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Old 12-31-2009, 02:16 PM   #26
jimb
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Disregard the diagram, I believe it might be different. You guys have got some of the circuitry back in the controller. General idea is the same though.

I remember an older thread over at RomRaider where some folks were looking into how the ECU determined the fuel pump duty cycle, and I believe one of the determinants was injector base width.

On a whim, does the car run properly if you force the fuel pump to 100% DC by hardwiring it to 12v/ignition? Yes, I realize that this is a bandaid.
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Old 12-31-2009, 02:45 PM   #27
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Quote:
Originally Posted by jimb View Post
On a whim, does the car run properly if you force the fuel pump to 100% DC by hardwiring it to 12v/ignition? Yes, I realize that this is a bandaid.
have no tried this yet, but i am def going to
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Old 12-31-2009, 04:57 PM   #28
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I agree with hardwiring the pump to help narrow down where the problem could be.

what are the fuel trims doing in learning view? I know you are using ap, but I believe you can still check it. Also have you tried hooking up something to simulate boost on the fpr?
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Old 12-31-2009, 10:00 PM   #29
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Here's a quote from MerchGod on the RomRaider thread.

"I took a brief look at it again and it is primarily determined by the base pulse width. There are RPM thresholds and several counters that are involved as well."

So I guess that what would be infomative for you would be someone else's log with IPW, FP Duty Cycle, RPM and the usual other parameters from a similar setup.

Here's the whole thread. It's good reading.http://www.romraider.com/forum/topic...ump duty cycle

There is some debate there Re: running the FP at 100% full time. I don't think it's a problem. The only real argument against it is that it could heat up the fuel. The gas tank has so much surface area that I don't see how it could be much of an issue.

Anyway, I'm wondering if:
1. Your injectors are scaled correctly.
2. Your Big MAF is scaled correctly.
3. Your MAP sensor is hooked up (the hose).

If your injectors are set too large, you would still be able to get a nice idle by messing with the MAF settings. This would lead to low IPW's further up the scale and maybe not trigger the FP to higher duty cycle.

Also, I have to believe that MAP is one of the inputs that change FP duty cycle. It's easy to check to see that the hose is connected to the sensor and to the manifold. Or you could just log MAP.

We really need to see a log of what's going on.

I hope you figure this out. If not, running the FP at 100% isn't the worst thing in the world.

Buck
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Old 01-01-2010, 01:53 AM   #30
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i had a friend with the same problem, wouldent go into boost watsover but was still drivable, ended up taking one of his boost pipes on his fmic (custom blow thru maf) and had condensation and water all over the place cause the maf to spike at 5v every time i tried to gas it... probably not your problem
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Old 01-01-2010, 05:26 AM   #31
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bunk injectors?? whats your injecotr duty cycle read under load? at it is one of the few things that has different maps for under load and at idle I would start there, I have had a few injector problems in my day and it sounds likely

also check the harness's from the ECU to motor for any breaks, pinches, etc I had this problem as well when I did my swap
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Old 01-01-2010, 05:30 AM   #32
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Quote:
Originally Posted by bucket7788 View Post

There is some debate there Re: running the FP at 100% full time. I don't think it's a problem. The only real argument against it is that it could heat up the fuel. The gas tank has so much surface area that I don't see how it could be much of an issue.

Anyway, I'm wondering if:
1. Your injectors are scaled correctly.
2. Your Big MAF is scaled correctly.
3. Your MAP sensor is hooked up (the hose).

If your injectors are set too large, you would still be able to get a nice idle by messing with the MAF settings. This would lead to low IPW's further up the scale and maybe not trigger the FP to higher duty cycle.

Buck
exaclty what I am getting at Injector scaling is a huge part of tuning that is often mis-understood

not a common suggestion but one that works, switch back to a stock map, car WILL idle correctly since your idle scaling shouldnt change unless you change engine size, the SLOWLY bring it up to boost while carefully watching your AFR (dont want to blow a motor) but just to check if it mechanical or tuning
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Old 01-01-2010, 08:37 AM   #33
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This is only vaguely related, but years ago I had a problem with my Alfa Romeo, where it would drop off at a precise RPM, around 4000. After replacing sensors, I've taken a look at the ground bus.
I decided to re-ground everything directly to the battery. That took care of it.
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Old 01-01-2010, 12:06 PM   #34
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Quote:
Originally Posted by 2gnt2wrx View Post
I guess you could start with these.

AF correction, AF learning, AF sensor 1, Accel pedal angle, cl/ol fueling, Engine load, eng spd, feedback kc, fine learning kc, IAM, Ignition total timing, IDC, KC advance, Manifold absolute psi, Mas airflow/voltage, Primary wgdc.
Why manifold absolute psi and not manifold relative pressure?
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Old 01-01-2010, 06:13 PM   #35
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Do me a favour and check your cam timing. Make sure its spot on.. It sounds very similar to a cam timing issue I have had in the past.

Then check your fuel lines and make sure they arent backwards or something.. Check your fuel pressure regulator (if aftermarket) and make sure the same thing.

