Please Help with codes and FP question.......

[Jeffs88]

Hey all,

As you can see I'm pretty new and just getting back into hod rodding after a long time off so let me apologize for the length in advance.

I have an 88 GT with what I believe to be a stock Speed Density 5.0 5 SPD, except I was told by the previous two owners it as an E-cam in it. It also has UD pullies an OR H-pipe and the smog and A/C have been deleted.

Since I've had it, I have put new plugs in it (just regular old autolites), new O2 sensors, cleaned TB and EGR and IAC. Replaced a ton of vacuum hose, a new stock FPR and fuel filter and did the 3G upgrade so the grounds have had the once over as well.

Before you all get started I already know through months of reading threads that the LAST thing that should be in this car is the E_CAM with the SD set-up.

It is in the plan to Do the MAF upgrade and probably the Explorer/gt-40 heads and intake and put some headers on her too. But she is what she is for now.

while I of course have some idle issues, The more I work on and fiddle with her the better she seems to run and idle, and I've finally gotten around to reading the codes with a test lite.

KOEO suprised me I was expecting to see several but it told me 11 - 11 (good right) and then 63 - 63 for the continuous memory.....should I do anything about the TPS or does this mean it used to be a problem?

KOER codes were 94 - 44 and 94 -44.

I wrapped the throttle real quick to run the cylinder test and it flashed 6 twice.

Now I know a harbor freight Fuel pressure guage isn't the best but when I hook it up to the schrader valve it reads about 31 PSI, when I unhook the vacuum line from the FPR it will jump to about 39. All at idle. when I rev and hold the engine at 2K or so, I thought the pressure would increase but the guage will jump to about 34 and then fall to about 28 real quick. Is this Right? It seems to low from what I've been reading here and other forums. when both driving and sitting still the engine has a vibration at higher RPM'S and i've been suspecting the balancer but it will do this if it's not getting enough fuel as well wont it?

Since it's a new FPR should I suspect the Fuel Pump? I don't know if it's the stock pump or if it's been replaced in the past but it is kinda loud when it comes on.

Thanks for listening and helping if you can and sorry again for the long post if you haven't all ready stopped reading.....

Jeff

 

[jrichker]

Codes 44 & 94 - AIR system inoperative - Air Injection. Check vacuum lines for leaks, & cracks.

The computer uses the change in the O2 sensor readings to detect operation of the Thermactor control valves. When the dump valve opens, it reduces the O2 readings in the exhaust system. Then it closes the dump valve and the O2 readings increase. By toggling the dump valve (TAB) and switching the diverter valve (TAD) flow from the back of the heads to the air pipe, the computer tests for the 44/94 codes.

Testing the system:
Disconnect the big hose from smog pump: with the engine running you should feel air output. Reconnect
the smog pump hose & apply vacuum to the first vacuum controlled valve: Its purpose is to either dump
the pump's output to the atmosphere or pass it to the next valve.

The next vacuum controlled valve directs the air to either the cylinder heads when the engine is cold or
to the catalytic converter when the engine is warm. Disconnect the big hoses from the back side of the
vacuum controlled valve and start the engine. Apply vacuum to the valve and see if the airflow changes
from one hose to the next.

The two electrical controlled vacuum valves mounted on the rear of the passenger side wheel well turn the
vacuum on & off under computer control. Check to see that both valves have +12 volts on the red wire.
Then ground the white/red wire and the first solenoid should open and pass vacuum. Do the same thing to
the light green/black wire on the second solenoid and it should open and pass vacuum.

Remember that the computer does not source power for any actuator or relay, but provides the ground
necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side
will go to ground or below 1 volt as the computer switches on that circuit.

The computer provides the ground to complete the circuit to power the solenoid valve that turns the
vacuum on or off. The computer is located under the passenger side kick panel. Remove the kick panel &
the cover over the computer wiring connector pins. Check Pin 38 Solenoid valve #1 that provides vacuum
to the first Thermactor control valve for a switch from 12-14 volts to 1 volt or less. Do the same with pin
32 solenoid valve #2 that provides vacuum to the second Thermactor control valve. Starting the engine
with the computer jumpered to self test mode will cause all the actuators to toggle on and off. If after
doing this and you see no switching of the voltage on and off, you can start testing the wiring for shorts to
ground and broken wiring. An Ohm check to ground with the computer connector disconnected & the
solenoid valves disconnected should show open circuit between the pin 32 and ground and again on pin 38
and ground. In like manner, there should be less than 1 ohm between pin 32 and solenoid valve #2 and pin
38 & Solenoid valve #1.

