I am working on a friends 89 and keep getting a code 44 (lean exhaust) if you let it idle and watch the O2's they are less than 100mv. If you hold the peddle to the floor it sounds like it has a rev limiter on it and kind of bogs but won't rev up. Backfires a little too whe you hold down peddle. If you go drive it and ease into throttle it does "OK" but not great but anything over about half throttle it starts backfiring and spitting and sputtering and bogs. Fuel pressure stays at a little over 10 PSI all the time so I think pump is ok. New fuel filter. Any other suggestions. TPS and MAP voltage seem to check out ok. If you unplug the O2 sensor it reads around 400 to 450mv. so I think wiring is ok.

 

just my opinion but 10psi of fuel pressure sounds kinda low

 

Alldata shows 9-13 PSI. It never seems to drop off any under any load or anything. Don't know though. I haven't messed with too many TBI's.

 

Sounds like a dying pump. You should have a minimum of 13 to 15 psi at idle.

 

Check this chart out and fuel pressure at the pressure gauge with the engine "OFF" should be between 9 - 13 PSI.

 

Part 2

 

Hello!

I have serious broblem with my 305 tbi engine. It shows code 44 every single time I'm driving highway. Driving in city makes no errors. Car is working fine.

Yes, I have changed Lambda sensor.

Other changed parts:

O-rings and filters on tbi
gasket between tbi and intakemanifold
fuelfilter
all vacuum tubes
all staf including ignition
thermostat
I have measured fuelpressure and it's Ok (I allso lifted pressure little pit up)
Ignition advance checked, was ok.
TPS and IAC settings checked, was ok.
egr function checked, was ok.
I blocked of air pumps hose which goes drivers side of header .
Naturally I have checked possible leaks in exhaust system and vacuumsystem. Not found any.
Idlespeed doesn't chande very much. It's +-25rpm checked with WINALDL.

I need some ideas concerning what to do next?

 

There is a post below yours that has someone with the same code as you. It is about 10 posts down. What is your fuel pressure at exactly? Someone has also posted information on code 44 from a tech book in that other post. Check it out.

 

Here is that tech info.

 

part 2

 

Hey welcome aboard. Unfortunatly it sounds as if you have now been bitten by the ever failing GM fuel pump. Sounds like you need to change your fuel filter and check your fuel feed line pressure to varify.

 

My mistake....

I have searched couple times information in this forum conserning about this fault getting no answers.

Anyway, fuelpressure is 10psi, and its what workshopmanual says. Fuelfilter is new. I will change fuelpump next weekend and hope that is end of this nightmare .

Thanks for advises to all of you.

 

i dont' know about the fuel pump, for some reason i would think a bad fuel pump would rear its ugly head when you are on the throttle more, on the freeway, your fuel consumption is rather small.

 

Hello Spitfire,

In my post above, you will find the troubleshooting chart for your problem. What workshop manual are you using? My information is from the GM shop service manual. The link that shiftycapone references also has the same information. What car do you have this engine in?

 

Hello Trickster!

I have Chiltons repair manual.

Car is -88 Chevy Van, hope I fit in the group?

Dewey316
- I'm just wondering about this pump thing. I thought that the pump has continously same pressure despite of having load or not. Anyway in Finland fuel cost a litle bit more than it cost for you (if i calculate right about 5,20$/1 gal ,1,144eur/litre). So it is worth to buy a pump or whar ever to get this fault resolved.

yep, fuel consumption is rather small ! About 20% more than usually....

 

The fuel pump does pump at a consistant rate but when you change the fuel demands that rate becomes to low to maintain the necessasy pressure. Kinda like if you have the flood gates open but only a garden hose to provide the water.

 

i tried a search but need to clear some things up. i am getting a "ses" light once and a wile when crusing around. so i retrived the codes and it says its a code 44 i was woundering is anyone could help me solve this problem.

 

Wow three code 44 posts in one week. They are popping up out of nowhere. Your fuel pump could be on its way out or it could be something as simple as a clogginh fuel filter. I would check your feed line pressure to varify that you have at least 13 psi of pressure.

I have merged the 3 threads together so that you guys can get all of your info in the same place. This should make it easier for you guys to get your problems solved sine you have exactly the same exact problems.

 

how do you check your feed line pressure? and fuel pump is pretty new.

 

There is a testing kit you can buy at autozone. You can also buy a fuel pressure gage and splice it into your feed line that runs along the driver side fraim rail. Both are very cheap to do and can provide crutial info on FP behavior.

 

Hi!

I'm replacing my fuelpump and have a little problem. How do I get tanks wiring disconnected? Is it just pull off or is there any special stuf?

Thanks!

 

Code 44 continues!

I have replaced my fuelpump and still same fault excist. What to do next? is it possible that my ECM is faulty?

Can I drive whitout MAP? If its broken or what?

I hope someone has a new ideas .

 

Thanks everyone, and thank you Trickster for the awesome diagrams as usual. I tried shotgunning parts at my Code 44, still in the dark, going to try the troubleshooting tips mentioned above. On the freeway, car runs okay, not a lot of power, but abrupt throttle change causes problems. I'm thinking fuel supply, possibly MAP. And from what I've read, your car won't run very good without a MAP sensor. The fuel pump, MAP sensor are about the only things that haven't been checked or replaced yet. Thanks again, we'l be back on the road again in no time! My mechanic told me a fault in the EGR system can cause the lean condition as well.

 

As someone mentioned above, could a bad ECM cause similar problems?

I jumpstarted someone the day before I started noticing problems. However, there had been a slight hesitation off idle up to that point...fuel pump is being changed as we speak.