20 psi on stock injectors...?

[polishshark]

k so i got this problem. i got front mount, walbro 255, stock turbo, stock injectors, stock fuel pressur regulator. for tunning i use maft pro and LC1 wideband. so my prob is that when i hit 20 psi the car starts to choke like it is getting a bad misfire or not enough fuel.. well my wideband says that's it running rich at 10.5. leaning it out adding more fuel changes the AFR but doesn't fix the prob. so i don't think that it's injectors. ...o and i'm also running a water injection and it's not helping any eather

thx

andrzej

 

[FORMONTOYA]

The stock injectors will not support 20PSI, and the 255 requires an AFPR.

The water injection is not going to do it.........now maybe running 50/50 meth/water injection will allow you to run on the OEM injectors (but I wouldn't recommend it).

 

[Generation1JeY]

sounds like boost leaks to me as well.

 

[94Jettameowpsst]

i've ran 20psi on 450s with a 255 pump, stock auto fpr, maft and afc2 on an evo3.....didnt max out the injectors and didnt knock

 

[polishshark]

did you guys see my AFR?? it's at 10.5 and i can add fuel and it goes down to 10... does it look like i'm running lean?? i don't think the injectors are maxed out.. and it's not a boost leak i'm running speed density so a small leak wouldn't make a difference.. i don't have a prob getting boost i got a prob with the car jerking when it goes above 20 psi..

at WOT and 20 psi i don't think that not having a FPR is a prob... maybe at idle but that's not the prob.

by the way i got 3" cat-back too..

now.. you guys think.. could it be timing?
what should be the base timing if i was reading it from my logger
to i check it at idle 700-800 rpm?
and can i change it turning the ignition module?

please stick to what i ask...

thx
andrzej

 

[94Jettameowpsst]

Sounds like not enough timing then, or like everyone else said a boost leak

check on vfaq for directions as to how to check/change your base timing, its not too difficult

 

[Gromit]

did you guys see my AFR?? it's at 10.5 and i can add fuel and it goes down to 10... does it look like i'm running lean?? i don't think the injectors are maxed out.. and it's not a boost leak i'm running speed density so a small leak wouldn't make a difference.. i don't have a prob getting boost i got a prob with the car jerking when it goes above 20 psi..

at WOT and 20 psi i don't think that not having a FPR is a prob... maybe at idle but that's not the prob.

by the way i got 3" cat-back too..

now.. you guys think.. could it be timing?
what should be the base timing if i was reading it from my logger
to i check it at idle 700-800 rpm?
and can i change it turning the ignition module?

please stick to what i ask...

thx
andrzej

OK, 1st off, your AFR of 10.5:1 is very rich & adding fuel makes you richer, not leaner. That's why when you added fuel your AFR went to 10:1.

Second, you are correct that not having an AFPR has more of an effect at idle than at WOT. However, even at WOT it can cause a problem as you have no way to ensure your fuel pressure is rising at a controlled rate of 1:1. If you're going to run the 255 lph pump then get the AFPR & be done with it.

Third, do a boost leak test, especially if you've never done 1 on your 14 year old car. You'd be surprised at the number of plastic/rubber seals, o-rings, gaskets, couplers, etc. that could have hardened with age & are now leaking. Even a small leak will make a big difference, especially at higher boost levels. The fact that you are rich up top & experiencing a stuttering sensation points directly to a boost leak. The ECU thinks there's a lot more metered air in the system that there really is & it's adding a pile of fuel accordingly. So even though your wideband indicates you're not running lean, your injectors probably are maxxing out due to a boost leak. If you posted a log with IDC values we could confirm that.

Fourth, in order to check your base timing you must do so with a timing light, not the logger. The logger only displays what the timing is supposed to be. Here's a link for that procedure:
http://www.plymouthlaser.com/timin.htm

Last, you're asking an awful lot of those stock injectors trying to run 20 psi. You might get away with it for awhile, but your duty cycles are going to be horrendous. I'd recommend turning the boost down a bit to try & get your tuning issues straightened out 1st & give your injectors a break.

 

[polishshark]

OK, 1st off, your AFR of 10.5:1 is very rich & adding fuel makes you richer, not leaner. That's why when you added fuel your AFR went to 10:1.

I understand that.. I was just trying to make a point that the injectors are not maxed out.

Second, you are correct that not having an AFPR has more of an effect at idle than at WOT. However, even at WOT it can cause a problem as you have no way to ensure your fuel pressure is rising at a controlled rate of 1:1. If you're going to run the 255 lph pump then get the AFPR & be done with it.

