maft cutoff problem and knocking

[91-gsx]

Hey im new to this site so i dont have a parts list yet but i have a, n1 downpipe no cat, 2.5 exhaust to stock muffler, pacesetter manifold, and just got my maft setup. without the maft setup i ran the 1/4 mile in 14.6 at 92 mph 1.9 0-60ft(low speed due to finding out my gasket that came with the pacesetter kit between the turbo and the manifold blew, replaced it with a metal mitsu one. so no more leak. when my car blew that gasket, the turbo ofcourse did not boost worth you know. but when i got the new gasket and no more leaks, the car idled like sh$% and it would not allow me to go past 6,500 rpms. i got the maft setup and that kept fuel cutting, they told me at dejon tool to run it either leaner or get bigger injectors to get rid of fuel cut. well i ran it leaner and it still had the problem of stuttering and not allowing me to go above 6,200 and lets say it took forever to get to 6,200 rpms. well i got a laptop data logger cable from ebay that works pretty well and i am using the software called tunerstein, it turns out that i cannot go past 6,200 rpms becuase there was 42 counts of knock and it would retard the timing back to 7 deg, basically idle. i richened the maft setup back to 0 and 0 for the MID and WOT and now there is that fuel cutoff but now the most knock was 25 and that seems to be at MID. Please help i see a lot of people running maft setups and not having fuel cut, help me if you can, any info will be greatly appreciated.
P.S. i am going to race my bosses 13 sec mustang soon, so i need to get this running in great shape.

 

[sweet97]

How did it run before the MAFT? The MAF is flowing a lot more air and you have stock injectors, stock fuel for that matter and who knows in what condition. ECU "sees" a lot of air and cuts fuel because it is protecting the motor. Then it is also so lean that it is knocking like crazy pulling timing. You need a proper mix of boost,fuel and timing. Backoff the boost enough and you will not fuel cut. But you want to boost or power so like dave(Dejontool) said get bigger injectors-550's since you are all stock or pull the MAFT for now until you have more mods. The MAFT is for fuel control which you have none to control. No upgraded pump, injectors/AFPR.
Hold off on your boss' stang for a while and you will crush 13's. Check out the tech guide and the path to follow, step by step, at the top of the page.Mark

 

[91-gsx]

so if i were to get bigger injectors and a fuel pump it would solve the problem?, given ofcourse that i can log and tune right. but i just had that other problem i think it was knocking and not allowing me to go past 6,200 rpms becuase it was pulling timing when i came back from the track and at that time i did not have the maft, before then and at the track everything worked really well. what do you think happened there, maybe the knock sensor came loose becuase of all the launching or something else? or did the blown gasket between the turbo and the manifold show up as knocking?
thanks for your reply great, info please keep it coming.

 

[sweet97]

Leaning the MAFT does 2 things. It lets the ECU "see" less air so it will probably not have fuel cut. Less air and the ECU "thinks" you are under a light cruise condition so it advances timing. That gave you the high knock count and the pulled timing.
Say you get a set of 550's and a Walbro pump which may not be needed right yet but if you continue to mod you will need a good pump. Now if you rev to redline or raise the boost you have fuel available. You set the base on the MAFT whih gives you a starting point. Where is your base set with the 450's? (The "book" says 2 but setting it on "0" would richen the mix but might raise the injector duty cycle too high.) With the 550's you have added the fuel to go with the extra air the MAF flows so you are able to "TUNE" much easier. You do not want the WOT knob to be turned too much to the lean side or you get high timing and too much to the rich may cause fuel cut. You can try the bigger injectors without the pump but rewire the stock pump. The directions are found at www.vfaq.com under FUEL. Go to www.fullthrottletech.com they buld the MAF-Translator and have a tech site for questions. You can PM me if you like(personal message) Mark

 

[91-gsx]

ok i am thinking of taking off the maft setup for now but i still do not know why it was not letting me go past 6,200 rpms after the track day, and the car takes forever to get their, it never did that.
thanks sweet97 for your help so far.

 

[psychlow]

What condition are your plugs and wires in?

 

[91-gsx]

i have accel wires and bosch platinums and they are both new. i am thinking of taking off the maft setup and go back to the basics to see what was wrong previously. what do you all think was wrong when it use to pull timing before the maft setup?

