lean 1984 w/ code 44 when warm
Thread Starter
Intermediate
Joined: Aug 2007
Posts: 28
Likes: 1
From: Crystal Lake Il
lean 1984 w/ code 44 when warm
Hello,
I have an 84 with the original crossfire set-up. The car runs ok when cold but after it is warmed up and has been sitting a while, it doesn't want to start and gets very lean with almost no power. It is setting a code 44 which is a lean mixture. I am going to change out the fuel filter and maybe the pump but since it runs ok when cold, I think that I may be wasting my money. Has anyone ever heard of this problem?
I have an 84 with the original crossfire set-up. The car runs ok when cold but after it is warmed up and has been sitting a while, it doesn't want to start and gets very lean with almost no power. It is setting a code 44 which is a lean mixture. I am going to change out the fuel filter and maybe the pump but since it runs ok when cold, I think that I may be wasting my money. Has anyone ever heard of this problem?
Melting Slicks
Joined: Apr 2003
Posts: 3,110
Likes: 6
From: Red Sox Nation! RI
I just worked on an '82 CFI that had the same problem. It was getting an intermittent code 44.
Do you have any upstream exhaust leaks? I'd clean your O2 as Scooter mentioned and check your timing. Pull your plugs and clean & gap them if needed, for starters.
Do you have any upstream exhaust leaks? I'd clean your O2 as Scooter mentioned and check your timing. Pull your plugs and clean & gap them if needed, for starters.
Thread Starter
Intermediate
Joined: Aug 2007
Posts: 28
Likes: 1
From: Crystal Lake Il
When I bought the car, it had an exhaust leak in the left header which I had welded. In the process of removing it, I broke the original O2 sensor so there is a brand new one in place. When It starts cold, it is a little rough but it smoothes out after a few minutes. I drive this to work (about 10 miles) and it operates fine. The problem is that after it has been sitting, it is very lean with hesitation at every acceleration. The first time that I noticed it, I thought I was out of gas. It acted like it was out of gas. The other day,I saw that one company supplies a complete wiring harness for the fuel pump circuit. Was there a problem in the original design?
Melting Slicks
Joined: Apr 2003
Posts: 3,110
Likes: 6
From: Red Sox Nation! RI
This is based on my understanding - maybe some other emissions gurus will jump in. The O2 sensor is what is going sense the lean signal and feed that info to the ECM, but only after it reaches 600* (?). the ECM will them try to enrich the fuel/air mixture once it's warmed up. An upstream exhaust leak can cause a faulty O2 reading by introducing more air into the front pipes & leaning out the exhaust, before it reaches the sensor. But none of this should matter once the car cools down.
Start with the basics, first. Other stuff I would check, beyond what I 1st posted:
-clear your codes by disconnecting the battery for a minute, then re-check after driving the car.
-check for a sticking EGR valve & see if it holds vacuum.
-Full tank of gas?
-Look for a good spray at the TBIs when you turn the key ON. Fuel pump will prime for 2 seconds.
-Do you have a factory service manual?
-Get a low pressure fuel gauge to test fuel pressure, regulators, fuel pump. You may have to make a fitting to run between the TBIs.
Start with the basics, first. Other stuff I would check, beyond what I 1st posted:
-clear your codes by disconnecting the battery for a minute, then re-check after driving the car.
-check for a sticking EGR valve & see if it holds vacuum.
-Full tank of gas?
-Look for a good spray at the TBIs when you turn the key ON. Fuel pump will prime for 2 seconds.
-Do you have a factory service manual?
-Get a low pressure fuel gauge to test fuel pressure, regulators, fuel pump. You may have to make a fitting to run between the TBIs.
Thread Starter
Intermediate
Joined: Aug 2007
Posts: 28
Likes: 1
From: Crystal Lake Il
The car has 145000 miles on it and the timing is right on. I did a compression test on it when I first got it and all cylinders were pretty close. It runs pretty well until you let it sit.
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Thread Starter
Intermediate
Joined: Aug 2007
Posts: 28
Likes: 1
From: Crystal Lake Il
I have cleared the code 44 and have replaced the fuel filter and put a pressure guage directly after the fuel filter. When I turn the key, I am lucky to get 6 p.s.i.. When it is running, it runs between 10 and 11 psi but drops when the throttle is cracked. I took a pair of the needle nose vise grips and clamped off the return line and got between 11 and 12 psi. I would think that the guage would have pegged the needle. I was reading about people with 84 models replacing their pumps with 85 pumps. Can anyone verify that this will help? The manual says that it should run between 9 and 13 psi. I also read that the 84 needs to run all the time at 13 psi to get any decent power. Can anyone validate this?
