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Discussion Starter #1
I took a few logs on the DH today when I took the car for a test drive. My hopes weren't up too high, so I wasn't that disappointed that fuel pressure isn't back to normal. I attached 1 excel file w/ 5 datalogs in separate sheets. The important parts and a couple notes are highlighted and boxed, so it's really easy to see/find. I left some of the filler there in case someone can gleam something out of it.

My mech was bummed that the new relays and resistor that I swapped out last week didn't work. The new tank pump from Monday didn't help either. He's gonna check the voltage from the tank pump (it's low/high for idle/off idle) at idle and under load to see what's going on. It may be a wire harness problem to the tank pump... we don't know. He's gonna start there, and work his way to the front starting next week, lol.

Again here's the issue in a nutshell:
1. Low idle fuel pressure
2. Normal pressure under Part Throttle
3. Insufficient fuel pressure under WOT

From the logs:
1. The above + AFRs are okay (maf needs calibration, but not important at this point)
2. Logged Injection amount mg/cl in the last log
**** I am NOT familiar with this PID at all, and was hoping some Guru could take a peek a this and give some feedback.


Thanks again, and sorry to :deadhorse:. However, every good idea gets me a bit closer to being back on the road, can save me money I don't have, and is greatly appreciated.


Thanks fellas!
 

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this is with the CPE pump? so it wasnt the PTP pump?

did you twizzler your fuel rail?
 
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Discussion Starter #3
this is with the CPE pump? so it wasnt the PTP pump?

did you twizzler your fuel rail?
This issue arose after the 1st PTP pump died. 2nd PTP pump, same issue. New stock pump, same issue. New CPE pump, same issue. It happened while the PTP pump was installed, but it may/may not be related to it's failure.

Please define twizzlering the fuel rail? lol Forzda mentioned it could be the fuel rail leaking, or possibly that the fuel pressure sensor, which is part of the fuel rail shit the bed... unlikely, but who the fuck knows at this point. Any input from the attached logs?
 

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while removing the large nut on the fp, philly literally twizzler'd/twisted the fuel rail... theres a fs thread on msf with a new hard line and pump housing just in case, real cheap too
 
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Discussion Starter #5
while removing the large nut on the fp, philly literally twizzler'd/twisted the fuel rail... theres a fs thread on msf with a new hard line and pump housing just in case, real cheap too
Oh yeah... no Bova and Philly I think mentioned that to me a couple months back on msf, and there was no twizzlering of the hard fuel line, lol. You must mean the hard fuel line going from the hpfp to the fuel rail, right? I don't think it would be physically possible to warp/damage the fuel rail without twisting the hard fuel line in the process. The hard fuel line is fine, but good suggestion.
 

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err yea, hard line not the rail...

its hard to say what the issue is from the log... my CDI internals did the same thing when the retainer locks wore down. low idle pressure, ok cruise... drop at wot... but my pressure built up slowly instead of instantly
 

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well.. if you only had wot fuel problems i would maybe be leading a voltage drop issue. you prolly have no idea what im talking about but for ex you can check wires, check voltage and resistance of wires with your new handy multimeter. But sometimes the wires can check ok in these test but when passing current through the wires(when the component is on) the wire could not transfer all the voltage and current needed. so it would make sense you could have a voltage drop issue in the wires going to either of the fuel pumps for WOT. but you also have idle pressures so there would be less current at those times and maybe a voltage drop wouldnt be the case..


im starting to lean more towards a pcm/ecu issure here man..... fordza how is the circuit for the hpfp controlled. ignition source to pin 1 and pin 2 pwm to ground?
 

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Discussion Starter #8 (Edited)
^Yeah if it was only at WOT, then the tank pump would be the prime suspect as there is just the low/hi voltage for idle/off idle (low flow/max) controlled by tank pump. However, the low idle pressure makes no sense as you said, if this is what you're talking about? Yeah, everything seems OK, which is why we want to test it under load to make sure the current holds. If this is what you're saying, I know exactly what you're talking about, and it's pita to problem solve.

Voltage going to the hpfp is normal at idle, but I didn't try it under load at the time. Again, this would be a wire harness issue, as the solenoid to the hpfp is fine.

It's a fucked up problem, right? LOL I hope it's not the ECU, but very well could be...

err yea, hard line not the rail...

its hard to say what the issue is from the log... my CDI internals did the same thing when the retainer locks wore down. low idle pressure, ok cruise... drop at wot... but my pressure built up slowly instead of instantly
CDI internals? I bought the pump pre-assembled, so I'm not sure what the retainer locks are, exactly. If it's part of the hpfp assembly itself, then that is definitely not my problem. I think there are some sort of gremlins in there... I think Rosie O'Donnel's grizzley snatch is haunting my fuel system... HELP!!
 

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Doogie, send me your damn car and I'll fix it....!!!!!!!!

