TBI code 43 44

[Chaz]

Need to smog my truck and I was getting a code 43 and 44. I was also running a Holley 670 tbi unit which is supposed to be a factory replacement smog legal part. Well the holley has been pissing me off cuz it wont idle down and I was tired of driving it that way,,,shifting it with high idle slamming in my drivetrain,,,,,plus the butterfly valves in the bore were sticking when in idle,,,,so went to a junkyard and got a stock tbi for 40 bucks,,,,put that bitch in there and also finally replaced the spark knock sensor,,,,,,,

Truck idles down to about 500rpms now but it seems rough and shakes,,,,good part is the code 43 is gone so I think my spark knock sensor was bad,,,,im happy with that but Im still not satisfied with how it runs,,,,,,maybe whatever is throwin the 44 code is makin it run like crap,,,says low voltage O2 sensor which is lean right,,,,i don't think its lean,,,smells like runnin rich and shakes at idle,,,,

Any advise on how to clear/fix my 44 code,,,,,,,,,????

 

[Chaz]

Oh yeah and I already replaced the O2 sensor about a year ago,,,,its the old one wire one,,,

 

[bucket]

Unplug it and see if that changes anything?

 

[Chaz]

It runs like crap with O2 sensor unplugged.

Today I pulled the old tbi from the JY because it was dumpin gas through one injector. I noticed the holley has an adjustable tps. I buffed the bowls and the butterflys with aluminum wheel polish so they don't stick anymore. I put the holley back on and adjusted the tps while engine was running. It did rev up and down while adjusting it at idle so I set it to idle low as possible,,,still a little too high though. It runs pretty good with the holley except for the high idle.

Now im getting a code 22 33 and 44. Code 22 is tps sensor voltage too low (duh???).

I hooked up a vacuum gage to the manifold port where the turbo 400 vacuum port plugs in. At idle im between 21 and 22 I think. The strange thing is the vacuum gage needle bounces rapidly somewhere between 21 and 22 at idle (engine warm closed loop). Ill up load a video of it tomorrow when I figure out how. It dosent look like the steady needle Ive seen on you tube videos of what a vacuum gage should look like. But its not showing any indications of serious vacuum leaks like intake manifold gasket etc like low vacuum at idle. Maybe someone can look at what the gage is doing and tell me what the hell is going on????

 

[bucket]

It would be interesting to see what it would do with a stock TB and good injectors.


You can take a look at this chart, but I wouldn't be too concerned with the bouncing needle. If it doesn't bounce very far it could just be that it's not the best quality gauge.
http://www.batauto.com/articles/vacuum1.gif

 

[Chaz]

I don't think the vac gage is bad I think its the engine causing it because sometimes I can hear the PCV valve buzzing like same way the vac gage needle bounces.

Thanks for the chart but I don't think any of those sypmtoms are whats going on with my truck. I read somewhere that if your getting rapid fluctuations of 1 on the needle it could be an ignition/missing problem. So today I replaced the plugs, wires, and the whole damn distributor. I was gonna just replace the ign contrl inside the dist but the dist was only 85 bucks so I bought it. They said its the same as a stock one. When I opened it up though I saw its got the magnetic pickup not like my original. I installed it anyway and of course now it runs worse and it immediately threw a code 42 with constant ses light on. I didn't even try to adjust timing im tired and pissed off at it right now.

 

[bucket]

I've had PCV's buzz/rattle before, replacing them with an ACDelco part always fixed it.

 

[Chaz]

Well I put the stock dizzy back in. And I had my gm tbi rebuilt at a carb shop. So I put the stock rebuilt tbi back on. Runs pretty smooth right now. I have a delco pcv valve on order. I tried to order a dizzy from the gm dealer but they said that part has been discontinued. Anyway im happy with the way it runs now,,,prob better than it ever has. But im still getting a code 42 and code 44. At this point I think im gonna take it to a mechanic so I can get the dang thing smogged,,,ugh,,,

 

[chengny]

Diagnostics for 42,43 & 44 - from the 1991 Driveability and Emissions Manual (should be the same):

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[Chaz]

Thanks Chengny........

 

[Chaz]

Yeehaw I cleared all the codes. I replaced the O2 sensor and everything went away. I think that holley tbi had fouled up my O2 sensor because as soon as I replaced it code 44,,,,GONE,,,,

 

[89Suburban]

Hooray!

 

[dhamp]

Did you buy that Holley setup new?

 

[Chaz]

Ya bought it new, been runnin it for a couple of years, it ran ok but I didn't like how it wouldn't idle down low enough,,,,truck feels like it has a little more power on the low end with the stock tbi,,,,
I think it would prob work better on a modified tbi motor if it was set up by someone who really knows how,,,,burn chips and whatever,,,due to the higher cfm,,,,if anyone wants it Ill ship it cheap I have no use for it anymore,,,,