Roblaw

It keeps getting stranger. Today I pulled off the VC to check valve lash, all in spec. Put it back together and timed it again. It was right on at 8 degrees advance, 800 rpm. It was purring like a kitten. Now the weird part. I ran the same test I did yesterday, pulling off #6 injector connector but this time it stumbled until I plugged it back in. I did nothing to the car but what I already detailed except I did disconnect neg battery terminal overnight last night, which I do often anyway. ECU? Any other thoughts?

I checked compression months ago. 170 psi #6

Been trying to tune the car. Idles really well. Seemed gutless on the road though. Pulled injector connectors one by one and each one made it stumble, sans #6 cylinder. Switched the #5 and # 6 connectors and still with #6 injector disconnected did not make engine stumble. Interestingly, with the #6 connector on #5 injector, it idled fine until disconnected, then stumbled. I figured it was the #6 injector (a new to me rebuilt one). Bench tested fine with 9 volt battery, sprayed carb cleaner really well. So, now I think it's cleaned out, reinstall. In my mind the #6 injector connector is good because it fires the #5 injector and the #6 injector obviously sprays when voltage is applied. Put it back together, however, again pull the #6 connector from the #6 injector when running and no stumble. It really does idle nice though. Pulled #6 spark plug and tested. It fires like mad when running outside of cylinder and it's not wet. When I pulled the #6 wire from plug when running, no noticeable stumble in idle. However, when getting wire close to plug, the idle picks up ever so slightly. Could this just be a timing issue that renders changes in #6 cylinder relatively inconsequential?

My tank was super rusty, with rusty fuel pouring out of my under hood filter when I pulled the hose off. So, Pulled the tank. Local radiator shop (the only one that would hot tank fuel tanks wanted $485 to clean and seal with over a month turn around time). So, I set out to clean it myself. Tried a few methods and here are my results: shook out 10 pounds of dirt consistency rusty crap and rust flakes out of it. Used electrolysis for 2 days, changing out the sacrificial steel and soda solution several times. Some, but not great results. Next, swished about a gallon of 1:4 muriatic acid:water a few times, then let it sit over night full at same ratio. It was looking pretty good now. Rinsed with water then dumped Ospho in it, swished it all over, drained it then dried it with a heat gun. I figured the Ospho had converted the rust to iron phosphate. Last thing was pouring a quart of ATF in it, swishing then draining (see pic). See the fuel return tube in bottom right of pic. That thing was clogged solid. I tried forcing wire through it, air pressure, to no avail. I stuck my propane torch in the tank, heated the crap out of it until it was smoking then hit it with air, then.... Thupe!!, the clog came out in a wad. I filled the tank with fuel and plan on keeping it full to prevent rust. I decided against sealing. We'll see. Bottom line. Muriatic acid worked the best at cleaning and Ospho may save it from rusting again.

Chock another FI problem to corroded wires. 1975 280z new to me. Got it running after new injectors and rehabbed fuel tank. It ran well until it warmed up then would sputter and eventually fail to start. Would start when cooled off but eventually it wouldn't do that either. Plugs were drenched in fuel. If I pulled the PCV hose off air intake hose it would run but not well. I blocked fuel line to cold start valve but no change. Next pulled connector to coolant temp sensor and snapped it back on, no change. Then traced wires back to the 2 bullet connectors, pulled apart, shorted them to each other and voila, it started, albeit it popped and stumbled until warmed up. I figured poor running on start was due to the lack of the extra shot of fuel to injectors during cold start. So, I pulled the entire wire set, CTS connector to bullet connectors, soldered a new CTS connector on pigtail, cleaned all terminals with Deoxit and a pick or wire wheel (depending on male v. female ends). Now it seems to run proper. When I get my clutch sorted out, I'll be able to drive it. It seems to be stuck on flywheel. The car sat for decades. BTW, that Deoxit seems to clean electric parts very well. It's pricey but you don't need to use much.