I am on Speed Density, and I noticed cold starts were getting progressively worse.

Last week it cranked and started fine, but driveability was poor until it had been 190+ degrees for several miles.

Within days it changed to hard start, with horrible driveability (bucking, missing, hardly would accelerate) until hot for 15 minutes or so.

I pulled the plugs, and they were fouled with fuel. I switched them out and was able to get a decent start-up. Driveability still was bad until it had been hot for a while.

Then last night I get no start at all.
If I bounce my foot off the throttle at a very rapid rate I am able to get it to run up to 1900rpm max, but if I let off or keep throttle at a steady rate, it will stall.
When I do have it running by bouncing off the gas pedal, it is missing, occasionally backfiring through intake, and dumping raw/half burnt fuel out of the exhaust.

Fuel pressure is 42ish psi the entire time, and I do have spark.

SES light is only on for P0172: Fuel system too rich; bank 1

Thanks for any suggestions!

 

maybe a change in tuner?

 

Man you need to get your tune fixed. I'm pretty sure that's your issue. Are you self tuning or doing mail in flash? Iv been out to Gillette wy and it looks like the only tuning they offer out there is for coal trucks haha

 

Have you contacted the tuner?

 

Lol!
Nothing was changed in the tune during this string of events.
I was just letting the viewers know I am on SD.
It is remote tuned, by a very experienced SD tuner.

Thanks!

 

Haha, and I am one of those who tunes the heavy equipment.

Yes, he will reply later tonight I'm sure. I just want it driving ASAP so I thought I could get your guys' insight.

 

Hmm bad batch of gas?

 

Possible, but it should still run, unless it's straight up water, which it is not. I have filled it since it started acting up. Shell 91oct. V-power from same station always.

 

Hmmmm if the plugs were fouled with fuel that may be an indicator of another problem. You got any CEL's (pending). I would plug into evoscan and verify that first. I think it could be a myriad of issues from a bad coil to a fuel sending issue or maybe something in your vaccum system is loose.

 

What fuel are you using?

Edit I just read above what fuel lol sorry.

 

I just updated my first post with the P0172 code before you posted.

I had my entire ignition system out with plugs inserted/grounded and checked that they were operating correctly, which they are.

The Walbro is about 500 miles old, and it is flowing well/creating the pressure needed to run. I have a DW300 I may throw in to verify.

I also have done a boost leak test to 35+psi with no leaks.

Thanks!

 

I was thinking a bad tune but it could also be a bad batch of gas.

 

Glwt.

 

 

shoot, I'm dead serious, not trying to be funny.

just throwing some good vibes your way. I hope you figure this out.