New G body owner - '85 GP
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Opie Knievel
Rum Fueled Midnight Mechanic and Moderator
Then you should be very happy. You'll have a quick Grand Prix.
Start a build thread when you get going on it. We will all enjoy following along with your project.
I will definitely start a build thread. The LS1 is a great idea for a DD, MPG or max HP. This car's goals are none of the above. I want a "muscle car" GP in the 350-400HP range to street and track without making it the focal point of my waking life and keep the car pretty stock. Plus the swap will go much easier, quicker and cheaper. I am trying to figure out how to keep the factory computer system functional. Because for emissions testing (which FL does not have) from what I've read they scan the computer to make sure there are no codes present and the car is ready. Then they put the sniffer on the exhaust pipes and get a reading. I also need to figure out how the 200R4 is controlled, via the ECM or what? But it would be nice to keep all the telemetry in the OBD 1 computer system functional along with all the factory lights and gauges. Quick list of telemetry I would need to convert over to the new motor setup.
ECM Coolant Temp - Easy
Dummy Coolant overheat light - Easy
Dummy Low Oil Pressure light - Easy
O2 sensor - Easy, weld a bung on the driver side header. It's a 1 wire O2.
Throttle position sensor - I'm sure I could fit that thing on the new carb somehow. It's a simple 3 wire deal that shows approx .54V at idle and 5V at WOT. The Q-jet is basically a carb with a throttle position sensor.
RPM - Should be able to pickup the signal from the new aftermarket distributor or ignition module.
Ignition. Probably the hardest of the metrics. I know GM used an ignition module and distributor. I've messed around with the HEI over the years. The build that Hotrod did used an aftermarket distributor with timing control, so the OEM ignition system is obsolete from the quick read I did. Not even sure if the ECM is looking for data back to it from the ignition module or not. I will have to do some more research and look at some schematics. Maybe leave the factory ignition module plugged in off to the side. I'll figure something out.
Q-Jet control. I've never laid eyes on it, but I'm envisioning some kind of 3 or 4 wire mixture control solenoid. Again, could probably leave it tucked away some where and be functional to keep the engine light off.
EGR control. My '89 K5 has a 2 wire solenoid that controls the vacuum to the EGR solenoid. Again, could leave the solenoid plugged in off to the side.
You can see what I'm trying to do here... Keep the factory computer "functional" so when I hook my OBD I GM scanner to the car, it's like factory... mash the gas pedal and see 5V, .54V at idle, see the coolant temp through the ECM etc. Functional with no codes is the goal. When I had my 80's corvette with the L98 I had the capability to reprogram the 256 PROM myself. I had the UV light, the PROM reader and the 80's looking software. So I could explore tinkering with the factory ECM to avoid having all this crap plugged in to fool the ECM. It would be nice to have the chance that it would pass emissions in the event I move from FL to a state that has emissions. Again, I just need to see the telemetry through the ODB I system and make sure the check engine light works and is not throwing codes. I plan on installing (Large) high flow cats on the car. Another tactic I will be doing is not building the motor with all chrome parts. I like the OEM look of black factory valve covers, black intake manifolds, black plug wires, etc. As stock looking as I can get under the hood so if fred McGillicutty at the service station does an inspection, it's not going to throw a big red flag. I'll go in with the guys of it's got an aftermarket Q-jet and an exhaust.
ECM Coolant Temp - Easy
Dummy Coolant overheat light - Easy
Dummy Low Oil Pressure light - Easy
O2 sensor - Easy, weld a bung on the driver side header. It's a 1 wire O2.
Throttle position sensor - I'm sure I could fit that thing on the new carb somehow. It's a simple 3 wire deal that shows approx .54V at idle and 5V at WOT. The Q-jet is basically a carb with a throttle position sensor.
RPM - Should be able to pickup the signal from the new aftermarket distributor or ignition module.
Ignition. Probably the hardest of the metrics. I know GM used an ignition module and distributor. I've messed around with the HEI over the years. The build that Hotrod did used an aftermarket distributor with timing control, so the OEM ignition system is obsolete from the quick read I did. Not even sure if the ECM is looking for data back to it from the ignition module or not. I will have to do some more research and look at some schematics. Maybe leave the factory ignition module plugged in off to the side. I'll figure something out.
Q-Jet control. I've never laid eyes on it, but I'm envisioning some kind of 3 or 4 wire mixture control solenoid. Again, could probably leave it tucked away some where and be functional to keep the engine light off.
EGR control. My '89 K5 has a 2 wire solenoid that controls the vacuum to the EGR solenoid. Again, could leave the solenoid plugged in off to the side.
