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Low Impedance injectors with a 1.8 N332 runs like crap?

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Low Impedance injectors with a 1.8 N332 runs like crap?

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Old 01-30-12, 09:53 PM
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Exclamation Low Impedance injectors with a 1.8 N332 runs like crap?

I just finished installing some freshly tested and cleaned GSL-SE injectors in my 87 TII as well as the Rtek 1.8 ECU I bought. My car used to idle at 1400 rpm, but it was smooth. After installing this my car is idling around 600 rpm and stumbling badly. It almost sounds like it is bridgeported. It's also smoking now...it used to just smoke on initial start up, but now it stays smoking. (Not a ton though)

The only other thing that I did to my car was install a banjo bolt and block off plate for the ACV and I remembered to cap off all the vacuum lines.


The guy I bought it from said he was running HIGH imp injectors with this ecu. I thought the N332 ECUs were for LOW imp injectors. The ECU I pulled out was an N332 and my car had the LOW imp 550cc injectors on it (orange top).

I went to drive my car and it seems fine in the lower rpms if I wasn't heavy on the throttle, but as soon as I try to get into boost it stumbles and doesn't want to rev higher, so I didn't try to push it.
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Old 01-30-12, 10:52 PM
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To add-I went and started the car again and could hear a relay or something clicking by where the oem resister pack thing is.
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Old 01-31-12, 12:29 AM
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And here's a video of it idling/revving:
http://www.youtube.com/watch?v=chfvVDHdCCc
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Old 01-31-12, 11:17 AM
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All ECU's expect high impedance.

That means you can use:

High impedance injectors, without resistor blocks
or
Low impedance injectors, with resistor blocks

The resistor blocks make the low impedance injectors "look" like high impedance to the ECU.

Failure to run one of these two options will cause the car to run bad and can damage the ECU (especially in the case of running low imp without resistor blocks)
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Old 01-31-12, 12:29 PM
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the only time i've had drivbility issues that were fine in vac, but horrible in boost(even 2-3psi) was b/c the injector wasn't seated properly. the boost would leak out around the fuel injector and cause the fuel spray to go every which-a-way. being that your just removed/reinstalled them.. i would check there.
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Old 01-31-12, 08:58 PM
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Just to ensure that I have the correct Rtek Chip in the ECU:

The chip says

Rtek 7S4T2 STG:1.8
SN:1457 Ver: 1.1.1

The injectors have all their resistances and flow rates recorded as well. Just getting a few things out of the way to be sure that it isn't the issue.
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Old 02-01-12, 11:10 AM
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That is correct for a N332. A stage 1.8 requires 720cc injectors. What injectors are you running?
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Old 02-01-12, 03:08 PM
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4 GSL-SE Injectors all flow tested and cleaned. All are low imp and flow right at around 720cc
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Old 02-01-12, 06:58 PM
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Okay - just so I can be sure I've gone through everything:

I took everything apart and put it all back together. I found no pinched fuel lines, no unconnected electrical stuff, or anything like that. I went to start the car and it still barely idles at like 500ish rpm and almost sounds like it wants to die. I went ahead and tested my stock ecu in place of the Rtek one that I bought with the 720cc injectors and the car actually idled nicely at 800ish rpms and drove pretty smooth. I even used about 40-50% throttle to 4500rpm and it felt fine. Would this be a sign something is up with the Rtek ecu I bought second hand?

Here's the sheet for the injectors:


Here's the stock ecu:


Here's the Rtek ecu (idk where the sticker on the cover went):



When I installed the ACV I capped the 3 lines that went to it. (The one with a vacuum hose has a bolt blocking it off. I just need to go buy more block off nipples):


If you can tell from this picture I have the vacuum source from the UIM T'd off going to the pressure sensor and the air bypass valve. The BAC isn't plugged in, but then again it never was even when I bought the car. I need a new harness since this one has missing plugs. Those random electrical connectors went to the BAC and the ACV btw:



Just a note - my engine harness is kinda messed up as well as my ignition harness. When I pull the key out of my car I have to kill it with the clutch and pretty much stall it. I have an ignition harness in the mail to fix this (I hope), but I don't think that is the issue at hand with the ECU's. The engine harness has missing plugs and some ghetto patch jobs. I'm ordering a new one soon, but the car runs fine with my stock ecu and the crappy harness, so I don't think that is the issue.

