Need Help with Fuel Pressure Issues!!

[CCC]

Hey Guys,

To make a long story short, I installed the new KMD internals on my car, when I first tested them after 100 miles, they held at 1700+psi through 3rd gear pulls. Once I started doing some tuning with the help of @rfinkle2 1500 miles later, he noticed that I was getting as low as 1250psi in the 3000-4000rpm range.

I immediately thought my internals had failed/ were failing. With the help of @adlpb, we took my pump out to inspect the internals, only to find that they were flawless. We recleaned and oiled them, and put them back in. After 60 miles, I just took this log (Stg 2 CS + TIH) and my pressure dropped into the 1500s in the lower RPM range.

Do you guys have any idea why this could be? Are they just bad internals, is there a bad/clogged fuel line, etc? At higher RPMs I am solid 1700-1800psi. Any advice or suggestions on where to start would be great.

Cliffs: KMD internals look flawless, used to get 1700psi for 3rd gear pulls, now drops to 1500psi (probably lower if I commanded more boost) at low rpms. What to do?

Attached is a 3rd gear pull with cobb stg CS + tih. Pull starts around line 85.

[rfinkle2]

@kmac, could you give us a hand when you have a free moment?

[superskaterxes]

when you cleaned them and put them back did your pressure go normal again for those 60 miles?

[CCC]

Originally Posted by superskaterxes when you cleaned them and put them back did your pressure go normal again for those 60 miles?

I didn't do any wot pulls because it was my understanding that it was a good idea to give them 50 miles to settle in. I was/am idling around 380-400psi and cruising around everything seemed ok as far as I know.

[rfinkle2]

Lines 101 -112 are what look a bit wacky. (to me @ least)

[adlpb]

@CCC , did you try reverting back to stock map and taking a log?

[CCC]

Originally Posted by adlpb @CCC , did you try reverting back to stock map and taking a log?

Not the stock stock map, just the Cobb Stg 2 CS + TIH one. Guess thats worth a shot though

[adlpb]

Yeah try that. Just to focus on the issue. Could be a faulty AP...you never know

[rfinkle2]

Originally Posted by CCC Not the stock stock map, just the Cobb Stg 2 CS + TIH one. Guess thats worth a shot though

The only issue with that is the stock fuel pressure map may not command enough fuel pressure to see the data you are looking for.

I would be happy to post a screenshot of the stock commanded fp when I get home tonight, but all stage 2 maps use 1749 psi.

[CCC]

Originally Posted by rfinkle2 The only issue with that is the stock fuel pressure map may not command enough fuel pressure to see the data you are looking for. I would be happy to post a screenshot of the stock commaned fp when I get home tonight, but all stage 2 maps use 1749 psi.

Are we talking stock, stock map, or the stock cobb map I am using? What map are you recommending that I try to log off of?

[rfinkle2]

Originally Posted by CCC Are we talking stock, stock map, or the stock cobb map I am using? What map are you recommending that I try to log off of?

I just want to be sure that we are comparing apples to apples (sorry for the cliche).

If you flash a stock map, fuel pressure is going to be lower in general than any of the Cobb ots maps, so looking @ the logs will also require looking @ commanded fp, regardless of map.

I would, however, like to see if you dip below 1600 psi on the stock map (stage 0).

[adlpb]

If need be, we can divorce (AKA unmarry) our AP's and I'll give you mine. Just to discard the possibility of AP logging issues.

[Ms32010]

Hi guys, about theses hpfp issues, i had same problems with my mods, so ive ordered a pump from cp-e. Them ive spoke with my buddy who works for mazda(technician) if he wanted to install it. So whe talked about hpfp issue on ms3 2010 and i told me that mazda released a new tsb for those pump. So i took an appointement and after testing the pump they saw it was not consistent and they changed it on WARRANTY. And its an upgraded version of the old one.....Yes ive flash with stage 2 map with my ap and did a road test...and guest what, it never went under 1700psi !!! Ive just saved mysefl 700$. And cars run big map with absolutely no problems!! SO i think everyone should take a look into this. By the way..i did not bring the car and told them: hey i have mods and my hpfp cant do the job. When temp gets colder at wot the car was runnig leaner and the engine was cutting and runnig bad idle....

[SLOWHATCH]

I have heard that the relief valve I think its called goes bad prematurely and starts to bleed off pressure. I noticed mine was acting weird and prompted me to get upgraded pump. When I sent it in for core charge I was told that sensor had shit the bed.

