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Discussion Starter · #1 ·
I've recently picked up a 1994 GT 5-Speed that i cant get the engine light to turn off. I've tried just about everything I can think of, so im seeing if you guys have any ideas. For starters, I picked up a code reader at orilley's and the codes I keep pulling during the key on engine running test are, 314 - thermactor air system/fault during engine run self-test / left side, 311 - thermactor air system fault during engine run self-test, 332 insufficient EGR flow detected.

Ok so with that said, I have sense replaced both O2's with brand new bosch units - I did this twice per side thinking I may have got a defective one so I got them swapped, but still can't get rid of the Thermactor codes. I put in a brand new EGR valve, and a brand new EGR position sensor. replaced the vacuum line running from the EGR to the tree under the air intake tube. Replaced the Idle Air Control Valve. Replaced the canister purge valve and corresponding hoses. I cleaned the MAF with MAF cleaner spray. Cleaned all my sensor connections with electronics cleaner spray. Also while I was at it did a full tune up, changed oil and filter, changed plugs with new motorcraft plugs, changed out the wires, put in a new PCV valve, installed a new fuel filter, new air filter (stock intake), and changed all the thick vacuum lines that go to the intake manifold. I also installed a new ignition coil and put in a brand new (not a remanufacture) richporter distributor from oriellys with the timing set to the stock 10 degrees.

Even after all of that, and multiple computer resets the same three codes pop up every time and my engine light still comes on after about a mile of driving.

So the final thing I have done to try and rule it out was got a short belt and bypassed the smog pump, ive left everything connected so that i dont have any leaks in the system, and it is my understanding that this is ok as theres one check valves on the pump so if its not spinning they dont open? Correct me if im wrong.

After the smog bypass, same three codes pop up. Also, the cats on both sides of the engine closest to the O2 sensors have been cut out with metal exaust pipe welded inplace so I know the lack of cats there shouldnt be choking the O2's.

Aside from the first two cats being deleted the car is bone stock. Factory mufflers and all.


What could I be missing here? With brand new O2's I still get the O2 codes, and with a brand new EGR and EGR sensor I still get the EGR code.

Car drives excelent and accelerates smooth and strong, it never bogs or chugs or anything like that when i give it gas. The only strange thing I get every now and then is at idle, which im assuming is from the engine light throwing the computer off, some days idles perfect, some days it will have a very slight studder, some days it will stall at idle, then start right back up, even when it does do this if I floor it it'll get up and go like a champ, but the idle issues are intermittant and sometimes i can go for a few days without them happening at all.

Can't pass inspection with this damn light on so trying to figure this thing out.
 

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For 332 have you checked the EVR (Egr Vacuum Regulator)? I believe its behind the fender liner by the passenger side strut. Not sure on the other two codes. Is the air pump still hooked up? If it is, check the hoses and any vac lines you find along the way.
 

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Discussion Starter · #6 ·
EVR, does that have vacuum lines running to it? Havent looked down in the fender yet for sensors, I'll have to get under the car and check.

As far as the air pump, it is hooked up and sealed, but it is bypassed with a short belt. I'm going to just remove the whole system here soon as im going to cap off the lines running to it, cap off the back of the heads where the metal tube runs to, and run a catless H pipe.
 

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Discussion Starter · #7 ·
Well, I went ahead and swapped out the EGR vacuum regulator solenoid in the inner fender, checked all the vacuum lines leading there and all were good. I reset the codes, fired it up let it run, took it for a drive, after about a mile or so, the Check Engine light came on again as usual, put my code reader on it same three codes, this thing is driving me insane, I cant think of anymore sensors or vacuum lines that I havent already replaced, there were two other solenoid looking things next to the EGR vac regulator, what are those called? Could those be causing the light?
 

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Those two solenoids look just like the one next to them, yes? Those are the TAB and TAD solenoids, also called AIRB and AIRD solenoids. They control the bypass valve and divertor valve, emissions stuff. The vac lines can look good, but the TAB/TAD solenoids themselves can go bad, as can the bypass and divertor valve. Pull the vac lines off and blow thru them to make sure they arent clogged. You can check the valves by pulling the vac lines off and sucking on the valve. If you can feel/hear the diaphragm inside move, the valve is good. If they are good, the TAB/TAD solenoids are the only parts left.
 

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Discussion Starter · #9 ·
Can I just remove those and cap off the lines? Or will that make my problem worse? Aren't AIRB and AIRD just part of the smog pump system? I want to just ditch all of the smog crap as I have the pump bypassed anyways. If I remove all of the smog pump hoses and lines and cap everything off will this cause more codes? I don't see any electrical connections to the pump itself, and I've read that a lot of people ditch the whole system without throwing any codes.
 

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Some don't get codes some do. I got codes from removing everything your talking about


Sent from AutoGuide.com App
 

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Im thinking its the diverter valve and by pass valve coming off the smog pump. Plus i think you need to have a functioning smog pump.

Sorry i skimmed the thread not sure if you replaced those valves and checked the vac lines going to them or not, i did see that you bypasses the smog pump, which might be apart of the issue
 

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Discussion Starter · #12 ·
The only snensors that I see left in the mix are the AIRB and AIRD solenoids that are in the passenger fender next to the EGR vacuum regulator. Can't really seem to find new replacements for them either. Seeing as how I'm not using the smog pump, is there a way to trick the computer into thinking those are functioning, like say with resistors wired inplace of the AIRB and AIRD solenoids electrical connectors? I'm wanting to just cap the vac lines going to those and ditch the lines going to the AIRD and AIRB valves in the smog system. I'm going to just rip the smog setup out this weekend. Does the EGR vacuum regulator next to those solenoids need those to function if the lines going to them are capped off?
 

