Tobias

iTrader: (1)

Hi folks, thanks for popping in and I in advance appreciate all the help.

Trying to bring back to life a very sad and neglected GSL SE. Had the engine rebuilt last summer by RPM Motorsports in Ontario, so we can assume the engine is then in good condition. Had the engine running last fall, extremely rich however and couldnt get it figured out before winter. Stored the car over winter, oiled the engine and brought it out this spring.

Car wouldnt start, turned out to be a bad ECU fuse, was causing the injectors to stay wide open during running. So, fixed that and it runs well now, perhaps a bit rich.

Air pump and pulley have been removed and capped, with a nipple attached to the exhuast system for the 5th and 6th ports to run.

Right now, the engine runs but it chatters and shakes, vibrating pretty harshly at idle. You can hear it missing. I've got the engine timed correctly, though it was tough with it missing.

As you increase rpm, it seems to smooth out the misfire until around the 6000 rpm mark and then it starts to backfire.

So far: Replaced distributor rotor, cap, spark plug wires (Bosch, I'm thinking of changing these again. I dont trust Bosch anymore) New NGK BR9EQ14s all four plugs, replaced fuel filter

Two brand new ignition coils. I replaced the ignitors with used ignitors, and they appear to work since I have tach movement when I switch trailing and leading on the ignitors, so that should be okay. Could a faulty one though appear intermittenly?

Were do I go from here folks?

Rx-7Doctor

iTrader: (13)

First.

Assumption is the mother of all evils! :-0

Don't assume that your engine compression is good, test it!

The other thing to look for is to see if both injectors are working. You may have lost a ground at one of the injectors or you have a bad injector.

Have you checked fuel pressure?

Leading plugs firing?
Vacuum leak?

fifth7

I noticed that you say you did all four plugs the same. there is a different plug for trailing and leading!!! I am assuming it is a 13B RE-EGI.

thunkrd

iTrader: (1)

second gens do.. first gens don't really

Tobias

iTrader: (1)

Rx7doctor:

I performed the ghetto compression test, and heard a very strong 3 wooshes on both the front and the back rotor, I'll be buying a cheap compression tester from one of our techs here at Honda to find out a bit better then my hearing allows.

One of the techs suggested putting the injectors on the noid light to see if they were pulsing, and he said that they are.

As far as fuel pressure, I never got around to checking that this evening. Will do tomorrow afternoon for sure!

Spark plugs are firing on leading without trouble.. And I cant hear a vaccuum leak, but there is a definate exhuast leak that I'll button up this evening.

mazdaverx713b

iTrader: (91)

all four plugs for the SE are the same. NGK BR8EQ-14's

Tobias

iTrader: (1)

I'm running #BR9EQ14's... Tis what Rockauto has for the part. Any problem with that?

mazdaverx713b

iTrader: (91)

nope, thats what is required for the 7. imo, the best and only plugs i'll use. i'm sure a lot of pther people would agree. nippon denso also makes a pretty good plug for the7.

SilverArrow

Have you adjusted the TPS sensor or checked the vane air meter?

Starfox07

I'm going to say vacuum leak at the LIM. My car had the exact same problem.

Tobias

iTrader: (1)

mazdaverx - Just to clarify, it's fine to run br9's instead of br8s you suggested?

Silverarrow - I know it sounds like a sketchy idea, and perhaps a bit lazy, but I bought a vane air flow meter that WAS running well in the car for pretty cheap, so I swapped that in instead of the one that came with my car. I've tested it with both, for the record, and both have not fixed the problem. So I left in the 'newer' one. So, without testing the resistance when you open the gate I couldnt tell you for SURE if it's working correctly. I'll try and test that this evening. I bought a pair of voltmeters this AM to test the TPS as you suggested, so I'll have the required tools.

Starfox, just a bit of a clarification please - I know a most of the acronyms for the rx7, but LIM is one I'm not famaliar with, could you specify please?

I'm going to remove the dynamic chamber tonight and take a picture for everyone to see it, to make SURE I have all the connections correctly.

gsl-se addict

iTrader: (3)

LIM = Lower Intake Manifold

fifth7

well that is not what I am getting at the dealership. the GSL-SE has different plugs for trailing and leading. A good friend of mine is a Mazda master mechanic and say's the same thing. So I don't know where your info comes from but I would look into it a bit further.

fifth7

The GSL-SE if very temperamental on the vacuum lines. I had mine for a couple months before I got it completely worked out. but before it really ran like ***, and acting like it was misfiring horribly. Good luck with it.

gsl-se addict

iTrader: (3)

That is not correct. All SE plugs are the same. NGK BR9EQ-14 is typically what is specified for the GSL-SE. NGK BR8EQ-14 is normally specified for the 12A cars. You can run either the 8's or 9's in the GSL-SE, though.

The different plugs for leading/trailing did not start until the 2nd gen cars. What plugs are the dealership giving you? BUR7EQ/BUR9EQ?

The 2nd gen plugs are more likely to be in stock, so that is probably why they are pointing you this way.

I've been dealing with GSL-SEs for 14 years now and Mazdatirix agrees with what we are saying:

http://www.mazdatrix.com/ign-2.htm

It is not that other plugs don't work, but they might be what is specified.

Tobias

iTrader: (1)

Thanks GSL-Se addict! I pulled out the chilton manual, and it was suggesting br7eq14s! Apparently anything in that series is good to go then.

I'll check the lower intake manifold this evening, and make sure it's not leaking. At the time I put it on, I didnt really know that some bolts need to be torqued in order, so perhaps I didnt do that. This has been a big learning project for me, and sometimes I think I bit off more then I can chew. However, I'll keep chewing. I'll get this figured out!