Melting Slicks
Joined: Sep 2006
Posts: 3,194
Likes: 27
From: Monroe Twp, NJ
I have cleared the code 44 and have replaced the fuel filter and put a pressure guage directly after the fuel filter. When I turn the key, I am lucky to get 6 p.s.i.. When it is running, it runs between 10 and 11 psi but drops when the throttle is cracked. I took a pair of the needle nose vise grips and clamped off the return line and got between 11 and 12 psi. I would think that the guage would have pegged the needle. I was reading about people with 84 models replacing their pumps with 85 pumps. Can anyone verify that this will help? The manual says that it should run between 9 and 13 psi. I also read that the 84 needs to run all the time at 13 psi to get any decent power. Can anyone validate this?
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Well, once you check everything else you may want to check the FP. The CF is rather sensitive to FP, yours possibly being too low. You need to install a fuel gauge and check and adjust it as needed to achieve 14psi and then the motor will have the proper fuel it needs to run correctly, No buts...its a fact on a CFI motor.
Another high interest item to check depending on the mileage is the TBs. If they have over 50K miles on the TBs, the TB shafts are worn and causing a large vacuum leak, No buts...its a fact on a CFI motor. The only way to fix this is to have them bushed. Whoever has the 145K CFI motor, I will put money on it that yours are very bad and need to be bushed. You won't believe the difference it will make on not only the idle quality, but the over performance of the motor. No buts...its a fact on a CFI motor. Send me mail and ask me how I know all this and more...
Another high interest item to check depending on the mileage is the TBs. If they have over 50K miles on the TBs, the TB shafts are worn and causing a large vacuum leak, No buts...its a fact on a CFI motor. The only way to fix this is to have them bushed. Whoever has the 145K CFI motor, I will put money on it that yours are very bad and need to be bushed. You won't believe the difference it will make on not only the idle quality, but the over performance of the motor. No buts...its a fact on a CFI motor. Send me mail and ask me how I know all this and more...
Instructor
Joined: Jul 2007
Posts: 174
Likes: 0
From: Toronto Ontario
No. The fuel pressure is regulated from a FPR on top of each TBI and is non adjustable. If you suspect the fuel pressure is bad because of the top mounted FPRs then either replace them or the TBIs themselves with reconditioned units. The only way to know for sure is to tee line a fuel pressure gauge.
Corvette Enthusiast
Joined: Oct 2003
Posts: 523
Likes: 139
From: La Quinta CA
I have to disagree with you there trackman44. The pressure regulator is adjustable on the crossfire injection system. I just installed an 85 fuel pump and bumped my fuel pressure up to 14 PSI as per Bucaneer's suggestion. (He knows his stuff)
Here's a link on how to adjust the stock pressure regulator on a crossfire system.
http://www.crossfire.homeip.net/cfte...ID=18&CAT_ID=1
You don't have to do the complete disassembly if you have a quadrajet adjusting tool, because that is what is needed. Just pop the plug off and your ready to start adjusting. You will however need to get a fuel pressure gauge on the line between the two throttle bodies to see where your pressure is set. Check with Buccaneer for one of these, he can set you up.
Here's a link on how to adjust the stock pressure regulator on a crossfire system.
http://www.crossfire.homeip.net/cfte...ID=18&CAT_ID=1
You don't have to do the complete disassembly if you have a quadrajet adjusting tool, because that is what is needed. Just pop the plug off and your ready to start adjusting. You will however need to get a fuel pressure gauge on the line between the two throttle bodies to see where your pressure is set. Check with Buccaneer for one of these, he can set you up.
Instructor
Joined: Jul 2007
Posts: 174
Likes: 0
From: Toronto Ontario
My bad on the FPR
I'm sorry, I didn't know this could be done. Personally i would get rid of the crossfire setup and go with a L98 intake and ECM (from a 90 or 91 corvette, they had MAP). And since 84 corvettes have flat tapit camshafts, it would be a good idea to go with diesel engine oil. They have the additives for flat tapit setups. Modern engine oils don't have this additive so flat tapit camshafts wear out sooner.
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Yep, James is correct...the FP "is" adjustable on "all" CFI rear TB regulators as soon as you remove the anti-adjust plate that is blocking the regulator adjustment screw on the bottom. You must disassemble the regualtor to remove the plate, its easy to do.
