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Fuel Injectors Stuck Open?

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Old 02-09-2011, 01:31 PM
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Exclamation Fuel Injectors Stuck Open?

Okay guys so to give you guys a background on whats been happening to my car and why I think this could be the problem that plagued me before to cause my First CAT that I receieved with my new reman to become clogged.

Roughly 2.5K miles ago I receieved a new engine and Cat. I went home and installed my BHR ignition kit and Cobb AP while starting to premix with Idemitsu to make this engine last. 500 miles ago (2k miles on Engine and Cat) I figure out my Cat is clogged because my fuel economy is HORRIBLE, I was getting 140ish to a tank, combined with Highway and city, plus I felt a loss in Power @ high rpms while my car bogging down because the Cat was clogged. I looked underneath the car and my Cat was glowing red at night.

I took it to the dealer, dealer said it was definately clogged but the BHR ignition system was to blame causing misfires. I told the dealer I have never SEEN a blinking CEL light and that you can feel the power increase from their system.

I came back to the dealer and reinstalled the OEM Ignition system while shipping back my BHR ignition to Charles who tossed me 4 new coils under his warranty. After installing OEM ignition system, my service advisor said the car was running alot better but the Cat was still gone.

Dealer approved new CAT (500 miles ago), I picked up car then with the OEM system and drove home. Car felt so much faster. A few days later my BHR Igntion system returns and I install it but NOT my Cobb AP. I continue to Premix with Idemitsu.

Heres where the problem starts:

I didnt install the Cobb AP because I figured the reason my Cat clogged the first time was because I was running rich with MM's Base Map toss more oil in while premixing with Idemitsu and that that probably clogged my Cat. So Im not installing the Cobb AP until my BHR midpipe comes so I dont clog my new(er) Cat, or so I think if thats still my problem, which I dont anyone.

My fuel economy is still VERY BAD. Im sitting at 120 at a quarter of a tank left. What would give me such bad fuel economy?

This is what I believe it is, a stuck open fuel injector, this thought came to me last night.

If my fuel injector was stuck open it was make sense that my fuel economy was horrbile and that I was burning through Cats. If this was the case then I would just be dumping fuel and my Cat would have to handle all of it, which would lead to a premature Cat Failure. My car has long starts every once in awhile and it would make sense because fuel was getting in.

All the symptoms of a stuck open fuel injector would/ can cause all the problems ive had yes? Any insight would greatly be appreciated as I dont know how to tell if my injectors are stuck open, this is just a thought that came to my mind because my fuel economy, especially with a brand new reman>>> BHR ignition>>> New spark plugs 6k miles ago>>> Cobb AP and Premixing with Idemitsu>>> Royal Purple oil... Hell my car should be running like a princess yet shes not. Horrible fuel ecomony. I mean the last 4-5 tanks have been ALOT lower. Im used to be getting 200miles to a tank (14.5mpg City on 14.5Gallon fill up).

Is there any way the Cobb AP datalogs can track if my fuel injector is stuck open or if there is a problem somewhere? How hard is it to remove my Primary and Secondary Fuel Injectors? (Noob question but ive never done it, BUT I have removed and cleaned my SSV so I dont think it can be harder than that, Im willing to learn). I know how fuel injectors work (voltage opens the injectors etc), is there any way I can remove them and check if they are stuck open? Any device that would check if they are?

Thanks for the help guys,

Brandon

P.S. - If this is the problem I have Im going to be so angry with Mazda with this new Reman. After initially getting denied and having to fight to get it approved This engine has caused my so many problems so far. My Low Oil Light Sensor is already broken causing my oil light to come on when I redline (WTF new engine???) and now this? This seems somewhat weird that this engine has this many problems already with less than 5k miles. I know the Fuel Injectors are a swap from my old engine to the new one (right???) but this is getting a ridiculous. If this happens to be my problem I might give MNAO/ my dealer a phonecall explainging how I feel about this...

Last edited by WTBRotary!; 02-09-2011 at 01:39 PM.
Old 02-09-2011, 01:40 PM
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If your injector was stuck open the car would not idle - probably it would not run at all .

More likely start looking at all the things that can cause a car to run rich

02sensor out of whack
maf sensor
blocked air filter

Do you have the ability to log AFRs - that may tell you something .
Old 02-09-2011, 01:48 PM
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Yes, I have the ability to log my AFR's.

I can look at my old Cobb Datalogs that I sent to Jeff (MM) before my Cat clogged. I was running 11.2 Air:Fuel @ WOT on Jeffs Base Map while premixing before I got my new(er) Cat, so I was probably running richer . I havent installed the Cobb AP since I got my New(er) Cat so I didnt clog it, but I will install it and toss you some new AFR's from it once my car is warmed up if youd like.

The reason I thought it was my fuel injector stuck open because I have NEVER HAD a CEL, I didnt think a stuck open fuel injector would toss a CEL. Would not the above reasons provoke a CEL to come on Brettus? Maybe my fuel injector is slightly stuck? idk...

I can rule out the MAF Sensor and Air filter because before my engine went 2.5K miles ago I cleaned my MAF senor and after I receieved my new reman I reinstalled my AEM CAI because the dealer didnt know how to install it properly.
Old 02-09-2011, 01:50 PM
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^ Yes, you have a cobb. Look at your afr's. If you had a stuck injector your car would likely not run well at all.


Also, how old is your fuel pump?