If after checking the resistance of the wiring & you are sure that there are no wiring faults, start looking at the
solenoid valves. If you disconnect them, you can jumper power & ground to them to verify operation. Power &
ground supplied should turn on the vacuum flow, remove either one and the vacuum should stop flowing.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

With the vacuum disconnected and capped, you should se 38-41 PSi at any RPM.

See http://forums.stangnet.com/attachment.php?attachmentid=50636&d=1180923382 for a very nice drawing of the Thermactor Air System (smog pump) plumbing

If you have a catalytic converter H pipe, you need to fix these codes. If you don't, then don't worry about them



Cylinder balance test:
Warm the car's engine up to normal operating temperature. Use a
jumper wire or paper clip to put the computer into test mode. Start
the engine and let it go through the normal diagnostic tests, then
quickly press the throttle to the floor. The engine RPM should exceed
2500 RPM's for a brief second. The engine RPM's will increase to about
1450-1600 RPM and hold steady. The engine will shut off power to each
injector, one at a time. When it has sequenced through all 8 injectors,
it will flash 9 for everything OK, or the number of the failing cylinder
such as 2 for cylinder #2. The report will always be a single digit number.
Quickly pressing the throttle again up to 2500 RPM’s will cause the test to
re-run with smaller qualifying figures.
Do it a third time, and if the same cylinder shows up, the cylinder is
weak and isn’t putting out power like it should.
See the Chilton’s Shop manual for the complete test procedure

Dump the codes and see what the computer says is wrong…Codes may
be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check
engine light, or test light or voltmeter. I’ve used it for years, and it works great.
You watch the flashing test lamp or Check Engine Light and count the flashes.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

Dumping the Engine Running codes: The procedure is the same, you start the engine with
the test jumper in place. Be sure the A/C is off and the transmission is in neutral.
You'll get an 11, then a 4 and the engine will speed up to do the EGR test.
After the engine speed decreases back to idle, it will dump the engine running codes.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the
check engine light, or test light or voltmeter. I’ve used it for years, and it works great.
You watch the flashing test lamp or Check Engine Light and count the flashes.

See Troublcodes.net Trouble Codes OBD & OBD2 Trouble Codes and Technical info & Tool Store. By BAT Auto Technical

If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method.
There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

The STI has a gray connector shell and a white/red wire. It comes from the same
bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

The STI has a gray connector shell and a white/red wire. It comes from the same
bundle of wires as the self test connector.


WARNING!!! There is a single dark brown connector with a black/orange wire.
It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector.
If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's
internal workings are OK, and that the wiring to put the computer into diagnostic mode is good.
No code 11 and you have some wiring problems.

Do a compression test on all the cylinders.
Take special note of any cylinder that shows up as weak in the cylinder
balance test. Low compression on one of these cylinders rules out the
injectors as being the most likely cause of the problem. Look at cylinders
that fail the cylinder balance test but have good compression. These
cylinders either have a bad injector, bad spark plug or spark plug wire.
Move the wire and then the spark plug to another cylinder and run the
cylinder balance test again. If it follows the moved wire or spark plug,
you have found the problem. If the same cylinder fails the test again,
the injector is bad. If different cylinders fail the cylinder balance test,
you have ignition problems or wiring problems in the 10 pin black &
white electrical connectors located by the EGR.

How to do a compression test:
Only use a compression tester with a screw in adapter for the spark
plug hole. The other type leaks too much to get an accurate reading.
Your local auto parts store may have a compression tester to rent.
If you do mechanic work on your own car on a regular basis, it would
be a good tool to add to your collection.

