: Code E49 Air Injection System Fault



Cristofo
04-06-11, 09:40 PM
1990 Deville 4.5

I got the check engine light twice and both times E49 reappears. I did some tests on the air check valve and egr valve to try to eliminate things and here is what I found.

Air Check Valve (car warm and idling) - When I removed the rubber hose from the end of the check valve it was making a loud "sputtering" air sound...I put my thumb over the opening to see which direction the air was flowing and there was vaccum, in towards the front of the car into the front manifold. It wasnt a constant suction, more like pulsating suction (off/on).

EGR Valve (car warm, not running) - Pushed up on the diaphram and it seemed to take quite a bit of force to push and keep it up. It says in the manual that it will take moderate force to move the diaphram up, and Its hard for me to gauge this. I went into pepboys to see how a new egr valve felt and it was noticeably easier.

I removed the metal air pipe (by accident) that is connected to the check valve and I cannot get the check valve to unscrew...I hope i dont need to buy a new metal tube because Im sure they're hard to get. The "bung" that is in the front manifold has a piece of the thread missing so Im not even sure the tube was tightly sealed, it came out without me unscrewing it from the manifold. Could this be the issue?

Any advice? I did search endlessly on these topics and I cant really find what Im looking for.

Thanks!

drewsdeville
04-07-11, 02:06 AM
You checked the one check valve to the manifold. Sounds like it's fine. There is also another on the line that runs from the diverter valve to the cat.

On the diverter valve, pull the hose that leads to the manifold and the one in the back that leads to the cat. Leave the other two on. Start the engine cold. Which port is the diverter valve dumping air? Is there air coming from both ports or just one?

Check again when engine is warm.

That tube leaking could cause skewed O2 sensor readings, which are what the PCM uses to gauge AIR system operation.

We had a discussion on the AIR system's operation a while back. I've written up an in depth description in this thread:
http://www.cadillacforums.com/forums/ht4100-4-1-4-5-4/214316-e49-code-possible-solutions.html

Cristofo
04-07-11, 09:47 AM
Thanks Drew, I'm going to do those tests today. My main concern is to fix the metal pipe that goes to the front manifold. I hope an autoparts place has that fitting that screws into the manifold...If I cant replace it I may temporarily plug the manifold until I can order a new one. I think my last resort will be to a local junkyard.

Cristofo
04-07-11, 03:20 PM
I read that the thread is a 3/8" NPT but what size thread goes into the manifold itself? I need that adapter/coupling that connects the manifold to the air injection pipe.

Cristofo
04-08-11, 01:46 PM
I bought a 3/8" plug, plugged the manifold, removed the check valve and capped the hose.

Cristofo
04-08-11, 04:27 PM
The car runs better but after driving for 30 min the SES light came on. Code 49 again! its been raining so I didnt get to check the diverter valve operation yet. This is a pain in the ass! I'm getting ready to bring it to Cadillac and have them diagnose it.

ehall
04-08-11, 04:42 PM
There should be a whole chapter in the FSM on how it works and the reason(s) it will throw code(s).

Cristofo
04-08-11, 05:09 PM
Awesome I cant wait to get mine, wonder how long it will take me to read all those pages ha.

Cristofo
04-08-11, 06:23 PM
Ok I checked the diverter valve at warm idle and I didn't feel any air coming out the bottom nipple that routes to the cat. I've read that you can't buy a new one so my only hope is to find one in a junkyard. If I can't find one can I plug the line going to the cat without adverse effects? Or I was thinking maybe I can route the air pump directly to the cat?

ehall
04-08-11, 06:56 PM
On my 85 the plastic valve unit is actually two valves, first a bypass valve that will direct air to the intake in some limited conditions, and then the main valve that directs air to different parts of the exhaust (when the bypass valve has not been activated). There are two solenoids that control these two valves.

From there on you have to monitor individual circuits with a test light to see if the signals from the ECM are getting to the solenoids, and then see if the valves are responding. Furthermore my 85 doesn't seem to use an E49 code so I can't track it down from that side either. My suspicion is that you need to replace the solenoids and/or the valves. You might call the dealership and ask if they have any, or if a part number is available then check http://www.vpartsinc.com/ to see if they have any, otherwise it's junkyard time. Really, read the material in the FSM and take your time, it's not terribly complicated.

