jgibbs22

also, i did try the vacuum while running, and I get no vacuum. its either ecu or wiring, so I am going to order a ecu off off ebay right now, but in the mean time, we still need to fix this exhaust passage.

HAILERS

You drove the car and watched the meter? And when in fifth gear at say 60 mph the voltage didn't drop down?

I don't see how the ECU got clobbered. How about when you put a meter on pin 2N with the key to ON? Get 12vdc at the meter? Should.

Then leave the meter lead in the back of the wire at pin 2N and go for a ride and watch the 12vdc. Go down when in fifth gear at 60 or so?

N338???????????? 88 convertible ECU.

HAILERS

Another thing I thought about is .........what if the solenoid is configured wrong? The solenoid should look like the one in the FSM pages. What I mean, is the filter can be pulled off and put on either nipple on the solenoid. What if the solenoid you have is configured wrong? The *vacuum* would be going to the filter instead of being routed to the EGR.

And example would be to look at the Relief solenoid(Blue) and the Switching solenoid (grey)and comparing how the filter is arranged on them. The relief only passes vacuum thru it to the acv if energized. The Switching solenoid is just the opposite. It passes vacuum when de-engergized.

The EGR solenoid should be configured like the Relief solenoid is what I'm getting at. Who knows what the previous owner did?

scrip7

iTrader: (6)

The FSM is a bit vague when describing how the engine should react when you apply vacuum at idle. It says it should either "run rough or stall". In my experience with piston engines, most of them run like absolute **** with vacuum applied, and probably 70% of them actually stall. In reality, if a rotary doesn't stall, it should at the very least run noticeably rougher, not slightly rougher.

I have a few extra TII rotor housings and irons lying around so I studied the exhaust gas flow to try to steer you in a direction of finding restrictions/ blockage.

The flow starts at the exhaust ports in the rear rotor housing, exiting there and going into the rear iron, then up into the LIM to the egr valve, then exits the valve and into a small passage that feeds the primary intake runners only. Carbon can collect in any of these passages, but I'd wager a bet that most of the buildup would be in the passage from the egr valve to the runners. They are smaller and also exposed to fuel vapors. When you remove the egr valve, you will see the small hole leading to the primary port runners. A coat hanger should fit in there but you might not have room to clean it out without removing the LIM. Removing it would be time-consuming, but might be the best way, I think it's better to remove the carbon on a bench rather than on the engine anyways, I'm not crazy about getting dislodged carbon into the combustion chambers.

scrip7

iTrader: (6)

As for the solenoid, we check it in a similar way as vacuum. When you apply 12v from a pair of jumper wires and connect them to the solenoid, you want to hear the solenoid click, and you want to be able to blow into the side port and air pass thru the top port. With no power applied, you want flow into the side port and out the filter at the bottom. To check power to the solenoid while driving, use a test light connected across both terminals of the harness connector, or use a spare bulb with wires soldered to it if you don't have a test light. You should see the light on during normal accel, and off any other time.

pfsantos

iTrader: (1)

I've been catching up with the posts...you were just recently doubting vacuum going to the EGR valve, or the signal to the solenoid. From this last post, it seems you are now certain vacuum is getting to the EGR.

If you get vacuum to the EGR, the following should be confirmed now - if not double check:

Can you confirm the solenoid is getting vacuum from the vacuum source? Is it receiving power and ground (use a multimeter on DC 12V range and switch leads if it doesn't read neg. volts) to the plug on the harness side when it should operate? Did you check the passage in the solenoid opens with power by blowing through it? Also, is the vacuum passage clear from the solenoid to the EGR?

If all this is confirmed 100% and everything hooked up properly in the system is working, I'm afraid you'll have to check the passages from the exhaust manifold to the EGR valve and from the EGR valve to the intake manifold in the center housing. Also make sure (as mentioned before - I think in this thread) the exhaust gasket was put on right, with the hole for the EGR lined up with the hole in the housing. It's symmetrical, so it's easy to have wrong if someone is careless.

Oh, check the gasket first...it's less work and more likely!

HAILERS

About the electrical part of the non working EGR: Here's what I did this morining. I put a meter on the 2n of the ECU and put the meter on the dash and went for a ride.

Anytime I'm in fifth gear the votlage drops from 14.1 down to 1.89 vdc unless I'm letting off the throttle. At steady speed the voltage drops in fifth.