With the engine warmed up, remove all spark plugs and prop the
throttle wide open, crank the engine until it the gage reading stops
increasing. On a cold engine, it will be hard to tell what's good &
what's not. Some of the recent posts have numbers ranging from
140-170 psi. If the compression is low, squirt some oil in the cylinder
and do it again – if it comes up, the rings are worn. There should be
no more than 10% difference between cylinders. Use a blow down
leak test (puts compressed air inside cylinders) on cylinders that
have more than 10% difference.

See the link to my site for details on how to build your own blow
down type compression tester.

 

[Jeffs88]

Thank you Jrichker,

It's your Massive amount of info that has gotten me this far so far.

It looks like I didn't finish the balance test so will repeat that test and see if # 6 remains an issue....

Since the thermactor pump has been removed I figured I didn't have to worry about the 94 and 44 codes. No, no cats on the h pipe ......

I'm still not sure if I need to address the continuous memory code of 63 for the TPS

And "With the vacuum disconnected and capped, you should se 38-41 PSi at any RPM" makes sense, that's why i brought it up but since I'm not seeing that, what's a logical approach of solving this issue?

 

[Jeffs88]

OH,

And like many others have posted, this beast will choke you out of the garage quick with the gas smell from the exhaust even with all the doors open.

I was really hoping to have the charcoal canister valve thing come up in the codes so I could remedy some of that problem. But since it seems to be functioning, and there is nothing else indicating an overly rich condition, will a MAF conversion help at all? I also have read on here somewhere I think that some of the newer cats these days dont require the airflow from the thermactor system so they ownt clog up. True? may be an option as well to help clean up the air AND get rid of the smell

 

[jrichker]

The E cam may be just enough to get outside the range that works good with the SD computer. However, I would check the vacuum plumbling to the MAP sensor on the firewall to make sure it is OK. After that, borrow or buy a vacuum gauge to check for vacuum al 1000-1200 RPM. I would expect to see 16"-19" of vacuum. Those figures are unconfirmed, but if you are way low, you may have a vacuum leak somewhere.

Newer catalytic converters do not use the Thermactor Air System (smog pump) because they are designed to work with an improved computer system that runs leaner and cleaner. They add an extra set of O2 sensors after the catalytic converters to monitor the oxygen and HC levels. Using this additional information, the improved computer system adjusts the air/fuel mixture for cleaner combustion and reduced emissions.

Code 63 - Throttle Position Sensor (TPS) signal too low.

Revised 02-Jul-2009 to update TPS setting procedure & add 10 pin connector layout.

Vref missing (5 volt reference voltage supplied by the computer), bad connections or damaged wiring, TPS sensor failed, TPS sensor way out of adjustment. Use a DVM to check for 5 volts on the Orange wire. If it is missing, look for +5 volts at the Orange wire on the EGR or MAP/Baro sensor located on the firewall near the center of the car. If there is +5 volts on the MAP/Baro sensor, but not on the EGR, clean the #2 & #5 pin on the white 10 pin connector. If there is +5 volts on the EGR but not on the TPS, look for bad wiring inside the engine fuel injector harness.

Setting the TPS voltage
You'll need a Digital Voltmeter (DVM) to do the job.

Wire colors & functions:
Orange/white = 5 volt VREF from the computer
Dark Green/lt green = TPS output to computer
Black/white = Signal ground from computer

Always use the Dark Green/lt green & Black/white wires to set the TPS base voltage.

Do the test with the ignition switch in the Run position without the engine running.

Use the Orange/white & Black white wires to verify the TPS has the correct 5 volts source from the computer.
Setting the TPS: you'll need a good Digital Voltmeter (DVM) to do the job. Set the TPS voltage at .5- 1.1 range. Because of the variables involved with the tolerances of both computer and DVM, I would shoot for somewhere between .6 and 1.0 volts. Unless you have a Fluke or other high grade DVM, the second digit past the decimal point on cheap DVM’s is probably fantasy.

Since the computer zeros out the TPS voltage every time it powers up, playing with the settings isn't an effective aid to performance or drivability. The main purpose of checking the TPS is to make sure it isn't way out of range and causing problems.