After viewing ALL the logs, I stick by my original theory of a blockage in the fuel hard line from the HPFP into the fuel rail. The issue here is not really the pressure, rather the FLOW. You and your mechanic may have washed it out, blown it out and blah, blah, blah, but I say it is the problem hands down.

At idle, there is very little actual HPFP action, so the pressure is low, but that is all you can see. The fuel flow at idle is such that the blockage is not allowing enough flow past to keep the pressure within spec. When you're at part throttle, the HPFP is ramped up to max output and the flow can keep up with demand while under that high pressure and relatively low demand at part throttle. When you hold it WOT for just a bit, the revs come on up and the flow requiirements are much higher. At this point the HPFP can't keep up enough fuel flow through the blockage to keep the pressure up. As soon as you chop the throttle at high revs, the pressure pops right up to 1800psi because the HPFP is running at max output and there is NO fuel demand. The AFRs are staying within safe limits as the fuel supply is more than adequate with a car in your state of mod/tune.

The pressure sensor is at the far end of the rail, so I'm saying the problem is in the hard pipe to rail or at the rail entrance. Now change out the damn fuel line from the HPFP all the way to the injectors (hard pipe AND the fuel rail) and start driving your car again!!!!!! Good Luck!
 
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that makes alot of sense fordza, i did find it odd with all the wacky fuel pressures afr werent off
 

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that makes alot of sense fordza, i did find it odd with all the wacky fuel pressures afr werent off

Yeah, my experience with this car says that the fuel system is WAY more than adequate (pressure and flow) to support near double the stock power(with upgraded HPFP). I ran my car with all current mods on the OEM pump for a LONG time with fuel pressure dropping into the 1k psi range occasionally at WOT with NO problems. I only went with the upgrade kit when I was about prepping for the bigger turbo, etc. Theory says we need the max fuel pressure, but the car will perform well at lower pressures unless going for the maximum power it can put out. If the AFR is leaning out, then the ECU will command more injector duty cycle (IDC) to keep up with AFR targets.

In Doogie's case, IMO, the PTP pump shit itself and spit "stuff" into the fuel line and the car would actually hit a cut driven from some where. It may have hit a max IDC driven fuel cut, I don't know. When he got that POS PTP pump off, the car still had fuel problems, but no cut, so that "proves" (to me) that the PTP pump had truely shit itself.

Now all this is MY theory based on what I've learned over the years and within the past 3 years on this particular car, so I could always be wrong about it all, but I've proven it to (convinced!) myself, so take as you will.:D
 
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Discussion Starter #13 (Edited)
Doogie, send me your damn car and I'll fix it....!!!!!!!!
If I could get it there for $200 each way, it'd be there.

After viewing ALL the logs, I stick by my original theory of a blockage in the fuel hard line from the HPFP into the fuel rail. The issue here is not really the pressure, rather the FLOW. You and your mechanic may have washed it out, blown it out and blah, blah, blah, but I say it is the problem hands down.
I know it's a flow problem, but the one thing that bugs me is that it's SO consistent. That is, if there is some debris in there, you would think that there would be at least SOME hiccups in fp under PT. However, there is not.

At idle, there is very little actual HPFP action, so the pressure is low, but that is all you can see. The fuel flow at idle is such that the blockage is not allowing enough flow past to keep the pressure within spec. When you're at part throttle, the HPFP is ramped up to max output and the flow can keep up with demand while under that high pressure and relatively low demand at part throttle. When you hold it WOT for just a bit, the revs come on up and the flow requiirements are much higher. At this point the HPFP can't keep up enough fuel flow through the blockage to keep the pressure up. As soon as you chop the throttle at high revs, the pressure pops right up to 1800psi because the HPFP is running at max output and there is NO fuel demand. The AFRs are staying within safe limits as the fuel supply is more than adequate with a car in your state of mod/tune.

The pressure sensor is at the far end of the rail, so I'm saying the problem is in the hard pipe to rail or at the rail entrance. Now change out the damn fuel line from the HPFP all the way to the injectors (hard pipe AND the fuel rail) and start driving your car again!!!!!! Good Luck!
This makes sense, but only if whatever is causing the possible clog is immobile. If there was a piece of shit or whatever caught in there, I would think it moving about in the narrow hard fuel line would cause intermittent problems in fuel pressure... inconsistent at least. If there is a static (immoble) clog, at low pressure (idle) I would think idle pressure would still be normal. If not, where is all the missing fuel pressure going? That is, if it's commanding 450-500 PSI, and I'm only getting 200, where is that pressure going? Backing up against the hpfp? I'm just trying to understand here.

Yeah, my experience with this car says that the fuel system is WAY more than adequate (pressure and flow) to support near double the stock power(with upgraded HPFP). I ran my car with all current mods on the OEM pump for a LONG time with fuel pressure dropping into the 1k psi range occasionally at WOT with NO problems. I only went with the upgrade kit when I was about prepping for the bigger turbo, etc. Theory says we need the max fuel pressure, but the car will perform well at lower pressures unless going for the maximum power it can put out. If the AFR is leaning out, then the ECU will command more injector duty cycle (IDC) to keep up with AFR targets.

