FireBirdKnight

every so often my car will run fine and all the sudden in drive will bog a little bit and the rpm will flux , then the rpms will hold at about 1100 rpms in drive , and will climb to 2000 rpms in park , so i disconected the idle air control valve and shut the car off it resets itself if you do that and will idle normal at about 800 rpms , so i disconnected it and shut her down started her back up and it idled between 1500-2000 rpms , so ok that means the ecm commanded a higher rpms out of the iacv for some random reason?? , i pluged it back in and the rpms droped to normal 800 rpms , this does this spazing out once in a blue moon , mostly when wet out or humid , so maybe a wiring problem? could my ECM be defective i baught a remaned one from cardone also baught a replacement IACV , ive only noticed these problems after i replaced the IACV and ECM , i do not get a SES light , i disconected the IACV and the light didnt come on , but the light came on as i disconected the TPS sensor to see if that was the cluprit


any ideas anyone!? sounds like ecm , wiring or the iacv

Justin1989

Mine was doing this too, but I had a SES light. Basically I unscrewed the Throttle Position Sensor (TPS) and played with it by hand, blew out the inside of the wiring harness with air, and put it back in and it worked fine, no more high idle or SES light.

transam85dudeman

its wet out??? hahaha i love that movie bedazzled. anyways i think i know y. i can give you several ideas, but not a solution, because obviously TPI is unpredictable(i think most everyone agrees) problems with these cars is kinda like a episode of CSI. i never watch but the idea is tight. i mean where theres a problem theres a solution... i suggest the following. 1. vacuum leak, number one cause of high idle, typically the throttle body passages on the IACV, and egr passages to the egr solenoid then the egr valve. also you have a Fuel evaporative canister with a purge valve,(when in wot or part throttle, the computer releases store fuel vapors to your throttle body) sometime a bad check valve on the canister, or bad;sticking solenoid on the canister consistantly purging fuel vapor to the TB(throttle body) creates high idle. theres also a vacuum rez in your bumper, its backed by a check valve by the windshield wiper motor above the steering shaft. if theres any leaks, even by the brake pedal under the dash the TCC controller switch, that will spin you in high idle. but considering that this problem occurred after the swap of the chip, im guessing GUESSING OK...that it may be programmed to activate the egr valve when it shouldn't really until highway speeds/revs 2500-3000rpm. or wot. and also it could be program into thinking you got a lower mechanical thermostat like 160* or something. sometimes, when driving with a bad stuck open thermostat,car never warms up, or does warm up-then highway driving cools the car below a set temp-and the computer can go in open loop,(meaning the chip resorts to preprogrammed setting, not of which your sensors are telling the computer, but rather a default typical setting, until the oxygen and coolant and MAT sensor(manifold air temperature sensor) reaches normal operating temps) hurts performance and defiantly squirts extra fuel too. that dude above was talking about a TPS (throttle position sensor) which tells the ECM the injection pulse and fuel delivery, could have dead spots delivering weird signals on how open the TB(throttle body) is and how much fuel to deliever/injection pulse. typically they dont go bad. because you get high rpm, i dont think its a fuel problem. 2. timing is very critical to out TPI. has to be PERFECT, the difference is night a day, oh i know its night and day, (one time i was off by 10 degrees and the engine would idle faster then slow down, but the timing was on, WHY you ask, it was because there was slop (too much freeplay) in the distributor shaft, i installed shaft shims and got it to about 0.008" endplay compare to 0.060"---i time my engine to 6*BTDC in base timing mode, with ecm disconnected at the base timing wire on firewall. next with the engine off i grounded the A and B terminals on the Assembly line diagnostic line and turn the key to on position (not start), then wait 30 seconds, then disconnect the IACV connector, then turn key to off, pull the grounding wire, then started the car. i set the idle to 400 rpm while in drive(yes i needed somebody holding the brake while in drive so i dont die just yet) and then turnd off car, reconnected the IACV, then with the A and B terminals grounded again with the key in the on positioin not start) i used my volt meter to adjust the TPS (throttle position sensor and its 'top and middle' wires coming out of the tps) to .555volts. then im done setting the idle (never ever start a car with the A and B terminals connected, never, it will eat you computer i think) . but sometimes a bad cataylic converter will hurt the idle, very not common though. when on that topic, the air diverter can switch from purge the air from the air pump to the exhaust manifold to the converter then back again...low oil will affect idle, also if PCV (positive crankcase valve on the valve cover) could be stuck. spark knocking, or just plan bad water pump can trick* the knock sensor into retarding the timing.. i recommend a vacuum pump to diagnose. then maybe a Throttle body 'tear down and clean'. if theres a hole in the diaphragm in the fuel pressure regulator that causing higher idling. sorry if that doesn't help. -mikey

FireBirdKnight

sounds like a good check list to start from , i guess first off ill start with the simple ones , ill replace the IACV , TPS and do a vacuum check lucky enough the sensors are under warrenty so ill just replace em and go from there , i know some of the vacuum lines are aged from 1985 , AIR system has been removed also my timing is not dead on 6*BTDC its slightly advanced so ill go back to the drawing board and have it perfectly timed to specs

transam85dudeman

hey if your AIR is removed then did you remove your EGR? i heard that when one deletes the egr, that the chip has to be programmed to open the egr (since its not there) to 199mph. Because we cant go that fast, therefore the egr wont be triggered. and i doubt your IACV and TPS is bad.those parts dont go out typically, it sounds more like a vacuum problem. if you have egr, then maybe its gunkd up, or the egr solenoid passages are clogged. (egr and egr solenoid, different parts btw) I tried one time, throwing parts at my broken car, it never worked just made me broke. its something so simple, has to be that new ecm. sometimes because you have an old ECM like mine, you have the CALPAK and the CHIP(memcal) two different chip, most TPI have only one.

FireBirdKnight

nope all parts are stock egr still there , the ecm is the correct ecm 1226870 for the 1985 model year the 1985 305 tpi model used the 2 chip setup , 1986 up tpis used the 1 larger chip , so i have the stock chips still its the computer where u plug the chips into is what was replaced idk maybe the cardone manufacturer messed up this ecm ill check some vacuum hoses , but it only does it usually on damp , humid , rainy days or fresh car wash is when it misbehaves so it sounds electrical to me

LuckyGen3

Check your distributor cap for cracks or an improper seal. Use a flashlight to look around your distributor cap seal. You should not see any metal. The cap has a notch that is on the drivers side that should be sealed to the wires for the Ignition Control Module. If you see a gap there then the Cap is not positioned correctly. Next would be the plug wires. You may want to replace them if you haven't already. Believe or not, most mechanics will tighten the cap even though it's a little off seal.

transam85dudeman

If it only happens when wet, then there you go.... I get boggin but only when i dont warm up the car, it gets real rich because the fuel evap canister purging fumes from overnight into the already rich chambers with the after market injectors and the EGR doesnt help either. In My case it because the oxygen, MAT, and Coolant sensors hadnt heatd to standard values, and triggerd the computer to go into close loop mode yet, and itd be in a default program mode for 5 minutes(until the car warmd up and closed the loop.and sometimes go back into the default program/open loop mode if when driving on the highway while cold outside and having a stuck mechanical thermostat 140*(DANG TOO COLD).. I used to jump and go, but i wait until cold start mode idling program changes to close loop, and the computer adjusts the injection pulse width to meet the environment changes

FireBirdKnight

so are you saying its just the computer doing its job , but being so primitave it spazes out sometimes when it feels something isnt right?

or should i check my wiring , it only does this once in a blue moon maybe once or twice a month , last time it did it was when i went to the car wash