turbinator3

i have a 86 iroc z with 305, automatic. i have been chasing a slight miss in the darn thing forever. so far this is what i have done to it.
1- plugs
2-wires
3-cap and rotor
4-coil
5-cleaned throttle body and i a c
6-cleaned maf
7-check everywhere for a vacuum leak
8- changed o2 sensor
9-cleaned injectors
10-new fuel filter
11-new coolant temp sensor
12-new cold start switch
all of this and i still get a low level miss that i can hear in the exhaust. i get the damn code 44 every few minutes too at idle or at speed. the code says lean, but the exhaust fumes say RICH. any ideas on what you guys have found if you have chased this rabbit would be appreciated. it also will never go into closed loop either. it had a 160 thermo from the factory and i replaced it with the same thermostat too. the car runs 150 to 160 degrees. sometimes it creeps up to 200 but it still throws the code 44 and stays in open loop.

Twin_Turbo

iTrader: (25)

Sounds like you have an exhaust leak upstream of the sensor, possibly a bad switch valve or check valve. What do you have, headers or oem manifolds? Your car didn't have a 160 stat from the factory, get a 180 one. It's running too cold now. How have you confirmed it stays in open loop? Scanner or by the flashing of the CEL?

turbinator3

twin it has all factory stuff. nothing has been done to it at all as far as mods go. i assumed the 160 was factory, but if i need 180, i will change that easliy enough. i wondered about that myself. seemed like 160 was a little cool but with everything else being oem when i got it, i just assumed. no exhaust leaks. quite as a mouse under the hood. i ahve a code reader that counts the blinks to tell me i'm in open loop. could be simply from being so cool.

turbinator3

i have also very carefully routed the plug wires to make sure there is no shorting on any component.they do not touch metal anywhere along their route to the plugs. i know chevy used to be bad about that back in the day. the car only has 61,000 on the clock. she is a real dream to drive too. the damn miss is making me mad though!

turbinator3

any easy way to find an exhaust leak on these tpi cars? i am down to that being the only source left for code 44. what about a leak in the air system? what is the best way to find that?

DrewsCam

iTrader: (2)

check valves... exhaust manifold gaskets... crush gasket at y pipe.. i'd go in that order.. if you have an exhaust leak i would bet its at the exhaust manifold to header point... i use dead soft aluminum gaskets.. they cost more but last nearly forever and haven't leaked in about 12 yrs..

Air system is not that complicated but doubtful its leaking.. if it is check the check valves.... or the gaskets to the air pump and pipe to the air valve.. thats my

Chevy86 IROC-Z

iTrader: (17)

I dont think the high light in red is the problem. I got an 86 IROC too but I have a 350 power plant in mine. Plus all that emissions junk is out. I dont have the smog pump or check valves, or even the diverter valves in mine. And she runs great,,,, sometimes but thats another issue that is not related to the issue at hand. Did you replace your pick-up coil? Many over look that coil because they dont want to go through the trouble of pulling out the dizzy and then re-do the timing and so forth. I had a SERIOUS problem with dizzy. Wouldnt rev above 2,000 rpms, It would start to hesitate and back fire. I replaced the guts of the dizzy including the pick-up coil and I was. Good Luck.

turbinator3

well the car runs great. has a little stumble at idle, but nothing serious. runs really good on the open road. i found many small vacuum leaks that i just knew for sure would stop the cel from coming on, but. i put a new maf on it this weekend and that didn't help, took it back too. she really runs good, just can't get that cel off and the exhaust has a gurgling sound to it at speed too. that is why i was thinking i had a leak somewhere. it would have to be in front of the o2 probe if so to through it off. i am running stock manifolds.

Chevy86 IROC-Z

iTrader: (17)

turbinator3

i have spent many hours under the hood chasing down the miss and finally found the vacuum leaks had more to do with it than anything. i just want that darn cel off. i have all leds' in the instrument panel and the cel always stays lit somewhat. when it comes on though, it gets really bright. i know it is throwing the code because i have a scanner. always good old code 44

88gta_hiflyer

iTrader: (1)

Have you checked your ignition timing with a light?

Chevy86 IROC-Z

iTrader: (17)

Before you test your timing, disconnect the EST wire and set at 6*.