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Bad fuel injector problem

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Old Jun 4, 2004 | 02:48 AM
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Bad fuel injector problem

Hi.
I did a full 60k tune up to my '91 Turbo II and I also had the injectors cleaned.
The shop told me that the injectors are bad.
They don't flow as they should at low and high rpms. One of them has a fuel leak, and the injector coils are bad too.
The only choise is to change them with new ones.
I checked with Mazdatix's prices and they are the following.
INJECTOR NEW 89-92 TURB (PRI/SEC) 13-2500-N370 $251.31
I suppose the price is for one injector only.
I don’t intend to keep the car stock so this is no option for me.
I did a search to see what other options I have and I found out that I can install 2x 720cc in place of the secondary injectors with the stock ecu having no problem managing them.
What aftermarket injectors can I buy? Where from and at what price?
Buying used stock injectors is a big gamble. It’s good for me moneywise, but I would like to buy new ones.
Thanks
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Old Jun 4, 2004 | 02:56 AM
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http://cgi.ebay.com/ebaymotors/ws/eB...category=33554
For a set of 4, I'd email the guy and ask if you can get 2.
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Old Jun 4, 2004 | 03:02 AM
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Marren injection.
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Old Jun 4, 2004 | 04:10 AM
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Thanks for the links guys.
Can i have a definite answer about the 720cc secondary injectors?
Can i use them or not?
RETed can you hear me in Chech Rep.?
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Old Jun 4, 2004 | 05:34 AM
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Un regulated 720s on a TII will work. Its alot of fuel, but I did it for a while till I got my SAFC>
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Old Jun 4, 2004 | 05:50 AM
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Will the amount of fuel be enough if I free up the intake and the exhaust? (hks style intake, no cats only a cb)
Planning on Haltech ecu in a year so no safc for me.

Last edited by FxF; Jun 4, 2004 at 05:54 AM.
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Old Jun 4, 2004 | 05:51 AM
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I was running fully opened up.. Hitting 12 PSI of boost. No problems.
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Old Jun 4, 2004 | 05:59 AM
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So are you saying i should get 2x 55 lb/hr (570 cc/min) Pro Import Low Impedance Japanese Low rect. $110.00 and 2x 72 lb/hr (750 cc/min) Pro Import Low Impedance Japanese Low rect. $110.00 from Marren?
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Old Jun 4, 2004 | 06:05 AM
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Well, your getting ahead of yourself. You gotta look at what Marren flows thier injectors for, PSI wise. That affects your actual CC rating. I would think that they use the same rating system as the Mazda ones use, but I could be wroing.

I am also finding it VERY hard to believe that all of your injectors were bad. I mean.. EVERY SINGLE ONE? Were they cleaned and flowed?
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Old Jun 4, 2004 | 06:17 AM
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From: On the mountain of Thessaloniki, Greece
Originally posted by J-Rat
Well, your getting ahead of yourself. You gotta look at what Marren flows thier injectors for, PSI wise. That affects your actual CC rating. I would think that they use the same rating system as the Mazda ones use, but I could be wroing.

I am also finding it VERY hard to believe that all of your injectors were bad. I mean.. EVERY SINGLE ONE? Were they cleaned and flowed?
Yes they were cleaned and flowed. They guy that did it said that they were a mess. All of them spayed near the 480cc area. The 1st primary had a small leak, the second primary sprayed -4,2% and 2nd secondary spayed -7,5% at 6000rpms. Also the coils were bad. So we can't tell if they spray correctly at all.
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Old Jun 4, 2004 | 07:57 AM
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I would get a second opinion.

-Joe
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Old Jun 4, 2004 | 08:52 AM
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So would i. I had mine tested after my j-spec ate a seal and the secondaries were spraying 30% less than the primaries and the place i took them to said he'd get them to spec no problem.
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Old Jun 4, 2004 | 10:00 AM
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From: On the mountain of Thessaloniki, Greece
I showed the results to the only person i trust and he told me that new ones are the best way to go since i am going to do modifications.
RX7.com sells 550cc and 720cc for 122$ a piece.
I don't want to play with the injectors since they are such a critical part of the car.