The Orange/White wire is the VREF 5 volts from the computer. You use the Dark Green/Lt green wire (TPS signal) and the Black/White wire (TPS ground) to set the TPS. Use a pair of safety pins to probe the TPS connector from the rear of the connector. You may find it a little difficult to make a good connection, but keep trying. Put the safety pins in the Dark Green/Lt green wire and Black/White wire. Make sure the ignition switch is in the Run position but the engine isn't running.

Always adjust the TPS and Idle with the engine at operating temp. Dive it around for a bit if you can and get it nice and warm.

When you probe the leads of the TPS, do not use an engine ground, put the ground probe into the lead of the TPS. You should be connecting both meter probes to the TPS and not one to the TPS and the other to ground.

The TPS is a variable resistor, must like the volume control knob on a cheap radio. We have all heard them crackle and pop when the volume is adjusted. The TPS sensor has the same problem: wear on the resistor element makes places that create electrical noise. This electrical noise confuses the computer, because it expects to see a smooth increase or decrease as the throttle is opened or closed.

TPS testing: most of the time a failed TPS will set code 23 or 63, but not always. Use either an analog meter or a DVM with an analog bar graph and connect the leads as instructed above. Turn the ignition switch to the Run position, but do not start the engine. Note the voltage with the throttle closed. Slowly open the throttle and watch the voltage increase smoothly, slowly close the throttle and watch the voltage decrease smoothly. If the voltage jumps around and isn’t smooth, the TPS has some worn places in the resistor element. When the throttle is closed, make sure that the voltage is the same as what it was when you started. If it varies more than 10%, the TPS is suspect of being worn in the idle range of its travel.


Charcoal canister plumbing - one 3/8" tube from the bottom of the upper manifold to the rubber hose. Rubber hose connects to one side of the canister solenoid valve. Other side of the solenoid valve connects to one side of the canister. The other side of the canister connects to a rubber hose that connects to a line that goes all the way back to the gas tank. There is an electrical connector coming from the passenger side injector harness near #1 injector that plugs into the canister solenoid valve. It's purpose is to vent the gas tank. The solenoid valve opens at cruse to provide some extra fuel.

Purge valve solenoid:

Carbon Canister:

 

[Jeffs88]

Vacuum at 1000 rpm is 16. hose is good to the Map sensor.

If the Purge valve is bad, wouldn't it throw a code. Is that a major cause for the fumes from the car.......?

 

[jrichker]

Vacuum is a little on the low side, but it does not lead me to think you have a large leak. Try testing it a again at 1500 RPM.

The purge valve tech info was just for clarification if you needed it. If the valve is missing or the coil inside it has open circuited, it will set code 85. If it is present and the coil is good, you won't get a code even if the canister is missing or the feed lines are plugged or disconnected.
If the canister is missing, broken or the lines disconnected, you will smell gas fumes.

 

[Jeffs88]

Cool, I'll keep looking for any small leak, if I have one.

How can I tell if the line form the canister to the tank is plugged. I replaced the hoses from the manifold to the valve, valve to the canister and canister to the hard line going into the firewall. Where is it routed from there, so I can trace it back to the tank?

Can the canister itself go bad or wear out, if all the lines are good to go?

I redid the balance test and it gave me a different cylinder each time. 1st was # 2

second was # 1 and third test was #3. Does it mean anything that they are on the same bank? And is it important that I keep working that test until It gives me the magic #9?

Thanks for all the help so far.

 

[jrichker]

Remove the gas cap and blow by mouth through the hose coming off the canister. If no air comes out the gas cap or the pressure makes your ears hurt, the line is plugged. You may need a helper to listen at the gas filler neck.

Fix the code 63 prior to running the cylinder balance test. It can affect the results by making the idle speed too low.

The wandering cylinder balance test is an indication that the engine speed is too low for the test to run properly. You should see 1450-1600 RPM for the test to run without problems.

 

[Jeffs88]

will do......I'll post back after I clear the 63 and test the canister line. Wont be till tomorrow though.

thanks

 

[Jeffs88]

OK,

Took a few days to get back to the car,

63 code fixed. The only codes given now are the 94 and 44 KOER due to smog equipment removed.

Vacuum at 900 is 16 in. at 1000 it goes to 17in and at 1500 it went up to 19inches.

