Chirping noise only in specific fuel pressure range. Pu.

Funktionull

Funktionull

Greenie N00B Member
Greenie Member
Edit :After almost a month of trying things related to fuel and spark I can safely say that it is not related to any of those things. Sounds valvetrain or cylinder related now and in the middle of the motor if looking directly downwards at the top of the valve cover. Definitely metal touching metal slapping type sound now. Is not slight or quiet and has gotten worse over only about 100 miles of test driving solutions. Don't have the time or the space in life to figure it out so pasta lasagna I suppose.???


It starts and is very slight between 900 and 1100 psi, louder between 1100 and 1300 and goes away entirely at 1400 psi.

Logs check out fine and WOT pulls are clean except for the usual SUB .5 spool up KR. Happens regardless of boost levels and in vacuum. Engine RPM has no effect. Gearing has no impact. No fuel smell. Trims are where they should be so boost/vac/exhaust leaks are maybe unlikely.

I had the high pressure hard line rupture about a month ago and the problem didn't exist after I replaced it but then DID start this week after a full plug swap.

Intuition would say injector failure/leak/etc but I'm not sure since WOT log are clean and show no parameters out of spec.

I haven't recorded it but for reference it sounds almost exactly like a cricket chirping.

Any ideas?
 
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Not that it is in anyway related to the platform, but iirc, there was a tsb on the GM 1.4T engines where there would be a chirping noise coming from the engine and it was caused by loose sparkplugs. I had a Chevy Trax come in with the symptom and one of the plugs was certainly loose. Again, I realize its a completely different animal but similar application. Might be worth checking if you haven't already since it's so easy.
 
OP I presume you mean rpm not psi... Chirping can be as simple as a warn belt or pulley give those a check.

However if it started after changing plugs then the post above me about loose plugs is probably onto something a definitely worth investigating
 
Awafrican said:
OP I presume you mean rpm not psi... Chirping can be as simple as a warn belt or pulley give those a check.

However if it started after changing plugs then the post above me about loose plugs is probably onto something a definitely worth investigating
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No I mean psi of fuel pressure. Rpms don't matter at all. I could be in the hpfp actual pressure range where it's chirping at 2k rpm or 6k rpm and it does the same thing. Went back per suggested and all plugs are to spec + 1/8th of a turn or so. Definitely not loose.

I've monitored essentially every parameter and the only static one that the chirping occurs in is that hpfp pressure range.

I DO have the solid copper rod coil pack mod so they aren't exactly stock config but I don't know how coil packs would chirp much less consistently with a parameter they have nothing to do with. Nothing other than the plugs and coil packs were touched between it not doing this and it starting to do this.

Gut feeling says injector. Possibly pieces of that hardline that ruptured. Possibly from E85 corrosion. Really no clue other than that.
 
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Funktionull said:
It starts and is very slight between 900 and 1100 psi, louder between 1100 and 1300 and goes away entirely at 1400 psi.

Logs check out fine and WOT pulls are clean except for the usual SUB .5 spool up KR. Happens regardless of boost levels and in vacuum. Engine RPM has no effect. Gearing has no impact. No fuel smell. Trims are where they should be so boost/vac/exhaust leaks are maybe unlikely.

I had the high pressure hard line rupture about a month ago and the problem didn't exist after I replaced it but then DID start this week after a full plug swap.

Intuition would say injector failure/leak/etc but I'm not sure since WOT log are clean and show no parameters out of spec.

I haven't recorded it but for reference it sounds almost exactly like a cricket chirping.

Any ideas?
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I had something similar but, would only happen on cold starts. Ended up being the pressure relief valve failing. Here is a video of the chirp I had... I had someone start the car when it was cold while I had a "mechanics stethoscope" on the valve. Sure enough it was clear as day. I also tried the pressure relief valve test and failed that as well.
Template public:_media_site_embed_youtube not found. Try rebuilding or reinstalling the s9e/MediaSites add-on.
 