-Fanis
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Old Jun 4, 2004 | 10:15 AM
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Why dont you contact RC and get thier opinion. They clean and sell injectors so you shouldn't be concerned about them being biased. http://www.rceng.com/
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Old Jun 4, 2004 | 04:03 PM
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carburetor
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Old Jun 7, 2004 | 10:14 AM
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From: On the mountain of Thessaloniki, Greece
Originally posted by SwooshMan
Why dont you contact RC and get thier opinion. They clean and sell injectors so you shouldn't be concerned about them being biased. http://www.rceng.com/
Just called the RC distributor in Greece. I am waiting for him to call back.
Does anyone else have any more info about this situation?
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Old Jun 14, 2004 | 07:52 PM
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Try and get a hold of hIGGI.
I think he has at least a pair of 550's that should be good.
If not, they do come up for sale regularly (check the for sale section in here?) for a better price than what Mazda wants for new ones.


-Ted
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Old Jun 15, 2004 | 05:54 AM
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From: On the mountain of Thessaloniki, Greece
Originally posted by RETed
Try and get a hold of hIGGI.
I think he has at least a pair of 550's that should be good.
If not, they do come up for sale regularly (check the for sale section in here?) for a better price than what Mazda wants for new ones.


-Ted
I think i am going to go for 2 550cc primaries and 2 720cc secondaries, new from RX7.com since i am going to mod the car also.
From your experience do you suggest they will work alright (720cc) with the stock ecu?
J-Rat said that he had no problems.
I am going to simply put out the old ones and install the new ones? Or is it more that that?

-Fanis
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Old Jun 15, 2004 | 08:18 AM
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Bigger injectors will not work with the stock ECU...you will be dumping around 30% more fuel into the engine. Yeah...it may run, but you will be running rich which will kill power and build carbon...unless you turn up the boost to compensate. I would rather just get an S-AFC and tune it on a wideband.

-Joe
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Old Jun 15, 2004 | 10:42 AM
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From: On the mountain of Thessaloniki, Greece
Originally posted by OverDriven
Bigger injectors will not work with the stock ECU...you will be dumping around 30% more fuel into the engine. Yeah...it may run, but you will be running rich which will kill power and build carbon...unless you turn up the boost to compensate. I would rather just get an S-AFC and tune it on a wideband.

-Joe
Once i get the injectors installed I will free up the exhaust and the intake.

-Fanis
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Old Jun 15, 2004 | 03:46 PM
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Originally posted by FxF
From your experience do you suggest they will work alright (720cc) with the stock ecu?
J-Rat said that he had no problems.
I am going to simply put out the old ones and install the new ones? Or is it more that that?
I have never had very good experiences with running larger secondaries with just the stock ECU.
I have always relied on fuel computers to smooth out the transition.
You might not notice the slight bog on the transition, but I find it annoying...even with 680's.

Even with the mods you're planned to do, the stock ECU already runs very rich in the midrange, right where the transition is.  With the airflow meter still working, the increased engine efficiency doesn't fool the stock ECU into being able to use the larger fuel injectors properly.


-Ted
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Old Jun 15, 2004 | 03:50 PM
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Yes, I did it with no problems.. No transition problems, etc...
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Old Jun 16, 2004 | 07:08 AM
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From: On the mountain of Thessaloniki, Greece
Originally posted by J-Rat
Yes, I did it with no problems.. No transition problems, etc...
I am going to simply put the old ones out and install the new ones? Or is it more that that?
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Old Jun 16, 2004 | 11:05 AM
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Buy new upper and lower grommets for the injectors and new o'rings for the top of the injectors.
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Old Jun 16, 2004 | 11:11 AM
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Buy new upper and lower grommets for the injectors and new o'rings for the top of the injectors.
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