Digi7ech

iTrader: (1)

update.

My coils are fine.

All spark perfectly.

Now I left the plugs in the car and used a timing light.

This flooded the car pretty quick and bad.

Good for my situation.
I then pulled the front leading plug out and cranked the engine.
A HUGE puff of gas comes out.
SO I know my injectors work there.

I pull the rear leading and crank it. Nothing. Just air.

So I know my rear injectors aren't squirting.

I then checked all th pins on my harness. I have an resistor box inline so they are singled out making it easier to find.

I had grounds on the grounds and 12v key on on all the injector lines.

So it's a bad ECU.

Digi7ech

iTrader: (1)

ARGH!!!!!!!!!!!!!!!!!!!

I put a new ECU in and it's still doing it!!!!!!!!!!!!!!!

Abso-*******-lutely NO GAS in the rear housing!!!!!!!!!!!!!!!!!!!!!!!

I flooded it again and puled the plugs out.
Huge puff of gas mist from front rotor but nothing from rear!!!!


****!!!!!!!!!!!!!!!!!!!
OK SO HOW DO I TEST FUEL INJECTORS!!!!!!!

It is the only thing I couldn't/didn't check.

I had 12v on the pins w/ key on so the harness is fine.
I changed ECU's and it did the same thing.................

Now the primaries are the only ones firing at idle/under 3k right? or do they squirt a little bit?

Looks like I'm ripping the UIM off again and will have to find a 550cc injector to replace the primary.

The primaries in my car are high impedance while the secondaries are low impedance.

88 SE

Primaries fire under 3000 RPM, yes.

Check to see if the plug going to the injector is in good shape and that its making good contact.

Try putting one of the secondary injectors into the primary injector slot, running a low imp injector for a few seconds wont hurt anything.

Or you could try swapping the front/rear injectors and see if the problem persists.


A BIG THING TO CHECK, im not sure if you used the new metal intake gasket from Mazda or not, but keep in mind once you use that thing, if you take the manifold apart you have to buy a new one.

Also be sure to follow the TSB procedure for installing it

TSB here:
http://www.wittybastard.com/RX7/00595.htm


That one little intake gasket caused me weeks of headaches on my rebuild. i know it may sound stupid, but its a good place to start since it causes these symptoms as well.

Bear in mind too I have yet to come across one RX7 where the rear rotor didnt act funky in some way or another, so I share your pain

WAYNE88N/A

Settle down, Digi, at least you're zeroing in on the bad guy...

Swap the primaries, or if the secondaries are the same size, swap a secondary in that rear spot. Rig up a couple of leads from the battery, and at least check whatever injector you're gonna put in for "clicking" using the leads (it's a tight fit on the injector plug, don't short them together) before you put it in. If you want to take it one step further, rig up a length of hose (air compressor hose works great) and fill it with some alcohol or acetone after securing it to the injector "inlet", then do the "click" test AND see if she flows too.

I had this same problem when I bought a set of injectors off of a forum member (*cough*Santiago*cough*), and like a dumbass installed them without first checking them, so I definetly FEEL your pain. The upside was, I got REAL GOOD at taking that UIM off in 15 minutes or less

Digi7ech

iTrader: (1)

well primaries are high imp and secondaries are low imp. So I can't exchange them without rewiring the harness.

I'll rip the UIM off and switch the two primaries.

DigitalSynthesis

Hell man, while they're out send 'em to cruzin' performance for a full clean. Probably about time too. $11 per injector and you'll get full flow statistics on each one (they put a serial number on each so you know which had which specs). I did that... very glad I did too. Cruzin does a good job.

WAYNE88N/A

You know what, Digi, I just thought of something, if you swap the primaries, and you're fairly certain that the rear injector is bad, you're just gonna throw everything back together to find that you still have the same problems, just different rotor now...Make sure you check out BOTH injectors as well as you can when ya get 'em out.

BTW- you could rig 'em up on the fuel rail and watch 'em go, kinda like the FSM test, but it tells ya to have everything like 6' away from the engine. Don't burn your nose hairs off

J-Rat

iTrader: (2)

C,

you have any other injectors laying around? I could have sent you one for testing purposes.

