Complete Cut Out in Boost

[DSM 2G Brendon]

I just traded off my 93 Honda Civic hatch to jump over into the DSM world! My first car was a 2g Eclipse GSX, but at the time i didn't know what i had...but anyways unfortunately this has to be my first post.. But anyways i'll explain my issue the best that i can. The car idles fine and when i'm not building boost it drives fine if i stay out of boost i can run it up all the way through the gears with no issue. My issue is when I get into boost the car completely cuts out.. feels like i'm going to go through the windshield.. this doesn't really happen in first gear often , most of the time i can run it all the way up through first gear no issue, but once i hit second gear and i keep into boost which right now my gauge reads 10 pounds when i'm mashing it down but it creeps up to 12 pounds at high rpm. The cut out usually occurs at around 5-6k rpm. i notice it happens more once i past the 10 pounds threshold. I've read up alot and I think i am experiencing fuel cut. I don't know where to check first or what exactly this could be so any advice would be greatly appreciated. I am excited to make the jump back to the better side!

Thanks!

 

[92AWDHX40]

Get a way to tune this thing if you haven't could be simple mainetenance, boost leak etc.

 

[Dsmkauai]

Most likely fuel cut dude! A 16g on stock fuel system and no way to tune is going to cause fuel cut at anything more than like 10ish psi, you need more than a gm maft to run higher boost. Also check for boost leaks and shaft play in the turbo.

 

[DSM 2G Brendon]

Yeah, i was thinking this as well, it has alot of stuff in the bottom end and head done also, and the 16g and higher boost, its also running on the stock fuel pump as well, for right now should i turn it down to like 8 pounds? Also, turbo has no shaft play just extremely minor side to side no in and out play, solid turbo..

 

[gusu]

It's not fuel cut. The 2g MAF is capable of reading flow rates for 400+ horse power, I believe through some tuning people have made nearly 500, but I could be wrong.

Fuel cut happens when the ECU sees that the MAF is no longer reading accurately because you are flowing too much air. So to save the motor it stops all fuel.

What is most likely happening is you have a boost leak. When a boost leak is bad enough you feel like you are running into a wall. They are easy to test for and there are plenty of write ups on how to do them. If you don't own a air compressor use one at a local gas station or something. A boost leak tester is a very simple thing to make.

 

[DSM 2G Brendon]

I have a GM MAFT installed right now, and yeah when that thing cuts out i have to let go of the pedal or else nothing happens it almost like the engine shuts off which it might... when it happens it feels like i am about to shoot through the windshield. Could a boost leak cause fuel cut?

 

[iiNFAMOUSCHRiS]

fuel cut is too much air, so a boost leak would be the opposite, in fact. i'd say it's a boost leak somewhere, a pretty big one too, check the IC piping.

 

[DSM 2G Brendon]

i can link YouTube to this right??? tomorrow i will upload a video of it so everyone gets a better idea, i could possibly have fuel cut and a boost leak? and i didnt realize a boost leak could cause your engine to cut out completely... so where should i start?? boost leak test?

 

[iiNFAMOUSCHRiS]

boost leak can in fact make it run like that, unhook the recirc valve on a stock car and see how it runs, that's basically just a massive boost leak. start with a boost leak test, it's always a good idea to routinely do the test anyways. and yes, you can definitely link to youtube videos on here.

 

[DSM 2G Brendon]

I was also told too check the plugs and the gap on the spark plugs. Could make it cut out? I'll just check tomorrow by doing the boost leak test, and check the plugs and maybe just replace them... are NGK BPR6EGP plugs okay? And what should i gap them too?

 

[iiNFAMOUSCHRiS]

Get some BPR6ES or BPR7ES, gapped to .28

As a side note, don't go into your local parts store and ask them for plugs for your car, or take their recommendation. they will steer you towards what they're told/paid to promote. just tell them you want BPR6ES.

If you can, order them online for store pickup at Advance Auto and use the TRT30 promo code

 

[DSM 2G Brendon]

hmm those will work, which one is better or are they pretty much the same?

 

[iiNFAMOUSCHRiS]

the 6's are good for stock, 7's are for modded cars. the number refers to the heat range.

 

[DSM 2G Brendon]

thanks! and yeah i noticed that's where i got the BPR6EGP at that's the ones they recommend.. and thanks for the promo code.

 

[iiNFAMOUSCHRiS]

yea, they'll recommend them and claim they're better -- just ignore the advice and get what 90% of users here are using, or else they'll just get fouled up in no time and you'll be back in getting the right ones anyways. i use that promo code on everything haha....with bigger items, the 30% off really makes a difference.

 

[97_4g63t]

I had the same problem and it was boost leaks. Think about it. Your ecu sees x amount of air going into the motor so it puts x amount of fuel in. If some of the monitored air escapes before it makes it into the motor your ecu wont know and it will still put x amount of fuel which would now be too much because you lost some air. Do a blt. You will be amazed at what you find. If you are running 12psi then do your test with 15psi. Spray your tb, vacuum lines & intercooler pipes with soapy water and if there's a leak you'll see it bubbling.

 

[DSM 2G Brendon]

Most likely fuel cut dude! A 16g on stock fuel system and no way to tune is going to cause fuel cut at anything more than like 10ish psi, you need more than a gm maft to run higher boost. Also check for boost leaks and shaft play in the turbo.

