Idle issue/kr under 10+ psi boost

King Crow

King Crow

Greenie N00B Member
I’m having what seems to be a very common issue talked about here but I have searched for several days to find a fix an I can’t seem to find anything that helps

Some background, I’m a mechanic. I’ve been working on cars for a few years now at a shop an know about engines an how to solve issues an nothing I can think of will resolve my issues

Issues: I’m having two issues that I just do not understand. 1 whenever starting my car it seems to have a long crank unless I prune the fuel system so I can assume it’s a fuel related issues mainly the injector seals. No biggie. How ever the next two I can’t figure out
2nd issue is at idle regardless of hot or cold. In the morning or afternoon the car sputters at idle with no real reason. No kr no misfires I can monitor even with an Apollo D9 scanner. It only throws codes during the third an last issue.

3rd issue is my big one. During any hard acceleration where I make more than 10 or so psi the KR as monitored via V3 AP shows upwards of 3 to 5 kr. It does also randomly through a misfire code or pcm comm code an I can’t figure out why. The car has fresh plugs properly gapped to cork sports rec .026 the coil picks replaced. No fix has been found. There’s no fuel issue I can see. The fuel pressure is optimal. The LT is good I think. I’m not a tuner so idk what great is but I know it’s not bad. The car is completely stock. 100% untouched. The only mod it has is the hpfp from cork sport an a brand new vvt/timing chain an washers which I did my self right after purchase as it’s at 100k an I don’t want no BOOM just the ZOOM.
Will be adding 2 data logs of 3rd gear pull 3k to 6k an two of just idling. Should be clear which is which
Im just looking for some peace of mind or maybe someone to just tell me “get a proper tune!” Comment even though the car is running stage 0 or stock map.
 

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Test the prv on the fuel system. Long start seems like your losing fuel and if so it could cause the other issued

Get motor hot and turn engine off. Monitor fuel pressure to see where it starts bleeding off
 
Easter Bunny said:
Test the prv on the fuel system. Long start seems like your losing fuel and if so it could cause the other issued

Get motor hot and turn engine off. Monitor fuel pressure to see where it starts bleeding off
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A prv can cause low rpm stumble and kr?
I’ll do that. It’s not gonna be good lol. Is there a number or amount of time I let it build ? What am I suppose to see
 
Just watch it build it is supposed to build to 1600 then trigger anything less than that and it is bad
 
Then that's not the problem. Have you taken apart the hpfp to clean it and the spill valve?
 
I mean as far as putting in the new hpfp internals yes? It’s been doing it before an after the hpfp install an stuff.
 
Awafrican said:
Not just the internals but a full clean of the pump

https://mazdaspeeds.org/index.php?t...nd-spill-valve-michael-rey-facebook-kit.8069/

When you replaced to coil packs please tell me you used OEM? Non Mazda ones on this engine usually = lots of issues.
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I did not. I have the stock ones which can go back in an probably will. I reflashed my car after updating the AP (I forgot to or didn’t think to when I got it) an I tried uninstalling an just running the stock map but the stock an stage 0 run the same. The kr has now become a little more of an issue. I mixed about 3 gallons e85 with about 7 gallons of 91 an the knock was better so that’s become my main concern. I will look into doing the full fuel pump tear down. I did the main internal an cleaned everything I could. I didn’t have the extra o rings.
 
King Crow said:
I did not. I have the stock ones which can go back in an probably will. I reflashed my car after updating the AP (I forgot to or didn’t think to when I got it) an I tried uninstalling an just running the stock map but the stock an stage 0 run the same. The kr has now become a little more of an issue. I mixed about 3 gallons e85 with about 7 gallons of 91 an the knock was better so that’s become my main concern. I will look into doing the full fuel pump tear down. I did the main internal an cleaned everything I could. I didn’t have the extra o rings.
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Don't necessarily need the o-rings, but corksport also sells a kit, cleaning that spill valve is a good thing.

