Backfire through exhaust under load...
- Thread starter cougar_68
- Start date
-
Sponsors (?)
striker911
Member
Hook a fuel gauge up to it and mount it where you can see it while driving. Go for a test drive and see what it happening when you are driving. It should increase with throttle due to the vacuum operated fuel pressure regulator. It should not drop, if it does, there is your problem.
If this is not it, I would look into the distributer. If timing is correct, and you say you have a new coil, then I would look into the function of the module and the distributer pickup inside the distibuter. Mine started doing this right before it broke.
If this is not it, I would look into the distributer. If timing is correct, and you say you have a new coil, then I would look into the function of the module and the distributer pickup inside the distibuter. Mine started doing this right before it broke.
I'm not sure if I did this right or what it means...lol. With the engine off and the key on, the test light blinked as follows:
2
3
3
1
6
7
8
1
8
2
8
5
8
4
2
3
3
1
(it appears to repeat from here)...
6
7
8
1
8
2
8
5
8
(I stopped here because it appeared to be repeating.)
So how do I read this? Also, from your post above it sounds like I should do this with the car on too? I'm going to go try that right now. Car on, in neutral.
I got nothin' with the engine on. I hooked up the test light and jumper, put the car in neutral and started it. Before I turned the car on the test light was on, after the car was started the test light turned off for a couple seconds, idle picked up then the test light came on solid. It did not blink at all. Did I ef something up?
Would it be a problem if there was only one oxygen sensor hooked up? This has been this way the hole time though...
Just went for another short drive with very minimal backfiring. Hypothetically speaking, let's say I had bad gas (well not me, but the car), would that cause the issues I was having? Maybe the fuel was slightly tainted and the coil was slightly warn causing the fuel to not burn like it should and causing a rich condition in the exhaust pipes. Now the new coil is over coming the bad fuel. What do you think of this new theory?
*Side note* It was much cooler when I went for a drive just now...
*Side note* It was much cooler when I went for a drive just now...
cjrpony
Member
You should have both sensors hooked up. If the computer can't read one of the sensors then it has to guess and I believe it will enrich that bank to be safe. As far as the codes you listed a couple posts back, there is a longer pause between each group of numbers, so what you should have is 11 (I believe your first number 2 was actually 11, which means your computer is operating ok) 33,167, 81... So you need to watch for the longer pauses so you know where to separate the codes.
And your spout connector looks right. You need to pull that plug out when you set your base timing and then put it back in when you are done. If you leave the plug out, then the computer will not be able to advance your timing. If you try to time your motor with it plugged in, your timing will be way off also.
Post back if you get the codes sorted out.
BigmacK192
New Member
The KOEO codes you threw are these:
23 -- "Closed throttle TPS voltage higher or lower than expected." You need to adjust your TPS. You can look up how to do this. Not too hard.
31 -- "PFE or EVP circuit has intermittently failed below minimum voltage of 0.24 volts." Pressure Feedback EGR sensor or circuit failure. Check your connections there.
67 -- "Neutral safety circuit failure." Pretty self explanitory there. Again, check your connections.
81 -- "MAP sensor vacuum was not greater than 2 in-Hg (7 kPa) during normal vehicle operation." Check your vacuum system for a leak, and then check the MAP sensor.
82 -- "Air management 1 circuit failure (AM1/TAB)." Is the car smog equipped? Thermactor Air Bypass solenoid valve (TAB) is part of that. If you're not running smog, ignore this one (My 89 throws it too).
85 -- "Canister Purge Solenoid circuit failure." Goes with smog usually.
84 -- "EGR Vacuum Solenoid circuit failure." Are you running an EGR valve?
If you can get it running, try the KOER set too. You pull them the same way. Report back to us.
P.S. For future reference, note what I did. The OBD-1 codes in these early EFI systems have two digit codes. So when you saw flashes in this order: *flash* *flash*........*flash* *flash* *flash*, that signifes code 23. Also, the codes will repeat themselves in case you miscount or missed one (I often get distracted
). Make sense? Also, you can look up the meanings of these codes in books, or online. Ford Fuel Injection will save your life sometimes.
Edit: Also, what is your timing set at? Do you have an inductive style timing gun? Try to re-set it to 10* base timing and see what that's doing for you.
23 -- "Closed throttle TPS voltage higher or lower than expected." You need to adjust your TPS. You can look up how to do this. Not too hard.