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YOU NEED TO DO THE (KOEO) TEST FIRST. This test check all the electrical components relays and selonoid for proper working condition if any component fail it will give you a code, indentified the component and replaced, you must (pass) or clear this test first before moving on to the next test with is the (KOER) test, also in the first test you would get the memory code store in the ECM, you can clear those code by disconnecting the battery for 15 min. and them start the (KOEO) codes, very importance for the engine electrical components to be working properly first.
 

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Discussion Starter · #14 ·
I do the KOEO test first each time. That test never brings up any trouble codes, always number 11 for "system OK" and number 111 for "System Checks OK" I only get trouble codes during the KOER key on engine running test.
 

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Well I hope this help, on my 95 GT auto, I removed the smog pump system completly and i never got the CEL on, I will get the codes on the KOER test but that's ok, the computer will adjust as needed, but when i replaced the cat with a O/R X-pipes and flowmaster them the CEL came on, I retrived the memory code and got 172 which is the passenger O2 sensor lean out of range, so I check and found an exhaust leak on the EGR tube from the headers to the EGR, I'm in the process of eliminating the EGR system all together.
What I'm saying is the CEL on could be the EGR system or a leak in the exhaust, and I dont think the a Smog system fail turn the CEL on at all.

---------- Post added at 12:34 PM ---------- Previous post was at 12:21 PM ----------

311 and 314 indicate that your smog pump is disconnected.

Also Is it possible that the vacuum line hooked to the EGR valve is leaking and not pulling enough to open the valve?
 

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Discussion Starter · #16 ·
Well, I yanked out the whole smog system this past week, installed my H-Pipe, and got some magnaflows welded up. The exhaust has made a difference feels like the engine can breathe better. I've gotten rid of code 332 finally, I'm guessing the EGR is now functioning correctly. The only thing I did with the vacuum lines that I could see turing 332 off was I took the white and tan vacuum lines and took them off of the two valves from the smog and looped them together with a piece of vacuum hose. Now all of the vacuum lines are sealed up together, and I'm guessing that that is what got rid of the 332 code now the EGR has enough vacuum. I get no codes during KOEO, and During the KOER test I still pull 311 and 314, which I'm guessing is from the AIRB and AIRD sensors. But since the 332 code is now off the check engine light no longer illuminates. I've driven it about 100 miles since the changes and havent had the light come on. Does this mean that 311 and 314 are just minor codes that show up during the KOER test only but are not important enough to effect the computer to turn on the check engine light? If so I can live with that until I can afford a chip to get the AIRB and AIRD sensors turned off in a tune, now knowing that everything else is functioning correctly.
 

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Does this mean that 311 and 314 are just minor codes that show up during the KOER test only but are not important enough to effect the computer to turn on the check engine light?
311 and 314 indicate that your smog pump is disconnected or did not pass the test and It will not turn on your CEL, when the computer detects no smog system it will used another fuel map and your car will run normal.
 

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I've recently picked up a 1994 GT 5-Speed that i cant get the engine light to turn off. I've tried just about everything I can think of, so im seeing if you guys have any ideas. For starters, I picked up a code reader at orilley's and the codes I keep pulling during the key on engine running test are, 314 - thermactor air system/fault during engine run self-test / left side, 311 - thermactor air system fault during engine run self-test, 332 insufficient EGR flow detected.

Ok so with that said, I have sense replaced both O2's with brand new bosch units - I did this twice per side thinking I may have got a defective one so I got them swapped, but still can't get rid of the Thermactor codes. I put in a brand new EGR valve, and a brand new EGR position sensor. replaced the vacuum line running from the EGR to the tree under the air intake tube. Replaced the Idle Air Control Valve. Replaced the canister purge valve and corresponding hoses. I cleaned the MAF with MAF cleaner spray. Cleaned all my sensor connections with electronics cleaner spray. Also while I was at it did a full tune up, changed oil and filter, changed plugs with new motorcraft plugs, changed out the wires, put in a new PCV valve, installed a new fuel filter, new air filter (stock intake), and changed all the thick vacuum lines that go to the intake manifold. I also installed a new ignition coil and put in a brand new (not a remanufacture) richporter distributor from oriellys with the timing set to the stock 10 degrees.

Even after all of that, and multiple computer resets the same three codes pop up every time and my engine light still comes on after about a mile of driving.

So the final thing I have done to try and rule it out was got a short belt and bypassed the smog pump, ive left everything connected so that i dont have any leaks in the system, and it is my understanding that this is ok as theres one check valves on the pump so if its not spinning they dont open? Correct me if im wrong.

After the smog bypass, same three codes pop up. Also, the cats on both sides of the engine closest to the O2 sensors have been cut out with metal exaust pipe welded inplace so I know the lack of cats there shouldnt be choking the O2's.

Aside from the first two cats being deleted the car is bone stock. Factory mufflers and all.


What could I be missing here? With brand new O2's I still get the O2 codes, and with a brand new EGR and EGR sensor I still get the EGR code.

Car drives excelent and accelerates smooth and strong, it never bogs or chugs or anything like that when i give it gas. The only strange thing I get every now and then is at idle, which im assuming is from the engine light throwing the computer off, some days idles perfect, some days it will have a very slight studder, some days it will stall at idle, then start right back up, even when it does do this if I floor it it'll get up and go like a champ, but the idle issues are intermittant and sometimes i can go for a few days without them happening at all.

Can't pass inspection with this damn light on so trying to figure this thing out.
This is happening to me and was wondering if there’s a fix for it? Or any way I can delete it or something
 
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