Running lean...need advice!
16 March 2009, 09:03 PM
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Running lean...need advice!
Hawkeye WRX running about 400ish.
Harvey Smith TD05/06 20G
APS TMIC.
Fuel side of things
Fuelab FPR
Some modified injectors (flow matched etc from Lateral Performance)
Bosch 6 bar fuel pump
It's always had problems running lean since day dot. Tried several pumps and finally settled on the bosch. It has to be ok...
Had STi pinks, still ran lean. Onto modified injectors which Mark had flow matched and checked.
Fuelab...not heard of them going wrong often but a possibility.
It's recently been mapped by Bob Rawle (3 or 4 weeks ago).
OK, the scene is set....took it out on the LM-1 tonight and top end it's leaning right out. I'm fed up to be honest, apart from possibly scrimping on the injectors everything has been spot on. I've tried to do the best I can! Looks like over 5k rpm it goes to like 12 AFR.
Thinking of buying a new FPR this week and trying it. It's certainly the cheapest possible fix. Failing that it's injectors and remap...
Any more suggestions about what could be causing it to run lean?
Many thanks in advance!
Harvey Smith TD05/06 20G
APS TMIC.
Fuel side of things
Fuelab FPR
Some modified injectors (flow matched etc from Lateral Performance)
Bosch 6 bar fuel pump
It's always had problems running lean since day dot. Tried several pumps and finally settled on the bosch. It has to be ok...
Had STi pinks, still ran lean. Onto modified injectors which Mark had flow matched and checked.
Fuelab...not heard of them going wrong often but a possibility.
It's recently been mapped by Bob Rawle (3 or 4 weeks ago).
OK, the scene is set....took it out on the LM-1 tonight and top end it's leaning right out. I'm fed up to be honest, apart from possibly scrimping on the injectors everything has been spot on. I've tried to do the best I can! Looks like over 5k rpm it goes to like 12 AFR.
Thinking of buying a new FPR this week and trying it. It's certainly the cheapest possible fix. Failing that it's injectors and remap...
Any more suggestions about what could be causing it to run lean?
Many thanks in advance!
16 March 2009, 09:22 PM
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Up to 12 is some cases is not a problem, that would be down to your mapper to decide.
Have you checked there is no voltage drop to the pump, also fuel filer? Fuel lab regs very rarely if ever give trouble in my experience, and if this was suspect I would suggest checking the diaphragm first.
It’s also good to recalibrate the LM1 on a regular basis to keep a constant accurate reading.
Have you checked there is no voltage drop to the pump, also fuel filer? Fuel lab regs very rarely if ever give trouble in my experience, and if this was suspect I would suggest checking the diaphragm first.
It’s also good to recalibrate the LM1 on a regular basis to keep a constant accurate reading.
Last edited by Slowboy Racing; 16 March 2009 at 09:26 PM.
16 March 2009, 09:28 PM
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Yeah, everyone seems happy with the FPR and as far as I can see I'm getting good pressure. 3 on idle, rising up to 5+ with 1.5 bar boost.
Think I'll have to do some checking with regards to voltage drops. I've never been entirely happy with the power side of things (electrical power). Thank you for your suggestion!
Think I'll have to do some checking with regards to voltage drops. I've never been entirely happy with the power side of things (electrical power). Thank you for your suggestion!
16 March 2009, 09:46 PM
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Find out the current capacity of the pump, it's probably way higher than the standard item. I would almost suggest a separate feed via a relay and a hidden "kill switch 
" using the correct gauge of wire. And a similar earth lead too.
dunx
" using the correct gauge of wire. And a similar earth lead too.dunx
16 March 2009, 11:32 PM
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As SlowBoy said, check you LM-1, has it been recalibrated in free air recently? Can you check it against your stock O2 sensor, this is reasonably accurate to about 11.2-11.1 AFR, so could tell you if your WB is in the ball park.
17 March 2009, 06:52 AM
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We'll get the LM-1 calibrated and take it out on a known good car. Then take mine out. Just finding the time with quiet enough roads (so as not to kill ourselves).