 

[danielbui]

when are you going to add a front mount? have you ever pressurized your intake track for boost leaks? try finding higher octane fuel maybe that will work

 

[91-gsx]

see why would i need to do all this when it was running fine i think someting went wrong after the track and it does not have to do with tuning, well atleast before the maft setup.

 

[danielbui]

just making suggestions

 

[FireyIce01]

The knocking is tuning... it might be that your SMIC is just not doing the job of cooling the air... I didn't see anything about how much boost you're running. If you're boost is too high, and you're not adding fuel, the car will run lean and knock. Bigger injectors and fuel pump with an AFPR and some tuning *should* solve your problems. Also, what octane are you running, I know you're stuck here in the wonderful state of 2.59 a gallon (and rising) 91 octane, but if you're buying anything less you're shooting yourself in the foot when it comes to a turbo car like this.

 

[sweet97]

Didn't a gasket blow? Boost leak, Vfaq shows how to make a tester, vac line off? Mark

 

[92awddsm]

Throw those bosch platinums away and get a set of ngkbpr6es. Ive never seen a dsm run well with bosch plugs.

 

[91-gsx]

i see what you guys are saying and all and i am going to take maft setup off for now, just bought a boost gauge so i do not know were my boost is, but i am not running a cat so it should be higher than stock, do you guys have a guess at were it is. anyway i took off the small part of the honey comb when i got the downpipe and exhaust so that there would be no cutoff, and everything actually wokred great, i even ran a not so bad 1/4 mile time for the mods i had remember that is without the maft setup. but when i came back from the track i had a leak of exhaust do to the gasket between the turbo and exhaust manifold exploding, shitty pacesetter gaskets dont ever use them, but i do like the manifold. after that day i had a leak and boost did not kick in so i replaced the gaskets on the head and between the turbo, but now the car pulled timing before red line so i cannot even get there, i can only go up to 6,200 rpms and becuase of the pulled timing it went to 6,200 very slowly, nothing like before.
please help me with figuring this problem out first then i will start doing the rest like maft, fuel, and tuning, and ofcourse i will need help with that later.
thanks for your help so far

 

[kicker91laser]

You may want to clean out your smic, it could be full of oil and be heatsoaking really bad, just a suggestion.

 

[91-gsx]

but would that make a difference of just a day, like it would run well at the track and then start heat soaking the next day or two, and make my car run really bad?

 

[kicker91laser]

but would that make a difference of just a day, like it would run well at the track and then start heat soaking the next day or two, and make my car run really bad?

Probably not, but if you have never cleaned it out, it would be wise to do so, it sure wouldn't hurt to do it.

 

[4GSixty3]

bosch platinums

Right there is your problem. Platinum plugs in a turbo car are very shitty. Go with NGK's.

 

[91-gsx]

do you really think that i need to take off my maft setup and go back to the basics? or if i make it run rich for now save some money for injectors, and maybe a pump, do you think i can run a while with the stock pump? o ya and if i get injectors and a new pump will my fuel cut still kick in?

 

[sweet97]

You are trying to do the improbable/impossible and rejecting good advice. NGK's gapped at .028. Gowith the 6's as told above. You CANNOT make the car richer with the MAFT and NOT HIT fuel cut. The translator does NOT increase the fuel. It lets the ECU "see" more air so the ECU does add fuel due to what it thinks is coming in air wise BUT it also has a limit to how much air it will see then IT CUTS FUEL!! It does this because it thinks the motor is going to grenade. And it might. You can only push the 450cc injecors so much. We can't begin to guess how much boost you are running except it is too much. If you get the gauge working and back it down to 10 psi you "might" be able to keep the maft until you get the 550cc injectors. Maybe find a set of 510cc EVO used injectors.
You can easily cause permanent damage running lean. Especially if the rest of the system is not up to snuff. Have you changed the fuel filter under the hood? Changed those Bosch plugs today? Read the tech guide to mod steps? Checked out www.vfaq.com for wiring the pump for more voltage which would give you more fuel? just throwing out suggestions, not really asking those questions. Make it right and then go for quicker. Check for boost leaks. nice pics on a howto on vfaq.

