leatherneckm

Ok, my car has like a 150 mile barrier. The car runs GREAT until I drive about 150 miles then all of a sudden it falls flat on it's face!! Some symptoms that have come up, code 44, I replaced the oxygen sensor. It will start and idle good for about 3 secs after it falls on it's face, then stall. If I drive it like this is will hitch and sputter and act like poopey until I get the rpm's up, then it runs fine... It is a 305 TPI 88 trans am... any help would be GREATLY appreciated.

fb305svs

wow... very intresting. i am assuming the check egine light satys on after it throws the code?

assuming it does, it might need the computer to be reset... but now there is still a reason it is triping the code. i dont have my book with me, so i dont remember what 44 is...

if it has to do with lean or rich o2, and u replaced ur o2 sensor, the i would look at the iginition and fuel systems. specificall look at the fuel system first i think- i am not great with tpi's so take what i say as a starting point and i am sure vader, amoung others, will input his knowledge also!

Steve

Steve

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88 Firebird Formula- deseased 2/9/99- 305 TPI, SLP 3 inch exhaust, SLP Intake runners, SLP cam, 3.45 BW disc brake posi, WS6, NOS, and all that good stuff, 13.~ sec 1/4 mile- hit by what else!?!? a FORD EXPLORER!!!!!!

86 Firebird, LG4, t-tops, slp 3 inch exhaust, catco cat, and a bunch of new/replaced stuff, open element, soon to come, 2 inch cowl hood, 3.42 posi disc rear from a 4th gen, and hopefully a 6 speed!
My Webpage- Battle of the birds, My own Thirdgen Page, still under construction, http://www.geocities.com/soares711/index.htm

Jester

That would be demon possesion. Some spirits of the underworld are tied to a certain place where they are cast, and throw a ****fit if the object or person they have possesed ends up past a certain distance from it.

Vader

Leather,

Hey! Watch your language! We don't like that "poopey" talk around here... I'm telling my mom!

Seriously, the '44' should be the code for a lean oxygen sensor reading. It's possible that the oxygen sensor is just not signalling like it should. Even though yours is new, you need to have a clean connection and solid ground for the sensor to operate correctly. But correct operation for 150 miles would tend to rule that out.

I suppose it's possible that something on the exhaust system distorts enough when heated from highway speeds that it loses a sufficient ground, but that's a way-out possibility.

A lean sensor would cause the mixture to go richer until the fuel offset is completely out of acceptable range, then a DTC would set and the ECM will use the "lookup tables" to operate the engine. Performance in this "limp home" mode is always poor.

It it possible that the sensor is correct and the engine is truly lean. This could be caused by a CTS and/or MAT sensor reading that trims the fuel leaner and leaner until you get the DTC. You could also have a vacuum leak that adds to the problem, or an EGR valve sticking open, or EGR solenoid, causing the poor idle, lean operation, and eventual '44'. An EGR that doesn't open when commanded will set a DTC, but a valve that sticks open partially might not set a code. The better operation at higher operation would be another symptom of this leaky EGR problem.

The PCV valve can also stick, but the results shouldn't be so severe. However, together with a couple of other small vacuum leaks and possible leaks in the MAF/air intake ducts, the mixture could go lean enough to set the '44' code without causing any others. If you have a hot engine, the CTS offset, MAT offset, a little excessive EVAP canister air, and a few small leaks scattered around the engine may just do the same thing.

Another very important thing to check is the proper operation of the A.I.R. diverter valve. If the valve is not sealing correctly and is dumping air into the exhaust manifolds instead of the converter or atmosphere, you will definitely get a lean error code. That would be enough to make me want to say "poopey", too.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

Kevin G

Sometimes fuel pumps need to be run awhile before they act up. Sounds like when your fuel pump heats up, it could be going out on your intermittantly...If it is the pump, it will slowly get worse....Any way you can drive aorund with a fuel pressure gauge strapped to your windshield to check it??