Fuel pressure would have been good info... Sure you trying to tell us it's the hpfp chirping? Where exactly are you hearing it? Honestly didn't know where it was coming from and the two of us clearly didn't get hpfp from it...
If it's the hpfp And you're running e85 probably time to clean hpfp and inspect for black death yes also do the prv test
 
Awafrican said:
Fuel pressure would have been good info... Sure you trying to tell us it's the hpfp chirping? Where exactly are you hearing it? Honestly didn't know where it was coming from and the two of us clearly didn't get hpfp from it...
If it's the hpfp And you're running e85 probably time to clean hpfp and inspect for black death yes also do the prv test
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I thought I had put it in the title of the post but maybe a mod added it after the fact. Either way, I'll check the prv and report back.
 
So I did the PRV test KOEO and it slowly climbed to around 1820 and stopped and started bleeding but it did not bleed in a linear fashion and was extremely slow. By not linear I mean it would bleed 15 off slowly and then fluctuate back up 10 and then bleed off 15 and then up some and then down a little more and then up etc etc. After about 10 minutes it was only around 1750 doing this. I know this isn't typically what is expected on the bleed down but it DID open and prevent it from ever going above the peak it hit when it originally opened.
 
From inside the cabin it sounded like it was coming from the fuel rail/injector area (more to the passenger side) but I had someone feather the throttle at idle to bring it up and down through that pressure range while I was listening and its 100% coming from the HPFP so yeah spill valve/gunked up internals I suppose.

Edit : Updating with a video. Probably will have to turn volume to max and hold phone to ear.

https://youtube.com/shorts/nyjJ-53R5lM?feature=share
 
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Serviced spill valve while on car. No change. Extremely gunked so attempted to do a full tear down and cleaning and the E8 heads on the mounting bolts just twist off way before there has been enough force applied to loosen the bolt
(yes I'm going in the right direction, yes they were torqued to spec on install).

Does anyone know the bolt specs on a replacement option that I can get locally? Also any pro tips on removing the stock ones in a way that doesn't involve things like drilling and grinding on a fuel pump and setting things on fire.
 
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The body of the pump isn't threaded so if you can snap the heads off the bolts you can pull straight up on the hpfp. It's going to be a bitch though
 
Easter Bunny said:
The body of the pump isn't threaded so if you can snap the heads off the bolts you can pull straight up on the hpfp. It's going to be a bitch though
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That was my original plan to just break the heads off but then read about instances where the bolts were loosened unevenly and it cocked the other bolts sideways enough that the female threads were boned when they came out.

In my brain I'm thinking if NONE of the bolts were unthreaded until all of the heads had been snapped off and the pump was removed there wouldn't be a chance for the threads to get messed up.
 
Gave up trying to find the bolt specs anywhere so I tried to order the corksport rebuild kit and can't because they won't ship here (as in I can't complete the order because it says no shipping options available).

I guess I'm just going to try to get at least one of them out intact and go unicorn hunting at lowes.
 
Easter Bunny said:
Do you have a Mazda dealer near you?
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An hour. I did find what I think is the part number for the 3 pack last night (L3K9-13-366B)

As easily as the OEM ones snapped at sub torque spec force I didn't really want to put the same stuff back in but will at this point because I'm totally over it.
 
Depending on how quickly you need them you could order from Mazda swag and get them in a couple of days
 
Got replacement bolts, got everything serviced and cleaned and oiled (was very bad) new orings etc. Back on the car. Cranked after priming the lines. Had a normal cold start like you would expect. Rpms settle to the 1k its tuned for and idle pressure slowly dropped from 400 to 300 to sub 200 over about 2 minutes and seems to bottom out at 160-175 idling. Blipping the throttle does NOT produce the amount of fuel pressure you would expect so it hasn't been driven yet.
 
I would recommend cleaning again. Use naphtha (lighter fluid) to clean, and redline injector cleaner to lubricate.

Questions:
What oil are you using?
Is that what you used to oil the pump with?
Do the internals look scuffed at all?
 
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