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CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
I have an 87 Camaro and I'm getting horrible gas mileage. Like 8mpg horrible. I'm trying to figure out what connections go to the sensors on this carb so I can be sure I have it hooked up right. I'm thinking that my connection to the teal green sensor might not be the right one. I could also use some vacuum diagram help if anyone has anything.
Mixture control solenoid wires are blue and pink/black so that appears to be correct. Someone must have spliced on a different weatherpack
connector because the original got damaged.
Just by looking at your picture there are a few vacuum leaks. Also wouldn't be a bad idea having it hooked up to a scanner and making sure all
the sensors are reading correct. A LG4 305 should be getting in the low 20's MPG.
As Dennis said, it would be a good idea to hook it up to a scan tool to see what is going on. Is the computer going into closed loop? Is it in a "limp home" mode? I had a broken TPS sensor on my '84 and there was essentially no TPS voltage reading for the computer. Car was getting about 9 mpg because of the built in protections when there is a sensor problem. Start with the basics and work from there.
those crimped connections should be insulated. if the power one grounds it will blow the eng control fuse and none of the carb electronics will work.
if the MCS solenoid is clicking with key on the power/fuse is good. it should click for about half a minute with key on if the engine isn't started.
the vac line going to the EFE TVS on the water neck should be going to the air cleaner heat stove. the TVS isn't hooked up to the EFE valve any way so it's just leaking vacuum while cold. that TVS is usually connected to a small port on the base (some years) or tee'd off of the line to the charcoal canister.
vac leaks are an issue but probably not why you're getting crappy mileage. you're likely running full rich either due to an internal carb issue, loss of proper ECM control over the MCS or stuck in enrichment due to a bad sensor somewhere.
if you want to get this running right you may have to put in some effort. I'd start with a carb rebuild and scan the live data for sensor issues.
05-12-2023, 05:59 PM
