Fire won't start

[Supreme Pizza]

4 minutes ago, richard wysong said:

codes don't mean replace the part, they are to help with diagnosing the malfunction

 

I would agree with that.

 

Although that would make things easier.

 

P0300 Engine random misfire .... So...replace the engine?

[jamie greathouse]

Yeah i got a backfire with starting fluid earlier today . It seems like the the MAF or TPS weren't telling the computer to give fuel . I agree the codes don't mean ya have to replace parts but they are factory 260K miles on it . And autozone is 5 mins away . I have a Hypertech programmer and cleared the codes unhooked the battery for the night and will try it again in the morning . I will also try cleaning the intake ( butterfly ) at the TPS and check pressure in the fuel rail again . 

[jamie greathouse]

Before i had the issue it had rough idle and boggy start but would clear up once i got going from a stop . So the fuel pump was keeping up at higher RPM's . 

[Supreme Pizza]

Backfiring out of the intake indicates that the engine is getting too much fuel. For instance, if your fuel system is working properly, and you add more fuel - its too rich and will pop out of the intake. A 5.3 that wont run can be frustrating, but its also very interesting to mechanics, because it can be easily solved if you eliminate the possible issues. Normally the problems that mechanics face are not usually so strait forward.

 

You do not need a throttle body to make an engine run. You do not need an exhaust system either.

 

Don't bother replacing any of that stuff until you find the problem.

 

Does it have compression?

Does it have spark?

Is it getting air?

Is it getting fuel?

 

A non running motor falls back to the very basics of engine diagnostics.

[richard wysong]

as with any diagnostics start with the basics, good fuel pressure and volume, compression, spark, vacuum. codes may give you a clue on what the problem is  but don't put parts in unless you know the parts ng. could be timing, vacuum leak, cam or crank sensors , injector wiring and on and on. try unplugging the maf  and try it. you may need a scan tool with data stream and  scope capabilities if the basics check out

[jamie greathouse]

I am leaning towards a crank / cam sensor . But all the codes were MAF and TPS 

[BlaineBug]

1)  New parts especially aftermarket aren't always good.

2)  Crank position sensor could be throwing the ignition timing off.

[richard wysong]

could be timing chain. vacuum gauge may help diagnose that. if it is you may have valve damage. again basics. whats the compression? at least the parts stores close to borrow the tools if you don't have them

[richard wysong]

extended crank may set maf code. They are very likely false codes and wait til its running to address them

[richard wysong]

crank sensor will cause no start but it wont have spark more than likely. cam sensor will throw the timing off but it should still run even with it unplugged

[jamie greathouse]

It was 23 gallons of bad gas 

 

[jamie greathouse]

[jamie greathouse]

The jar came out of the truck , the glass on the right is year old gas for the snow blower from last year . The new gas ( 20 gals ) was what i topped off with and had to drain . Truck is back to normal . 

 

[Supreme Pizza]

Nice. Glad you got it sorted out. Out of curiosity, how did you determine that the integrity of the fuel was the problem?

 

Any chance you put Flex Fuel in it by mistake?

[richard wysong]

that will do it! NEVER buy gas when they are refilling the tanks, it stirs up any water or crud in the tanks and most dispensers/ pumps don't have filters. almost ALL storage tanks have some water in them