And FYI,

You can open your injectors manually with a 12VDC source (I use a car battery). Just dont hold them on there, just tap it.

Digi7ech

iTrader: (1)

I posted the tests these injectors had when I sent them into Cruzin in another thread.

They all passed.

These injectors probably have 8 hours or so of running time in a car since the cleaning.

Wayne.
I do realize that but keeping the injectors in the fuel rail while out seems pretty hard since that's 40psi behind them.

You said the FSM has a test procedure in it?

Digi7ech

iTrader: (1)

I have 4 S5 550cc's from the Jspec uncleaned.
I have 2 S4 low imp 460cc's cleaned sitting here too.


No high imp S4 550's though.

If I put in the S4 460's I have to rewire the harness again with some 10ohms resistors.

J-Rat

iTrader: (2)

Dude, Its EASY to test your injectors with the rails pulled up!!

I just zip-tie them in place!!! Easy cheesy!

Damn, I need to get up there this weekend and help you..

Digi7ech

iTrader: (1)

ZIP TIES! The answer to everything!!!!

I'll pull the UIM off tonight and see what I can manage.

I'm getting good at taking that thing off.

Digi7ech

iTrader: (1)

k,
Took the UIM off and cranked it w/ ZIP TIES!!

The rear primary injector harness is bad.

I swapped injectors around and both sprayed correctly using the front primary harness.

SO I have to buy a new harness and start modding it to make it NA/TII Compatible.

Digi7ech

iTrader: (1)

oh yeah I also ripped the harness almost fully out.

Just have to unplug from the ECU and pull through the firewall.

J-Rat

iTrader: (2)

Oh ****... Are you serious?

jacobcartmill

iTrader: (6)

the NA and TII wiring harnesses are almost the exact same. infact i have an NA wiring harness in my car, i just used the VDI wire as the knock sensor wire. wait, you have an s4... i dont know how closely compatible those are betweem s4-s5.

Digi7ech

iTrader: (1)

S4 and S5 harnesses are very different.

S5 TII and NA harnesses plug right into each other.

I have to rewire for an alternator,temp sensor, and voltage guage.

Not really that hard.

Especially when I have a harness already done so I can just look at it and cut the same lines and rewire it.

I'm waiting for one guy to PM me back on a harness. Once I get it. It should be 2 days or so before it's back in the car.

Oh yeah......
If any one wants me to rewire their harness for S4 TII conversions I'm up for it for a small fee

jacobcartmill

iTrader: (6)

you're putting an s5 wiring harness in your s4 car?

s4 wiring harnesses are all over the place

WAYNE88N/A

Digi, if it's only your rear primary circuit that's bad, why are you pulling the whole harness? It should be a cinch to run new wires- you know the ground is good, or the front primary wouldn't be working...

jacobcartmill

iTrader: (6)

wayne you are the new hotness in the FC section

WAYNE88N/A

I don't know how I'm supposed to read that...

Thanks, I think?

I enjoy helping guys troubleshoot major problems, especially electrical stuff, the "thrill of the chase" type thing. Now that I've been an inspector for a while, I miss that on our airplanes. I just hope I'm giving you guys good info all the time...

jacobcartmill

iTrader: (6)

now, if you could only give me advice on what to do with my 91 NA/turboII

WAYNE88N/A

LOL, you have successfully hijacked Digi's thread!

Well, what is it? an n/a or a turbo II?, j/k...

I know you had a thread going, but I can't remember what your problems were...What's the thread title?

jacobcartmill

iTrader: (6)

something about "low compression" and how i just spent 1300 dollars on a piece of **** "remanufactured stock port s5TII engine" that is mixed and matched of s4 and s5 parts. it happened to have an s5 front cover so i could use it in my car... DAMN THOSE PEOPLE

WAYNE88N/A

There are a hell of a lot of "mixed & matched" motors out there, you think because it has S4 parts in it that's the problem? Are the rotor housings used?