/7879/...b7c312f9_o.jpg1553638990305 by jon sutherland, on Flickr

and a quick clean of the throttle intake, disconnected the ecu controlled idle air valve, and started up, just to make sure the base line idle was ok....

https://farm8.staticflickr.com/7891/...6b2b21bd_o.jpg1553638990097 by jon sutherland, on Flickr

42.34 hz relates to 848rpm... (just multiply the Hz value by 20!)

fortunately this is ok, maybe a little high, but it'll have to do, as my throttle body doesn't have the idle adjust screw as per the usual drawings....

https://farm8.staticflickr.com/7881/...d7364ca5_o.jpg1553638989789 by jon sutherland, on Flickr


clock fuse removed for 10 mins, just to make sure, AICV reconnected,car started and allowed to do its thing for 15 mins....usual reports are of the car changing engine speeds as its relearning its basic settings... mine just sits there, and slowly drops it's idle.... switch off and straight on again, and we have this....

https://www.youtube.com/watch?v=jyzXhF8MiTE&feature=youtu.be

that'll do then!!!


edit... small pics... odd!!!!!

in other news, my aerial got into the habit of doing this....

https://farm8.staticflickr.com/7861/...4c6bd64b_o.jpgIMG_20190215_104757 by jon sutherland, on Flickr

so i got a comprehensive repair kit from croooober....

https://farm8.staticflickr.com/7866/...30910ac7_o.jpgIMG_20190215_135104 by jon sutherland, on Flickr

and with a new flush grommet made up....

https://farm8.staticflickr.com/7871/...ec271035_o.jpgIMG_20190215_180437 by jon sutherland, on Flickr

.... it was all refitted and now works fine.....

in other, other news..still chasing the intermittent fault that convinces the gearbox computer that the throttle has dropped off and is lying in the road somewhere.....

i thought i had a breakthrough when the ecu and tcs computers flagged up the same fault.... it MUST be the throttle pot...so, ordered a replacement off the 'bay....

https://farm8.staticflickr.com/7911/...18848416_b.jpgScreenshot_20190215_173439_com.ebay.mobile by jon sutherland, on Flickr

to find that despite what the listings said re. fitting a NSX no problem, the spring return was bias the wrong way..... as supplied the lever tang is parked between the bolt hole and connector.....

just to be awkward the nsx rotates the other way and the tang ends up pointing toward a mounting hole..... so an annoying re-jig of the spring (you basically have to turn it inside out!!).... and end up with....

https://farm8.staticflickr.com/7905/...f05153ba_b.jpgIMG_20190213_165025 by jon sutherland, on Flickr

refit, and calibrate to the requisite 0.5 v at no throttle, and off we go...

all the ecu's are happy now, hurrah...

.....until the gearbox one decides it's not! grrr.... still hunting then....... now bought a portable oscilloscope so i can monitor the tps output levels!

https://lh3.googleusercontent.com/UA...w=w697-h929-no
The base idle air adjust screw for non-DBW model.

Ah, so it's buried under some sealer, I thought it was the casting!!! I'll have to do some digging!!!

https://lh3.googleusercontent.com/B8...=w1080-h608-no

https://lh3.googleusercontent.com/Zx...=w1080-h608-no
If it's covered in grey locking paint/sealant, then it's never adjusted after leaving the factory.

It will look like this.
Different TH body (no TCS) but still, non-DBW so same location.

Please ignore the black marking (like half moon) as it should be all brass/gold colour.

Kaz

had a bit of a dig tonight..... started with this, hence why i thought i had a really early special top secret throttle body powered by magic.....

https://farm8.staticflickr.com/7880/...972dc795_c.jpgIdle jet adjuster by jon sutherland, on Flickr

and eventually got the adjuster out......

https://farm8.staticflickr.com/7904/...2ebdc341_c.jpgIdle jet adjuster by jon sutherland, on Flickr

hmm.. that's what 26ish years of being ignored does!!!!

anyhoo,cleaned up, new o-ring and refitted....

https://farm8.staticflickr.com/7805/...df66161c_c.jpgIdle jet adjuster by jon sutherland, on Flickr



with the ecu controlled air intake valve unplugged, i can start the car and screwing in the adjuster drops the revs as expected, i can get it down to around 600rpm but i cant get it to stall! blocking the pcv valve makes a little difference, but not much!

reconnecting the air intake valve, reset the ecu, and start up, the revs rise to 1500rpm, then drop to about 850 after about a minute or so... so the ecu is holding the revs up... makes no difference if AC in, lights on or in gear, it has a little dip in revs, then corrects itself back to abot 850... i guess thats where it wants to be! at least its being stable now!


edit.. i might check the coolant controlled fast idle valve tomorrow, just to make sure that isn't having a vacuum leak

as this is turning into a mini build thread........

friday afternoon.....

after waiting an age for these to get out of customs....
https://farm8.staticflickr.com/7899/...6ed62048_c.jpgIMG_20190329_144141 by jon sutherland, on Flickr

i swapped them in.....
https://farm8.staticflickr.com/7861/...90e6e397_c.jpgIMG_20190329_150434 by jon sutherland, on Flickr

so now i have windows that go up and down with a little more purpose! which is nice :)

while i was there, and because i had to, i made up some new weather/damp/condensation shield sheet things....
https://farm8.staticflickr.com/7857/...79849c4e_c.jpgIMG_20190329_164044 by jon sutherland, on Flickr


saturday.....
fitted overhauled steering rack...
https://farm8.staticflickr.com/7838/...201c9224_c.jpgIMG_20190330_111942 by jon sutherland, on Flickr

saturday afternoon....


then went back to the idle issue.......

throttle body off, and while it was, i checked the internal butterfly screws...

https://farm8.staticflickr.com/7858/...0414f940_c.jpgIMG_20190330_153120 by jon sutherland, on Flickr

a terrible pic, but they are all present and correct!

gave the throttle body a good clean, and checked the idle screw shuts down and closes properly, it does!

so put the throttle body on, a little silicon grease on the mounting seal just to make sure there's no leakage there....

disconnect the EACV (Electronic Air Control Valve) and started up, I can wind the idle screw til it bottoms out and still be over the ideal tickover..... hmmm... carb cleaner liberally applied over anything that looks like it could leak..... block the pcv valve and that makes little difference, so pop the top off the fast idle valve to see if there's any leakage there....

a squirt of carb cleaner on it as the car is running makes it stall.... now is that because the carb cleaner is sealing a leak, and the idle screw that's closed is the only official source of air?? so unscrew the fast idle valve seat and valve part, and i simulate it being closed, i can still blow a little air through it... is that my issue? a valve seal not sealing right? i do what i can to improve it, but still not perfect so put it back together! put it back together, and start the car.... idle is a little slower, but still over what it should be, and i'd expect to be able to stall the car with the idle screw.. which i can't!

tomorrow's job is to set the fast idle valves fast idle speed when it's cold!

then i might order a new fast idle valve and a new pcv to eliminate them!



reset/double checked the voltages coming out of the throttle positioning sensor, all present and correct, and checked the voltages getting to the gearbox computer, the same, just to make sure, as it's still being a pain!