You might also be able to fake it with a resistor from Radio Shack in the plug, and then delete the whole valve assembly. FWIW, I had the pump seize and break the belt on a long road trip once, that was a magnificent pain in the butt. The whole purpose of the thing is to help burn off excess hydrocarbons by pumping oxygen into the hot exhaust. Literally, they could not pass the emissions standards, so they dump oxygen to burn the bad gasses. About the only thing you need to worry about is closing off the tubes so they don't let unmetered, unfiltered outside air into places you don't want it (close off the cat, close off the exhaust tubes, etc), and faking out your computer.

Cristofo
04-08-11, 08:47 PM
On my 85 the plastic valve unit is actually two valves, first a bypass valve that will direct air to the intake in some limited conditions, and then the main valve that directs air to different parts of the exhaust (when the bypass valve has not been activated). There are two solenoids that control these two valves.

From there on you have to monitor individual circuits with a test light to see if the signals from the ECM are getting to the solenoids, and then see if the valves are responding. Furthermore my 85 doesn't seem to use an E49 code so I can't track it down from that side either. My suspicion is that you need to replace the solenoids and/or the valves. You might call the dealership and ask if they have any, or if a part number is available then check http://www.vpartsinc.com/ to see if they have any, otherwise it's junkyard time. Really, read the material in the FSM and take your time, it's not terribly complicated.

You might also be able to fake it with a resistor from Radio Shack in the plug, and then delete the whole valve assembly. FWIW, I had the pump seize and break the belt on a long road trip once, that was a magnificent pain in the butt. The whole purpose of the thing is to help burn off excess hydrocarbons by pumping oxygen into the hot exhaust. Literally, they could not pass the emissions standards, so they dump oxygen to burn the bad gasses. About the only thing you need to worry about is closing off the tubes so they don't let unmetered, unfiltered outside air into places you don't want it (close off the cat, close off the exhaust tubes, etc), and faking out your computer.

I should have my FSM by mid week...it should clear up everything. In the meantime before I read your post Ive been watching and testing things based on all the info I've gathered. I monitored my results on the diverter valve and air is being forced to both the air cleaner and front exhaust manifold but not to the catalytic converter. Two test runs...first plugged front exhaust manifold, removed check valve and capped the hose coming from the diverter. Drove for about a half hr and mpgs were up around 2-3 in the city. Code and ses light came on when I was almost home. 2nd test was unplugging the hose coming from the diverter that I originally plugged so the air has a place to go. Idle and mpgs seemed to be even better. Throttle response even felt better from a standstill and no ses light yet.

Went to home depot to get the right size plug for the cat hose. That will be my 3rd test.

drewsdeville
04-09-11, 02:04 AM
Ok I checked the diverter valve at warm idle and I didn't feel any air coming out the bottom nipple that routes to the cat. I've read that you can't buy a new one so my only hope is to find one in a junkyard. If I can't find one can I plug the line going to the cat without adverse effects? Or I was thinking maybe I can route the air pump directly to the cat?

good, you just found the problem. When warm, the diverter valve should switch from the manifold to the cat. The fact that you don't have air coming from both means the diaphragms are probably in good shape. That means either the solenoids aren't working or there is no vacuum supply to pull the diaphragms.

If you want the light to go out, the only way to do it is to fix the problem. There is NO way to trick the PCM. It relies on O2 sensor data (front bank) to monitor AIR system operation. The leads to the diverter valve are only two wire: one hot, one ground for solenoid control. There is no "signal" wire to modify that monitors diverter valve operation directly, nor does the PCM monitor the ground.

ehall
04-09-11, 11:52 AM
There is NO way to trick the PCM. It relies on O2 sensor data (front bank) to monitor AIR system operation. The leads to the diverter valve are only two wire: one hot, one ground for solenoid control. There is no "signal" wire to modify that monitors diverter valve operation directly, nor does the PCM monitor the ground.
Interesting. Like I said, my 85 FSM does not list E49 and does not describe its cause or how to diagnose it (obviously). The only diagnostic it lists is to check ohms resistance on the solenoid, so my assumption was that the ECM was using the same test.

