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wvumtnbkr
wvumtnbkr UberDork
5/18/19 9:17 a.m.

I have seen some really strange exhaust failures on rx7s.  Collapsed inner wall of exhaust pipe, weird restrictions at y pipe, etc...  the test of disconnecting before the cat is very beneficial.  Just looking in the mufflers won't give you the entire picture.

BirgerBuilder
BirgerBuilder Reader
5/21/19 2:59 p.m.

For the update: 

wired 6 ports open- idled like crap/ no change

realized I also pulled a vacuum line off - idled normal/ no change

pulled TPS sensor off- no change

built a led blinker light for the 'OBD 1' diag. - port throws no codes

Did FSM check of secondary injectors, (Just trying to listen through a screwdriver) Do not hear any firing

 

Next step: build injector noid light, then pull injectors and attempt to get them to spray manually. 

 

BirgerBuilder
BirgerBuilder Reader
6/17/19 3:00 p.m.

After a bit of hiatus, my brother came over and we didn't have any particular project goal. so he helped me with the RX-7

I wired the injectors to the rail and pulled 'em out. I jumped them and one clicked, one didn't. I spun the motor and ran the fuel pump, one sprayed, one didn't. 

Hmm. So I had two extra injectors that I had gotten form the junk yard.

Problem is, these are the low resistance injectors and I have the high resistance ones in the car. 

So I could swap the plugs and bypass the resistor box but first, lets try something...

I took the old injectors, some fuel line, jumper wires, a compressor and carb cleaner. 

So, you just fill the fuel line  with carb cleaner, add about 20-30 psi ( I didn't turn down the  compressor, so I'm not sure how many psi I was using. But I can say that with too many, the fuel line will pop off and spray carb cleaner in your brother's eye and he will be sore about it.) And then jump the injector. (I've also heard that a 6v battery is sufficient) 

Anyway, potential disasters aside, IT WORKED BRILLIANTLY. What started as a drip in the bad one, turned to a stream, then an actual atomized pattern.

The car now revs up past 4,000 with only the slightest hint of hesitation.  

Success! Now I need to get at the primaries because they are likely a bit clogged as well.

Kids celebrated by eating a whole bag of pop-corn in the car, yay.

 

Mezzanine
Mezzanine Dork
6/17/19 4:49 p.m.

Yay, cleaning up the mess the kids make in the project car! I actually love this, because it's one of the ways my daughter gets exposed to some shop time. She doesn't need to be working or learning how to do something just yet. Osmosis is enough at her age (8). Good job dad.

wvumtnbkr
wvumtnbkr UberDork
6/17/19 5:50 p.m.

What's the plan for this car once the engine is running well?

 

Clean all your grounds.  All of your grounds.  I mean, all the grounds.  Then see if hesitation is gone.

BirgerBuilder
BirgerBuilder Reader
6/17/19 8:08 p.m.
wvumtnbkr said:

What's the plan for this car once the engine is running well?

 

Clean all your grounds.  All of your grounds.  I mean, all the grounds.  Then see if hesitation is gone.

Plan? Whats a plan? I've gone from Rally-cross to 'just sell it' to sell the motor and buy an LS to fix the body and paint it and make it a driver. Who knows what'll happen.

 

I have done all of the grounds, that's the first thing I started with, and I ran new ones to the ECU. I think there was one more to potentially add, near the boost pressure sensor? I'll have to look it up again. 

wvumtnbkr
wvumtnbkr UberDork
6/17/19 8:43 p.m.

Yep.  I believe it is a brown wire.  Careful.  There are 2 brown wires.  One is sensor voltage.  Run a ground from battery to chassis.  From that exact bolt on The chassis, Run a ground from chassis to engine.  From that exact spot, Run a ground from chassis to edu.  12 or 13 gauge should be fine.

BirgerBuilder
BirgerBuilder Reader
6/18/19 1:45 p.m.

In reply to wvumtnbkr :

Thanks, I'll link the chassis and ECU grounds together to see if it helps. 

In the mean time...

I still feel like I way overpaid but, that's the cheapest I've seen one so I snagged it. 

 

The0retical
The0retical UberDork
6/18/19 2:13 p.m.

Jesus those are expensive. I should get a set and pop some molds.

BirgerBuilder
BirgerBuilder Reader
6/25/19 1:45 p.m.

Nothing major happening but I got my new to me, and over priced door handle. 

Installed, thanks to an extra plastic clip robbed off of the auto-cross car. 

Now, as for the 10 year old packaging tape that had been covering the hole and left in the sun...

