I have a 1994 Blazer, 5.7 TBI, 4l60e, 4x4. 217k. Silverado trim, all stock. Had the truck for a little over 2 years. Its always started well no matter the temperature. Now, I'm suddenly having an intermittent flooding condition on cold start. Happened overnight.
Not necessarily cold weather, but engine cold. Every 3rd or 4th time I go to start the truck it tries to pop off like normal and stalls, then floods. Hold gas pedal to the floor and it will start. Strong gas smell the whole time. If I pull a plug its wet and smells like gas.
Once there truck starts, it runs great and drives great. Smooth idle, no issues. Doesn't burn oil or anything. Gets about 14 mpg running 75-80 on the highway. Restarts perfectly after its been running for a minute.
In the last year or so, the truck has had:
New fuel pump/sender/tank/filter
New MAP sensor
New distributor/coil/plugs/wires
New 02 sensor
complete new exhaust (manifolds to tailpipe)
NewCoolant temp sensor
New thermostat
New radiator/hoses/water pump
New starter/alternator/battery/belt/idler/tensioner
What I have done so far to troubleshoot:
Found leaking injector and leaking fuel pressure regulator. Rebuilt a spare TBI unit with all new parts. New reman injectors, new diaphragm and spring, new TPS, new IAC. No change whatsoever in starting, but no longer have leaks. Driving performance vastly improved. Better throttle response and power.
Checked all the vacuum lines and around TBI base and intake manifold with carb cleaner. Can't find any vacuum leaks.
Checked coolant temp sensor with multi meter per info I googled. Tested fine but I decided to change it anyway, even though it was only about a year old. No change.
Replaced EGR valve and solenoid. Both look original so I figured for GP I'd do those as well. No change.
Changed plugs. AC Delco plugs. No change. Had a couple old ones that looked a little fuel fouled but not bad. They had about 16k on them. No visible electrode wear.
Checked base timing, its at zero degrees with the wire unplugged. Seems to advance properly with the wire plugged in.
I've run out of things I know to troubleshoot. SOMETHING is causing way too much fuel, but not all the time. My last guess is something is wrong with the ECM, but I hate to buy one just to find out that wasn't it either.
Anybody got any guidance? Huge thanks in advance!!!!!
Not necessarily cold weather, but engine cold. Every 3rd or 4th time I go to start the truck it tries to pop off like normal and stalls, then floods. Hold gas pedal to the floor and it will start. Strong gas smell the whole time. If I pull a plug its wet and smells like gas.
Once there truck starts, it runs great and drives great. Smooth idle, no issues. Doesn't burn oil or anything. Gets about 14 mpg running 75-80 on the highway. Restarts perfectly after its been running for a minute.
In the last year or so, the truck has had:
New fuel pump/sender/tank/filter
New MAP sensor
New distributor/coil/plugs/wires
New 02 sensor
complete new exhaust (manifolds to tailpipe)
NewCoolant temp sensor
New thermostat
New radiator/hoses/water pump
New starter/alternator/battery/belt/idler/tensioner
What I have done so far to troubleshoot:
Found leaking injector and leaking fuel pressure regulator. Rebuilt a spare TBI unit with all new parts. New reman injectors, new diaphragm and spring, new TPS, new IAC. No change whatsoever in starting, but no longer have leaks. Driving performance vastly improved. Better throttle response and power.
Checked all the vacuum lines and around TBI base and intake manifold with carb cleaner. Can't find any vacuum leaks.
Checked coolant temp sensor with multi meter per info I googled. Tested fine but I decided to change it anyway, even though it was only about a year old. No change.
Replaced EGR valve and solenoid. Both look original so I figured for GP I'd do those as well. No change.
Changed plugs. AC Delco plugs. No change. Had a couple old ones that looked a little fuel fouled but not bad. They had about 16k on them. No visible electrode wear.
Checked base timing, its at zero degrees with the wire unplugged. Seems to advance properly with the wire plugged in.
I've run out of things I know to troubleshoot. SOMETHING is causing way too much fuel, but not all the time. My last guess is something is wrong with the ECM, but I hate to buy one just to find out that wasn't it either.
Anybody got any guidance? Huge thanks in advance!!!!!