When the air pump blew up I drove around for a while with a short bypass belt, and I don't remember either of the Service lights illuminating. Presumably this means that my exhaust is not monitored either. Good news for me if so.

Sevillian273
04-09-11, 07:30 PM
You can cap everything and remove the valve if you want. You can even take it one step further by removing the air pump pulley(three 10mm bolts), and running a belt for a '91 deville which did not have an air pump or stupid diverter valve. The '91 belt will fit perfectly and pass right by the air pump as long as the pulley is out of the way. Yay for free horsep0werz!

drewsdeville
04-09-11, 07:58 PM
^^^ That is another option, if you can live with the light on. If you want the light out, you'll have to fix it. Completely up to you, chris.

Sevillian273
04-09-11, 08:48 PM
Unless of course some clown from the EPA snoops around in your engine compartment once a year.....

Cristofo
04-10-11, 10:57 AM
Great news! I had my exhaust checked because it was making a vibration/knock coming from the cat area. Cat is bad and I have an exhaust leak where the front pipe meets the cat which needs a gasket.

As of right now I have the front manifold plugged and I'm debating on what to do with the valve and air pump. Maybe I'm nuts but I need to check the operation of the diverter again because I'm getting different results when I check air flow.

I'm in PA so I'm not exactly sure what they test for on a car that's 21 years old. Thanks for the input!

Cristofo
04-10-11, 02:49 PM
Diverter Valve update* Ok maybe it was my Catalytic Converter/Exhaust leak the whole time thats been giving me all these issues. I rechecked the diverter valve and pulled all hoses, started a cold engine and here's what happened...

From start up until maybe 20 seconds the air blew to the front manifold, after that the air blew to the air cleaner...Once the car was warm the air was blowing to the converter. Never was the air coming out more than one hole at a time leading me to believe now the diverter is/was good.

I'm getting a new cat installed early this week, so I cant wait to see how she runs after that...

Cristofo
04-13-11, 08:26 PM
Got the magnaflow converter put on today and what a big difference! Car sounds really good I'll take some audio. I have the stock muffler still on. it accelerates quick and smooth with no hesitation. haven't driven it more than 6 miles yet so I would like to monitor it a little more.

Cristofo
04-15-11, 11:26 PM
Just to end this thread...after triple checking all the vaccum hoses and rubber elbows or connectors I corrected my issue. The smog pump output hose that goes up towards the bypass and diverter valve wasn't fully on, 2 suspect elbows that I replaced, new air filter(wasn't really dirty) and tapping on the egr valve with a wrench the car is running great! Still will monitor mpgs and codes (if any).

Cristofo
04-20-11, 11:00 PM
I started to get some hesitation again and today was another warm day around 82 degrees. The car was fully warm and started to hesitate and not accelerate quickly. I decided to replace the Coil, Control Module, Coolant Temp Sensor and Manifold Air Temperature Sensor.

1. The MAT sensor was totally black and gummed up, not sure if it was functioning correctly but I replaced it.
2. Removed Cap, Rotor and removed the ICM and was very scared I was going to break something. Finally got the connectors off and replaced it with a new ICM and even went out and bought thermal compound. Smeared the backing plate of the ICM and mounting surface after cleaning and screwed it back down, reinstalled the rotor.
3. Replaced the Coil, but did not replace the ground strap(which was rusted at the straight end). Cleaned the metal strap and reinstalled everything, including the wires and firing order. I was careful to replace everything as I removed it.

Well I get the intake on, connect the battery and CAR DOESNT START. The engine is rotating but no start. It got dark and I need to figure out if one of the parts I bought was bad or if I missed I step. I need to now replace the Cap because the location where the ground strap connects to 1 of the 4 coil hold-down screws stripped the plastic. Im going to buy a new coil ground strap and check for resistance according to the manual for the ICM, pickup and coil.

