DIY: EGR and Intake Manifold Cleaning - Acura Forum : Acura Forums
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post #1 of 49 (permalink) Old 05-09-06, 12:06 AM Thread Starter
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DIY: EGR and Intake Manifold Cleaning

I did this on my 96 RL and am including how to remove and clean the intake manifold. The dealer wanted $400 to do this job and I am no longer under warranty to get it done. I despise the dealers and this is by far the biggest undertaking I've ever done. I didn't have to buy any parts per say, just the gaskets to rebuild the manifold. This is one of those seldom maintenance things but I thought I would post it to share.

This job is quite difficult. It involves disconnecting and removing the fuel injectors, throttle body, water passage, vacuum solenoids, and the manifold itself. There about 50 little vacuum pipe connections that have to be removed and it can be easy to mix them up.

So here’s how this whole thing started:

I received a P0401 code from the ECU. This is the same as 8 short blinks from the MIL. The code is for insufficient EGR flow. This can be from either a clogged EGR pipe or a faulty EGR valve. I took the chance that the valve was fine (That costs another $150) and that the pipe was just clogged. I could have done a cheap job and just cleaned the pipe, but I saw some other pics and that the intake manifold chamber gets just as bad as the pipe. I decided to go all out and take the entire thing apart and do a good job. It took me, a novice, one day to just take the manifold apart and another day to clean put everything back together. Here goes:

Items required:
Good mechanics tool set
Metric sockets and wrenches
Lots and Lots of WD-40 (This stuff is amazing)
Torque Wrench
Lots of clean shop rags
Plastic bags
Tape (It helps to label the vacuum pipes with tape so you know were they go)

Parts and Materials:
Carb Cleaner
“Permatex” Instant Gasket
Gaskets (I went to to buy all the required gaskets)

A couple of tricks I learned from other people. First after each step, place bolts and nuts in a labeled bag. Second, use the tape to label all hoses, especially the little vacuum ones. There are so many and they all look alike. And last if you don’t know what goes through the tube your disconnecting, place a rag under it. Air tubes and coolant tubes look a lot alike and you don’t want to have engine coolant all over the place. Not good times.

1. To help yourself out and your back, move the hood to its vertical position. Remove the 2 screws on both struts and reinsert one into the lower hole. You don’t need to tighten these, just make sure they’re in good.

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2. Make sure you know your radio code. Disconnect the ground wire from the battery.

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3. Next, we remove the strut brace. That’s the black tube going from the left to right side. There are 2 bolts and 4 nuts to remove. Toss that thing and the bolts aside cuz you got a long way to go before that goes back on.

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4. Remove the engine cover. There are 4 bolts holding the top on. The manual says there are 2 more on the front side…but I didn’t have any. The dealer probably jacked them and that was that. O well, 2 less to get lost. You can also toss that aside for the same reasons as above.

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Part 1: The fuel Injectors

5. We have to relieve the fuel pressure before we can play with the fuel injectors. Start by removing the fuel fill cap. Leave that off for the duration of the project. Next, place a wrench on the banjo bolt at the base of the stem. Use another wrench to hold on the service bolt. Place a shop rag under/around the filter as fuel WILL shoot all over the place. Turn the top wrench at least one turn. If you like me, you’ll lose count at to where 1 turn is. Don’t worry, just turn until the fuel plays Old Faithful for half a second and you’ll be all set.

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Last edited by petthepeep; 05-09-06 at 12:22 AM.
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post #2 of 49 Old 05-09-06, 12:09 AM Thread Starter
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6. Disconnect the 6 connectors from the wire harness to the fuel injectors. This is perhaps the easiest step in this whole operation.

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7. Disconnect the PCV valve from the cylinder head cover. No wait, this is the easiest step.

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8. Disconnect the vacuum pipe and fuel return line from the fuel pressure regulator. This is located in the rear of the right fuel injector. The fuel return pipe is pretty easy to get to. However, the vacuum pipe isn’t. There isn’t a lot of slack to move around and it’s a tight squeeze for your fingers. Have fun.

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9. Disconnect the fuel supply hose from the fuel filter. Once again, fuel will spray all over. Cover the area with rags to absorb as much as possible. You will have to use 2 wrenches again. The bottom one goes on a bolt under the mounting bracket. The other goes on the banjo bolt. Loosen until all the way off, remove the hose, wrap the hose in rags, and reinstall the banjo bolt, this way you won’t loose it and you’ll know where it goes.

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10. Disconnect vacuum pipes. There are like 40 of them. Or just 7. The first 3 are located coming out of the top of the manifold. The other 4 face the firewall. Label these 4 with their corresponding pipes.

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post #3 of 49 Old 05-09-06, 12:11 AM Thread Starter
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11. Remove the retainer nuts from the fuel rails. There are 4 retainer nuts, along with some bolts that hold the vacuum pipes in place. Remover all the nuts off the fuel rails for ease. There is also a bolt holding the MAP (Manifold Absolute Pressure) sensor on board. Take ‘er off and you’ll be a happy camper.

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12. Disconnect the connector from the MAP sensor.

