help. sputtering popping and backfireing under boost.
 

this is a small t25 turbo running a 1.6 16v suzuki engine. it has a wide band 02 sensor that is staying around 14-1 inder boost but will start to pop and kinda sound like it backfireing when the rpm get up around 4000rpm during wide open throttle.

the internal wastegate is set at 8psi and i havent seen it open so im shure its still pretty low boost.

im just running it off factory efi for now and have the initial timeing backed off from 8 degress to 5 right now.

i have a friend who is running this same setup but havent been able to get ahold of him for any info and im conmpletely new to turbos. any help would be great.

14's under boost is a bit lean.

Any chance it's spark blowout? What are you using for ignition?

the plugs are gapped at 30 right now. theres 300 miles on the complete rebuild and new plugs,cap and rotor. this engine ran flawlessly last weekend and as soon as i added the turbo it started doing weird stuff.

stock efi is now backed down to 0 degress at idle but seems to jump up to like 40 before tdc when the rpms come up.

it seems like the afr is jumping all around when idleing it strtes getting lean like 17-1 ans when i rev it it goes to 12-1 when its just running down the road it stays near 14-5 but as soon as the boost kicks in itll start popping and losses power.

also while messing with it today it seems like the engine runs without the 02 sensor i tried swapping in a differant one and no change so i unplugged it and its still acted the same plug in or not.

the cel light has been reading aok the hole time.

If this is a totally stock distributor type ignition, try adding an MSD 6BTM or similar CDI / timing retard device.

stock dist. but like i said earlier my buddys is running bone stock and kicking ass.

today i swaped out ecu and maf and was hopeing to do a 02 but the one i pulled from my buddys didnt fit.

after all this swapping i finally unplugged the 02 sensor and started the rig and with no 02 at all it ran just the same as it did this hole time. my guess is that the engine is running in a ''limphome'' mode and isnt being controlled by the 02.

looking further into the limphome feature of this engine it says that even tho the engine is running in open loop it still will NOT throw a engine light at all. the check engine light has never came on and i guess if the 02 is the problem it never will. huh?

i pulled all the turbo stuff and put it back to stock and its back to running like it always has even with the 02 unplugged.

anyhow ill be installing a brand new 02 and putting all my turbo stuff back on and ill report back when i get the results.
https://www.homemadeturbo.com/attach...ine=1341359787

http://img4.imageshack.us/img4/9464/...otobsdklu1.jpg

Could be ignition (spark blow out) But if your running low amounts of boost and your gaped to .030 then its really doubtful in my opinion if your ignition is in ok shape.

If your running 14+ AFR under boost then it could just be that your way too lean, fuel cut basically. I would get the AFR to be a constant 12.5:1 or less first and see if that helps before chasing the ignition down.

I tune for 12:1 for up to 6psi 11.5:1 for up to 9psi then 11.0:1 for levels up to 15psi. I have alky injection also so thats why its a tad lower AFR then peak Tq range. So without my alky running the afrs are roughly 1pt higher. I would say that 12.5:1 is the safest lean AFR to go. 14's AFR will burn up some rings and such in time if your on it for a while.

i know the factory efi will try to keep the a/f ratio at 14.7 it should aways stay near that number on a stock motor with no turbo.

im looking into ways to add another injector without being over complicated.

Had same problem. Gap plugs at .02-.022, your Proly boosting higher then u think. Do u have a gauge?

I wouldn't be so worried about the spark gap till you get the afr down pat. .028-.030 is plently tight enough IMO> The tighter the gap the less powerful of a boom=less fuel needed and lower afrs. So tightening the gap may help but its just a bandaid for the real issue you may have.

Are you not able to tune the ecm?

Am I the only one that sees hes runnign 14+ AFRs with boost and how big of a issue that is?? This really jumps out as a major issue that will inevitably kill any motor.
14.7 afr with boost is just asking for a catastrophy. :eek:

Very true ,,,,that bandaid might be why my motor left? Wasn't getting enough fuel?