Last edited by SmogSUX; 02-01-12 at 07:20 PM.
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Old 02-01-12, 08:16 PM
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Turbo2ltr might want to chime in here, but those injectors were tested at 43.5 psi, which is at least 10 psi higher than stock. Is the 1.8 expecting to see 720cc's @ stock fuel pressure?
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Old 02-02-12, 12:05 AM
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Denso 195500 0900 are 680cc/min, according to the FAQ (Mazda rates them at 37.5 psi).

Stock ECU is expecting 550cc, so you're running rich but getting enough fuel at idle.

RTek 1.8 is expecting 720cc, so you're running lean and have insufficient fuel at idle.

Where's yer wideband?
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Old 02-02-12, 03:32 AM
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Originally Posted by 088 View Post
Denso 195500 0900 are 680cc/min, according to the FAQ (Mazda rates them at 37.5 psi).

Stock ECU is expecting 550cc, so you're running rich but getting enough fuel at idle.

RTek 1.8 is expecting 720cc, so you're running lean and have insufficient fuel at idle.

Where's yer wideband?
The 680cc injectors usually flow around 720cc, so they've been proven to work fine. With the Rtek my car almost seems to be running too rich. And I can't afford a wideband lol
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Old 02-02-12, 03:40 AM
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Originally Posted by SmogSUX View Post
And I can't afford a wideband lol


fail!
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Old 02-02-12, 11:48 AM
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That Rtek was sold in 2008 as a self install, so there is a possibility that the self install wasn't done correctly.

Do you have the resistor blocks installed?

We never recommend 680 injectors with an rtek expecting 720s (or "proved they work") without an additional means of fuel control.

You have your FPR properly connected to vacuum?
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Old 02-02-12, 02:52 PM
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I see. I've just seen other people run the same injectors, so I figured they were fine. My FPR is properly hooked up to vacuum as well. Would installing my 240lph fuel pump and rewiring it to get the full voltage help at all? The resistor pack is hooked up correctly as the car ran fine with the 550cc injectors I had in it which also had about 2 ohms of resistance.

I'll call digital tuning to see if I can have them check out the ecu.

EDIT: Also my fuel pressure is right around 40psi at idle.

Last edited by SmogSUX; 02-02-12 at 03:14 PM.
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Old 02-02-12, 10:41 PM
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Originally Posted by turbo2ltr View Post
We never recommend 680 injectors with an rtek expecting 720s (or "proved they work") without an additional means of fuel control.
You mind telling us what psi "injector test pressure" the so called 720's the RTEC is tuned for needs? I'm been looking for this info on your site and can't find it. Is it 720 cc at 3 bar i.e. 43.5psi test pressure?

Here's some nice to know/ fact about so-named "GSL-SE 680cc" injectors "FSM says GSL-SE injectors flow 173 cc/15 seconds at 39.7 psi, or 692 cc/min. Multiply this flow by sqrt(43.5/39.7) to get nominal flow at standard 43.5 psi(3 bar) test fuel pressure = 724 cc/min."
which is pretty much what SmogSUX's flowed injectors show.Get tired of reading this horsesh#t about GSL-SE 680cc injectors.
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Old 02-10-12, 06:13 PM
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I also just installed the 1.8 into a N332 ecu. The injectors I used were previously cleaned and tested but sat in a ziplock bag for a year. Car started and idled like crap (almost like yours but worse). I sent them off to be cleaned again, one was almost completely stuck and the other had a partial block. They cleaned and flow tested again, both were at 750cc. I installed them in to the secondaries and put the Marren 750cc I had been running in the secondaries into the primary. Car idle perfect after a little tuning. It reved fine to redline, drove under normal conditions just fine. Better than it had before. BUT, under boost different story, once the secondaries kicked in wideband would hit 16's at 2lbs of boost.

Called and ordered a new pair of 750cc injectors and problem fixed. Car pulls better than ever.

You can get a pair of 750cc low impedance Bosch injectors for 69 apiece.
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Old 02-12-12, 05:41 PM
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I found the issue (I think). Digital Tuning has done great keeping in contact with me. I tested the ECU's and the Rtek Chipped ECU definitely has something up. I'm gonna pay them to move the chip from their ECU to my Stock one.
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