Pablo

iTrader: (1)

my fuel pump did the exact same thing when it was bad, and kevinG is right

youll notice it happens sooner when you have an empty tank too, if you keep the tank full it wont happen as often

leatherneckm

I accidently posted this as a new topic, but i will re-post it here, so you guys know what is up... Thanks for the help...

Ok, it has a new fuel pump... so I can pretty much rule that out... I did however have some serious pressure inside the tank once, another time I found a vacuum leak that seemed to fix the problem, another time, I found a leak from the Heater valve that seemed to fix the problem. The code 44 dissapears after a few minutes, or after I jump on it, sometimes no code sets when it runs like "poopey". It only does it after 150 miles of highway driving! I can drive around town for 6,000,000 miles and it's fine. (exagerated of course) It seems to make no difference where the fuel is, as it's been almost empty and almost full when it did it, only after 150 miles of straight driving. I am going to drive 149 miles and then directly into a brick wall very soon. Thank you.

johnyIROC

What's your temp gauge say just before the bad stuff happens? It has to be something heating up... Do you have stock exhaust? Sometimes if you are running headers and driving hard if the collector comes apart the heat generated will fry wires and stuff... check your plug wires.. etc. My carpet caught on fire last week-end, and after 20 min of highway driving, my radio antenna melts and I loose reception... needless to say I was more concerned about the radio than I was about the car fire.

Here's a little tip... if your car catches on fire, don't roll down the windows... it turns a small fire into a big fire real fast.

I wonder if my insurance company will cancel my fire and theft coverage if they read this...




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johnyIROC 1983 Z28
Silly rustang, 5.0 is way too slow
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-87 IROC front clip and ground effects
-Hand pollished Z28 wheels
-Hurst Pro Matic 2 shifter
-Functional hood ducts
-Limo tint all around
-350 stroker coming this winter

FJK

Maybe MAF sensor related. Check that all duct work out of the MAF is tight & intact (no leaks). When problem occurrs, unplug the MAF & see if symptoms change.

Box of Rocks

Dadgummit !!!

Alright, let's get this straight for once and for all.

It's "P-O-O-P-Y

"Poopey" rhymes with "Bombay"

And smells like Bombay too.......

Unless that's Bombay Gin we're referring to.....

That smells like a little bit 'o heaven.

No, not Heaven Hill, Bombay Gin. Ah, forget it. HaaaaRRRumph.

Fellers - I'm bad, I'm back, and I'm sippin' the black. (coffee that is).

Vader, Ima' warnin' ya, get out the windex and the slop bucket, I've been waitin' a long time for a blast.

Oh, about that car problem.......I'll be right back.

BOR

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oldvette

[This message has been edited by Box of Rocks (edited September 13, 2000).]

Box of Rocks

Leatherface,

Hey, were you the funky looking dude in "Texas Chainsaw Massacre" ?

Nah, did'nt think so. Uh, I recommend you do exactly what Vader says - he would be like the "Karnac the Magnificent" of Thirdgens.

Yup, he's got the Mondo, Zen, Elevated awareness of the mobility factor on the motor, with a twist of the intuitive, "I can smell another 5 horsepower in there", funkified, get down,get brown, "ain't no such thing as too much cam just too little motor", power solution.

Seriously, the cat knows his stuff.

BOR
HELLLLLLLPPPPPPP !!!!!!!

Vader

Leather,

If you don't find one of more of the previously recommended possibilities at least partially responsible, you might want to check with MikeInAZ. For a brief while, he was the Executive President of the "Code 44" club.

I presume your TPS is set to factory specs, but had to ask since you didn't mention it earlier.

So far, all we know is that you have a new O2 sensor and fuel pump, and your car runs like "poopey" (sorry, Box - Poopy) after about 150 miles of highway driving (or about two hours for most of us). When this occurs, the engine will stall but restart and idle, albeit in a poor state, but will perform better as engine speed is increased. Do I have it right so far? (I'm still thinking sticking EGR.)

