Hi All - my 1st post and a 60yr old newbie to small blocks and emissions stuff-Have an 85 Camaro sport coupe with 305 VIN H and 700-R4 & am on tight budget and need to clean up engine bay for future cruise night. Emissions items are all rusted to **** and relatedhoses/lines deteriorated. Live in IL and classied as an antique with no emissions test required

Have done the following:
1. Cut off AIR pipes, and removed related hoses/lines and AIR pump
2. Removed broken EVAP can, EGR blocked off, coolant/oxygen sensors
3. Removed exhaust manifolds/pipes and cat and related sensors
3. left on computer, orig carb w/sensors, MAP sensor, orig distributor and cruise control stuff

Am clueless and worried about what sensors/items are needed for 700-R4 TCC function (do not understand auto trans or mess with!) AND for the original carb & distributor to work properly, not necessarily "perfectly"- Car starts and seems to idle OK, but can't really test drive it right now

Your help is greatly appreciated

 

Welcome Aboard!

In order to make the carb work properly, there a a few items which are required at a minimum. The ECM must remain, the coolant temperature, MAP/BARO, and the oxygen sensors must be in place. The intake air temperature sensor input can be faked, but the ECM needs to see an input. It's also very easy and cheap to mount an IAT sensor in almost any filter housing or intake duct. The carb needs to have a functioning throttle position sensor, and the mixture control solenoid needs to be connected. The rest is adjustment.

The distributor will send engine speed reference pulses to the ECM, so if the wiring and modules are intact, it should be good. There should also be a module for spark timing (EST module) mounted to the firewall which works in conjunction with the distributor and ECM.

The TCC should operate with those inputs functioning, the brake switch input, and a signal from the three-wire connector on the trans indicating 4th gear. All that was original and should remain.

Eliminating the air injection system should not pose problems if the original cat converter is gone. Some of the early cats needed extra air injection to reach and maintain operating temperature. Newer 3-way cats don't care, as do the non-cat installations. In any case, however, the oxygen sensor needs to be installed. If the car has original exhaust manifolds there is a provision for mounting the sensor, and aftermarket pipes and headers can have a bung welded on to provide a mount (been there).

Eliminating the EGR should not pose operational problems but may trigger nuisance codes and the "SES" light. If the EGR manifold is still in place, the EGR can be reinstalled if problems occur.

Eliminating the EVAP should also not be a problem, but remember to provide an alternate fuel tank vent.

 

:YUP:

For the EGR, you can block off the EGR valve itself, but keep the electrical connector connected and just block off the vacuum line. This will prevent the SES light.

 

THANK-YOU for taking the time to thoroughly address this issue in a concise, effective and prompt manner !! The numerous postings on this subject on the various forums at 3rdgen are very hard to piece together. You guys are great to help others not as knowledgeable. I think and hope this will be valuable info for others as well. These cars are very difficult to work on, compared to my 65 Lemans (A-body) with a 1969 396-375 hp engine i've had for over 40yrs

I'm sure I will have some followup questions in the near future as I digest and identify all the items and their whereabouts and condition on the car. The car needs tons of other work as well so I skip around based on what I feel like doing on a given day. Some days everything goes wrong and you need to get away from what you started for awhile.
thanks again
tom

 

Just a quick add on the EGR issue.... the ECM has no way of DIRECTLY knowing it's operating correctly. However, it does a "test" of the system in certain steady-state part throttle conditions- like driving down the highway at constant speed. SOMETIMES it will figure out you have defeated the system, sometimes it won't. It's not a very smart system, but sometimes it will catch it. So you can either just live with it if it does, or you can make the system fully operational again. No big deal either way, but I thought you might like to know in case you're ever out for a drive and the check engine light suddenly comes on with no ill symptoms or obvious reason.

I'd also keep the PCV system operational (just one big fat vacuum line from the valve to the big front port on the carb). Not that it won't run fine without it, but it does wonders keeping the valve covers and breather clean.

 

Keeping EGR will allow more timing advance at cruise (without the KS pulling it back). I installed a 350 under the LG4 system and ran it for a while without the KS. Got some definite light pinging at low speed cruise with throttle tip in. Traced it to a faulty EGR.

I'd also recommend keeping the EVAP canister. You can relocate the valve assembly over next to it, tucked out of the way.

Your 85 should also have the knock sensor installed in the block coolant drain on the right side.

Haven't seen an IAT on an LG4?