Definately going to have to check the wiring thing though, been reading about how much current the bosch pulls at 5bar of FP and it's quite high. (checking for other sources).
Cheers
Stew
Definately going to have to check the wiring thing though, been reading about how much current the bosch pulls at 5bar of FP and it's quite high. (checking for other sources).
Cheers
Stew
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17 March 2009, 08:49 AM
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It's ran lean in the past. It's been mapped twice since, both times I've had suspected fuelling issues which have led me to get a remap (once changing injectors).
Maybe it's the LM-1. I need to get it checked on another one. That said, my mechanic has tried it on other cars and it's been spot on.
EDIT - Also had two rebuilds in 16k miles since new. First time fitted Mahle pistons, second time just replaced the knackered one. Ringland both times.
Maybe it's the LM-1. I need to get it checked on another one. That said, my mechanic has tried it on other cars and it's been spot on.
EDIT - Also had two rebuilds in 16k miles since new. First time fitted Mahle pistons, second time just replaced the knackered one. Ringland both times.
Last edited by Semper; 17 March 2009 at 08:50 AM.
17 March 2009, 06:53 PM
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Hopefully off to try it on another LM-1 on Friday. Will update.
Going to ask some of the lads at work the best way of checking the current while I'm at 5 bar of pressure.
Going to ask some of the lads at work the best way of checking the current while I'm at 5 bar of pressure.
20 March 2009, 10:25 PM
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Quick update.
Took it out on the LM-2 today (Thanks Harvey). Still running lean toward the top end (6k+) and appeared to be lean in the midrange too.
Current tasks are
Move FPR, replace hosing and make sure everything ok. DONE (No change)
Uprate wiring to Bosch. Doing tomorrow so we'll see what happens.
Thinking of putting a 8-10 bar Bosch in. Possibly changing FPR temporarily. Beyond that, not a lot more I can think of.
Took it out on the LM-2 today (Thanks Harvey). Still running lean toward the top end (6k+) and appeared to be lean in the midrange too.
Current tasks are
Move FPR, replace hosing and make sure everything ok. DONE (No change)
Uprate wiring to Bosch. Doing tomorrow so we'll see what happens.
Thinking of putting a 8-10 bar Bosch in. Possibly changing FPR temporarily. Beyond that, not a lot more I can think of.
20 March 2009, 11:52 PM
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Quick dumb idea, swap the fuel connections and back flush the fuel pick-up, to clear any debris.
Mine is managing around 400 bhp on a Walbro.
dunx
Mine is managing around 400 bhp on a Walbro.
dunx
21 March 2009, 11:30 PM
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Today we rewired the pump direct from the battery with a relay for switching pump on and off using the standard wiring to switch the relay.
Car ran spot on. 11.2 ish. Then we got a CEL. I think it was "Fuel Pump Primary Circuit" but will check with laptop in the morning. From then on, car ran lean again. Not dropping below 12. Ran it on LM-1. Same, so at least my LC-1 is working. Cleared the CEL and tried it again. Ran spot on, leaning out at top end as expected, but 11.2 until 6k rpm. Light keeps returning, so clearly a fault in the wiring is causing light to come on and car is entering a "limp" state. Only symptom is lean running. Still boosts etc.
Also, the hose from the tank cover to the pump was seriously degraded. Possibly been ballooning up in the tank and causing problems. This MAY be the root cause of the issue!
Anyone know how to resolve the CEL? Got a wiring diagram for that end of the car?
I'll never use a walbro ever again after a failed one taking an engine out and probably causing a second to go. Too many horror stories for me! Lots of people using them without issue, but it's a case of I've had my fingers burned, never again!
Car ran spot on. 11.2 ish. Then we got a CEL. I think it was "Fuel Pump Primary Circuit" but will check with laptop in the morning. From then on, car ran lean again. Not dropping below 12. Ran it on LM-1. Same, so at least my LC-1 is working. Cleared the CEL and tried it again. Ran spot on, leaning out at top end as expected, but 11.2 until 6k rpm. Light keeps returning, so clearly a fault in the wiring is causing light to come on and car is entering a "limp" state. Only symptom is lean running. Still boosts etc.