You can see what I'm trying to do here... Keep the factory computer "functional" so when I hook my OBD I GM scanner to the car, it's like factory... mash the gas pedal and see 5V, .54V at idle, see the coolant temp through the ECM etc. Functional with no codes is the goal. When I had my 80's corvette with the L98 I had the capability to reprogram the 256 PROM myself. I had the UV light, the PROM reader and the 80's looking software. So I could explore tinkering with the factory ECM to avoid having all this crap plugged in to fool the ECM. It would be nice to have the chance that it would pass emissions in the event I move from FL to a state that has emissions. Again, I just need to see the telemetry through the ODB I system and make sure the check engine light works and is not throwing codes. I plan on installing (Large) high flow cats on the car. Another tactic I will be doing is not building the motor with all chrome parts. I like the OEM look of black factory valve covers, black intake manifolds, black plug wires, etc. As stock looking as I can get under the hood so if fred McGillicutty at the service station does an inspection, it's not going to throw a big red flag. I'll go in with the guys of it's got an aftermarket Q-jet and an exhaust.
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I am a sucker for the "stock" look. No chrome under my hood and some oil seepage to complete the look. It appears completely stock until your hear it running. I dumped my CCC system but there are more than a few guys running in the 400+ hp range on the stock CCC system. My vote for cheap power would be to keep the gen1 with more cubes like a 355 or 383 on a "roller' block.
MCSS board tends to have more guys running the CCC system. Look for SSlance and Monte_ExpreSS if you want to check out their builds over the years
MCSS board tends to have more guys running the CCC system. Look for SSlance and Monte_ExpreSS if you want to check out their builds over the years
I read you referring to an ECM so I assume your car is computer controlled. Plug in the carb and another in the distributor. EMC behind the kick panel in the PS Footwell ?
CCC is the OBD1 computer system used in the Gbody ( Computer Command Control ). It seems to have been optional in some instances ( esp canadian cars ) but every single factory Monte SS had the CCC installed with the 5.0 sbc. Most people ( myself included ) yank the system out but some of the guys over at MCSS have worked with the CCC system to build some pretty stout machines whilst keeping them factory correct with working emissions equipment intact.
If you are indeed talking about keeping the car "factory fresh" then you can leave the system intact ( with a few tweaks ) on a larger displacement motor say 350, 355, 383, 400, 406 all in the gen 1 SBC. Vortec heads don't have the EGR port so you would need a ZZ4 prom with egr delete so it doesn't set off the check engine light. Don't get too radical with the camshaft and regular Q-Het tuning should apply. Keep your eyes out for an old school dwell meter to help set up the carb
Wideband 02 sensor will help as well
CCC is the OBD1 computer system used in the Gbody ( Computer Command Control ). It seems to have been optional in some instances ( esp canadian cars ) but every single factory Monte SS had the CCC installed with the 5.0 sbc. Most people ( myself included ) yank the system out but some of the guys over at MCSS have worked with the CCC system to build some pretty stout machines whilst keeping them factory correct with working emissions equipment intact.
If you are indeed talking about keeping the car "factory fresh" then you can leave the system intact ( with a few tweaks ) on a larger displacement motor say 350, 355, 383, 400, 406 all in the gen 1 SBC. Vortec heads don't have the EGR port so you would need a ZZ4 prom with egr delete so it doesn't set off the check engine light. Don't get too radical with the camshaft and regular Q-Het tuning should apply. Keep your eyes out for an old school dwell meter to help set up the carb
Wideband 02 sensor will help as well
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In the non-Hillary voting states, a 1985 is going to be emissions exempt. Testing old cars is too much hassle for too little gain. Roller Dynos cost thousands of dollars to maintain and aren't needed for anything 1996 or newer. So the $Thousands of dollars sits there unused until somebody realizes "this is stupid" and makes old cars exempt.
1993-1995 cars are screwed right now in Texas, because they aren't the magic 25 years old and need dyno testing and when dyno's break, shops aren't fixing them.. so its hard to get a sticker.
The OBD1 telemetry is pretty rudimentary for a carbed car... not really worth doing anything with.
1993-1995 cars are screwed right now in Texas, because they aren't the magic 25 years old and need dyno testing and when dyno's break, shops aren't fixing them.. so its hard to get a sticker.
The OBD1 telemetry is pretty rudimentary for a carbed car... not really worth doing anything with.
All good info. I'm not keeping the factory carb. It's going. I will probably run some sensors to keep the car functional and look stock and re-flash the EGR and some other items out so the CE light does not come on.
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