Other than that.. Do you have the ability to see the injector milliseconds with the accessport? If so I would like know what they are when the car will not rev above 3000 on the road.
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Old 01-02-2010, 08:44 AM   #36
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also are you logging with a wideband when it won't go past 3000? Would love to see what the air fuel is actually doing before and at 3000 rpms.
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Old 01-02-2010, 11:24 AM   #37
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that diagram is worthless don't look at it. I doubt the FPC is wasted but its possible. The reason you aren't seeing any % increase is because the car is not making boost. The ecu increases % based on throttle AND MAP pressure.

my guess

after maf leak
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Old 01-02-2010, 02:51 PM   #38
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Quote:
Originally Posted by St0k3d View Post
im going to go put the car on my dyno right now and try driving it and making some changes... any suggestions?

check the FPR while the car is on the dyno. that way you have a load on the car and its not going anywhere
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Old 01-02-2010, 05:40 PM   #39
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Quote:
Originally Posted by sidewayz View Post
that diagram is worthless don't look at it. I doubt the FPC is wasted but its possible. The reason you aren't seeing any % increase is because the car is not making boost. The ecu increases % based on throttle AND MAP pressure.

my guess

after maf leak
Agreed.....sounds similar to another car I know of that had uncalibrated/altered MAF issues
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Old 01-02-2010, 06:22 PM   #40
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Quote:
Originally Posted by wrxtasy555 View Post
Have you tried swapping out the plugs? I know that it's unlikely they would fail, but I have come across bad plugs before.

faulty plugs will not cause a lean condition.



Maybe try an aftermarket fuel management like Hydra. Im at a loss here man.
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Old 01-02-2010, 06:53 PM   #41
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I'm just waiting for a log so we can see what the ecu is doing.
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Old 01-02-2010, 07:13 PM   #42
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Quote:
Originally Posted by teesutt View Post
faulty plugs will not cause a lean condition.



Maybe try an aftermarket fuel management like Hydra. Im at a loss here man.
Well, to be fair, a misfire directly signals a lean conditon.
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Old 01-02-2010, 09:08 PM   #43
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Quote:
Originally Posted by 2gnt2wrx View Post
I'm just waiting for a log so we can see what the ecu is doing.
+eleventy billion
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Old 01-03-2010, 05:17 PM   #44
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Quote:
Originally Posted by modaddict View Post
Well, to be fair, a misfire directly signals a lean conditon.
I disagree. I had a coil go bad on the 3 cylinder. Car ran rich as hell.

If a plug doesnt fire, the fuel isnt going to ignite, raw fuel is dumped into the exhaust. Would make for a nice firework out the tailpipe though.
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Old 01-03-2010, 05:34 PM   #45
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Quote:
Originally Posted by teesutt View Post
I disagree. I had a coil go bad on the 3 cylinder. Car ran rich as hell.

If a plug doesnt fire, the fuel isnt going to ignite, raw fuel is dumped into the exhaust. Would make for a nice firework out the tailpipe though.
There is no way to disagree.

a misfire WILL DUMP OXYGEN in the exhaust! What is an oxygen sensor? IT DOES NOT MEASURE FUEL! It measures oxygen.

Therefore, a misfire will send a charge of OXYGEN in the exhaust which will send the o2 sensor into showing a lean voltage conditon. (which is around 0.0v rather than 1.0v.)

FYI, AFR is 14.7:1. 14.7 parts of OXYGEN to 1 part FUEL or, to say it another way, there is 14.7 times more oxygen than fuel in 1 combustion event.

The reason why you ran rich is because the oxygen sensor thought your car was running lean. Therefore, it poured the fuel into the cylinders to try to compensate for the lean condition. (which it really wasn't lean, it was being fooled by a misfire)

Understand now?
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Old 01-03-2010, 07:54 PM   #46
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Quote:
Originally Posted by bucket7788 View Post
Here's a quote from MerchGod on the RomRaider thread.

"I took a brief look at it again and it is primarily determined by the base pulse width. There are RPM thresholds and several counters that are involved as well."

Anyway, I'm wondering if:
1. Your injectors are scaled correctly.
2. Your Big MAF is scaled correctly.
3. Your MAP sensor is hooked up (the hose).

We really need to see a log of what's going on.

Buck
I have to agree with this, though the thread is talking about the 16bit ecu and I haven't looked at the 32bit(I will try to do so this week) but I can't imagine it changed much.

I would definitely look into the injectors being scaled correctly, as that seems to be the most likely cause.

Andy
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Old 01-03-2010, 08:29 PM   #47
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If you modified voltage instead of MAF G/S when scaling the MAF this could cause the Fuel pump to get stuck at 33%. Make sure your load zones are at or above stock values at WOT.

Check the injector scaler as well. It should be at or above stock.

Gabe

Last edited by gabedude; 01-03-2010 at 08:36 PM.
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Old 01-04-2010, 01:25 PM   #48
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Did you try bypassing the fuel pump control module yet? The main purpose of multi-speed fuel pump control on a return system is to reduce the amount of fuel vapor generated. The vapor is bad for HC emissions and under some circumstances can cause hard starting. Extra fuel vapor is caused by lots of hot fuel returning to the tank, so the duty cycle is adjusted.

It is VERY common to hardwire a fuel pump in performance applications. It's not going to cause serious problems if you keep an eye on the tune. Older cars have a 2 speed system using a resistor, and the ECU will switch a relay to go from low to high speed. Frequently the resistor is bypassed.
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Old 06-04-2010, 06:59 AM   #49
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Hmmm, this is interesting, I bet it is something small. I got a weird feeling that maybe along the way a wire got pinched somewhere and is shorting out. Same thing happened to my friends Supra, except his would bog and wont rev past 4K, then it would just flat out stall while driving and going around corners. We found the ground wire was all bashed up along with the power wire shorting to the chassis. Just a thought.

Update?
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Old 10-02-2012, 02:06 PM   #50
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opps way old thread lol
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