...and Trackman is correct about most oil manufacturers pulling out the zinc content amoung other items to help cushion things internally to the motor. Rotella oil was recommended by CompCams a few months back, but even they (Shell) is pulling out even more zinc content from the Rotella oil.
The best thing to do and it it "highly" recommended is to buy a few bottles of EOS from your local GM dealer parts store and add a full bottle of EOS to each oil change and you'll be fine with the flat tappet cams and the wear issues. The bottles are 4oz. and the PN is: 12345501. The name on the bottle is actually..."Camshaft and Lifter Prelube" just in case the counter guy doesn't know what EOS is.
I hope this helps and clears up a few things for everyone. Enjoy!
...and Trackman is correct about most oil manufacturers pulling out the zinc content amoung other items to help cushion things internally to the motor. Rotella oil was recommended by CompCams a few months back, but even they (Shell) is pulling out even more zinc content from the Rotella oil.
The best thing to do and it it "highly" recommended is to buy a few bottles of EOS from your local GM dealer parts store and add a full bottle of EOS to each oil change and you'll be fine with the flat tappet cams and the wear issues. The bottles are 4oz. and the PN is: 12345501. The name on the bottle is actually..."Camshaft and Lifter Prelube" just in case the counter guy doesn't know what EOS is.
I hope this helps and clears up a few things for everyone. Enjoy!
Safety Car
Joined: Nov 2005
Posts: 3,532
Likes: 1,185
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Also...Here is my opinion on your code 44 issues as well. You also have a PM from me on this topic PS374.
Here are the main causes for the code 44 you are getting:
Typical causes for this code include:
1) O2 sensor defective or lead shorted
2) Lean injectors (dirty or blocked)
3) Water in fuel
4) Exhaust leaks upstream of O2 sensor
5) Fuel pressure or volume too low
6) Vacuum leaks
Notice #'s 2, 4, "5" and 6. Take a "REAL" good look in those areas and you should find your issues and get your CF running well again. "ANY" FP that is 12psi or under is NOT good enough for a CF to run properly. Adjust it for 14psi and you'll be fine. If your stock pump won't support that flow, install an 85-87 pump. When you blipped the throttle and the FP dropped, that "isn't" good. The motor is running too lean for sure and possibly more issues to repair.
Good luck and post your results.
Here are the main causes for the code 44 you are getting:
Typical causes for this code include:
1) O2 sensor defective or lead shorted
2) Lean injectors (dirty or blocked)
3) Water in fuel
4) Exhaust leaks upstream of O2 sensor
5) Fuel pressure or volume too low
6) Vacuum leaks
Notice #'s 2, 4, "5" and 6. Take a "REAL" good look in those areas and you should find your issues and get your CF running well again. "ANY" FP that is 12psi or under is NOT good enough for a CF to run properly. Adjust it for 14psi and you'll be fine. If your stock pump won't support that flow, install an 85-87 pump. When you blipped the throttle and the FP dropped, that "isn't" good. The motor is running too lean for sure and possibly more issues to repair.
Good luck and post your results.
Last edited by Buccaneer; Aug 10, 2007 at 09:48 PM.
Instructor
Joined: Jul 2007
Posts: 174
Likes: 0
From: Toronto Ontario
Blocking return line not recomended
You could damage the diaphrams in the CF if you block off the return line and then you'll have too rich condition. I would replace the fuel pump but not before checking the sock in the fuel tank ( to see if its clogged up with gunk) or the inline fuel filter (which is located on the frame beside the passenger side front tire). Replace the sock first, then disconnect the flexible fuel supply line hose at the steering rack frame and let it drain in a bucket. Apply +12 volts to the G terminal on the ADLD and check for flow. It should be a steady and strong rate of flow. If it is weak then bypass the inline filter with a hose and check again. If it is strong, replace the filter. If still weak replace pump.
Racer
Joined: Jun 2006
Posts: 461
Likes: 0
From: ilion ny
I have cleared the code 44 and have replaced the fuel filter and put a pressure guage directly after the fuel filter. When I turn the key, I am lucky to get 6 p.s.i.. When it is running, it runs between 10 and 11 psi but drops when the throttle is cracked. I took a pair of the needle nose vise grips and clamped off the return line and got between 11 and 12 psi. I would think that the guage would have pegged the needle. I was reading about people with 84 models replacing their pumps with 85 pumps. Can anyone verify that this will help? The manual says that it should run between 9 and 13 psi. I also read that the 84 needs to run all the time at 13 psi to get any decent power. Can anyone validate this?