In any other gear it's rare I see the voltage drop. The most often is in fourth gear and rare even there. But fifth gear, always there at a steady speed cruising.

I've a suggestion. Go to the ECU and determine if your fifth gear (over the top switch) is working or not. It seems to be a key player. Pin 1I (one eye). I know the manual said nothing about this. I guess I could prove it by extracting that pin and going for a ride again, but...............

I'd check that before buying another ECU right now. Ah heck, I'm not doing anything right now. I'll go extract that pin and see what happens.

HAILERS

Back: Well that fifth gear switch was bogus. Extracted pn 2I and the results are the same. Little to no action out of the EGR unless in fifth gear at a steady speed. I reckon it's the vacuum in fifth to the pressure sensor that is a large player plus TPS. About the only thing of value I have is that virtually anytime in fifth and at a steady speed the EGR is working i.e. voltage pulls down to below 2vdc meaning the solenoid part is working. I drove several miles in fifth and it was always ON and working.

No wonder they got rid of it on series five.

jgibbs22

You guys have been awesome in responses! Let me see if I can clarify a little more what has been asked and where we are now.

Scrip and I beleive one othe rposter asked about verifying the solenoid is operational and operating correctly. I will stand by with a yes on this one. There is over 20" of vacuum at idle to the egr solenoid valve. When I put 12 volts to the switch it opens up and lets through the vacuu,m to the output port. This was verified with a vacuum gage.

Hailer, do you by chance have part of the engine assembly out and could post some pics of the egr connection point showing where I should shove a wire through? From the fact that the car does change very little when I put a vacuum to the egr directly (which it holds just fine and does open up, this I have also verified) I will have to pull the manifold off and take a look.

Hailers, any idea why the egr would only work when it is in 5th gear? That concerns me for two reasons. 1) I do not understand why it would not oeprate under accelerating conditions, and 2) They do not do the driving functional test in 5th gear, they just go around the block. I can not find any literature stating the egr only works in 5th gear.

As I start to dissassemble this thing I will include all the pictures I can to help describe this problem. I really want to get this car completed so I can get ready to by my third generation rx. Trying to get one of them all :-)

Now, to remove the manifold to look at the gasket, can I leave the exhaust pipes and cats attached? They were an absolute bitch last time for me to get back on so I was hoping not to deal with that again, but if I must, I must....

Keep the good info coming (and special thanks hailers!)

HAILERS

At the engine I just find the yellow connector of the EGR. Then I put the neg lead on a known ground and the other lead in the back of the yellow plugs blue/white wire with the connector still on the solenoid. It will read 12vdc like that. When the thing operates i.e. a ground from the ECU, the voltage will drop below 2vdc.

Unfortunatly this does not work because it only puts a gnd on that wire when driving. So I go to the ECU. Put the meters neg terminal on one of the studs that hold the ECU bracket on the firewall. Then I have a piece of wire that I stick up the back of the wire that is in pin 2n and attach the meter pos lead to that piece of wire. Wire is insulated so it does not short out. Then I set the meter on the dash where the idiot lights are and drive the car. In fifth gear at steady speed, the voltage will drop to less than two volts dc. Prior to fifth it reads about 14vdc.


Sorry about the scribbling. The EGR WILL engage in other gears but it's so rare I see that. In forth gear around three grand or so I sometimes see it under light acceleration.

I figure that in fifth gear cruising the vacuum at the pressure sensor is right and the tps voltage output is right and the moon is in the eastern sky and my fingers are crossed and that's why the voltage drops from 14 to less than two in fifth.

Like I say, I disabled the over the top switch and the EGR acts *almost* the same as with the over the top switch engabled. So let me correct myself and say the over the top fifth gear switch evidently has nadda to do with the EGR. I jumped to that conclusion when I noticed it always works in fifth. Like I say, probably just the right vacuum to the pressure sensor in fifth vs other gears??????

So if you put the meter to pin 2n inside the car as described and put the meter where you can see it, go for a fifth gear ride at say sixth mph steady and see if the voltage drops less than two volts from whatever you see prior to that ( alt voltage).