Last edited by 9krpmrx8; 02-09-2011 at 01:53 PM.
Old 02-09-2011, 01:52 PM
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^^^ Well for the last 500 miles I havent been looking at my Cobb because it hasnt been installed. I didnt want to clog the next Cat, so I havent been able to log my AFR's
Old 02-09-2011, 01:54 PM
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Originally Posted by WTBRotary!
^^^ Well for the last 500 miles I havent been looking at my Cobb because it hasnt been installed. I didnt want to clog the next Cat, so I havent been able to log my AFR's

Plug it in, got for a ride, datalog, post results. What about your fuel pump (mileage, etc.)?
Old 02-09-2011, 01:58 PM
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I will go reinstall it and try to go for a ride Scott haha but it snowed up here so I will have to be carefull when driving. I might have to go out tomorrow to test it because of the Ice and Snow.

As far as the fuel pump I just hit 50K miles ago like 3 weeks so thats all it has on it. Car is a late model 2005 WB GT.
Old 02-09-2011, 02:13 PM
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When you look at AFRs you want to look at the idle/cruise/light throttle numbers not WOT .

Have you had your plugs out to see how they look ?
Old 02-09-2011, 02:19 PM
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Usually my AFR's before my new(er) Cat were around normal 14.7, but I will double check to make sure. Ill post my datalogs hopefully today in a few hours. Its still all Ice outside.

I have not had my plugs out since then, I figured they would be fine since I just changed them like a few months ago.
Old 02-09-2011, 02:24 PM
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Also check your fuel trims - that might offer a clue ...



When my 02 sensor went bad the reading I got was a constant 14.7 . It would run ok for a few mins then crap out .
Old 02-09-2011, 02:26 PM
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Damn, new O2 Sensors are $$$.

Question: When your O2 Sensor went out did you get a CEL or no?

Ill Log my fuel trims as well and post them up when I can get out of the house..
Old 02-09-2011, 02:31 PM
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Originally Posted by WTBRotary!
Damn, new O2 Sensors are $$$.

Question: When your O2 Sensor went out did you get a CEL or no?

Ill Log my fuel trims as well and post them up when I can get out of the house..

I don't want to hear any crying about snow Get those data logs soldier!!!
Old 02-09-2011, 02:33 PM
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^^^ Yes Sir... lol Im getting ready now... I should have them within the hour...
Old 02-09-2011, 02:35 PM
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Originally Posted by WTBRotary!
Damn, new O2 Sensors are $$$.

Question: When your O2 Sensor went out did you get a CEL or no?

Ill Log my fuel trims as well and post them up when I can get out of the house..
I got a second hand o2 from Mazmart for under $100 IIRC

Don't think I got a cell but can't be sure because my cel is always on anyway .
Old 02-09-2011, 02:43 PM
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Originally Posted by Brettus
I got a second hand o2 from Mazmart for under $100 IIRC

Don't think I got a cell but can't be sure because my cel is always on anyway .

Okay cool, If this turns out to be the problem Ill that a try
Old 02-09-2011, 04:28 PM
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Okay Im back... Read Datalogs 5,6,8,9... Those are the ones I made. They are slightly long but they contain what you asked for Brettus

Datalog 5: https://spreadsheets0.google.com/ccc...cG&hl=en#gid=0

Datalog 6: https://spreadsheets1.google.com/ccc...sL&hl=en#gid=0

Datalog 8: https://spreadsheets1.google.com/ccc...kB&hl=en#gid=0

Datalog 9: https://spreadsheets0.google.com/ccc...CJH99-8N#gid=0

Last edited by WTBRotary!; 02-09-2011 at 04:36 PM.
Old 02-09-2011, 04:30 PM
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Give me access to see it, i sent a request.
Old 02-09-2011, 04:31 PM
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Ugh Goddamn Google Docs, How do I make it Public?

Edit: It should work now Scott...
Old 02-09-2011, 04:34 PM
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Still no worky.
Old 02-09-2011, 04:37 PM
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Work now?
Old 02-09-2011, 04:50 PM
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OKay well I hope that works fellas, it says they are "Shared with Link" so anyone that visits this thread should be able to see them.

I felt everything I saw was normal, Idk... Nothing seems strange to me...but hell thats why im asking yall...
Old 02-09-2011, 04:51 PM
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Yep, I see some spots where you are lean for almost two seconds. I will have to compare to some of my logs but from memory, I only get that lean for a few tenths of a second. But I will have to compare to really see. But if you are cruisng at a certain speed you really should not be going lean while staying at the same RPM.

Still reviewing.

Last edited by 9krpmrx8; 02-09-2011 at 04:53 PM.
Old 02-09-2011, 04:57 PM
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If Where my AFR's go to 20.3 is what your talking about Scott, thats where I let off the throttle and stayed in gear slowing down. Its always done that, when I get on the throttle roughly constant again it goes back to ~ 14.7
Old 02-09-2011, 05:00 PM
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Originally Posted by WTBRotary!
If Where my AFR's go to 20.3 is what your talking about Scott, thats where I let off the throttle and stayed in gear slowing down. Its always done that, when I get on the throttle roughly constant again it goes back to ~ 14.7

Yeah but on log 9 and in other spots it goes to 20 for a while and your RPMS and speed are constant. Can you go out, set the cruise control in 4th gear, start logging for 2 minutes, then stop logging. That way we can see what the car does at cruise, with a load at a set speed.

Last edited by 9krpmrx8; 02-09-2011 at 05:03 PM.
Old 02-10-2011, 06:51 PM
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Bump... I couldn't get that log today Scott but I'll try again tomorrow

Anyone else have any ideas? I'm still scratching my head on this one.


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