Also, the hose from the tank cover to the pump was seriously degraded. Possibly been ballooning up in the tank and causing problems. This MAY be the root cause of the issue!
Anyone know how to resolve the CEL? Got a wiring diagram for that end of the car?
I'll never use a walbro ever again after a failed one taking an engine out and probably causing a second to go. Too many horror stories for me! Lots of people using them without issue, but it's a case of I've had my fingers burned, never again!
23 March 2009, 08:34 AM
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Well...it's back (the problem that is).
Sorted the pump/relay wiring. CEL cleared and gone. Grommets in fuel tank cover leaked when I filled to the brim so we sealed that up properly. Gave it some WOT and seemed sorted. Driving to work today, 11.2...11.5...11.9...12.0 CEL back! ARRGGHHH. What a proper ballache. Ran lean after about 4.5k but probably due to CEL. Guess it retards the fuel supply somehow when it's on. Anyone confirm? No other symptoms.
I'm really at the end of my tether. Spent about 24 hours this weekend moving FPR, rewiring pump, fannying on...still no further forward really.
Think I'm going to have to start throwing money at it, but don't know where to start.
FPR, Injectors, Pump?
Exhaust Gas Recirc system has been brought up. Any ideas on whether that could be defective somehow?
Many thanks
Stew
Sorted the pump/relay wiring. CEL cleared and gone. Grommets in fuel tank cover leaked when I filled to the brim so we sealed that up properly. Gave it some WOT and seemed sorted. Driving to work today, 11.2...11.5...11.9...12.0 CEL back! ARRGGHHH. What a proper ballache. Ran lean after about 4.5k but probably due to CEL. Guess it retards the fuel supply somehow when it's on. Anyone confirm? No other symptoms.
I'm really at the end of my tether. Spent about 24 hours this weekend moving FPR, rewiring pump, fannying on...still no further forward really.
Think I'm going to have to start throwing money at it, but don't know where to start.
FPR, Injectors, Pump?
Exhaust Gas Recirc system has been brought up. Any ideas on whether that could be defective somehow?
Many thanks
Stew
23 March 2009, 06:59 PM
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I've stuck a Defi gauge with the sensor screwed into the Fuelab regulator on mine, to monitor the differential pressure boost/fuel, this way the gauge just sits at 3.8 bar, and any movement downwards = weak mixture = ALARM !
HTH
dunx
HTH
dunx
23 March 2009, 07:02 PM
#22
Having looked at the logs now and as suspected this is topping the maf scale out - that is causing the leaning out.
The WRX ROM turns over at the top anyway and with you hitting the 295.11 max level at about 5100 it has no idea of any airflow above that and thus doesnt know that it should be adding more fuel.
You could tweak it in the map but I reckon that wold be a bodge - bigger MAF tube required (remap to suit) and job done.
The WRX ROM turns over at the top anyway and with you hitting the 295.11 max level at about 5100 it has no idea of any airflow above that and thus doesnt know that it should be adding more fuel.
You could tweak it in the map but I reckon that wold be a bodge - bigger MAF tube required (remap to suit) and job done.
23 March 2009, 07:11 PM
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Thanks for checking that out Duncan. Will speak to Bob about getting a slot booked in.
I've asked on the other place, but any recommendations for a bigger maf pipe/intake?
Cheers
I've asked on the other place, but any recommendations for a bigger maf pipe/intake?
Cheers
23 March 2009, 11:44 PM
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Just talking about that now...done some logging and posted on 22b. MAF certainly looks maxed out. Wouldn't be surprised if this was the root cause.
Going to ring Dave Stone tomorrow about the APS kit.
Going to ring Dave Stone tomorrow about the APS kit.
24 March 2009, 12:03 AM
#26
Therefore the car is underestimating the air flow in by 55 gram/sec - and would be going lean (dangerously lean)
Depending on how the map was done (I am led to believe not all mappers rescale the loads columns fully) it may be in a completely different load cell for timing (ie running more timing than it should) and fueling (possibly running leaner still) aswell as running leaner from the under read on the maf.
Was it the same turbo and map on the other engines?