31 -- "PFE or EVP circuit has intermittently failed below minimum voltage of 0.24 volts." Pressure Feedback EGR sensor or circuit failure. Check your connections there.
67 -- "Neutral safety circuit failure." Pretty self explanitory there. Again, check your connections.
81 -- "MAP sensor vacuum was not greater than 2 in-Hg (7 kPa) during normal vehicle operation." Check your vacuum system for a leak, and then check the MAP sensor.
82 -- "Air management 1 circuit failure (AM1/TAB)." Is the car smog equipped? Thermactor Air Bypass solenoid valve (TAB) is part of that. If you're not running smog, ignore this one (My 89 throws it too).
85 -- "Canister Purge Solenoid circuit failure." Goes with smog usually.
84 -- "EGR Vacuum Solenoid circuit failure." Are you running an EGR valve?
If you can get it running, try the KOER set too. You pull them the same way. Report back to us.
P.S. For future reference, note what I did. The OBD-1 codes in these early EFI systems have two digit codes. So when you saw flashes in this order: *flash* *flash*........*flash* *flash* *flash*, that signifes code 23. Also, the codes will repeat themselves in case you miscount or missed one (I often get distracted
). Make sense? Also, you can look up the meanings of these codes in books, or online. Ford Fuel Injection will save your life sometimes.Edit: Also, what is your timing set at? Do you have an inductive style timing gun? Try to re-set it to 10* base timing and see what that's doing for you.
Sadly, I do not have a timing light. I will have to find someone who has one and check that out...meanwhile, I'm going to go for a drive again tonight and see how it performs. If it does ok, I'm going to drive it to work tomorrow (little longer of a drive).
It drove fine again. So are the symptoms I described at the begining of the thread consistent with a bad coil (and possibly bad gas)? Hopefully these latest tests haven't been flukes. I will keep you posted.
Did you have to replace the whole computer or were you able to replace the capacitor?
Well, still running like crap. Borrowed a code reader and confirmed the codes that I came up with manually.
Still couldn't read codes with Key on, Engine on.
Anyway, one of the codes was TPS out of range so I adjusted it (I know, I know, but it threw a code, give me a break
) It was initially set at 1.2__. I was able to adjust it down to 1.040. Couldn't turn it anymore than that. I read the codes again and that one is gone now.
Took it for a drive, still ran crappy for like 1 minute. I kept the RPM low enough so it wouldn't backfire. Then suddenly it came out of it and was like double RPM? Wonder if the computer is not adjusting the timing properly.
What would happen if I drove with out the spout connected?
I did pull the spout, then revved it a couple times. It revved up and down much quicker w/out the spout in. What do you think of all that?
I talked to someone that thinks I could have a bad plug wire? can I do a continuity (sp?) test on these?
Still couldn't read codes with Key on, Engine on.
Anyway, one of the codes was TPS out of range so I adjusted it (I know, I know, but it threw a code, give me a break
) It was initially set at 1.2__. I was able to adjust it down to 1.040. Couldn't turn it anymore than that. I read the codes again and that one is gone now. Took it for a drive, still ran crappy for like 1 minute. I kept the RPM low enough so it wouldn't backfire. Then suddenly it came out of it and was like double RPM? Wonder if the computer is not adjusting the timing properly.
What would happen if I drove with out the spout connected?
I did pull the spout, then revved it a couple times. It revved up and down much quicker w/out the spout in. What do you think of all that?
I talked to someone that thinks I could have a bad plug wire? can I do a continuity (sp?) test on these?
If the TPS voltage increases wihile the engine is running, the idle speed will increase. Do ALL the TPS testing and you will find the source of your problem.
Code 53 - Throttle Position sensor too high – TPS – TPS out of adjustment, bad connections, missing signal ground, bad sensor.
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.
Here’s a TPS tip I got from NoGo50
When you installed the sensor make sure you place it on the peg right and then tighten it down properly. Loosen the back screw a tiny bit so the sensor can pivot and loosen the front screw enough so you can move it just a little in very small increments. I wouldn’t try to adjust it using marks.
(copied from MustangMax, Glendale AZ)
A.) 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.
B.) 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.
C.) Always reset the computer whenever you adjust the TPS or clean/change any sensors. I just pull the battery lead for 10 minutes.