Agreed, I probably should be harping on that point more too. :p

Yes could be. Im scared to death to run any higher the 12.5:1 Afr's under boost. Lean is mean but rich is just safe im my mind. Id rather be safe(under12:1 Afr's). Last thing I want is to have a hicup with boost and melt rings, psitons, plugs..exc

your first and only problem is your not adding fuel to compensate for the additional air the turbo is putting into the motor. your stock fuel injection will not compensate for boost without a tune or without the addition of some kind of additional fuel controller. you can adjust the timing all you want but without more fuel it is not going to make a difference. stop driving the vehicle before you blow it up. right now your damaging the pistons by running lean. the popping and sputtering is a sign of running lean.
if you cant afford to tune it then remove the turbo as your just going to have to buy an engine. your next cheapest option is to install a fmu (fuel management unit) or better known as a rising rate fuel pressure regulator. this will increase the fuel pressure as boost is applied causing more fuel to exit the fuel injectors.

AGREE!

ive unplugged the vacume to the fuel pressure regulator and it will bring the fuel pressure up to 40 psi from 32psi. and driveing it the 8 pounds dosent seem to make any differance. any idea of how much pressure i need to get the injectors to add more fuel? i may need a better fuel pump maily due to the fact hat this pump is only makeing 40psi when i plug the line with a pressure gauge installed.

back to what i was saying earlier about the motor running without a 02 sensor pluged in. it seems that if its not useing the 02 to control the fuel that theres another issue other than the fuel delivery.

with a good 02 sensor installed how much can the factory efi change the amount of fuel that goes into the engine? i ordered a new 02 sensor but i will not see it till the end of the week.

What injector size do you have in the car? If you get a FMU the pressure matters but its way better in my opinion to just get larger injectors and do a quick tune. I know this is a homemade site so Im not sure what you can afford and what not.

If 8psi doen't feel like much you have some issues. As it should! I started with a 140Hp car and when I got to 8psi it was a monster compared to before.

YOU NEED TO HOOK THE VAC LINE BACK UP!! As when you are boosting the pressure in the vac line is what will make sure the fuel pressure stays like it should. Imagine 40psi of fuel and 8psi in the cylinders (boost) pushing back? Now you are worse then you started. That vac line allows the boost pressure to push down on the fuel pressure regulators, diaphram. Im most cases 1:1 ratio. Which means for every PSI of boost=raise the fuel pressure 1 PSI. So it will equal out.

Take for example, I raised my fuel pressure awhile back from 43psi to 55psi both with the vac line unhooked. BUT I hooked it back up. I used a 1:1 AFPR. Now I had 28lbs injectors on a V6. And the results. I added 12 psi and it only made those injectors "act" like 32lbs. That is nothing. Im my opinion. You need you need to at the very least get a FMU. Im not sure about your emc and if its speed sensity or MAF so I can't say much about that ATM. But you really need to have the capibilities to tune the car. Mainly the spark and fuel managment part.

I now have 48lbs injectors with the stock 43 base Psi and they can handle way over 400hp on a 6 cylinder. My prior 28lbs injectors could only make 275Hp and I had them maxed out all the way. So if you do tune get large injectors. As what you have will only flow so much without jacking the fuel pressure sky high. I bet your so lean that you have no substantial HP gain whatsoever for those amounts of boost. IIRC about 13.2:1 is prime afr for Hp although thats on the edge of frying a engine.

I have a walbro 255LPH fuel pump. Im not sure what your stocker will flow if you plan to make some real big Hp numbers. I tosted mine after 10psi of boost, poor thing couldn't keep up with the injectors.

Have you changed up the timing at all? Retarding it at a minimum of 1 degree per lbs of boost? A BTM.

Just some ideas here, I don't want to see anyone trash a motor.

everthing you say makes perfect sence to me this is my first turbo setup so ive got alot to learn.
still im looking for answers about this 02 sensor issue i seem to be haveing.

to me, if my buddy is running the exact same setup for 2 years with zero issues ever, why the hell is my engine not running at all?

hes running up to 4 more psi of boost thats up to 12 psi on a bone stock engine with bone stock efi. my engine just idleing will lean out and 17-1 or even worse it will not even register at all on my wide band aem guage even with no turbo on the engine. im still trying to find the underlying issue. i relize that my motor is very lean and isnt working at all.

im now looking for the problem. if my engine would run at 14-1 afr at 8psi of boost i would then look into a way to get the afr down but with the engine just leaning the hell out when ever and running just the same with or without the 02 id like to get that squared away first.

if i were smart id probly just put in a bigger engine but now that ive heared the turbo whistle and seen how it looks under the hood id really like to finish this the right way. i was told i would get the turbo fever once i had a turbo and now i kinda see what he meant.

i appreciate all the help and im takeing in all that ive been told i just still think ive got other issues even when there is no turbo installed ive got nearly the exact same issues. i welded a bung in the stock exhaust so that i could use the wideband to see how the engine acted without the turbo and its nearly the exact same. only dosent pop and krackle when the rpm get up above 3500 or 4500.

my thoughts

engine is stuck in ''limphome'' due to bad 02 sensor
bad injectors
bad ecu
bad mass air sensor. for some reason when i hold my hand over the intake, i can get the afr to change just by how much i restrickt the airflow into the engine?