Rx-7Doctor

iTrader: (13)

Sorry but your friend and the Dealership are incorrect.

The SE takes the same plug for leading and trailing and always has. The only ones that take a different plug for the leading and trailing are the 2nd and 3rd gen models.

This would not cause this persons issue anyways.

Tobias,

I am going to assume that the issue was not there until you removed the intake?

Tobias

iTrader: (1)

Thanks for coming back in Rx7-Doctor. I appreciate the help from respected members most profusely:

Unfortunatly, I dont have a bench mark to tell you how it ran before I got the car. I purchased the car with the engine having overheated and imploded. I took the engine out and had RPM in Ontario rebuild it. I've actually never had the car 'running' perfect like factory, ever. And, to make matters worse this is my first stock SE. I've played with 12As, and all my fathers experiance is with carbs so my access to mechanics in my back water city of Moose Jaw is limited! So in short, I havent 'done' anything to make it run poorly. It just hasnt run right since I put the engine back in.

mazdaverx713b

iTrader: (91)

i get my info from 11 years of RX-7 restorations and over 30 personally owned RX-7's. as other have stated, the information that i provided is in fact correct.

to veer a little, i have heard of people using the FC standard BUR9EQ and BUR7EQ in some applications with results that are favorable. usially used when upgrading to an FC ignition setup and sometimes when going to a DLIDFIS setup.

gsl-se addict

iTrader: (3)

Check the things Doc was saying. I know that you have checked some already. If you can't find an EFI fuel pressure tester around there, you can borrow mine. I can ship it to you and you can send it back when you are done with it.

You say air pump has been removed. Did you remove the ACV (Air Control Valve) too? If so, make sure the plate is sealed correctly. Also check the vacuum switch. It is burried back in the corner on the passenger side (under washer fluid bottle). It is easy to overlook in connecting the electrical or vac line back up. Also the other vac lines in that area (blue/grey solenoids on firewall, cruise control) seem to come undone easily, easy to overlook a vac connection, or one of the tees can be broken due to age.

Double check that all nipples are connected up on the dynamic chamber. There are some on the back and some under the BAC valve that are easy to miss. Also, be sure that the lines the run under the UIM (Upper Intake Manifold) are all plugged in too. Also, the intake gaskets can be a big vac leak source as others have mentioned.

When you put the timing light on, does it look like it is missing (unsteady/missing flashes)? Compare the flashes on leading compared to trailing. Try the light on all 4 plug wires as you might just have one bad plug wire or a boot that isn't fully seated on the plug.

Good luck. Let us know what you find out.

Kent

Tobias

iTrader: (1)

Kent:

Come to think of it... I think the ACV is still on there! The ACV runs to that bizzare little canister underneith of the air box that appears to do nothing right? The previous owner of the car removed the air pump, but I'm damn sure that the ACV Is still attached to the engine. Im at work, so I cant say for sure for a few hours.. but I plugged it in and attached it to the canister if thats the case!

AVC being seen here: https://www.rx7club.com/showthread.p...ngine+Pictures

Has the big nipple on it? So... if so, what does that mean?

Starfox07

The only reason (I think i'm right here) the ACV would be causing your engine to run badly is if it simply wasn't there with a gaping hole sucking air in. If it is still installed, thats probably not your problem. I think you have a vacuum related problem. Check all of your hoses (there really are not that many) and make sure your lower intake is seated perfectly against the block.

Tobias

iTrader: (1)

Hey folks, made a little progress last night and hit a major snafu. BTW, I borrowed a fuel pressure tester from work here at Honda, and came back at 35psi.

There was in-fact, a leak at the lower intake manifold. I retorqued down the LIM according to the FSM and it seemed to go away. I might just get a new gasket and do it again. Anyway, that helped idle drop a bit, but we're still experiance shake and vibration, and I.. figured out why when I removed the dynamic chamber.

It's definatly a vaccuum leak. I've plumbed the oil injectors wrong. According to the FSM for engines, the front oil injector goes to one of the four nipples on the front of the dynamic chamber. I've instead plumbled all for to a vacuum spider thing, and past that point, I have no idea were one or two of the vacuum lines go. Thats the problem with installing parts of the engine every month or so, you miss things.

The father and I reviewed the vacuum solenoids, and they're all plugged in right, we think. However, after having fought to get the LIM off, we've decided that we've gone beyond what we're confortable doing. So we've got it booked in at Rx7 specialities in calgary. It's a helluva drive, but that way I can watch as Adam works on the RX7 and learn by seeing - the best way possible.

I HAVE taken pictures of the intake nipples and etc before I removed the LIM, but forgot to take them after. I'll upload them later, as well as the pictures of the solenoids. I'm going to keep everyone informed though with the progress.

gsl-se addict

iTrader: (3)

There is a color diagram of the way the vacuum lines route for the GSL-SE on here. I have posted it a couple of times. Take a look at posts under my username in the search. It will really help get them back to how they are supposed to go.

BTW: all oil injectors do go to the spider. There is another nipple under there (air bleed socket) that goes to one of the front nipples

EDIT: Here you go.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/13b-color-vacuum-diagram-656912/

Tobias

iTrader: (1)

Huh. I found the colored diagream kent, I actually have it printed off and laminated. I did follow that thing to the letter when I was installing the chamber..

The one line that I couldnt figure out last night was hanging out the back of the dynamic chamber and had a brass fitting on it to be attached to something. It looked fairly pliable, so it musnt have been in any contact to anything heat or acid related. It's in good shape. I cant find where it goes on the color diagraam, and when I attach a vacuum unit to it, it doesnt hold vacuum. It looks about the right length to go to the cold start assist bottle... Which I've removed.

That wouldnt do anything would it?