D.) The key is to adjust the TPS voltage and reset the computer whenever the idle screw is changed.
The TPS is a variable resistor, much 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.
Adjusting the TPS fails to resolve the problem:
Always take resistance measurements with the circuit powered off.
Check the black/white wire resistance. Connect one ohmmeter lead to the black/white wire on the TPS and one lead to the negative post on the battery. You should see less than 1.5 ohm, more than that indicates a problem. Measure the resistance between the black/white wire on the TPS and the black/white wire on the EGR: it should be less than 1.5 ohms. More than that indicates a problem in the engine EFI wiring harness. There is a solder or crimp joint that joins the signal ground for the TPS, EGR, ACT and ECT. It has been known to fail.
Clean the 10 pin salt & pepper shaker connectors. This can fix TPS signal ground problems
.
See Ford Fuel Injection for more help
Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests. You can generally ignore this code, since it has no effect on engine performance.
The computer wants to make sure the A/C is off due to the added load on the engine for the engine running tests. It also checks to see that the transmission is in Neutral or the clutch depressed (T5, T56, Tremec 3550 & TKO). This prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.
The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis. Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from the computer wiring connector. Use a safety pin to probe the connector from the rear and jumper the safety pin to the ground near the computer.
Code 53 - Throttle Position sensor too high – TPS – TPS out of adjustment, bad connections, missing signal ground, bad sensor.
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.
Here’s a TPS tip I got from NoGo50
When you installed the sensor make sure you place it on the peg right and then tighten it down properly. Loosen the back screw a tiny bit so the sensor can pivot and loosen the front screw enough so you can move it just a little in very small increments. I wouldn’t try to adjust it using marks.
(copied from MustangMax, Glendale AZ)
A.) 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.
B.) 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.
C.) Always reset the computer whenever you adjust the TPS or clean/change any sensors. I just pull the battery lead for 10 minutes.
D.) The key is to adjust the TPS voltage and reset the computer whenever the idle screw is changed.
The TPS is a variable resistor, much 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.
Adjusting the TPS fails to resolve the problem:
Always take resistance measurements with the circuit powered off.
Check the black/white wire resistance. Connect one ohmmeter lead to the black/white wire on the TPS and one lead to the negative post on the battery. You should see less than 1.5 ohm, more than that indicates a problem. Measure the resistance between the black/white wire on the TPS and the black/white wire on the EGR: it should be less than 1.5 ohms. More than that indicates a problem in the engine EFI wiring harness. There is a solder or crimp joint that joins the signal ground for the TPS, EGR, ACT and ECT. It has been known to fail.
Clean the 10 pin salt & pepper shaker connectors. This can fix TPS signal ground problems
See Ford Fuel Injection for more help
Code 67 - clutch not depressed (5 speed) or car not in neutral or park (auto) or A/C in On position when codes where dumped. Possible neutral safety switch or wiring problem. This code may prevent you from running the Key On Engine On tests. You can generally ignore this code, since it has no effect on engine performance.
The computer wants to make sure the A/C is off due to the added load on the engine for the engine running tests. It also checks to see that the transmission is in Neutral or the clutch depressed (T5, T56, Tremec 3550 & TKO). This prevents the diagnostics from being run when the car is driven. Key On Engine Running test mode takes the throttle control away from the driver for several tests. This could prove hazardous if the computer was jumpered into test mode and then driven.
The NSS code 67 can be bypassed for testing. You will need to temporarily ground computer pin 30 to the chassis. Computer pin 30 uses a Lt blue/yellow wire. Remove the passenger side kick panel and then remove the plastic cover from the computer wiring connector. Use a safety pin to probe the connector from the rear and jumper the safety pin to the ground near the computer.
Attachments
Checked spark plug wire resistance. Most of them were about .5XX, a couple were .8XX & .9XX, but the 2 and 6 cylinder were both in the 1.5XX range and the coil to distributer wire was about 1.1XX. Does this seam ok. Still fairly low resistance, but 2 of them were way out of range of the others?
A couple things to note. I didn't really pay too much attention to length of wire. Also wasn't watching to make sure I was connecting positive and negative to the same end of each spark plug. I don't know if that matters. I'm pretty much a newb with a multimeter.
A couple things to note. I didn't really pay too much attention to length of wire. Also wasn't watching to make sure I was connecting positive and negative to the same end of each spark plug. I don't know if that matters. I'm pretty much a newb with a multimeter.