In saying that, the question is because i have stock injectors.. well a complete stock fuel system for all that I know. Should i turn down the boost to 8psi until i get it all upgraded? or should 12 be fine? The previous owner said he was going to run 18psi once it was broke in and that the engine internals could take 24psi. I need to check to see if their is a walbro 255 or some type of aftermarket fuel pump installed.. I looked it up here and its right under the seat in the back on the passenger side. So that is something i should pull out and check too see. Right now until the beginning of February I won't have the extra cash to shell out for ECMLink yet.

 

[iiNFAMOUSCHRiS]

a 16g on low boost and stock fuel shouldn't be an issue, turn it down just to be safe though. perform a boost leak test just to be sure there aren't any leaks though.

 

[DSM 2G Brendon]

yeah also, the turbo has a aftermarket internal wastegate actuator on it, no MBC. Do you have to do the pre load turns when turning it down or is it as simple as just taking the clip off the rod extender and turning it a few times to turn it down? or is there a certain number of turns i need to do?

 

[Dsmkauai]

Fuel cut just doesn't happen when the maf is over run guys. It happens when you run out of fuel hence the name fuel cut!! If the pump isn't pushing enough for the boost/air flow your running and the injectors are over 100% duty cycle and can't keep up, your hitting fuel cut! You should be ok between 8-12psi, but every car is alittle different bro. I also highly suggest doing a boost leak test to like 20-22psi and make sure there's non adding to your problem. And I'm sure the previous owner said that . Your lucky he didn't get the chance to or that motor would probably be toast after awhile running like that. 18psi on the stock fuel system and no way to tune or see how lean and how much knock is happening is not a good idea, besides you would hit fuel cut around 14-16psi I'm sure and quickly realize 18psi definitely won't work !

 

[97_4g63t]

Just remember to stay out of boost till you get everything straight. I spun a rod bearing within the month it started.

 

[DSM 2G Brendon]

thanks, that explanation was pretty good on fuel cut. I am sure i have a boost leak the previous owner didn't have enough of the rubber intercooler boots so he just used a large size of black radiator hose, and he also has a piece of steel exhaust pipe he used as intercooler piping, a big hack job, the top he did right the bottom was just thrown together. it still has the stock side mount.

Just remember to stay out of boost till you get everything straight. I spun a rod bearing within the month it started.

Yes i agree i don't need that, it was rebuilt around 2000 miles ago by the previous owner.. I wonder if advanced auto or auto zone carries something i can use better then the radiator hose or whatever it is he is using as a intercooler boot/coupling what ever you call it..

 

[Dsmkauai]

When your ready to upgrade to a fmic get a vrsf kit http://www.vr-speed.com/vrsf-2g-dsm...it-fmic-95-99-eclipse-talon-turbo-2g-dsm.html . I just picked one up for my new eclipse project and love the kit everything you need to bolt up and go. If you just need a few pieces of piping and couplers and clamps to ensure things are sealing and not a hack job. Go to http://www.siliconeintakes.com and you can order anything you need ic pipe wise. I also just ordered a 3" piping kit and all the couplers and clamps I need for my talon project, I'm doing all custom welded pipes and shortest route possible! Also if your ecu is seeing to high of air flow coming in its not going to cut fuel its going to try and make it richer to compensate. And there's no way the o.p. is over running a gm maf on 12psi boost and a 16g. My last setup was maxing out a 16g at 37lb/min and 20psi and my maf was stock 2g and not a issue at all. I remember way back when I first started modding my eclipse. I threw a 16g on and had boost around 14-16 and was hitting fuel cut super easy, I quickly learned my lesson and upgraded to a walbro 190 and 550's and also got ecmlink and problem solved! I finished with that setup running a walbro 255 and fic 850's and running low 12's all on the stock 2g maf!

 

[DSM 2G Brendon]

okay well, that's a good option i will look into that for sure. They have a good price on it. Anyways i'm off to bed tomorrow i will go to advanced auto and buy some new plugs and see how that does for me. I also will do a boost leak test tomorrow and report back on my findings.. Also i have a glow shift air/fuel gauge but its not currently hooked up i don't think.... does that directly tap into the stock 02 sensor or do i need t get a aftermarket one?

Also sorry i forgot to ask, how exactly do i test at the certain psi ?? I'm not quite sure on exactly how to do a boost leak test, just look for rips in a coupler? I searched it on here and there are a ton of ways just wet it down with soapy water and do i have the car running?? or just hook up a compressor to a vacuum line? not clear on this.

 

[Dsmkauai]

Well you can't have the car running because your just testing the intake system. Basically you remove the trunk inlet tube/ air filter tube. And with your boost leak tester, can be made with a 2.5" Pcv end cap and a rubber or metal shrader valve. You clamp it on and using a air compressor or bike pump, you add air till your boost gauge if you have one reads like 20psi. If you don't have a aftermarket boost gauge you can add a gauge to your boost leak tester so it's easier to see what your at. Then just listen and look around for leaks. They are pretty easy to hear when your in a quiet place doing the test. Once you see them just do what you need to do to fix it and then test again. Become friends with the tech articles on here they are great!! http://www.dsmtuners.com/forums/art...-boost-leak-test-how-boostpro-net-tester.html