I'm sure lots of others here would appreciate more info on the tsb.

[rfinkle2]

Originally Posted by adlpb @CCC , did you try reverting back to stock map and taking a log?

Originally Posted by SLOWHATCH I have heard that the relief valve I think its called goes bad prematurely and starts to bleed off pressure. I noticed mine was acting weird and prompted me to get upgraded pump. When I sent it in for core charge I was told that sensor had shit the bed. I'm sure lots of others here would appreciate more info on the tsb.

This is what I like to see... brainstorming.

@ this point, I think that flashing the stage 0 map as suggested by adlpb would help us find out if you are having a relief valve problem like slowhatch mentioned.

If you are confident the internals look good after reinstallation, the stage 0 map, if it dips below 1600 would tell us there is something else (like the prv) that needs attention.

I'm sure kmac will hit us with his ideas too.

[superskaterxes]

why not just lower the pressure targets in his current map?

[rfinkle2]

Originally Posted by superskaterxes why not just lower the pressure targets in his current map?

There is some strange ecu logic specific to gen2 that causes the ipw to crank up when fp < 1600 psi.

I don't see evidence of it on his logs, but am apprehensive to turn up the wick if fp commanded isn't sustained.

Hit me with your advice @superskaterxes...

[SLOWHATCH]

Strange that it only dipped in pressure in that one spot. Either do a log on stock map and see how it looks or re log with current map. Pressure seems to be fine in the higher rpm range.

[superskaterxes]

Originally Posted by rfinkle2 There is some strange ecu logic specific to gen2 that causes the ipw to crank up when fp < 1600 psi. I don't see evidence of it on his logs, but am apprehensive to turn up the wick if fp commanded isn't sustained. Hit me with your advice @superskaterxes...

wait, i thought his pressure was already raised (aka OTS levels of 1750-1800) and he was seeing pressure drop at peak torque?

i was just saying to lower them back to stock values (1669.7 i think) and see whats up rather then swapping to a whole different map. then you have too many variables that changed which may not lead you to your solution.

[CCC]

Hey guys, thanks for all the advice.

I will try the stage 0 map tonight, as well as any other suggestions that you might come up with.

@adlpb I may take you up on that offer if we can't figure something out soon, thanks!

[CCC]

Originally Posted by superskaterxes wait, i thought his pressure was already raised (aka OTS levels of 1750-1800) and he was seeing pressure drop at peak torque? i was just saying to lower them back to stock values (1669.7 i think) and see whats up rather then swapping to a whole different map. then you have too many variables that changed which may not lead you to your solution.

So you think I should keep using the ots cobb stage 2 map, but lower pressure targets?

[rfinkle2]

Originally Posted by superskaterxes wait, i thought his pressure was already raised (aka OTS levels of 1750-1800) and he was seeing pressure drop at peak torque? i was just saying to lower them back to stock values (1669.7 i think) and see whats up rather then swapping to a whole different map. then you have too many variables that changed which may not lead you to your solution.

OK! We can certainly try anything. I'm down to try whatever gets the problem solved.

@CCC, if the map that created the logs in this thread is OTS, let me know the skinny on the map name etc., and I'll adjust the fp tables accordingly (to 1669.7).

We can certainly try the same tune @ 1669.7 and see how things react.

[CCC]

So @rfinkle2 adjusted my map again, and I am still having the same fp drop between 3k-4k rpm. As far as I can tell, everything else on my log seems good.

So at this point I am completely lost. I am hoping I am not killing my car by driving around in it, but I am staying out of boost as much as possible and monitoring my fp, any insight on this would be appreciated.

@adlpb helped me take out my internals last week and put them back in, they looked flawless but this issue still seems to be happening.

@Cobb Tuning @Lex @kmac @David@COBB Do any of you have any insight on this problem?

edit:here is a log

Thanks to anyone who can help/try to help!!

[G26]

Originally Posted by CCC So @rfinkle2 adjusted my map again, and I am still having the same fp drop between 3k-4k rpm. As far as I can tell, everything else on my log seems good. So at this point I am completely lost. I am hoping I am not killing my car by driving around in it, but I am staying out of boost as much as possible and monitoring my fp, any insight on this would be appreciated. @adlpb helped me take out my internals last week and put them back in, they looked flawless but this issue still seems to be happening. @Cobb Tuning @Lex @kmac @David@COBB Do any of you have any insight on this problem? edit:here is a log Thanks to anyone who can help/try to help!!

