I'm working on a stock 86 Camaro w/LG4.

It is extremely hard to start. When it does start, it runs very rough. Firing only a couple of the cylinders. To keep the engine running at 1000rpm requires almost %25 throttle.

The following has happened.

around thanksgiving
Car began running very rough, low on power. <cr>
Next day would not restart.

the next week
a new module was installed <cr>
still won't start. <cr>

A timing chain was installed (old chain was fine) <cr>
still won't start <cr>

Spark plugs changed (very fouled) <cr>
Coil changed <cr>

The car starts and runs great. <cr>
Timing is adjusted to factory spec (off by 6 degrees) <cr>
Car continues to run good <cr>

one week later
the car loses power again, same as before <cr>
Module tests ok, pickup coil measures 739ohms (in spec) <cr>
Coil tests ok <cr>
can't get it started <cr>

A scan tool shows all sensors in range. <cr>

Please some one throw me a bone here. I'm stumped.

 

Choke problem? Does it improve when it warms up?

------------------
1984 Camaro Z28 Astral Silver w/ 2 1/2" cowl induction hood
Engine: Decked 383 cid 4 bolt w/ oil cooler, 9.6:1 compression, ARP fasteners, 600 cfm Performer carburetor, Torker II intake, Performer RPM Heads, XE268H cam, Magnum roller tip rockers, MSD6AL ignition, Blaster2 coil, recurved HEI distributor
Exhaust: Terminator headers, Custom 3" TIG welded stainless exhaust, Twister muffler
Transmission: 4L60 w/ Corvette servo, .500 boost valve, TransGo 7-CS clutch springs, 700 PKH pump rings, 700-2 reprogramming kit, Borg-Warner High-Energy frictions & bands, 2400 RPM lockup torque converter
Drivetrain: 2.73:1 limited-slip Dana 44 w/ disc brakes
Tires: Front P225/50VR15 Rear P265/50VR15 Eagles

 

The choke was investigated. The choke heater is failing but it is not causing this problem. Wired the choke open.

This is a severe misfire.

 

Well, the first thing i would do pull the plugs again.... maybe you have a problem in the carb with the m/c solenoid. Did you test the vacum to? is there any at all? (not that a half runnin car is gonna make much vacum) but the only thing that i can think of is at this point would be something wrong with the fuel system. if your sysmtem is a AFTER fire, then that would give you the reason to believe cyliders are not fires, AND there that there might be a rich condition...

Steve

 

well , I assume that this is about stuart's LG4 iroc...

anyway , as I've told him before and will keep saying , REPLACE that carb... I don't care if the choke seems to be okay or is hot wired, either borrow a good working one (could use mine if u guys didn't live so damn far away I even thought I would give stu my new q-jet for couple bucks but I need the engine and carb for another 6 months).

so , new q-jet is $170 or so , ask if you can return it if it doesn't solve your problem, and if so definitely get one... it takes 25 minutes to swap them so it's well worth it...

u guys should have done that before the "tune up", I would have changed the plugs , but I still think it's the stupid carb and that's it... (not sure what is wrong with it though, mine was acting all funny too, one day it runs , hmm I figured it doens't run well when it's cold , the next week it's 10 degrees outside and car runs even better, then it gets warmer and the stupid crappy thing starts messing everything up, so I threw it in the trash and got a new one... problem solved...)

U guys have replaced just about everything that can be easily replaced (+ timing chain), so why not try the carb...

 

stu keeps saying that it's the ignition , I can't say that he's right or wrong , but while you're at the carb, rip out the distributor too

(can't u guys borrow these from some "working" cars ??? that way it wouldn't cost u any money to try them all...)