Author Topic: Banging sound from Air Box and Difficulty warming up (Read 10585 times)

Coochas · « **on:** December 30, 2014, 22:17:22 »

Hi All,
My new water pump is installed and everything seems great in that department thanks to the forum.

The car starts just fine but until it is warm it just bogs down when you give it any gas. I read about the WRD and using a stethoscope I was able to confirm that the WRD does indeed continue to draw air even once the car is warmed up (although less air). I will get to this in time.

This car hasn't been run in years. When I first got it it was running VERY roughly so I emptied the gas tank and put fresh fuel in which seemed to smooth out the idle. I didn't try revving the motor at that time because I need to address the water leak.

I put a new air filter in at the time of the water pump/radiator work. When I rev the engine now I am hearing a very loud single bang. At first I thought it was detonation but it seems to be coming from the air box. I loosened the cover and this seems to be the case.

Does anyone know what this sound could be?

ja17 · « **Reply #1 on:** December 31, 2014, 05:05:21 »

A "coughing" or even a "popping/banging" sound back through the intake is most often caused by a lean running condition. Make sure the rack is not stuck in the injection pump. Next, make sure that the WRD (warm-up-device) is working. Make sure that the main fuel filter is not clogged. Do the linkage tour to make sure the engine linkages are correct. If problem persists, measure fuel pressure and volume. If the results are poor, check the screen in the electric fuel pump and the screen in the fuel tank.

Ask more questions if any of this does not make sense or you need more details.

gorgoo · « **Reply #2 on:** December 31, 2014, 10:25:59 »

Hello,
Would be worth checking camshaft timing as well. A worn out chain and clogged tensioner may have caused the chain to jump a tooth or two.
Didier.

Coochas · « **Reply #3 on:** January 01, 2015, 01:58:59 »

Thanks guys. I'll report my progress as I make more time to work on the car.

Coochas · « **Reply #4 on:** January 01, 2015, 18:27:42 »

I removed the air filter box from the equation and the banging sound definitely comes back through the intake as soon as the baffle is opened in the intake. The car is up on stands so I can only warm it up by gently revving it over time. The pops become fewer in number as the car gets warmer and warmer but never goes away. As mentioned above I listened with a stethoscope over what I believe is the WRD air filter and I can hear a lot of air when the engine is cold and still some air flowing once the engine is warmed up. I'll need to read about the refurb for the WRD in the tech manual.

I looked for my IP rack as suggested. The first photo shown below is what I am guessing is the IP cap. Mine has a black plastic knob on it which is easy to turn back and forth. Do I need to pry this off or is this turning the IP pistons? I saw another pic on this site with a 10 mm head/cap.

The 2nd photo is the WRD, am I correct?

Thanks and please excuse all the rookie questions.

ja17 · « **Reply #5 on:** January 03, 2015, 07:23:46 »

Yes the black plastic cap pries off. It gets old and brittle with age. It may fall apart.

Coochas · « **Reply #6 on:** January 05, 2015, 19:56:46 »

More QUESTIONS!

I removed the black plastic cap on the IP as shown in the pic below. Is this still some sort of cover for the rack? I can't figure out how it comes off if it's another cover. If it is the end of the rack it is immobile.

On my WRD, I have successfully removed the thermostat and plunger. The spring on the plunger is firm and can be compressed. The head of the pin inside the plunger spring is about 3-4 mm inside and does not move. Is this normal or should the pin move freely within the spring area?

??

There was no apparent gasket between the coolant tower and the base of the WRD. Should I put some type of sealant there when I eventually close it up?

TIA

ja17 · « **Reply #7 on:** January 06, 2015, 03:27:42 »

The cylindrical part is just a fitting. The rack is in the hole in this fitting. You can stick a rod or screw in the hole and should be able to push the end or the rack back a bit. You should feel a bit of spring tension. Also the rack will move forward about 1/4" if you manually move the engine linkage to full throttle (engine not running).

The piston in the lower part of the WRD should move if you push on it. The rack in the IP will also move when the piston is pushed. The upper part of the WRD is a thermostat-type device which moves depending on engine coolant temperature. It is called the "heat feeler". Below the heat feeler is a piston which should move. The heat feeler moves the piston which in turn opens or closes a passage for additional air for cold idle. The piston also pushes down on some internal linkages of the IP to move the IP rack, which leans or richens fuel mixture depending on engine coolant temperature via the heat feeler.

Yes, there is no seal or gasket at those connections on the WRD. Make sure the mating surfaces are clean from dirt or corrosion. You can use a little grease to help the metal parts slide together nicely. They should not leak if done carefully.

Coochas · « **Reply #8 on:** January 07, 2015, 00:12:10 »

I sprayed down the plunger with PB and it now compresses. It needs a decent amount of force to compress. Is this normal?

ja17 · « **Reply #9 on:** January 07, 2015, 00:17:35 »

Yes, some force is required, since it is sprung from below. If it returns on its own you should be OK.

Coochas · « **Reply #10 on:** January 09, 2015, 18:40:06 »

I've now reassembled the WRD with a new air filter and sealing ring. At the same time I also changed the fuel filter and put some injection cleaner in the gas tank.
I also used my boroscope to look at the IP rack. It seems to move back and forth with no problem (see video below).

When I first started the car I was very excited because the banging/popping sound seemed to disappear. The bad news is that the car started idling rougher and rougher with some blue smoke coming from the exhaust. It will not hold an idle at this point. I pumped out the gas tank thinking maybe I messed things up with the injector cleaner and put fresh gas in which didn't change things.

I'm scratching my head again!