The resistance readings need a little bit of help on your part to make them useful. Most multimeter's have several different ranges for Ohms. The ranges typically look something like this: 0-200 ohms, next range is 200-2K (K=1000), 200-2K, 20K-200K, 200K-2M (M=1,000,000), 2M-200M. Your meter may be scaled differently, but the idea is the same on almost all of the multimeters I have used.
So depending on where you have the Ohms selector set, your reading of .5xx could be either very low - less than 1 ohm (typical for metal core wire) or very high - 500K ohm (typical carbon coated glass fiber in poor condition). The desired range is 1K-2K per foot of length. I recommend that you spend some time with the instruction manual for your multimeter.
Remember two things when using a multimeter:
1.) Do not to touch the metal probe tips when making any kind of measurements. When you do it with Ohms, it causes the meter to give false readings since you are measuring the resistance of your sweaty little body along with whatever us under test. It is obvious that measuring voltage or current while touching the probe tips exposes you to potential electrical shock.
2.) Do not take resistance readings on a circuit that is powered up. If you do, the readings will be incorrect, and you stand a chance of damaging the multimeter. Always make resistance readings with the circuit powerd down or disconnected from the power source.
Using your multimeter:
Step 1.) Find the instruction book that came with your Multimeter. Read it and familiarize yourself with how it works and how use it. If you lost the book or didn’t get one with it, do a Google search on the web to find the manufacturer’s web site & download a copy of the manual.
Step 2. ) Make sure that you know what test lead plugs into which jacks on the Multimeter. There are usually several different jacks on most Multimeters, and they have different functions. Make sure that your battery(s) in the Multimeter are good: if you have any doubts, replace the battery(s).
Step 3.) Once you are sure that the Multimeter is functional and you have the leads plugged into the jacks for Ohms ( the upside down “U” symbol), do some simple measurements to make sure that you know how to use it correctly. Set the switch to the lowest range and touch the leads together: you should not see “nothing” but you should see 0.3-1.0 ohms. Measure a 60 watt light bulb: cold it will measure about 17.5 Ohms. It you measure it while it is hot, the reading will be greater.
Step 4.) Make several test measurements using the ohms function and the DC volts function. Remember all resistance measurements must be done with the power off the circuit. This avoids false readings and possible damage to the ohmmeter.. Repeat steps 3 & 4 until you are sure that you can do it without making any mistakes.
Try Automotive Online Instruction for a beginning course. The course is very good and best of all, it is FREE!!!
Thanks for the reply! I do need to get more experience with my multimeter. It is a great tool to have for both home and car.
In the meantime...I tried something else to see if it would make a difference or not.
I took off in my car. Of course it was running like crap, so I pulled over, turned the car off, and unplugged the harness from the IAC.
When I fired the engine and took off again it ran a lot better. Drove it like that for a couple minutes, then stopped again and plugged the IAC back in.
Drove ok for a couple minutes, then it started acting up. So I pulled over, unplugged IAC and it ran fine.
Drove it like that until I got home and it was pretty good. No lose in power, but some really quiet backfiring (was provoking it a little by holding first and second gear with the RPM’s steady around 3000-3500RPM.
This was a used IAC I bought off ebay (it was fancy and polished). So I’m thinking it could be defective and/or dirty. I’m going to test some more, but I need to figure out another way because starting and stopping the engine could be affecting my results (although I tend to believe, for now, that it is not).
In the meantime...I tried something else to see if it would make a difference or not.
I took off in my car. Of course it was running like crap, so I pulled over, turned the car off, and unplugged the harness from the IAC.
When I fired the engine and took off again it ran a lot better. Drove it like that for a couple minutes, then stopped again and plugged the IAC back in.
Drove ok for a couple minutes, then it started acting up. So I pulled over, unplugged IAC and it ran fine.
Drove it like that until I got home and it was pretty good. No lose in power, but some really quiet backfiring (was provoking it a little by holding first and second gear with the RPM’s steady around 3000-3500RPM.
This was a used IAC I bought off ebay (it was fancy and polished). So I’m thinking it could be defective and/or dirty. I’m going to test some more, but I need to figure out another way because starting and stopping the engine could be affecting my results (although I tend to believe, for now, that it is not).