 

[91-gsx]

ok thanks for the advice on that post and the others i am taking it all in so do not be misguided into thinking that i am ignoring your advice, thank you for all your posts guys i was just about to go buy the plugs right now, no i have not changed the fuel filter, i have not rewired the fuel pump. i need to get my boost gauge in the mail that i ordered. i am also going to get an mbc. i do not know what i am running because all i have done is got bigger piping and removed the cat. Do you think i should just buy bigger injectors like 850cc and reset my maft to compinsate for them, i want to do this for future mods, dont want to keep selling and buying things. ok and once i turn down the boost and rewire my fuel pump and get bigger injectors, when i later on want to turn up the boost, how do i go about doing it so that i do not hit fuel cut?
thanks in advance

 

[sweet97]

MAFT can't handle 850's. You would get sky high timing as you would have to lean them out so much not to run super rich. Remember the translator changes the AIR the ECU sees which adjusts the fuel it supplies. It would cut the air and raise the timing so you would get wicked timing pulled. 650cc's are the best all around injector and the tanslator would be OK with them. You may have an EPROM ECU in your car as many of the early models do. Then you could have it socketed and get a chipburned, then you could run 1000cc injectors if you wanted! Vfaq shows how to pull the ECU and you can check inside for the EPROM. Vfaq has pics. I run the MAFT and 650's with an EPROM ECU and a 60-1 turbo which willmake over 500whp on a built motor. I can run 20 with these injectors and that turbo. To goover 500HP larger inj's than 650's would be needed bu I willnot be there for a long time! Get 650's if you think you might go with the very popular 50 trim or even an EVO big 16G.
What do you get for timing at WOT when you have trouble pulling to redline? You mentioned removing the honeycombs, that was before the maft right?

 

[91-gsx]

well i did not have a logger before the maft setup, but now with the maft setup what happens is that it showed about 42 counts of knock and then pulled timing to idle, which is 7 degrees at this time sense i had advanced the timing becuase i thought that is what caused me not to pull to redline. thatis when i ran it a stupidly 20% leaner in MID and 15% in WOT, i say it is stupid obvioiusly becuase it was running lean enough as is. that is when i got that much knock. now i have it set back to 0 for mid and 0 for wot. it has fuel cut now, but the knocking is no where near as much most i saw was 10 and 25, but i think i have a loose knock sensor due to the fact that it seems to knock when i let go of the gas and there are a few knock when i am driving but most i saw was 7. About the 850cc injectors, i bought the newest version of the maft and it has enough settings to handle up to 1030cc injectors. for 850cc it says to set the AUX to 2 and BASE to C. i know the older versions do not handle anything over i think it was 660cc. might be wrong. just went to kragen and bought a fuel filter and new plugs NGKs ofcourse.

 

[91-gsx]

o ya and i did remove the smaller honeycomb before i bought the maft becuase i red in import tuner that when you get a n1 downpipe that removes the cat boost goes up and fuel cut kicks in unless you get a fuel cut defencer by HKS or remove the smaller honeycomb. it idled a little worse but no fuel cut when i removed the smaller honeycomb. but after that track day lets just say things went downhill, becuase of the gasket going out between the turbo. the car did not boost at all and sounded really loud do to the manifold leak and once it was fixed the car did not pull to redline or really at all past 4,000 rpms.

 

[sweet97]

I have the newest version of the MAFT and I know what the chart goes to. Remember the translator changes the air the ECU sees which will change the fuel accordingly BUT IT WILL NOT CORRECT THE TIMING, I tried 720cc's and got sky high timing. Trust me and go with 650/660cc's after you get an MBC and lower the boost to stop the fuel cut.
You don't want to buy things twice and none of us do so be prepared to have a couple grand at least to spend at once as the stock IC will not handle a big turbo. If you get something like the pump gas king 50 trim you will have to run low boost until you get a good front mount IC.
Start with the MBC and the gauge and find out where you are with boost and then the injectors. Then you should be able to boost to 16 psi safely. Lower the boost with the MBC until you get rid of the fuel cut. have you read the tech guide next to the home page at the top of the screen yet? It gives you the order to domods and the approxiate HP you might expect.mark