Well I want to try everything else before putting more money into it.

Third, do a boost leak test, especially if you've never done 1 on your 14 year old car. You'd be surprised at the number of plastic/rubber seals, o-rings, gaskets, couplers, etc. that could have hardened with age & are now leaking. Even a small leak will make a big difference, especially at higher boost levels. The fact that you are rich up top & experiencing a stuttering sensation points directly to a boost leak. The ECU thinks there's a lot more metered air in the system that there really is & it's adding a pile of fuel accordingly. So even though your wideband indicates you're not running lean, your injectors probably are maxxing out due to a boost leak. If you posted a log with IDC values we could confirm that.

Like I said before, I'm running speed density, I got no maf the ECU receives whatever the maft pro sends it, so a small leak wouldn't make a difference.. see the unit checks the pressure in the manifold.. so any leak before it just shouldn't make no difference.. but i'll check, it is a 14 year old car afterall.

Fourth, in order to check your base timing you must do so with a timing light, not the logger. The logger only displays what the timing is supposed to be. Here's a link for that procedure:
http://www.plymouthlaser.com/timin.htm

Thx

Last, you're asking an awful lot of those stock injectors trying to run 20 psi. You might get away with it for awhile, but your duty cycles are going to be horrendous. I'd recommend turning the boost down a bit to try & get your tuning issues straightened out 1st & give your injectors a break.

What can be a prob with running high duty cycles?

 

[polishshark]

Sounds like not enough timing then, or like everyone else said a boost leak

check on vfaq for directions as to how to check/change your base timing, its not too difficult

Not enough timing meaning should i retard or advance it?

 

[selmerguy]

I had the same thing. I ran 18 psi on stock injectors and my afr's were good>(at least they seamed good) What happens is, at least for me I was at like 146% IDC. So the afrs looked good but sometimes the injectors would not get all the fuel inthere and the AFR would spike lean for a stroke. My wideband didnt pick this up because it measures all 4 cylinders togeather. Anyway that is where the knock sensor came in handy. Get bigger injectors or eventually you will blow your motor up.

 

[pballer]

The problem with this is that an injector works on low impedence (4 ohm), and at that low of a resiatace, a lot of current flows. therefore a lot of heat is generated inside the coils of the injector. So the longer the injector is open, the more heat is created and the potential for burning out an injector circuit goes up. I ran my 450's up to about 24-25 mili-seconds before i upgraded, but I also burned an injector out weather that was related or not, I'm not sure. Hope some my info is useful to you...

 

[polishshark]

I had the same thing. I ran 18 psi on stock injectors and my afr's were good>(at least they seamed good) What happens is, at least for me I was at like 146% IDC. So the afrs looked good but sometimes the injectors would not get all the fuel inthere and the AFR would spike lean for a stroke. My wideband didnt pick this up because it measures all 4 cylinders togeather. Anyway that is where the knock sensor came in handy. Get bigger injectors or eventually you will blow your motor up.

that makes sense. i got get my logger running and check for knock and IDC.

thx

 

[polishshark]

The problem with this is that an injector works on low impedence (4 ohm), and at that low of a resiatace, a lot of current flows. therefore a lot of heat is generated inside the coils of the injector. So the longer the injector is open, the more heat is created and the potential for burning out an injector circuit goes up. I ran my 450's up to about 24-25 mili-seconds before i upgraded, but I also burned an injector out weather that was related or not, I'm not sure. Hope some my info is useful to you...

i see.. any recomendation on what injectors to get .. with my unit i can -/+ 60% of fuel

i'm thinking of upgrading the turbo in the future to big 16. Would big 16 max out 660's??

thx

 

[94Jettameowpsst]

Not enough timing meaning should i retard or advance it?

Well first you shoudl check it to see where its at (5btdc is where it should be.) See the thing with not havin a chip or afpr is that with stock injectors and havin an afc; well let me start by saying if you had 650s for instance, the deadtime on the injectors is much greater than stock so when you put them in your car, it will automatically raise your timing advance because your ecu is thinking your car is running rich already so its compensating by throwing in the extra timing. So when you lean out the afc the timing keeps going up and up.
With 450s, since the ecu is set to have them already, when you lean it out *(which you should be doing right now), you're not going to see nearly as much timing advance so its not going to feel as fast. ( I really hope im right on this, i know what im talking about its just hard to explain)
All i can really say and stand by it is if you have a logger, watch your knock, thats most important, and you should be set since you have a wb already, hope that could help.

