Hey guys I need some help getting my niece's car running. It's an 86 IROC, CC Carb 305, believe it's an LG4. Ive been researching the boards and using all the tech articles/threads here but now I'm stumped.

Here's the deal; the car was running fine two weeks ago then while driving, it lost all power and would not rev above 1500 with pedal to the floor. Eventually, while troubleshooting it, we couldn't even get it to start anymore. It has good spark and fuel pressure but the plugs were being fouled out. I have since pulled and rebuilt the carb, removed and cleaned the EGR, removed intake manifold and replaced the gaskets, replaced ign coil and module. This morning I went to crank it and it is still doing the same thing and will not start. While cranking, it will start to pick up RPM but will not start and again I have a heavy fuel smell. I have the dist clocked right, already re-checked. I havent set initial timing or dwell yet cause it wont start.

The idle mixture screws are at 4 turns out and the IAB is at 4 turns out from lightly seated. Lean Mixture screw is at 3 turns out from lightly seated, Float was set to 11/32 as per rebuild kit, MCS travel test shows 3/32 travel, TPS is .48v and increases with throttle movement. Choke and idle settings were untouched during the rebuild. I have replaced most of the vac lines so I know there are no vac leaks.

During the carb rebuild I thought I had the culprit, the float had a hairline crack in it but, apparently that wasn't it. The plugs/cap/rotor/wires were just replaced within the last month, a few weeks before the problem.

I need some more ideas cause all the work I have done hasn't changed a thing. Any other ideas?
Also, no codes are being stored in the ECM

 

maybe a wire is shorted, or prob with the starter, just an idea

 

clogged catalytic converter?

 

I don't think it's a prob with the starter, it's spinning the motor over fine. The batt has 12.21 volts at the terminals and the batt wire at the Dist has 11.92 volts so, no short there. What other wires should be checked? Plug wires are nearly new and I rechecked connections at both ends.

I'm starting to think the timing chain has jumped/spun a tooth...

 

what about a clogged catalytic converter?

 

I guess it could be the CAT. But shouldnt the motor at least start? How do I check for a clogged CAT? Disconnect it and try starting?

 

well if it's clogged up enough there's no way for the exhaust to get out. and the no power and having trouble getting the rpms up are generally symptoms of the clogged cat. lol honestly i would take it off all together and put a cheater pipe in there or take a large piece of pipe and knock the insides out. i don't run a cat on my car.

 

Thanks for the help, at this point I'm game for trying anything. I'll check the CAT out tomorrow after work cause I got a Superbowl to go watch now!

Magman

 

Well I'll be.... Turns out, it was the CAT. I was thinking about it the whole night during the Superbowl and decided to come home and drop it tonight to give it a try. Sure as ****, removed the CAT and it fired right up! If it didn't just happen to me I wouldn't believe it!

Boosted_SS I can't thank you enough! I was sure as **** stumped with this one! Thanks for the help!

Stay tuned though, I still need to set the dwell, cold idle and so on...

Woo Hoo!! She's alive!!

 

Congrats on geting it running. It is alwayse something simple.

 

How dose the CAT get cloged and what dose it actualy do?
I payed $250 for a high flow cat to be installed when i got my custom exhaust done because they wouldent do the exhaust unless i got a new cat put in (old one had a big hole in the side).

 

The CAT as I understand it, heats up to an operating temp that helps burn off harmful gases created by the combustion process. I ordered a stock replacement, Catco CAT from Summit last night, $105.00. Anyone can install it.

Magman

 

In general, a catalyst promotes a chemical reaction without being consumed in the reaction.

An automotive catalytic converter promotes conversion of noxious gases into carbon dioxide and water. It only works when heated. More heat is released when the chemical reactions take place. If the engine is running rich, burning oil, or the exhaust gases are excessively hot, the catalyst bed can become overheated and melt, or be clogged by exhaust residue.

 

Finally finished getting the car running and everything set right. Idle is about 100 RPM high (600 in drive), but I can live with that. It has quite a bit more power now and can actually break em loose (well it can spin the peg leg anyway). The dwell was new to me, I got it to settle around 26-32 by adjusting the IAB. It doesn't seem to be able to narrow in any less. Is that normal?

Magman