Idle is at 900, pretty steady,not much hunting at all.......It will idle lower but
not very smoothly.

Question...... If the dufus who put in the E-cam left the stock springs on the E-7 heads, would that keep it from reving freely up to the 5000-5500 it should be good for. It seems like the throttle response is ok, it just seems like it doesn't really care for being revved that high. It'll do it, just not as smoothly or freely as I thought a SBF should. I see the suggestions to upgrade the stock GT40/40P springs so it's making me question the set-up on mine......

Balance test results this time indicated #1 on first test #'s 8 and 2 on second and #2 on third. The factory tach said it went up to about 1600 during the tests.

I did blow through the hard tube leading back to the tank from the canister. It was pretty hard to blow through but I did hear some air coming from the filler tube.

If it is even partially clogged, can it be cleaned out or does it need to be replaced.

Whats a good way to test the valve?

Thanks again Jrichter, It's running much better than when I first bought her. Now I have to save up for maf upgrade and a good HCI combo.

 

[jrichker]

The vacuum readings are good, with those readings it is unlikely you have a vacuum leak large enough to upset things.

The carbon canister is probably OK.
It would be a better test to apply 1-2 PSI to the filler neck and see if the air came out the carbon canister plumbing. I haven't figured out a simple and reliable way to do that, so go with what you have.

The wandering cylinder balance test puzzles me. The only time I have seen it give different cylinders every time you run the test was when the engine RPM was too low. You seem to have eliminated that as a possible cause, so I am without a solid answer.

 

[Jeffs88]

Wow! If it wasn't my car, I'd be proud to say I've got you stumped..!

The car still has a heck of a gas smell. Maybe the valve is plugged.

Like I said in my last post, If a car still has the stock valve springs and they are weak or at least too weak for the E-cam, or maybe not adjusted correctly, how would the engine behave?

Maybe I need to just stop working so hard to make this less that optimal set-up run right and concentrate on planning and aquiring a better set-up.

Thanks Jrichter, I'll keep fiddling with it, there is still a lot the car needs and I'm confident I'll need more help.

 

[Jeffs88]

UPDATE!

Well, I broke down and got a new TPS. After probing it wit a meter, it didn't seem like the voltage climbed very smoothly when openning the throttle.

Made a Big difference is driveability! Then I got the chance to check out the engine bay when it was pitch dark out. Looked like a small war going on in there! So new wires went on too!

I re-did the CBT and the results came back a little more consistant.

test one gave me Cyl #2
test two gave me Cyl#2 and #1
rest three gave UP Cyl #2 again

So whats a good process to find the cause of that cyl being weak?

 

[jrichker]

Do a compression test on all the cylinders.
Take special note of any cylinder that shows up as weak in the cylinder
balance test. Low compression on one of these cylinders rules out the
injectors as being the most likely cause of the problem. Look at cylinders
that fail the cylinder balance test but have good compression. These
cylinders either have a bad injector, bad spark plug or spark plug wire.
Move the wire and then the spark plug to another cylinder and run the
cylinder balance test again. If it follows the moved wire or spark plug,
you have found the problem. If the same cylinder fails the test again,
the injector is bad. If different cylinders fail the cylinder balance test,
you have ignition problems or wiring problems in the 10 pin black &
white electrical connectors located by the EGR.

How to do a compression test:
Only use a compression tester with a screw in adapter for the spark
plug hole. The other type leaks too much to get an accurate reading.
Your local auto parts store may have a compression tester to rent.
If you do mechanic work on your own car on a regular basis, it would
be a good tool to add to your collection.

With the engine warmed up, remove all spark plugs and prop the
throttle wide open, crank the engine until it the gage reading stops
increasing. On a cold engine, it will be hard to tell what's good &
what's not. Some of the recent posts have numbers ranging from
140-170 psi. If the compression is low, squirt some oil in the cylinder
and do it again – if it comes up, the rings are worn. There should be
no more than 10% difference between cylinders. Use a blow down
leak test (puts compressed air inside cylinders) on cylinders that
have more than 10% difference.

See the link to my site for details on how to build your own blow
down type compression tester.