Weird, fp loss at max torque like that is usually the cause of the stock fp internals giving up. Shit, I can run 18 psi and not drop that low on my stock fp.

[CCC]

Originally Posted by G26 Weird, fp loss at max torque like that is usually the cause of the stock fp internals giving up. Shit, I can run 18 psi and not drop that low on my stock fp.

Yeah it is really weird. I want to try to put my stock internals in and see how they hold up. If it seems like it is the internals, I am not even sure if KMD would warranty internals that look so flawless.

So people usually lose fuel pressure where I am when there stock pump is crapping out? I always thought it was at higher rpms, guess I was wrong.

[kmac]

Your pump is no good. If it drops at peak torque It's no good.

Just because they look good doesn't mean they r. You r talking about tolerances beyond anything you can see.

[rfinkle2]

Originally Posted by kmac Your pump is no good. If it drops at peak torque It's no good. Just because they look good doesn't mean they r. You r talking about tolerances beyond anything you can see.

Thanks Kmac for checking into this thread.

CCC has tried everything to diagnose the issue, and having you pop in seems like the definitive answer.

Kmac to the rescue (again).

[adlpb]

So CCC, looks like it's time to show those logs to KMD and warrantee the parts

[rfinkle2]

Originally Posted by adlpb So CCC, looks like it's time to show those logs to KMD and warrantee the parts

If they need any info as to other logs showing fuel pressure that does not dip in that area,

or would like to see the fuel pressure tables that correspond with a solid log, I could give

you a shit ton.

[CCC]

@kmac @rfinkle2 thanks for all of the help. I will call KMD on monday and see about getting these warrantied. I wasn't sure if there was a common sensor/fuel line issue that could be causing this, but that seems to not be the case.

[kmac]

No problem, glad I could help.

[86AmishMs3]

Originally Posted by CCC So @rfinkle2 adjusted my map again, and I am still having the same fp drop between 3k-4k rpm. As far as I can tell, everything else on my log seems good. So at this point I am completely lost. I am hoping I am not killing my car by driving around in it, but I am staying out of boost as much as possible and monitoring my fp, any insight on this would be appreciated. @adlpb helped me take out my internals last week and put them back in, they looked flawless but this issue still seems to be happening. @Cobb Tuning @Lex @kmac @David@COBB Do any of you have any insight on this problem? edit:here is a log Thanks to anyone who can help/try to help!!

Yep definately a fuel pump issue. You're linear flow limited, and that's an issue with the pump. CDFP can flow fuel linearly as RPM's rise. But on our cars power is hardly linear. That's why you see pressure fine, then it dips, then it comes back again. Classic sign that the pump is not doing what it should. Either you received bad internals, or somehow the housing is fubar. I vote on the internals. Those are the most likely issues

Inserted 2nd grade picture for reference

[CCC]

Originally Posted by 86azms3 Yep definately a fuel pump issue. You're linear flow limited, and that's an issue with the pump. CDFP can flow fuel linearly as RPM's rise. But on our cars power is hardly linear. That's why you see pressure fine, then it dips, then it comes back again. Classic sign that the pump is not doing what it should. Either you received bad internals, or somehow the housing is fubar. I vote on the internals. Those are the most likely issues Inserted 2nd grade picture for reference

That drawing makes a lot of sense, thank you.

The other thing I was concerned about was the housing, but I guess that is less likely. Thanks again.

[spnkr21]

OK who wants to take bets its the relief valve?

wait is this for a genpu?
fuck

But seriously, replace the relief valve

[CCC]

Originally Posted by spnkr21 OK who wants to take bets its the relief valve? wait is this for a genpu? fuck But seriously, replace the relief valve

Whats the relief valve?

[spnkr21]

It's on the fuel rail and bleeds excess pressure back to the fuel pump.
It's located right next to the feed line on the rail itself.

[CCC]

Originally Posted by spnkr21 It's on the fuel rail and bleeds excess pressure back to the fuel pump. It's located right next to the feed line on the rail itself.

Is there any way to test this aside from replacing it? Where can I get one/how much are they usually? Thanks for your opinion.

[spnkr21]

Your local Mazda dealer or streetunit.

[kmac]

If it holds pressure upstairs and doesn't bounce like crazy and unable to get stable pressures It's not the valve.

[spnkr21]

Ok
Don't replace the valve
Let me know when you find the problem kmac