HAILERS

If you ever get the chance, ask the operator how he KNOWS the EGR is not working and write back and let us know. Thank you.

arghx

iTrader: (3)

**** cali CARB *****. We don't even have smog tests in NC anymore for pre OBD II

jgibbs22

Thanks Bro! I will take it out for a ride as soon as I can, might not be till morning tomorrow. I guess if it works in 5th, I will just have to bug these jerks at the smog place and see what the deal is with failing the EGR. I honestly felt they had no idea what the hell he was doing, the guy looked freaking lost. But alas, we shall see.

jgibbs22

Yeah, I pretty much live in the wrong god damn state for this! hahaha

pfsantos

iTrader: (1)

As said recently and one of the first posts, find you why he failed (and how he tested) the EGR. Tell him a bunch or crazies from the RX-7 club want to know or he'll ge a couple of slaps.

You shouldn't have to unbolt more than the exhaust manifold to get to the gasket (well, I forgot about the heat shields, but no more with the right tools). Hurry, and let us know!

HAILERS

This was not a question about how the owner tested the EGR, it's a question on how the emissions testing station checked out the EGR. I understand how JGibbs checked it, just thought the next time he goes by the testing station, he might ask the operator how THEY check the EGR.

By the way, I failed GAS CAP on my American car this year. I found they remove the gas cap and put a vacuum on the cap and see if it passes a leakage test. I always wondered about the GAS CAP test the last couple of years and how it was done.

scrip7

iTrader: (6)

Here are some shots of the passages that may have carbon buildup:
This one shows where the passage feeds the primary runners:

The smaller hole is where the coat hanger goes:

The port opening in the rotor housing:

Close-up view of the rotor housing port:

Another view of the rotor housing port hole:

Rectangular port in rear iron just below intake port:

Exhaust port in LIM (bottom port, below intake runner) :

HAILERS

Something is amiss here. This is a series four non turbo car. Right? Yes.

The EGR is located on top of the intermediate housing on a series four non turbo.

The exaust gas is fed from a hole in the exaust manifold. this hole is right below the exaust port on the rear rotor housing. The gasket for the manifold has one hole in it that lets the exaust gas in the exaust manifold enter the triangular hole in the intermediate housing. It travels from there up to the top of the intermediate housing thru a cast hole inside the intermediate housing. On top of the intermediate housing is a large hole where it exits. When the EGR opens, it allows that exaust gas to enter the two small holes next to the LARGE hole mentioned. The small holes lead to the intake passages in the intermediate housing and on to inside the rotor housing.

The pictures above seem to be for a turbo???? EGR is mounted on the intake manifold on series four turbo cars , unlike on na cars where it's on top of the intermediate housing.

scrip7

iTrader: (6)

WOW!....my bad!.....I looked back at the first post and saw nothing written about series or asparation type. My mistake for assuming it was a TII.

scrip7

iTrader: (6)

Interesting that they used such an outdated method for checking the gas cap. Most dealerships use a "smoke machine". According to the OBDII emissions laws, all 1996 and later cars are required to have an evaporative emissions test port installed. This test port is used to perform vacuum and pressure tests for the vapor canister, gas tank, lines, etc. Where I work we have the same type machine that connects to this port. It supplies a non-carcinogenic smoke under low pressure to quickly find the smallest of leaks, most often the gas cap, but occasionally a split vacuum hose, leaky vent solenoid, etc.

I use this machine daily for checking vacuum leaks. It works even better than propane, carb cleaner and starting fluids, with no risk of fires. A bit off-topic, sorry for the rambling.

HAILERS

EEEEK! Keep that outfit off my car. I'd probably fail that test. humor

jgibbs22

I heard they were doing that now!!!! It has not been enacted here in CA yet, but its on its way. Hey guys, I wont get this off and checked until sunday, but in the mean time:

Does anyone have access to the wiring diagram for the ECUs? would love to see it. Trying to find out why these egrs only like to operate in 5th gear.

HAILERS

I see I need to clear something up. I HAVE seen it come on in fourth gear and maybe second gear. It took a bit of playing around to do it. BUT, in fifth gear it always comes on under steady throttle, say at 40 to 60 mph. I stressed fifth gear because it seemes the most reliable time for you to see if it's working or not without playing with the engine speed in a lower gear etc.

There are NO wiring diagams of the ECU itself. And there seems to be no really description of how/when it works. IN the series FIVE FSM, they have several pages on the sensors and how/when they work. Called the Input/Output pages of the FUEL SECTION. But...........no EGR on series five, so no description.

jgibbs22

thanks bro! Hey quick question, is the N338 a EGI or ECU> I am getting the two things confused. is the ecu inside the EGI?

HAILERS

It's a ECU. IF I wrote the letters EGI somewhere, it's just a typo.