Hey guys, its been about 3 years since I've been around here but the truck has run into an interesting issue with my 04 Silverado. So a ago when gas was around $4 a gallon up here I was working at a ford dealership as a summer job and some guy with an excursion filled up his 32 gallon DIESEL fuel tank with gas so we put the siphon at the bottom of the tank and pulled all the diesel out until it only smelled like gas. Then after a few 2 gallon tanks of just gas that they were just dumping into the yard truck I was like hey if your just getting rid of that I'll take it. (I know I know stupid stupid BUT I was a poor college kid and it was free gas!) Well the next morning I go to start up my truck and blew 2 huuuge clouds of smoke outa my pipes and it stuttered for a bit then donezo.... so I was like sonofa! whatever bit of fuel that was left must have re-separated and sunk to the bottom and that's all that was drawn. After some new plugs and some injector cleaner it fired up but still kinda ran bad. Over time it has gotten MUCH better but its been at least a year maybe a year and a half since then and even still on the highway from about 1500 to 2k rpms its skips then its fine once its above 2k. Also form a stop to 1k slowly it skips and sputters too. If I go right to the boards its fine. I no longer think this has anything to do with diesel fuel in the system still. It seams to me that it is running very rich possibly? Also the fuel millage has dropped as well pointing to being rich. What could the diesel fuel have done to cause this? There is a trouble code and I know one of them is a multiple random missfire but havent gotten to autozone lately to see if any other codes have been added. When I got the diesel in it I took the plastic Vortec cover off and pushed on the fuel rail valve and let all the remaining fuel blow out into a cut soda bottle. Is there something I could have bumped doing this making it run rich? Or could the fuel have F'd an o2 sensor up making it run in a limp rich mode?

Sorry for the book and thanks!

 

I think you answered your own question in first getting the codes read. That is always a good place to start and should at the very least direct you to the issue. Let us know what codes pop up and we can be of more assistance. Also check your plugs, wires, when is the last time your throttle body was cleaned, etc. Good luck and keep us posted.

 

Diesel Fuel and gasoline injectors do NOT mix. Most of the time what happens is the o rings swell and things get gummed up and injectors stick open ect.....but scanning the computer for codes IS the first step.....also how about dumping some "HEET" in the tank diesel fuel condensates real easy and at $4 a gallon gas ALOT of people were "watering down" fuel and gas....but first is codes codes codes

 

Two thing make it run rich. Temp sensor or 02 sensor. I would try for temp every other sensor relies on the reading it is giving. Could be giving - 22 degree cause flooding.

 

I was aware of those 2 things but wont a bad MAF sensor make it run rich too if thats no good? The temp sensors appears to be working accurately. Same readings as it normally used to. Not sure on the o2 sensor .. its got just about 100,000 miles on the truck and those are the original ones. Gotta go get the codes check tho. Hopefully this weekend.

 

Im thinkin a bad MAF wont cause it to run rich. It would only lean out the mixture and retard the timing a little.

 

Ah alright good to know! thanks

 

Unburnt fuel down the exhaust may have cooked the cats. This will cause the poor running condition and fuel mileage. Check the codes if this is the case you will have to replace the cats & sensors.

good luck

jvp

 

Alright guys so I read my codes this weekend and here's what we got.
P0300 - multiple random misfire

P0420 -
* Leaded fuel was used where unleaded was called for
* An oxygen sensor is not reading (functioning) properly
* The engine coolant temperature sensor is not working properly
* Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
* Retarded spark timing
* The oxygen sensors in front and behind the converter are reporting too similar of readings

The second one is the one that interests me because I certainly could be an O2 sensor. The truck is JUST about at 100,000 miles so maybe a cat is going or gone? The coolant temp sensor seams to be working fine because the temperature goes up and down when the truck is cold and warm etc. I have true duels with bullets and an x pipe so I cant hear much besides the exhaust if there is a very minimal exhaust leak so I will crawl under and in the engine bay and listen for one but there certainly isn't an obvious one. Haven't ever played with the timing and always used leaded fuel besides the stupid diesel incident... any thoughts or ideas other then to try some new O2 sensors? Other bummer is that the code since it is an 0300 it isn't telling me which bank so I wouldn't know which one is bad.... is there a resistance value or voltage that I can check with my multi-meter to see if one is bad?

Edit: from what JVP sounds like it may be the cats >.< which aren't cheap... Suppose its time for some aftermarket highflows if thats the case.. I'll maybe try the 2 rear O2 sensors first and then move from there?

 

when I get codes like that I like to watch the system in "real time" which most code readers will do....each one names it a little diffrent but most of the time its called read pids. This shows real time data and is very help full if you know what you are looking at