Roy James

arright, i have a terrible *** idle, **** goes up and down, from about 100 RPM up to like 1200 back and forth and sometimes it just shuts off. I have all my solinoid rails off, my ACV blocked off, my coolant cold start blocked off, the two nipple in the back of the dynamic chamber blocked off, the nipple under the BAC valve for that vac line blocked off... and when i disconect the boost sensor/map sensor vac line.. its rock solid at 900RPMs. If i do the suck/blow test in on the boost sensor, it is unresponsive. The TPS also fails the push button test, where you rev it up and push the button with your finger, nothing happens where as it is supposed to cut the engines revs down. I have a spare TPS around so i replaced it, and i know it was good bc it was on my other car and was fine.. well.. its also unresponsive, what gives? i set them both using the ohms method correctly..hhm. sorry so choppy, im not a writer by anymeans, LOL, thanks everyone. Exactly what does everyone think? if i take the vac line off the nipple for the boost sensor and plug the nipple up.. it acts the same way, idle gets all choppy and wants to cut off. other than this.. the car runs great, quick and everything, just idles like ****. thanks again and sorry so long

Roy James

another thing, its RRIICCHHH as hell, eye burning rich, i was thinking that it might be in "safe mode" or "limp home mode" but Felix Wankle enlightened me in saying that S4 cars have no such thing...hhmm... , im so stumped. the only thing i can think of is i might have messed up when i blocked off the vac lines where i should have rerouted them or something, but.. i dunno, it was ******* down before i even touched them...hhmm.. thanks again everyone

Rotarius

Dont know exactly what your problem is but if you unplug the "boost" sensor and the idle changes the sensor must be doing something, also its hard to build enough vacuum with your mouth to actually activate the sensor (not enough air volume). One question if u capped the auxiliary ports how do you manage to run a 14.6 et? I also have a91 n/a and my best was a 15.3 all motor. thank you

Roy James

ok 14.6 isnt that fast, there are plenty others. i didnt run the car on this, my freind was the driver, i havent had time to get it to the track, i wanted to do some other mods to it before i took it down there myself. capped aux ports? where did you get such a nutty idea? the sleeve were just removed, im soon to get some nice sleeves from a forum member that should help it out some and a VDI swap... oh yeah... i gotta get the damn thing running right first, thanks

Rotarius

is quite fast for me for an all motor dude i had an 91 all motor full exhaust ,full intake no a/c or spare and my best was an 15.3 et .
so if u removed the sleeves then that explains it , i did the same thing.
the ACV controls your idle by bypassing your throtle plates; try putting that back it should solve your problem.

Roy James

ACV is blocked off..hhmm... i have the connectors just sitting there, should i run a resistor in them or something?

Rotarius

I dont think the FCs computer checks for missing components like the FDs. But if the computer is telling the computer to step up the idle and the ACV is not working, the engine will stall because the computer will add extra fuel but if theres no extra air the engine will start running way to rich and stumble until it dies.

Roy James

i dont think that the FC checks for that, i know tons of people that block everythign off with no problem.. though.. i think somewhere you need a resistor in the place of something you take out, but that may be only FD cars..hhm.. thanks man.

Thaniel

ACV does not control Idle. It controls how much air is going from air pump to the exhaust ports and to the split air pipe (cat). Another part of it allows fress air to be sucked into the intake under deceleration to avoid and over rich condition. If you didn't get the block off plate sealing the hole to the intake good, you could have problems.

The boost sensor on a NA tells the computer what the intake vacuume is. Foot the the floor, low vac. Crusing or idling, High vac. It uses this info for a number of things, one being when to turn on the secondary injectors.

Here's a post with a bit of info on it.

https://www.rx7club.com/forum/showth...456#post675456

With the vac line removed from my boost sensor my car ran real rich (the fuel economywent in the toilet). Could be a bad electrical connection?