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13. Now its time to remove the fuel rails. This will be both trying and fun. The right fuel rail comes off without a hitch, just apply evenly distributed pressure upward on the rail and it will pop right off. The left hand side can be a little trickier. The metal vacuum hoses have to be moved around quite a bit. Also, the large AC tube that I’m sure you’ve noticed by now and wondered, “When the f*** are we taking that thing outa here?”…..well we’re not. At least I’m not; you’ll just have to work around it. She stays for the whole ride. Work the vacuum hoses around, move the plastic wire harness out of your way and try to maneuver. Give it time.

Place the fuel rails upside down off to the side. I recommend not taking the injectors off the rails. There are 2 o-rings per injector that would need to be replaced and the injectors themselves cost about $100 a piece. So be very careful.

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Part 2: The air intake

14. Next is to remove the entire air/throttle assembly. Star by unhooking the 4 clips that hold the air filter box. Remove the 2 pipes and the vacuum tube and loosen the clap screw. Remove the entire assembly and toss it aside. Also, there is a thick pipe which comes out of the air pipe and goes direct to the throttle body. Take out the support screw on the valve cover, disconnect the other end of the pipe on the throttle body and throw that pipe aside.

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15. To remove the TCS Sensor/Actuator assembly, remove the 2 support brackets on the top and bottom of the assembly. Disconnect the connector on the top which is the valve sensor, and on the bottom which is the actuator itself. Loosen the clamp screw and take the assembly off.

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post #4 of 49 Old 05-09-06, 12:13 AM Thread Starter
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16. Next is to remove a lot of hoses and pipes from the throttle body. Take the upper water hose off from both ends. Be careful with the radiator side b/c it’s a plastic fitting and breaking that would mean new radiator time. The red arrows are the coolant filled hoses. Use a rag when disconnecting these; they will be probably full of coolant. The blue arrows are electric connectors. There is a plastic fitting on one hose for a wire. Use a flathead to disconnect the fitting. The green arrows are the vacuum tubes and the aqua arrow is an air tube. Disconnect all hoses, connectors and pipes from the throttle assembly.

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Part 3: Manifold Rear

17. Now we are going to move to the rear of the engine and really break our backs. This is why we raised the hood to its vertical position. First off, we have to remove the vacuum solenoid assembly. This is a bracket of 3 cylindrical tubes with a bunch of vacuum hoses sticking out of the sides. First, disconnect the 2 electrical connectors mounted on the bracket. Next, disconnect AND LABEL all vacuum hoses. 2 go to the intake air bypass diaphrams located on the back of the manifold, 3 go to the ones that we disconnected back when the injectors where removed, 1 goes to the control box, and 2 on the right side go somewhere not that important. Anyway, make sure these all get labeled b/c its impossible to remember where they all go. Last, remove the 2 bolts holding the bracket in place. Remove the bracket and all the attached vacuum tubes.

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18. Now that the solenoids are removed, disconnect the wire harness. There are 2 bolts holding it to the manifold. Now the harness should be pretty free to move around, now you can take the last 2 bolts off to remove the mounting bracket which held the harness and solenoid valves. Also, remove the brake booster vacuum hose that connects to the back of the manifold.

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19. Now we can remove the EGR valve. There are 2 nuts holding the valve on the exhaust manifold, a vacuum pipe and the electric connector. Take that off and clean out the inside really good. Also, scrape off any of the old gasket remnants and clean the both surfaces real nice.

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20. The EGR pipe should be pretty clear now. We can remove the 2 bolts on the exhaust side, and the 2 nuts on the intake side to remove the pipe. It will be pretty gunked up inside, but that’s only the beginning!

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post #5 of 49 Old 05-09-06, 12:15 AM Thread Starter
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Part 4: Manifold Removal

21. Now for the fun part. Remove the 4 bolts and 4 nuts from the intake manifold. Also remove the 4 bolts on the water passage. The water passage combined with the manifold and the throttle body all look a lot alike. The way its designed is that the water passage lies in a small cutout in the manifold assembly. Although we have no business with the passage it has to get removed in order to remove the manifold.

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The left and right side of the water passage lie in front of the manifold. Take the 4 bolts out to free everything up. Once the throttle body is disconnected, the water passage will fall free. I will go into more detail when it comes time to put everything back together. The manifold assembly should be loose by now.

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22. Check for and disconnect any other hoses or pipes that I may have not mentioned. Lift the manifold assembly out of its place. Its tough to work around the plastic fuel injector things…just work around them. I chose to leave the throttle cable and cruise control cable connected to the throttle body. I didn’t want to mess around with them. This limits the maneuverability of the manifold assembly. Once its out of its place turn it upside down and remove the 4 bolts in the front. This should disconnect the throttle body and free up the manifold. Toss the water passage and body aside, its time to play with the manifold. Put some paper towels in the intake passages on the engine block to prevent debris from getting in the cylinder. Btw, your going to get coolant all over the engine block…is inevitable. Just blot it up later.

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23. Turn the manifold assembly upside down and remove the 5 bolts and 2 nuts.

