Fuel Pressure and Code 44

corsair231

Well-Known Member
Joined
Jul 8, 2005
Hey guys,
This is actually a problem I'm chasing on my Sy but I put it here due to better traffic and it should be the same for our Buicks. Occasionally on my Sy at warm idle I will get a code 44 (lean exhaust) and the idle will get rough. Sometimes the truck will even stall. My BLM will be at the upper end of the range. I have not found any vac or exhaust leaks. The O2 sensor cross counts seemed a little lazy so I changed the sensor. It helped but didn't cure the issue. The truck is driven enough that bad fuel shouldn't be the issue. Another typical cause is low fuel pressure but mine is actually a little high @50 line off and @40 line on with a stock non-adjustable regulator, but I did read somewhere that high pressure could cause it too but they didn't elaborate. I just cannot understand how though so I figured it was a typo and it was supposed to read low fp. Anyone had any experience with this caused by high fp?

I've read it could also be a clogged or stuck injector. I've put a stethoscope to the injectors and they are all clicking like they should so is there anyway short of pulling the injectors to see if they are clogged? Could a clogged injector cause high fp?

Truck has good power and runs good otherwise so I didn't think I have any kind of fueling problem but I'm running out of ideas. I have thought about just upping the idle fuel in the chip but I don't want to crutch a problem that really needs to be fixed.

Thanks
 

TexasT

Texas, Where are you from
Joined
Sep 10, 2002
I would theorize that if the fp is somewhat erratic, the clogged injector theory might be what is causing that. As the injectors are opened the fp will drop but a clogged injector holds that pressure up. And this would make the fp move around.
Maybe try a different station for fuel to rule out the fuel as a problem.
 

corsair231

Well-Known Member
Joined
Jul 8, 2005
Iac seems to be about right as does the tps, mat, and map readings. They all look reasonable. Sy/Tys use a factory speed density system so no maf or Translator.

I have gotten fuel at a couple of different stations so I don't think fuel quality is the issue.

Would a clogged injector cause the fuel pressure gauge needle to jump or vibrate? Like how a burned valve will make a vacuum needle jump? Mine stays pretty steady and doesn't vibrate at all.
 

John Larkin

Sublime Master of Turbology
Joined
May 25, 2001
When is the last time you changed plugs or fuel filter? It would be a good idea to look at them for sure. I don't know much about Sy/Ty obviously but the ignition module may have a clue also?

About the only thing you can do otherwise is pull the injectors and send them to Chuck. He turns them around fast. Best deal around.
 

corsair231

Well-Known Member
Joined
Jul 8, 2005
Plugs, wires, cap, rotor, and distributor with module all fairly new and in good working order. Truck pulls good under boost with just a little transitional knock if I just slam the pedal down. About the only thing I have left is the injectors but like I said the truck doesn't do it all of the time. Seems if it was an injector it would be clogged all of the time. I've thought about waiting to the truck is acting up and using one of the no touch thermal readers to see if I can identify a particular cylinder by the exhaust temp. If I can then I would almost be certain it would be a bad injector. If I can't tell a difference then I will probably up my idle fuel just a little. Of course with my luck the truck will probably start running rich due to the higher fuel pressure then.
 

turbo87adam

Active Member
Joined
Mar 18, 2012
Start with the basics. Check grounds and battery connections. Then check fuel pump connections and wiring. Have you changed the fuel filter and has the fuel pressure regulator been checked? How old is fuel the pump?
 

corsair231

Well-Known Member
Joined
Jul 8, 2005
Thanks guys for all the ideas but I believe I may have found my culprit. The truck just didn't seem to act right at stoplights. It would do what I talked about above and it also pulled hard against the brakes. It would just about jump off the line when I would release the brakes. Truck felt almost like having a manual clutch that wouldn't release cleanly, like a bad throw-out bearing. Anyway, trying to trouble shoot that issue, I unplugged my TCC lock-up solenoid thinking the solenoid might be sticking. Drove the truck and that issue was better plus I noticed the idle was smoother and the truck has stopped setting off the code 44. My BLM's are back into the 130's too. I guess the converter was putting enough drag on the engine that the computer was having to add fuel to keep it idling. Anyway, I have a new solenoid on the way hoping it cures the issues I've been having.
 
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