How have your LTFTs been on the accesport I presume you've checked for boost leaks, what's the mileage? I'm wondering if the injectors are due for a service and some new s
 
Awafrican said:
Don't necessarily need the o-rings, but corksport also sells a kit, cleaning that spill valve is a good thing.

How have your LTFTs been on the accesport I presume you've checked for boost leaks, what's the mileage? I'm wondering if the injectors are due for a service and some new s
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The LTFT have always been positive I haven’t driven long enough without fucking with something like the tune or changing a pry chasing this cuz the kr scares me as I don’t wanna buy a new engine. The inj duty cycle never seems to go above 65 or so an recently since the update of the AP an reflash it now hits kr randomly but sometimes smack 6 at random. Should I just drive the car awhile without messing with anything and see if any codes show up?


Also it’s at 100k more or less an a side note the previous owner kept up with oil changes religiously however didn’t do much else in the way of maint like spark plugs. He’s been on the same plugs for 100k
 
Have you cleaned your valves? You're also mixing E85 but has it been tuned for that? Done any compression or leak down tests on the engine?
 
I see you mention that your KR will hit 6 at random. I know others can speak to this but from what I've gathered that's the ECU logic attempting to maximize effeciency.

I see it happen on my car randomly while just cruising around 40-50 mph sometimes.

I believe it's been covered in one of the videos Will from PD made also.
 
L337TurboZ said:
Have you cleaned your valves? You're also mixing E85 but has it been tuned for that? Done any compression or leak down tests on the engine?
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I’m from az an the stations here are really over like e50 an I’ve heard it resolves issues. Which it definitely seemed to. I have not comp tested it or leak down but I’ve test for head gasket an inspected the pistons an valves. The valves look a little dirty but not like 100k that wasn’t maint well I’ll look into cleaning the valves an try a compression test. I should mention although the kr spikes the car continues to pull an hits 17ish psi on spikes I let out as it’s stock tune shouldn’t see over 15 +/-1
 
Could see 17psi on stock tune ecu logic is load based not boost. Partial throttle KR is a thing I did used to notice when I was on the Cobb garbage ots maps, @BAT-man has done some dyno runs of stock tune vs Cobb ots stage 0 and found that the stage 0 tune is actually a little more powerful than the actual stock tune.
 
Awafrican said:
Could see 17psi on stock tune ecu logic is load based not boost. Partial throttle KR is a thing I did used to notice when I was on the Cobb garbage ots maps, @BAT-man has done some dyno runs of stock tune vs Cobb ots stage 0 and found that the stage 0 tune is actually a little more powerful than the actual stock tune.
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I assumed this actually seeing as I’ve own a vw in the past an with a simple tune you could make another 50hp no mods needed! So it makes sense they try an up the power with their stuff. The E mixture seems to have made it hunt slightly when coasting in neautral I’ll throw a log up of it sometime an maybe a sound clip of the idle issue as it’s more audible than mechanical from what I’ve seen.
 
I would bypass the fuel pump resistor , when mine was bad/going bad it would take multiple cranks before the car would start. Now that I have bypassed it she fires right up. It is easy to do and can eliminate one thing from the equation. https://mazdaspeeds.org/index.php?t...build-maximum-carnage.7025/page-21#post-97649

Looking at the 2nd log the AFR is pretty terrible, this is stock tune?

https://www.revisionsrus.com/logs/2229

It is very very rich.

If you just did VVT, are you sure the car is timed right? You could be running some crazy timing and not know it.
 
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It went back on the exact tooth it came off an it ha no issue boosting or driving. I recently updated the AP. I have to relog as it’s definitely better at the moment. But I don’t have a windows computer or Mac near me. I’m going to upload an audio of the e issues an a new log with new stage 0
 
If it is 1 tooth off it will still drive fine but you will start to see issues at WOT. One tooth is like 3 degrees so even if you were two off that could be 6 degrees more timing across the entire map. That would show KR at WOT so it is worth double checking. I had an issue with my timing getting off as the wheel slipped. It took me a while to diagnose. https://mazdaspeeds.org/index.php?t...build-maximum-carnage.7025/page-18#post-81233
 
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