Questions About My 92 K1500

darisb · February 12, 2008

Newbie here. My wife and I just bought a 92 K1500 with a 5.7L. We were looking for a cheap beater that we could used to haul building materials up to our cabin. I'm sorting through a few minor issues, and have a couple questions.

The truck is running a little rich. I was poking around, looking at the TBI. The gaskets on the TBI are falling apart. I see that I can get a TBI tune up kit locally for about $30. I also noticed that the fuel pressue regulator is part of the TBI. Is there any adjustments on the pressure regulator, or do I just clean it and put it back together with the new diaphram and gaskets?

Secondly, how do I remove the fuel injectors? I tried to gently wiggle them and turn them. Not knowing the correct procedure, I didn't want to force them.

Lastly, is the knock sensor located between the #1 and #3 plugs?

Thanks in advance,

Daris

redvett · February 12, 2008

The regulator is fixed and shouldnt need any adjustment. The injectors have an "O"ring that seals the injector and can be pulled/twisted to remove. Assuming the SES light works and isnt on all the time i would make sure the engine gets up to 195-210F or closed loop so your arent running rich. Check the timing it should be at zero with engine at 195F in park you must remove the EST tan/blk wire to time. The knock sensor is by the starter close to the pan rail.

darisb · February 12, 2008

Awesome. Thanks so much for the reply. I got an SES light when bought it I drove it the 35 miles home. I used a paper clip to jump the OBD-I port, and got a 43. I saw a couple posts on the web, that seemed in indidate that I needed a Ignition Control Module. I put one in, and a couple of ounces of SeaFoam into the 4 gallons that were in the tank. I pulled the wire by the junction panel, and set the timing a TDC (0 degrees). I put some new plugs in it (gapped at 0.035), a PCV valve and an air filter.

The SES was out from pulling the battery. I took the truck on the freeway, and dropped it out of OD to burn off the SeaFoam. A couple miles later, I got another SES. I put another 15 gallons of mid grade in it on the way home. I pulled the codes again, and this time I got a 42 and a 43. That seemed to indicate a knock sensor. I bought a knock sensor. The SES never came back on, so I haven't installed the knock sensor yet (not to mention the fact that I wasn't sure where it was located). I know I need a manual, but I really need to get it to pass smog as quickly as I can.

I took it down to the smog station, and it failed pretty bad. The pre-heater hose was mangled and the hose from the TBI base to the vapor canister was broken off at the canister. HC and CO were high, the third value was ok. The guys said that even with the preheater hose replaced and the vapor canister replaced, it probably was running too rich. The plugs were black but not caked when I changed them. I had sprayed a lot of carb cleaner on the TBI right before replacing the plugs, so I figured it might have been that when I changed them.

The truck runs pretty good when cold, but hesitates a little when it's warm. When it's warm, the temp gauge is always shy of the 210 mark. It seems little restricted to me for a 350, but I don't have anything to compare it to. I was able to spin the rear tires from a dead stop. I thought the throttle response could be could be normal. I looked down the TBI while it was running. The injectors looked like they were both spraying in a nice cone shaped pattern, and we didn't see any dribbling. The fuel seemed to be hitting right round the outer edge of the throttle plates.

The mechanic wants an hour labor to diagnose it. The seller Pep Boys crate motor put in it 25k miles ago. It starts right up and runs smooth when cold. No noticable knocking or pinging. Thinking about replacing the hose, canister and TBI gaskets and then taking it back to the shop.

darisb · February 16, 2008

Thanks for everyone's help. I picked up a TBI rebuild kit, and replaced all the gaskets and o-rings. I replaced the distributor cap and rotor at the same time. The truck is definitely running better. It still seems a little sluggish when I'm rolling at about 30 and stomp on it. We will take it to the mechanic after we get the new charcoal canister installed. I'm wondering if it has a bad cat or O2 sensor.