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post #6 of 49 Old 05-09-06, 12:17 AM Thread Starter
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24. Once everything is out, it should come apart. Here are some before and after photos of my problems. I used a paint scraper and Brillo to remove the old gaskets. Carb cleaner and more Brillo helped get the nasty brown s*** out and restore the original aluminum.

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post #7 of 49 Old 05-09-06, 12:20 AM Thread Starter
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Ok, time to start puttin everything back together. Do a good job on the cleaning. Make sure ALL the old gaskets are scraped off, you don't want to find you have a leak once everything is back together. As you put the different pieces back together, you also might want to "detail" them up as well. Your engine probably won't be apart like this for a while, so if your up for it, do a nice job detailing the various pieces.

As you put the pieces back together, all the gaskets need to be replaced. Spray each new gasket with the instant gasket. This will provide a stronger seal as well as holding the gasket in place while you get the bolts in.

For the most part, everything is done in reverse order. I just want to provide a little advice, some torque specs, and pics to help along the way.

***Torque Specs: All the 10mm Bolts and nuts get torqued to 8.7 lbft/12 Nm. All 12 mm bolts get torqued to 16 lbft/22 Nm***

24. Start by putting the EGR plate on the intake manifold chamber. The 3 bolts get torqued to 8.7 lbft or 12 Nm

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25. Assemble the manifold upside down. The 5 bolts and 2 nuts get torqued to 16 lbft or 22 Nm. Torque the bolts and nuts as you would a drum (i.e. cross pattern; if you were looking at a clock, that would be 1,7,2,8,3,9...)

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26. Call a friend for the next step. Holding the manifold on its side over the engine, place the water passage in between the manifold and the throttle body. The throttle body attaches directly to the manifold with 3 bolts (torque to 16 lbft/22 Nm) while the water passage is held in between the two. Remember to watch out for the throttle and cruise control cables.

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27. Spray the intake gaskets and set them into place. Place the manifold assembly over and bolt down the manifold and water passage. The 4 bolts on the water passage get 8.7 lbft/12 Nm of love and the manifold nuts and bolts get 16 lbft/22 Nm. Once again, do the drum style tightening to the manifold head.

28. Once the manifold is set and in place, venture into the back and reattach the EGR Pipe, EGR valve, mounting bracket, wire harness, vacuum solenoids. This is where the labeling helps out. Reconnect all the various vacuum pipes to there proper locations.

29. Move back to the front and reattach the TCS valve, and air cleaner. There are once again a lot of pipes so reference the photos from steps 14-16.

30. Time to reinstall the fuel injectors. Remove all the old insulators and seal rings from the bottom of the injectors. Insert the new insulators in the manifold. Coat the new seal rings with oil and stick them into the manifold. Place one side of the fuel rail into place. Make sure you here a little popping sound to knwo its in there good. Next, applying constant pressure to the rails, put the retainer nuts on both bolts. Do the same for the other side
***If you don't use the nuts to hold the fuel rail in place, it will pop out and it won't seat properly. I made this mistake. Do one side at a time.** Reconnect all the vacuum hoses, connectors ect ect.

**Important: The service bolt on top of the fuel filter gets torqed to 16 lbft/22 Nm. If it is not torqed properly, it WILL leak fuel***

31. Once everything is back together, turn the ignition to ON(II) not start the car. You will here the fuel pump come on and build up pressure in the lines. Check extensivly for leaks with the injectors, fuel lines ect.

32. Give the car a start. It will sound and idle wierd for a while. It has to burn off all that wd-40 and carb cleaner you hopefully sprayed EVERYWHERE, along with the loss of all that coolant that is all over the floor. Give it time.

I hope this was helpful to any and all who are having the same symptoms. It took me 2 days to do this. Take your time, label and torque everything properly and it will be well worth it. This is my first DIY, so please give some feedback. If I left anything important out please let me know.
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post #8 of 49 Old 05-09-06, 10:17 AM
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Very nice write-up! One addition... if you pull the fuel pump fuse and start the car for a few minutes, you can avoid the "old faithful" effect when you disconnect the fuel lines.
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post #9 of 49 Old 05-09-06, 06:33 PM
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Awesome! good work! Stickied!

I'm still alive on the internet!
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post #10 of 49 Old 05-19-06, 02:37 PM
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This is really useful! Thanks for all the great photos. You really did a great job
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post #11 of 49 Old 07-31-06, 12:51 PM
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Awsome and helpfull writeup. It is great help to all do it yoursefers!!
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post #12 of 49 Old 08-06-06, 02:49 PM
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check engine light

does anyone know where is the engine switch in acura RL 1998.
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post #13 of 49 Old 08-31-06, 12:29 AM
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grreat write up!!!!!! by doing this do u think we might get more mpgs????
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post #14 of 49 Old 09-07-06, 01:06 AM
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yeah, does someone mind explaining what EGR & Manifold cleaning does and when it is recommended to be done? Clueless over here...
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post #15 of 49 Old 09-11-06, 12:26 PM
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I made ittoo!!!! In the preventive purposes. The result, is better than I expected!!!!! I recommend....
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