In Doogie's case, IMO, the PTP pump shit itself and spit "stuff" into the fuel line and the car would actually hit a cut driven from some where. It may have hit a max IDC driven fuel cut, I don't know. When he got that POS PTP pump off, the car still had fuel problems, but no cut, so that "proves" (to me) that the PTP pump had truely shit itself.

Now all this is MY theory based on what I've learned over the years and within the past 3 years on this particular car, so I could always be wrong about it all, but I've proven it to (convinced!) myself, so take as you will.:D
I was the same... stocker was fine and I was watching fp like a hawk. After 6 weeks, it staring dipping to 1,100 PSI or so, so I 'upgraded' to the PTP pump. I had no problems w/ the stocker either, but didn't want to lean out, so I upgraded as recommended.

Just to clarify, the stocker that followed the PTP pump cut as well. Not true fuel cut, but pressure cut, and I dumped the clutch... who wouldn't when PSI dropped to 400 PSI under wot? The fuel press issues lessened quite a bit w/ the CPE pump, but obviously the underlying problem persists. I don't mind ordering a new hard fuel line as they are like $80, but I can't shake the feeling that this is an electrical problem. I'm not saying you're wrong buddy, but how else do you explain the hpfp shitting out at the exact same time as the ebcs? Too much of a coincidence for my liking :/

Funny aside... I went back to load/gear based tuning, and I swore I flashed a stage 2 + fmic map on there w/ some tweaks AND the reduced wgdc values for the Perrin from the boost based tune. However, I may have fucked up, because it was idling at 750, and maxing at 16 PSI ish, so I thought I flashed the stock tune by mistake, lol. (I keep my idle at 950, so I was like wtf map is this? haha). I'll have to check. The other thing is the test drive was in 1st and 2nd as the shop is in the city, and no place to open her up in 3rd/4th. It's quite possible that the +fmic map made less boost w/ the conservative wgdc table values I dialed in to get boost on point w/ the boost based map. The car screwed today on the test drive.... pulled real hard, and felt great. Thank God I monitor everything and I'm extra careful.... if not I'd be romping on it with no 'outward' signs of an issue until throw a rod. Also, this issue is 100% NOT tune related, before someone chimes in, but thanks for the thought. I had flashed the stock map on over a month ago as a shot in the dark diagnosis. Obviously, no luck there either.

FINALLY---> Thanks again to all you guys, especially Forzda for helping me out w/ this fp crap. I'm sure you're tired of hearing it (I am too). I try to help others out when I can, but I've never worked on cars, and the little that I know is from what I've read on here and other forums, but it's mostly just inductive reasoning on my part. So thanks for the patience and help :).
 

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^has nothing to do with the convo... and your proving yourself a dbag... use the strength of your logical mind and let it go...
 

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Discussion Starter #15
thats why were over here and no msfail with a bunch of dbags. we dont like to see a fellow owner without a car for months,although everyones help hasnt solved the problem "yet".
^has nothing to do with the convo... and your proving yourself a dbag... use the strength of your logical mind and let it go...
Don't start brawling about msf/6club shit in this thread please. Start one up in the lounge if you really want to waste your time. Thanks
 
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so dougefresh i have some good news for you... i was reading your same thread on msf but i figure its easier to post here and keep track of whats going, the threads get soo long so fast over there

as far as you fuel filter problem... from my understanding there is no external fuel filter on the ms6. the only one is the in tank one that connects to the bottom of the fuel pump. most technicians refer to it as a "fuel sock". when you mechanic replaced the pump it probably came with one, if not it would have been somewhat easily cleaned out before reinstalled..

anyways i have mazda epc(electronic parts catalog) the filter they sent you was the dmtl air filter or the filter for the evap system. The only fuel filter i can find or think of is the fuel sock that connects to the bottom of the fuel pump its listed as a fuel filter in epc

LFB6-13-ZE1 $16.64 plus shipping at

Online Mazda Parts
ive found this site very well priced and have had great cust service with them.

i think its unlikely to be clogged and causing issues but i figure id help ya out with the info. the pump would need to be removed again to replace it. actually now that i looked at the picture again that fuel filter/sock did come with your new pump.

if you need any other part numbers let me know
 

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Discussion Starter #17
Thanks man. I was actually talking to Forzda for a bit about all this earlier this evening, and he said the same thing, and referred to it as "fuel sock." Glad to get confirmation that it is already a part of the new tank pump assembly, and in the tank.... that's one less thing I need to worry about! Thanks for the link and help on part #'s down the road (hopefully I won't need any more parts!!).

My mechanic is going to check the voltage to the tank pump Monday at idle, and under load, and see what's going on. Forzda said to have him visually inspect the line going from the tank pump to the hpfp for good measure. I guess we'll take it from there.
 
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