Well you do have MAF then so it will further meter the boost a tad. Probly about 6-8psi on its own.

Boost is very addictive! Your friend is completly right!

yes its a maf engine.

ive been doing some research on the megesquirt and it seems like its probly the cheapest way to go but holy ---- its confuseing.

the maf will see the extra airflow coming into the engine up to a point. this isnt the concern. the stock fuel injectors can only supply so much extra fuel while in boost.

if your o2 sensor has failed then the ecm is going to run in open loop. in open loop the engine is being run from a programmed map in the ecm. when in open loop the ecm doesnt look at o2 sensor data so it doesnt know if your rich or lean and it will not compensate for it.

your friend is not telling you something because there is no engine in this world that can run 12 psi without some sort of fuelling modification. a naturally aspirated ecm can not see boost so it cant compensate for the extra airflow with extra fuel. theres only so much adjustment outside the programmed map an ecm can do. this doesnt include larger injectors and timing adjustments that are also required when boosting.

talk to your friend and find out what he did to the engine. there has to be something he forgot to tell you.
does he have a rising rate fuel pressure regulator?
does he have larger than stock injectors?
does he have an extra injector controller setup?
does he have a different ecm from a boosted engine?

megasquirt is a great way to go as it has an internal 2.5 bar map sensor and its the most affordable stand alone ecm available today.

buy the one already assembled. wiring is pretty simple as it gets rid of all the emissions devises.

soon as my 02 gets hear ill be able to get a better idea of how the engine is running. with no turbo installed and my wideband in the stock exhaust i should see some major changes to the afr. if not i know there is another issue all together.

the price of mega squirt adds up quik and its probly not gonna be an option for me at this point.

id really like to see this turbo run well on the stock efi. maybe by adding a 5th injector or something thats not so expansive and not a complete engine harness rebuild.

i could even turn the boost down on the wastegate a bit if that would help but as i said before it will lean out and pop well before any real boost kicks in.

What specific ecm do you have? My thoughts are can it be tuned and also can you toss a different mask in it. Research is the key as I have no idea what you have on that and if its abe to be modded easily.

MegaSqt. Is a option. Its a good idea, and is somewhat easy to set up if you understand electronics a bit and mainly tuning. I didnt choose that because I could retain my stock ecm and do what I needed. Basically it was cheeper to keep the stocker in my case.

I am using a stock ecm with a $59 mask on it. Its obd1 GM stuff. Very easy to tune at home. 3 bar map, boost control, datalogging the AFR's and any thing else you can think of that you would need.

Guy above is RIGHT. No car can handle 12psi with no tune if it was N/A to start with.

as far as what ecu i have all i can say is its a stock one out of a 1995 geo tracker with a 16v engine and manual tranny. its the exact same in the suzuki sidekick and also the chevy tracker.

its also an obd1.

my harness has been modified to control the engine and thats it. its a very simple 6 plug or so setup that untill now has been flawless.

can you tell me more about the ''mask'' you mentioned.

ive never heared of modifiying my stock computer but that dosent mean it cant be done.

the dist advance is all computer controlled.

i dont know much about injectors im starting to wonder what other injectors would fit and work with my engine, as far as i know there are no after market injectors that add more fuel than the stock ones.

Are you sure its a obd1? 12 pins is obd1 16 pins is obd2 BUT there were a few years in teh 93-96 era where it was 16 pin but a OBD1.

This is good news if you can find out the specific ecm is in the car and it is a GM one, GM Obd1 is easy to tune, very! I will look arround a little and see if I can find out which on it has.


Heres the best way to explain it so you understand...

The Mask or as its called a XDF file, is sorta like a piece of paper that you can write on, it has certaint lines and places to put stuff. But you dont change this, its is just like a pad of paper that is what it is. It also is a sort of translation for your bin file, I hope you sorta understand what I mean.