Higway driving generally gives you lots of vacuum, lots of EGR opening, and 100% canister purge. It also tends to make the engine fairly warm, and exhaust gasses really hot. That's why I suggested some of the possibilities above.

It would help if you could get a little more data about the problem. What is the coolant temperature when this occurs? How about ambient air temperature? If you have a serial interface with your ECM, you could monitor O2 crosscounts and observe the trend from startup to failure. Is the sensor is reporting correctly? What is required to get the engine running in "normal" mode? Several hours of cooling? Resetting the ECM? Toilet paper? What?

More hints would be helpful.

BOX- Welcome back home (both ways). Windex and Bounty are loaded and ready...

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

leatherneckm

My coolant temp never gets above 170, and yes, i've actually checked that with a thermometer because I thought that was pretty cool. I live in the desert so the ambient air temp is usually pretty hot, although it has happened at night too when it was like 75. I have stock exhaust, I haven't modded the comp at all. It won't really idle after it happens, it will for like two seconds then it stalls. or it will start and stall immediately. I'm not really sure what is required to get it running again, sometimes it will just magically work again, other times I have found small problems that mysteriously fixed it. (Vacuum leak, leaky heater hose)
The MAF is 4 months old, although I did remove the screens, I recently replaced the MAF burnoff relay also. I'm not sure how hot the upper part of my intake should get during highway driving, but I have noticed it's pretty damn hot, I can touch it, but only for a few seconds. Thanks for the help.

johnyIROC

Do you actually go and drive 150 miles every night to see if it's fixed? And how much does that suck when you find out it isn't?

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johnyIROC 1983 Z28
Silly rustang, 5.0 is way too slow
----------------------------------------
-87 IROC front clip and ground effects
-Hand pollished Z28 wheels
-Hurst Pro Matic 2 shifter
-Functional hood ducts
-Limo tint all around
-350 stroker coming this winter

leatherneckm

Actually, yes I do drive about 150 miles every night. The Marine Corps has sent me to Twenty-nine Palms, CA so I drive to Palm Springs just about every night, and it sucks very bad when I find out it still runs like poopy on the way back.
VADER - U da man, actually U da man that helped with the MAF burnoff relay and figuring out i'm supposed to have an air dam.
So, how do I test an EGR valve, or is this just one of those replace it and cross your finger deals?

leatherneckm

Well, on the way back from Palms Springs it once again ran like the proverbial "poopey" please help, or I just might drive it off a cliff....

Vader

Leather,

It is getting to the point where you may need a data scanner to read actual sensor outputs and determine the reliability of the sensors. However, there are a few more things you can do before that.


<h1>MAF</h1>
The new MAF should be reliable, even with the screens removed. However, remanufactured units can report erroneous air mass and still be within the range of acceptable limits - just barely. It is possible that the air mass is being reported too low, but not low enough to cause a code '34'. The ECM would meter less fuel accordingly, and would cause an overall lean condition. One way to counteract that possibility to some extent is to set the TPS voltage to the high end of the specification at idle. The normal target is 0.54VDC, but you can set it up to 0.62VDC without falling out of the acceptrable range. This will tend to fool the ECM into thinking there is a bit more throttle angle, and assuming there is a bit more engine load at a given air intake mass, and offset the fuel a bit more rich.


<h1>EGR</h1>
As for your more direct question, the EGR is difficult to diagnose if you have a positive backpressure EGR valve. I believe your '88 should have this type. One thing you can do is to operate the valve by hand to check for binding. Unfortunately, the location of the valve requires you to remove the plenum for any such inspection. If you go this far, you might as well remove the valve and visually inspect the pintle and valve seat to assure a good seal.


