My '88 G20 van had been sitting in my yard for about 5 years, and hadn’t been started for about 4 of those years. No “moth-balling” preparations had been made. That was a year ago now when I changed the fuel filter, and to my amazement the van started and after some initial coughing and sputtering, it ran beautifully for about 45 minutes when I shut it off. I was never able to get it started again, and about a year ago I posted a thread “Unrepeatable Miracle”. Thanks to input from that thread it was determined that though my fuel pump and/or in tank filter HAD been OK, they were no longer, for upon disconnecting the in-line filter, no fuel was being pumped out.
Last week, though I am no mechanic, I pulled the fuel tank (while lying on the dirt) and used a floor jack (set on cardboard) to lower the tank down. The in tank filter or “sock” was a total mess. The pump may or may not have been good. I took the tank to a radiator shop to be flushed and cleaned. They seemed to have done a good job. I replaced the pump and in-tank filter with new Bosch parts, and used the floor jack to help me re-install the tank. After not too much cranking the van started … blowing out a lot of blue smoke at first which eventually stopped (I know that the engine has bad valve-stem guides allowing some oil to get into the cylinders). Also while it was running, I would hear backfire sounding pops each time accompanied by a puff of BLACK smoke, and I think I saw a spark come out of the tail-pipe. If I didn’t keep the pedal way depressed the engine was sure to stall, but after maybe ten minutes I became concerned about coolant because I had forgot to check it. I had no bricks at hand to hold the gas pedal down so I had to stop the engine to check the coolant (which was OK). I then could not get it started again, and my battery ran out and needed to be charged. (The battery is marginal in condition.) The next day, with the battery charged I tried again, but first I put a bottle of STP Fuel System Cleaner for Ethanol Fuels into a gas can, then bought 2 gallons of gas and added that to the tank which already had about 3 gallons. So, the 1 bottle of cleaner was diluted into 5 gallons of gas. The bottle says it can be added to a half tank of gas, and since a small fuel tank (not mine) may be only 12 gallon capacity, I figured 5 gallons would be enough. When I tried to start the van I got a lot of combustion, and several times the engine chugged on its own for 20 seconds or so, but chugging is not running, and I wasn’t able to “rev” it into truly running. Then my battery died again.
This morning I tried again, and to my great disappointment, there seemed to be much less combustion than before, and I couldn’t even get the engine “chugging” like the day before. I then became concerned that the STP Fuel System Cleaner for Ethanol Fuels was not adequately diluted, and that it was making it impossible to start the car. Upon checking the internet, somebody said Fuel System Cleaners can actually dissolve the nylon in-tank filter “sock”. Could that actually be true ?!! . After a bit of searching I found no other site that confirmed that as a concern.
I’d like to know if any of you on Car Talk’s discussions feel that the Fuel System Cleaner could cause damage, … or if not adequately diluted might make the engine harder to start. … And more generally, why am I getting less combustion than before, and what might I do to get the engine running. It’s an '88 Chevy G20 Van with a 5.0 liter engine and throttle body fuel injection. Thanks!