The BIN file is what fills those lines up(what you will change for tuning) Information such as fuel maps, rev limiter, spark, stuff like that.

A ADX is for certain software, is basically a translation so that you can record the data as you drive and read it. I use Tunerpro RT V5, its FREE> Its what you see on the laptop.

What you can do with some ecms is put a different mask (XDF) file on a chip and add the information (BIN file) as you chose. I chose a $59 mask and Bin file to use. It is for a sy/ty Truck. You know the turboed charged trucks Gm made back in the day? It works perfect for me and it was as easy as buying some inexspencive hardware. Such as a chip burner, a few chips, a chip adapter, and a ALDL cable which you use to datalog(record info on a laptop) This (aldl cable) is pluged from your OBD1 port into a usb port on your computer. 200 bucks later and I can do anything to my ecm and record it, watch it back, print info out, whatever you want to do.

I will skip PIN OUT infromation as that is what you may have to phsically do, such as slighly change some wiring to your ecm, once again Very Very Easy to do. BUT in my case I didn't have to do any "pin outs"

I can get into more info later if you want, we need to conferm you do have OBD1 and what ecm though first. And also if you would be interested in taking this route.

Here is a peak of the laptop when recording info... neat hu? Just a random video when I had boost lag problems. Boost is on the left middle, Spark is under that. AFR's on the right, then I also have the intake temps, the engine temps, RPM, MPH and Spark Retard all on that screen so that I can see it when I want. This is only the tip of what is on the TunerPro Software.


EDIT: Now reading that its probly a suzuki ECM in those cars only not a GM one, this may be a issue as Im not finding much info at this point. I read this after I wrote this reply above.
Heres is the link im seeing and the others look the same. http://www.suzuki-forums.com/suzuki-...rogrammed.html

on the harness im now useing i know for a fact that i have no obd pug at all. i may have before but this harness was moddified by a off road shop that cut it down to a bare minimum.

i like the laptop in your ride and haveing the ability to tune it to perfection. thats pretty cool stuff.

so in all honestly this cheap easy turbo i wanted isnt going to be as easy as i thought.

id still like to pursue the turbo setup.

i had a thought.

if i used a btm for timeing. what else could be done to give it more fuel?
maybee bigger injectors with a riseing rate fuel pressure regulator?

in that case id have to start researching larger injectors that will work along with a better pump that will build more than 40 psi.

You could use the BTM for timing, and use a FMU or "rising rate fuel pressure regulator". This will allow you to boost the fuel pressure when so much boost is made. For example a, 4:1 would add 4psi of fuel pressure for every Psi of boost. Its more old school to tune like this but has been done. You may need to upgrade the fuel pump to handle the extra flow in time. I got a walbro 255lph, which will handle alot, for 90 bucks. I've not done this personally but am sure someone on here has and there is also a ton of info on it on the net. Google is your best friend in reasearch such as this.

Since you may not look to tune the car, larger injectors may not be a good idea becasue if you get too large of injectors you will be rich as can be and have no way to tune the ecm and tell it you have larger then stock ones.

Best thing to start is to see what size injectors you car has stock and what is the base fuel pressure on the car. Then you can start doing the math to see how much fuel presssure you would need to add under boost to support some HP> Obvously if you have to add ungodly amounts of fuel pressure, this is not a good idea as you can just imagine what 80-100psi of fuel pressure will do if the lines are not new or in great shape.

ok ive been reading all day now heres a bit of info ive come up with.

stock injectors 18lb. (190cc)
stock computer can control up to 23-24lb 225cc) or so ive read on the internet.

stock fuel pressure running at idle 30-37lbs.

static fuel pressure 36-40lbs.

65psi when return line is blocked no info on how much the regulator changes the pressure.

reading on zuki world theres a post on someone useing injectors out of a 2.3 liter ford car and haveing great luck on a boosted 16v. another thread on zuharrie has a complete turbo build and hes running stock injectors and pump while useing a vortech 10:1 rrfpr. the link below is to this rig.

lots of stuff to learn but ill keep at it till i have a set plan.

heres a thread that details a great running 16v engine start to finish. most the usefull info is in the first 2-3 pages if you get a chance check it out theres alot of tech. the pictures used to be up and have just left in the last month or so wtf?
Turbo 1.6 16V Tracker/Sidekick motor in a Samurai = FAST FUN!

heres a poser pic of my crawler sorry its a poser shot but its all i have.

https://www.homemadeturbo.com/attach...ine=1341973924

can someone tell me in mathmatical terms how to calculate the amount of fuel pressure increase i would need to get my engine to run at 12:1 afr at 8psi. boost useing a 10:1 rrfpr.

all the other stuff needed should be in the last post other than i would change fuel pump to say a e 2000 thats capable of 95 psi.

im lost here.

rite now my afr goes leaner than 18:1 before i hit 4000 rpm so im shure ill need a fair amount of pressure to make much differance.