I  was hoping that Goof-off would just melt it away but it wouldn't seem to get under the plastic of the tape.

So, a razor blade was deployed. Much the same way you clean gasket material off of a block, I scraped it off with the blade perpendicular. 

Mixed results. Took the tape off, and a bit of paint too.

So, heads up, don't do this on a car with salvageable paint. This one... I was willing to risk it. 

After that, the kids and I gave it a wash and it actually looks okay from 20 feet, depending on if you're wearing your glasses or not...

 

BirgerBuilder
BirgerBuilder Reader
10/29/19 1:50 p.m.

So I've been putzing with the car off an on for a few months now. It now seems to run reliably, but the shifter feels like it is attached with a chain. Also, it is so dead flippin slow.

First, I had to do something about the shifter. I pulled it out and sure enough, there was zero bushing in there. I didn't feel like waiting or spending $50 bucks of new ones so I pulled a piece of Delrin out.

I didn't take too many pictures of the process but it was fairly simple to make, The only hard part was making a cutting tool with the same curve as the shifter ball.

This was too tall since I modeled it after the rubber one which has much more give. So, i sanded it down and cut some grooves for the spring to sit in.

And, we're done. It is so, so much better now. I bought the centering return spring as well but I may put that off until I am able to pull the transmission, it's way easier if you can get at it from the side.

I also pulled the primary injectors and cleaned them out as best I could, hoping that would help with the sluggishness.

Didn't really, as far as I can tell. I don't remember the car being this slow 8 years ago, I mean, it's a pig. Is there anything I should be checking to see if the motor is running properly? I have the Actuators wired open and the intake is clear, I was thinking about hooking the AFR gauge up to it. Maybe pull the exhaust off and do a comparo? RX-7 guys, do you know what would make the car run smoothly/normal seeming and still have no power?

 

 

 

wvumtnbkr
wvumtnbkr UberDork
10/29/19 2:49 p.m.

2 things...

1) there are actually 2 of those bushings for the shifter.  1 under the ball and 1 above.

2) it had 143 hp at the crank when it was new 30+ years ago....

 

If you have a catalytic converter on there, check to see if it is plugged.  If you unbolt the exhaust it will be crazy loud!  Be aware if you do that and drive it around.

Does it start easy hot or cold?

Brett_Murphy
Brett_Murphy UltimaDork
10/29/19 3:34 p.m.

It will be dead slow unless you have it screaming and the secondary ports are open. Even then it will feel and sound faster than it actually is- it's an inertia car.

If the secondary ports are stuck shut, it will be dead slow all the time.

BirgerBuilder
BirgerBuilder Reader
10/29/19 4:58 p.m.
wvumtnbkr said:

2 things...

1) there are actually 2 of those bushings for the shifter.  1 under the ball and 1 above.

2) it had 143 hp at the crank when it was new 30+ years ago....

 

If you have a catalytic converter on there, check to see if it is plugged.  If you unbolt the exhaust it will be crazy loud!  Be aware if you do that and drive it around.

Does it start easy hot or cold?

I replaced the cat earlier, it does only have one muffler instead of the dual set up but it shouldn't make that much difference.

It does start fairly easy at all times, though the idle still bumps up and down for about 5 minutes until it warms up.

And yes, I don't expect it to be "fast" but it feels so much slower than the 91 Miata of similar power.

BirgerBuilder
BirgerBuilder Reader
10/29/19 5:00 p.m.
Brett_Murphy said:

It will be dead slow unless you have it screaming and the secondary ports are open. Even then it will feel and sound faster than it actually is- it's an inertia car.

If the secondary ports are stuck shut, it will be dead slow all the time.

I'm pretty darn sure that the secondary ports are wired to the open position, but I can stick the endoscope in there to be sure.

wvumtnbkr
wvumtnbkr UberDork
10/29/19 7:11 p.m.
BirgerBuilder said:
wvumtnbkr said:

2 things...

1) there are actually 2 of those bushings for the shifter.  1 under the ball and 1 above.

2) it had 143 hp at the crank when it was new 30+ years ago....

 

If you have a catalytic converter on there, check to see if it is plugged.  If you unbolt the exhaust it will be crazy loud!  Be aware if you do that and drive it around.

Does it start easy hot or cold?

I replaced the cat earlier, it does only have one muffler instead of the dual set up but it shouldn't make that much difference.

It does start fairly easy at all times, though the idle still bumps up and down for about 5 minutes until it warms up.

And yes, I don't expect it to be "fast" but it feels so much slower than the 91 Miata of similar power.

Check for a dragging brake.

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