Any thoughts?

https://www.youtube.com/watch?v=6lnjs_MY6tI&feature=youtu.be

Coochas · « **Reply #11 on:** January 09, 2015, 20:11:42 »

Ugh, now it won't start at all !!!!!
Could I have somehow messed up the fuel supply by changing the fuel filter? I used a MB filter.

ja17 · « **Reply #12 on:** January 09, 2015, 21:16:33 »

Probably ready for a fresh set of spark plugs.

ctaylor738 · « **Reply #13 on:** January 09, 2015, 23:08:32 »

Second the spark plug idea.

But also, it can take a while for the filter canister to fill up. Did you run the pump for a while before starting? You can run the pump and loosen the fitting on the line that runs to the cold start valve to make sure you are getting fuel.

Did you knock a wire off the coil? Sorry I had to ask.

Coochas · « **Reply #14 on:** January 09, 2015, 23:29:39 »

Quote from: ctaylor738 on January 09, 2015, 23:08:32

Second the spark plug idea.

But also, it can take a while for the filter canister to fill up. Did you run the pump for a while before starting? You can run the pump and loosen the fitting on the line that runs to the cold start valve to make sure you are getting fuel.

Did you knock a wire off the coil? Sorry I had to ask.

I did let the pump run for a while. I'll swap the plugs tomorrow and let you know. I checked all the wires to the plugs and distributor cap. Two of them are a little loose but they've been like that since I got the car.
I feel like I'm missing something. The WRD went back together fine and didn't leak. It definitely got hot and didn't leak any coolant.

It's weird that the car started initially and then died. As it started running rougher and rougher, I noticed that I had to give it full throttle just to try to keep it running.

I'll change the plugs first thing tomorrow.

ctaylor738 · « **Reply #15 on:** January 10, 2015, 16:35:58 »

There are three places where the fuel system can clog up. The passages in the tank, the strainer in the tank, and the little filter in the inlet side of the fuel pump. I suspect that as you ran the fuel pump, rust and debris has come loose and clogged one or all of these. This is typical when a car sits for a long time. Like I said earlier, you can quickly check for fuel flow by loosening the fitting where the CSV line connects, run the pump, and see if you are getting any fuel.

Coochas · « **Reply #16 on:** January 10, 2015, 17:54:27 »

Hmmmm.

I changed the plugs and the car started up. As the car got warmer the idle got rougher and rougher. At idle, there is dark smoke coming out of the exhaust which can turn my hand black in about 30 seconds. When you rev the car up the emission is cleaner.

I noticed that plugs 1,2 and 3 had some oil around them in particular number 1. They were all the same dark color at the tip.

Is there something 'bad' going on in the motor?

ctaylor738 · « **Reply #17 on:** January 11, 2015, 19:06:50 »

Well, glad to hear that my suspicions were wrong and you don't have a clogged fuel system.

You are obviously getting way too much fuel at idle when the engine is warm. You could have a) leaky cold start valve, b) the WRD may still be enriching, c) your pump lever may be off the stops, or d) your idle mixture is too rich

a) with a warm engine, remove the CSV, reconnect it, stick it in a container, and run the fuel pump. No fuel should drip.

b) with a warm running engine, take the air filter off the WRD and see if you can feel suction

c) with the throttle at idle, be sure that both that the linkage levers at the throttle body and at the pump are on their stops; adjust as necessary if they are not.

d) sometimes people try to adjust the idle mixture while the engine is running and the adjustment gets jammed in the full rich position. See if you can move the little knob on the back of the pump a few clicks counter-clockwise (lefty leany) and see if things improve.

Coochas · « **Reply #18 on:** January 11, 2015, 21:10:01 »

SUCCESS !!!!!! I'm psyched.

Chuck, I started thinking the same thing about the WRD. I figured since the initial banging sound was caused by the WRD giving a lean mixture that perhaps the WRD was stuck giving a rich mixture. The car got to the point where it was nearly impossible to start and when it did it was blowing out blue rich smoke.

I wondered if I had done something wrong when I put the WRD back together. I felt like the plunger/air valve was sitting higher than where I initially found it and I confirmed this by looking back at some pics I had taken during disassembly (I'm so glad I take pics of everything).

Here's what I did wrong. The bottom of the plunger in the WRD was not seated in the small hole at the bottom of base. When I put the plunger bottom end in the 'correct place' I noticed that the air valve was about 2 mm lower. I bolted everything back together and the damn car wouldn't start! I was despondent.

Then I remembered two of you guys saying "time for new plugs." I examined the fresh plugs I had just put in and they were trashed. I put in new plugs and she started right up BEAUTIFULLY! Although I don't have a hood on the car and my inspection sticker is 6 years out of date, I decided it was time for a test drive (including a stop for gas!).

I only drove 16 miles because I wanted to come back to make sure everything was nice and tight. The car drove beautifully.

THANK YOU all for helping get my baby back on the right path. Very excited here!!!!!!!!!!!!!

ctaylor738 · « **Reply #19 on:** January 11, 2015, 23:41:18 »

Way to hang in there! Maybe we'll see you at the Mid-Atlantic Pagoda Group's Spring Meet.

CT

Coochas · « **Reply #20 on:** January 12, 2015, 00:36:47 »

Quote from: ctaylor738 on January 11, 2015, 23:41:18

Way to hang in there! Maybe we'll see you at the Mid-Atlantic Pagoda Group's Spring Meet.

CT

Thanks Chuck!
I'd love to meet some other Pagodas. I'll be on the lookout for events after the thaw.

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Author Topic: Banging sound from Air Box and Difficulty warming up (Read 10585 times)