Its a pain for me to figure it out right as Ive never really done it but. Read though this.

Fuel Injector Calculator from WitchHunter Performance

a 10:1 would net 209Hp@ 90% injector duty cycle if I did it right. 120psi I used. The static 40psi plus the 80 you added from 8psi of boostx10 from the 10:1 RRfrp.

ALL stock you can handle 124Hp@90% duty cycle.

So that is a extra 85Hp you could handle. And if you want 8psi of boost, Id say that you would be close on the fueling but may be ok. Although the stock fuel pump may not keep up. A different one may be needed.

its damn near impossible to figure that out. its a trial an error method as all engines require different fueling characteristics at different rpms and throttle position. if you search ebay for fmu there should be some on there that come with different ratios all in one package so you can decrease the ratio to dial it in. always start with the richest ratio and work your way down in ratio(leaner) till you get that 11.5 - 12.0 :1 afr. these will require a high flow pump as your stock pump will burn itself out pretty quickly running very high fuel pressure and it also will flow less volume at high pressure which is not good.

so maybee i should turn the boost down to 6psi. the factore set the wastegate at 7-8psi so i may have to research how to change that.

at 6psi boost and useing an vortech 10:1 fmu with a airtex e2000 pump.

e2000 pump is rated at 95 psi and 40 gph.

this setup with the boost lowered to 6psi should be a safer setup than maxing out all the componets.

before i order the vortech 10:1 fmu (id be able to buy adjustable pressure plates from 4:1, 6:1, 8:1, 12:1) but 10:1 seems like the best starting point.

an airtex e2000 pump.

is there anything else i should consider before spending the cash on this stuff?

id also like to do the msd btu but for now id like to think this will at least get me running without worrying about blowing it up.

well after talking with a friend who has some knowledge of turbos he suggested
useing a begi brand fmu.
i guess its compleatly adjustable and is good for up to a 120 psi system.

its not much more than the price of a vortech so i guess i should go this route instead.

the adjustable ones are convenient but from my experience they fail often.

well i need to get a plan here and the more i read the more im up in the air.
reading on another forum there a guy saying that useing ms i could wire it and be up and running in half a day.

ive sent him my number and asked him to call me but no answers yet. by the time i buy a fmu and new pump and a btu id be spending even more than the ms.

ive tried leaving my number with diyautotune.com but still havent heared back from them yet.

as i understand it it somewhat easy to do but im not much of a wiring person.

megasquirt would be a great choice. most affordable standalone on the market. it also has a built in 2.5bar map sensor for boosted applications.

im currently using the microsquirt for a motorcycle application and cant wait to get it wired up and running.

+1 for the MS in your situation. Personally I would't want 120psi of fuel going through my fuel lines, but my car is old.

A friend of mine showed me how to set up MS and its really easy. I was there for the install, took 3 hours then started up the car and started tuning. He was really good with a soldering iron though as the kit he got, we had to piece together.

If you can get a tested assembled one to ease your mind if you assembled the ecm right. Cost about 100 bucks IIRC.. more but If it was me, thats the route Id go.

theres no kit for the engine im useing so basically buying seperate parts that would all come together and make it work would be my only route at this point.

id be interested in useing the ms and the price dosent sound to bad but that leaves me wondering how to get all the right parts and what to do when i get them all.

ive sent email to diyautotune.com and tried to get ahold of megasquirt but still no call back from either.

peaple say its pretty easy but im at a loss for where to start. hopefully they will get in touch with me soon. another weekend will come and go and ill still have made zero progress.

the kit he was referring to was the megasquirt. you can purchase a megasquirt assembled for ~350.00 or you can buy it in a kit for were you put it together by soldering all the components to the motherboard for ~150.00.

I think I tried calling you earlier but I seem to have called at the wrong time. I've emailed you a list of questions about the build. I'll also send you a number to call.