Edit: And you should advance it some, it shouldnt hurt anything with afr's like you have now

 

[polishshark]

k so i got mine logger running tonight and made one run it turns out the the IDC goes above 100% ...115%-125% and the injector pulse goes 21-25ms... so afterall i guess it is time to upgrade the injectors

thx guys

 

[bastarddsm]

ahhem ahhem......fuel cut anyone?....common 20psi stock injectors it's cold out....

 

[MyBeatGSX]

Ditto a few other people. I did 20psi on a small 16G, stock injectors, 255HP, and an AFPR for 6 winter months with no problem. AFR was around 11:1 completely untuned and untouched.

 

[polishshark]

ahhem ahhem......fuel cut anyone?....common 20psi stock injectors it's cold out....

just so you know i tuned the car and it runs at 23 psi on stock injectors without fuel cut... at 11.5-12.0 AFR... i do get knock .. but it's possible

look into this forum for a log

http://www.dsmtuners.com/forums/showthread.php?t=247316

 

[polishshark]

Ditto a few other people. I did 20psi on a small 16G, stock injectors, 255HP, and an AFPR for 6 winter months with no problem. AFR was around 11:1 completely untuned and untouched.

first person that doesn't repeat what others say and is not trying to be a smart ass

 

[MyBeatGSX]

first person that doesn't repeat what others say and is not trying to be a smart ass

Thanks.

I didn't actually read your original post, I just read the title and quick replied. I just realized it had nothing to do with your original post.


It is possible to run so lean that the mixture never ignites and all the fuel just dumps out the exhaust and onto the wideband, causing a false rich reading. Have you tried going WAY lean and WAY rich? What AFR values does this give you? If the values corrispond (sp?) to the adjustments you make, you can look into something else.

How does it run on lower boost, say 10-15psi? Even though we both know from experience that 20psi can be done, diagnosing is always easier at low boost. It's just one less variable.

 

[MyBeatGSX]

Just looked at your log. There's a chance that that could be real knock. It corrisponds pretty well with the injector pulse width. Do what I said to check your AFR and make sure the WB sensor is in good condition (although the ones I've seen tend to fail lean, not rich). Then again, it could be a bad knock sensor. That would cause the same symptoms. It'll bring your timing way down which doesn't give a clean burn and you end up with the same gas laden exhaust which gives a false rich reading.

 

[95blackGsTurbo]

Do a boost leak test. Your boost gauge can say 24psi but only be getting 15psi into the cylinder and not have a miss or anything like that. And your 14b at 24psi is useless anyways.

 

[MyBeatGSX]

Your boost gauge can say 24psi but only be getting 15psi into the cylinder

Short of a blocked intake port... how do you figure?

 

[polishshark]

Thanks.

I didn't actually read your original post, I just read the title and quick replied. I just realized it had nothing to do with your original post.


It is possible to run so lean that the mixture never ignites and all the fuel just dumps out the exhaust and onto the wideband, causing a false rich reading. Have you tried going WAY lean and WAY rich? What AFR values does this give you? If the values corrispond (sp?) to the adjustments you make, you can look into something else.

How does it run on lower boost, say 10-15psi? Even though we both know from experience that 20psi can be done, diagnosing is always easier at low boost. It's just one less variable.

Well the knock sensor is brand new.. maybe 2000 miles on. I tried running it rich the AFR did change to a lower one, and I would hit fuel cut, or maybe my injectors were just giving out, eaither way.. At lower boost the car runs fine.. I don't have a log though at lower boost. The wideband seems to be fine. It shows 22 or so with the sensor in free air and the AFR at idle and cruse seems fine.

When you look at my log you can see big knock that starts at like 2000rpm... i don't think that's right.... I'm preety sure that I do get some real knock but i don't think that 40 counts of knock at this low rpm is right.

Is there anyway to silence the valves(the lifters i guess), someone in the other forum said that could be the prob. with the knock.

thx

 

[polishshark]

Do a boost leak test. Your boost gauge can say 24psi but only be getting 15psi into the cylinder and not have a miss or anything like that. And your 14b at 24psi is useless anyways.

I might have a small leak somewhere. Don't have time to check anytime soon.. finals in school.. but i'm sure the car is close to 20.. it pulls harder than 15 or 18 psi...

useless... I dunno... it does pull harder than at lower boost but I do see a drop in power after 5000-5500rpm.. I just don't have money now for a new turbo... so i'm trying to get as much as i can from 14b.

thx