I did not replace the coolant temp sensor yet because I cant find my 3/4" deep socket so I have to buy a new one. Could that thermal compound cause it not to start? I used a liberal amount basically so the whole metal surface was thinly covered. Or the new Air Intake Temp Sensor? I'll retrace my steps and follow the manual again but it doesnt add up so my guess is 1 of the new parts I installed was no good.

Sevillian273
04-20-11, 11:37 PM
You did a bunch of stuff at once so it's hard to say w/o looking at the car.

-My MAT sensor looked the same way but was functioning ok. The gunk is normal and comes from the EGR system. I replaced mine with a BWD brand and got E074 constantly afterwards. I swapped it back with the old one but that's just my experience...

-I replaced my ICM with a 'Duralast' and it only lasted a year. I now have the original 20 year old unit back in there. That says alot about factory original parts. The new unit should have come with thermal compound in the box. I prefer to use 'Arctic Silver 5' instead. It's designed for computer CPU heatsinks. Not necessary, but cant hurt... The lack of a thermal compound will not cause a no-start on the first try, however it will burn out during the first run without it.

-Use a digital voltimeter to test for continuity between the ground strap and the alternator casing. Testing positive for continuity will prove that the strap is indeed grounded.

-The car will start and run with both the IAT and ECTS unplugged so that cant be it.

ehall
04-21-11, 12:19 AM
The MAT should not prevent the car from starting. It's possible but the usual effect is to make it run like crap, since the computers usually default to something like 70 Fahrenheit (I think the specs are in the fuel injection part of the FSM).

I'm betting on coil ground wire. Did you check for spark? Pull one of the wires and lay a plug against something with a good ground while somebody else cranks the motor, should see a good spark.

Cristofo
04-22-11, 11:01 AM
Hey Guys,

Yesterday I went back and reinstalled my original coil and ICM and still no start, I even tried starting fluid and still nothing. This basically tells me that Im not getting spark.

Im going to slow down and go through the basic checks again.

1. Check for spark and check all fuses
2. Check the resistance at the coil
3. Check voltage at the ICM and Resistance at the connector from the pickup coil.

I also put my original air temp sensor back in and nothing...I have a strange feeling that I left something unplugged.

I'll let you know how I make out. Thanks guys!

Cristofo
04-22-11, 01:37 PM
WOW, i cant believe i missed this...The white single battery connector that plugs into the cap was hiden underthe distributor body. I must have pushed it out of the way and totally forgot about it. This has to be the reason for no start...I checked and no spark was getting to the plugs. I need to resinstall everything and make sure I reconnect that white connector and it should be good.

Cristofo
04-22-11, 02:49 PM
Well the battery power would definitely help to power the componenets in the distributor...Thank god that nightmare is over. She's running again.

Cristofo
11-08-11, 09:54 PM
Update

So when I was up for inspection I replaced the brass plug in my manifold with the original setup. Now I decided to go back to bypassing the diverter valve. For the first time I decided to connect the air pump output directly to the cat hose that originally was connected to the diverter valve. My question is do I need to disconnect the vacuum hoses that plug into the diverter and cap those? And should I cap the air intake and remove the front hose that also routes to the airpump? I've immediatedly noticed that connecting the air pump directly to the cat improved my performance.

Sevillian I remember you did this but wasn't sure of the small details.

drewsdeville
11-08-11, 10:00 PM
If you are going to disable the system, it would be pretty senseless to keep all of the components and re-route the piping. Just rip it all out. Remove the diverter valve assembly and hoses, plug the exhaust ports, remove the air pump, install a 4.9L belt, and , from a 4.9L junkyard car, pull the supplementary brace that takes the place of the air pump on your 4.5L model.

Cristofo
11-08-11, 10:23 PM
Drew that is a great point my only concern due to my lack of knowledge would be....can I just cap the exhaust tube? Will this affect the cat heating up and helping introduce oxygen? Or would capping this tube have the same effect? Thanks I appreciatte the input.

drewsdeville
11-09-11, 08:08 AM
Yeah, you can just cap it, no problem.