Hi guys, is this a carb or timing issue? stock 70 GS455 with correct q-jet/lectric ignition. Nice warm S. Florida mid-morning. started car in garage and let it get up to 180 degrees and shut it down. 30 minutes later started car to take a drive. drove around a mile+, stopped at about 5 intersections/stop signs. Then I came to a stop at a stop sign, the engine shut off. started car and drove 2-3 blocks and stopped at sign and engine shut off. rest of the way home I shifted to neutral or rolled the stop sign. When driving, all was normal so I am not suspecting the obvious out of gas. My gauge is stuck but I believe there to be plenty + car starts up and runs. got the car back home and checked temp a few minutes later, was mid 180s. q-jet was rebuilt 2 years ago has less than 750 miles on it, but never been happy with it and likely will have another q-jet expert look it over and get it right. But with warm engine, car never cut off on me just for stopping.
Could be lots of things. Just some thoughts: large vacuum leak, debris in carb, idle set too low, etc. If the fuel gauge is stuck, it suggests that the tank hasn't been removed and the sending unit replaced or the filter screen replaced. If there is crap in the tank, it settles when the car is not moving, but goes into the filter screen when it gets mixed up from driving. However, clogged filters/screens would show up more when you are running at higher rpms and less so when idling. I would check first for a large vacuum leak (disconnected hose, bad diaphragm... listen for hissing), then check idle adjustment. If its an automatic, idle should be checked in drive with engine hot. When the engine heats up, the fast idle is kicked down, so too low an idle and vacuum leaks would show up mostly when engine is hot.
When an engine shuts down suddenly, it is ignition, when it progressively runs rougher and quits, it is typically fuel related. You should be looking at engine vacuum first.
Hector... How are you Sir? I agree with everyone above me, but.... Once I had vapor lock. Ok, twice. When my car stalled, in traffic, I luckily pulled off the road, popped the hood, and the carb. was frozen big time. A lot of humidity down there. Glad I'm not down there. I'll be back in 2 weeks. That sucks!
i need to check the brake booster but anyone see anything amiss in the pics.i have a thin hose just lying on the manifold not connected to anything on drivers side . ter but anyone see anything amiss in the pics.d
With the engine running, does the end of that hose hiss, you know, like a vacuum leak? Looks like the other end goes to the vacuum switch on the intake.
As long as there is no vacuum being supplied to the transmission control solenoid, the vacuum hose going from it to the thermal vacuum switch shouldn't affect anything. I assume you disconnected the ported vacuum that goes to the thermal switch (lower left base of carb) and fed it directly to the distributor. Everything looks like it should work without hissing. Just make sure when you pump the throttle the choke place slaps shut when the engine is cold. If not, you may need to do some choke rod adjustments. Might also apply some vacuum to both pull-off diaphragms just to make sure they do their thing. Looks like a 71 set-up (carb is definitely a pre-72), but I can't remember if the 70 models came with the controlled combustion system.
Here is the set-up for a 71. Doesn't hurt nothing bypassing this, just increases emissions (and makes the engine run cooler and boosts HP). Your carb shouldn't have the extra port from the base plate that goes to the charcoal canister if it is a 70.
Another thing to check is the wires that go to the pick up coil inside the distributor. These small wires flex at the same spot as the timing advances and retards. It is not uncommon for the wires to break inside the insulation near the pickup coil. When the timing changes, the wires sometimes lose their connection.