<h1>Hot Plenum</h1>
The plenum will get quite warm during extended operation. At least hot enough so you wouldn't want to lay your "wee-wee" on the surface. (If you can say "poopey", I can say "wee-wee".) This heat can affect the accuracy of the MAT sensor, causing a false intake air indication and offsetting the fuel mixture a little more lean. If you feel this may be a problem, you can install a 4.7K ohm, 1/4 watt resistor in place of the sensor. This will report a constant 55°F to the ECM and cause a bit more fuel to be administered. Disconnect the sensor at the socket next to the distributor and plug/tape/insulate a resistor in its place.



Unplug the existing MAT sensor (yellow arrow) and connect a resistor at the harness connection (blue arrow). To make sure you have the correct wiring, the wires to the MAT sensor should be tan & black.

- - - - - - - - - - - - - - - - - - - - - - - - -
The coolant temperature sounds very good. The adjustments suggested may give you just enough extra fuel to eliminate the code. It is a cheap-and-dirty way to diagnose the sensors. If your changes make the problem disappear, undo one of the bypasses one at a time. If you disconnect the resistor and replace the MAT connector and the problem recurrs, it's time to replace the MAT, or better yet, relocate it using a new sensor. If resetting the TPS to 0.54V causes the code '44', you need to look into the MAF once again. If none of the band-aids repairs the problem, it's time for the Diacom or Auto X-Ray.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

leatherneckm

Thanks for the help Vader... once again U Da Man... By the way, there shall be no wee wee talk around here... It's just wrong...

freeze92

My '89 GTA did the exact same thing on night. It was the MAF. I too had a new one from, mine was from NAPA. I replaced several things, including the fuel pump, before I actually found this. I could not get any tests for the MAF to tell me it was bad, but I got pissed at the car one day when it was messing up, and dogged the hell out of it. After a few minutes of hard doggin', the check-engine light came on and the car ran fine. I chacked the codes, and it turned out to be the MAF. I replaced it and the problem went away. May not be your problem, but it sure sounds familiar..

leatherneckm

Ok, now can someone tell me a good test for the MAF? I already read the one Autozone recommends, beat on it, if the car stutters VOILA! but somehow that just doesn't seem right to me...

Vader

Leatherneck,

It's called a "tap-test", not a "beat-on" test. You're supposed to lightly tap the MAF housing with a screwdriver handle to determine if the hot wire is cracked or an internal connection is failing.

Typically, the loss of a MAF signal for more than 600mS will set a code '34', not a '44'. However, if you have a marginal connection at the MAF hot wire without a completely broken wire, you might be getting erroneous signals from the MAF.

I do recall one instance earlier this year where the removal of the MAF screens caused a '44'. We surmised that the air flow was no longer getting turbulent from the inlet screen, and was flowing around the long curve in the intake duct and tended to flow toward the outside of the MAF housing instead of through the sampling tube. Since air flow is relatively low at part-throttle cruise, this seemed plausable and the only reasonable conclusion. The MAF screns are present not only to protect the hot wire from lean backfire and sonic shock from intake valve "howl" at WOT, but to create enough turbulence in the intake air stream, insuring adequate flow through the entire MAF at all throttle angles, it would seem.

If you suspect the MAF is reporting incorrectly, you can test the output with a data scanner connected to the ECM. At 550 RPM hot idle in DRIVE, the flow should be at or above the range of 12-15 g/S. At 900 RPM hot idle in neutral or park, the intake air should be flowing around 22 g/S. If you don't have a scanner, you can monitor the MAF output voltage with a DMM. At 900 RPM in PARK, the 22 g/S would equate to about 0.75VDC. (See below for my 305 results.)



The screen removal normally would not cause this problem, but if you have a remanufactured MAF, the tolerance may be on the edge of lean, and the combination of other factors on your engine may all be tending toward lean, causing the oxygen sensor to report the lean error.

The tap-test can also indicate a poor electrical connection at the MAF, but you can inspect that if you test with a voltmeter, since you'll be right there. As I mentioned, losing the MAF signal for more than 600 mS is supposed to set the '34', so I am suspicious of the diagnosis.

