I wanted to check the timing, but cannot find the marks anywhere. If it’s a bolt on degree scale It is long gone. As I can’t find it.
If this is like my '88 K1500 5.7L, it's at 12:00 above the damper. There is a bigass hole in the accessory bracket that the timing light is pointed straight-down through. I need both knees on the radiator hold-down, one hand on a valve cover or the cowl, and the other pointing the timing light down through the hole in the bigass accessory bracket near the belt tensioner.
It's a real pain in the tuckus. It works, but it's not intuitive.
For folks with more tools than sense, using a magnetic timing indicator is ENORMOUSLY easier. The timing pointer has the tubular extension molded into it, that the "magic wand" fits into. Set the machine for a 9.5 degree offset, and read the timing and RPM on the display.
You must be registered for see images attach
I wonder how often the TBI injectors go bad.
Possible. Not common. VERY not common if you're buying Top Tier fuel, and/or using Chevron Techron Complete Fuel System Cleaner at each oil change.
I have a new Holley tbi unit I bought at a swap meet 10+ years ago but have not been able verify it is right for the truck. the number on the box doesn’t cross anywhere. All I can do at the moment is query and investigate online.
There's lots of Holley TBI part numbers. Some are replacements for OEM throttle bodies, others are aftermarket intended to be used with a Holley computer to run the injectors.
The direct replacement for a 5.7L '87--'91 (I think) is the 502-6.
www.summitracing.com/parts/hly-502-6
Free Shipping - Holley OE Replacement Throttle Bodies with qualifying orders of $109. Shop Throttle Bodies at Summit Racing.
www.summitracing.com
Holley sells a thicker throttle body gasket with tapered throttle holes, so the big 2" throttle plates clear the smaller holes in a stock intake manifold. This is the rebuild kit which includes the gasket, the gasket is (or was) available separately.
www.summitracing.com/parts/hly-503-5
Free Shipping - Holley Throttle Body Rebuild Kits with qualifying orders of $109. Shop Throttle Body Rebuild Kits at Summit Racing.
www.summitracing.com
I had rotator cuff surgery Thursday so I won’t be lifting any hoods for a bit. Thanks for the checklist. I have done plugs, wires cap and rotor. Next up the O2 sensor and timing, if I can find the pointer.
BTW, what / how is fuel trim accomplished? Based on prior experiences I have to assume that everything that can be manually adjusted is misadjusted.
Fuel trim is done by the computer, continually, based on O2 sensor feedback. Not something done by the owner/operator.
You'd check it to see that it's near the baseline. The farther away from baseline, the more likely there's a fuel system problem.
Misfire screws up the O2 sensor, produces false "lean" signal. That, in turn, causes the computer to go into "rich command" where the fuel trim numbers increase. Or the O2 sensor can be faulty, the computer doesn't get accurate rich/lean indication...so it does what it's told and goes overly-rich or overly-lean based on faulty information.