My MAF Soapbox

First, no 305 ever requires removal of MAF screens, period. The math just doesn't support the theory until you get to somewhere above 7,500 RPM. Even a 350 at 6,000 RPM will not see a problem with a stock Bosch MAF. I've covered the numbers in detail more than once, so I'll spare you the boredom.

If you do determine that the MAF is reporting incorrectly, try to get a refund instead of a replacement. A more permanent solution to the hot wire frailty and the inlet screen "restriction" is to install a Wells/Conrad SU-145 MAF sensor. It uses a thick-film sensor in place of the fragile hot wire. It also has a flat metal honeycomb matrix in place of the inlet screen, reducing flow restriction. There is no outlet screen. It has a larger I.D. that is oval, with a minimum diameter of 73mm versus the 69mm round I.D. of the Bosch unit.



It has no internal heat sinks, increasing flow ability even more. If this sounds a lot like the description of the LT1 MAF, it's because the design is cloned from the LT1-style MAF, right down to the matrix on the inlet side. It has no hot wire and requires no burn off, but "fools" the burn off circuit by loading a resistor on the burn off terminal to prevent false code '36' trips in the ECM.

Lifetime warranty and virtually bullet-proof. It was about $170.00 with no core charge, since it is not a rebuilt unit. It is flowed at 700+ SCFM @ 0.1" SP. I've had one for well over a year with complete satisfaction.

(I should get a commission for all the free advertisement I give them...)

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

leatherneckm

Ok, I changed out the MAF, it no longer has a 150 mile barrier, HOWEVER, it is running VERY rich. Any ideas?

leatherneckm

Any help? It is running pretty rough at idle
but not all the time. Sometimes it will
stall when I stop, other times it will
stumble to like 100 RPM's then shoot up to to 800, then idle at 700 with no probs.
Other times it is just fine. But it is running quite rich, any ideas?

Blade

I know this is a very late reply... but a friend with an 86 IROC with a 305TPI has the exact same problems you did. He changed his MAF and it got better for awhile, but the car ran like crap. It turned out to be... *Drum roll*... the ECM !! He went to CSK Auto and bought a remanufactured one for like $75 and hasn't had a problem since.

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92 Z28 L98 350
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Ported and polished heads, ported stock TPI base, ported plenum, Comp Cams XR270HR-10 cam (lift .495/.502 duration 218/224 lobe separation 110), Edelbrock TES headers, LT4 valve springs, Crane AFPR, Flowmaster catback with LT1 style tips, MSD coil & wires...

"Take that auto, drop it in first, hold the brakes, stomp the gas and grin from ear to ear! :-)

leatherneckm

Any way to teest that beforee I waste a lot of money???

leatherneckm

Can someone please help and tell me why my car is running so RICH? It STINKS!!! Or at least tell me what/how to check?? please??

IrocManiac

Vacume line or a fuel filter or pump might be the problem.

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TPI 305,
Gutted airboxes,
gutted MAF,
K&N filters,
Corvette Servo.
14.9@93mph

"Speed kills, wanna live forever, drive a Ford."

Corry

If it is the ECM, I was just at a junkyard w/ a thirdgen camaro. I was steeling parts out of. Well, this is a U-Pull it yard=very cheap. Well, wouldn't ya know it, but on the passanger side floor, sits the cars ECM! I left it sicne I have a 350 TPI. If I get my car up and running, I can go check it out for ya.
Corry

MikeInAZ

Ya, I know this is an older post but I've been out of touch for awhile. Vader, I was "president" of the "code 44 club" for a lot longer than a short while (10 months) before I found my solution.

If you are still having problems or anybody else out there with code 44 try this before you nickel and dime yourselves to death (like me).

Check the tightness of the torks bolts holding down the intake manifold. I turned mine with a 1/4 inch ratchet with two fingers they were so loose.

wallahhhhhh

vacuum leak = code 44