Backfire "not boost leak" Help!

[joeyzaza]

Ok, I have searched everywhere on this site for about 2 months, with no results.

Here is my problem. I get a single backfire, seems like fuel cut, but not too sure, when I am at WOT. This seems to only happen in second gear and up. The car is an automatic. I am currently at stock boost levels, about 11 PSI, with a small creep to 13. I just hooked the stock BCS back up, after thinking it was my MBC.

Here is what I have done so far. Changed the plugs "NGK 6es" gapped at .28. Did that twice. New plug wires, new fuel filter, new battery, and new ground cable. I have fixed every boost leak that the car had on it, and have reset the computer by unhooking the battery a few times.

The car is a 2g 97 GSX. I have a front mount intercooler, with all custom made hard pipes. I have a 1g BOV on it, and aftermarket exhaust turbo back, with no cat. Hardpipe air intake. Aftermarket Boost guage.

My plugs look grayish brown, so I'm not running rich anymore. My BOV is recirculated properly.

I ordered EVO Scan logging software and cable, I should have it here in a few days. My turbo has 0 shaft play "stock t25"

WTF Anyone else have issues like this before, and fixed it???? Please help.

 

[Backinajiffy12]

You want the 7's its a colder plug. and those 6es are the iridum ones arent they? if so you cant gap those

 

[joeyzaza]

Really??? I read a bunch about what plugs to get, and I thought the NGK 6s where the right ones.

I will try the 7s tomorrow, will they come gapped at .28???

 

[Backinajiffy12]

You should gap to .35 or .32 cant remember but they should come pre-gapped but double check

 

[t25fury]

you have the right plugs (BPR6ES) since you are still on stock boost and turbo,no need to upgrade the plugs yet,sounds like your fuel pressure may be low,possible culprits are : failing fpr,failing fuel pump,leaking fuel,bad fuel pump oring. Not enough fule pressure can cause backfiring and loss of power.

 

[joeyzaza]

I thought I had the right plugs, I've been looking into this for months. I think the EVO Scan software will help me to find out if I am having fuel problems. I'm going to search for trouble shooting fuel components. Thanks

 

[Backinajiffy12]

the 7's arent the upgraded plugs. Get 7's gap them to .30" for up to 16psi and .28" for 17 and up.
7's= BPR7ES

 

[joeyzaza]

I knew what the 7 meant, . This is so frustrating for me, I've been going crazy. I read a bunch of posts about what plugs to use, and I thought most people were using the BPR6ES gapped at .28.

This could be a spark issue, but it could be a fuel issue aswell.

I'll try the 7s just for the heck of it, 8 bucks big deal, I just wont drink Starbucks for 2 days.

I'm going to be doing some mad searching on trouble shooting fuel, as soon as my girlfriend quits harrassing me about being on the computer. They just don't understand what we go through. : )

 

[Backinajiffy12]

girlfriend quits harrassing me about being on the computer. They just don't understand what we go through. : )

I feel ya there

 

[joeyzaza]

Tried the BPR7ES plugs, gapped at .28. Took off in first at WOT 12 PSI on the guage, car shifted into second "automatic" boost spiked to 14 PSI, and backfire! When it backfires it bucks once, and then is fine. Went home and started to look at the vaccume lines for the FPR, it all looks good, did boost leak test a few days ago, with no leaks.

I did check the fuel filter and I saw a small amount of liquid on the top hose. Seems to be leaking a bit. From where the top hose goes on. Like t25fury says, I think this may be a fuel issue. When we put on the filter, we put in new O rings, how can this leak.

I'm going to try to fix the leak, and I'll post the results. Thanks

 

[Backinajiffy12]

What codes are you throwing?

 

[1992GSX]

The BPR6ES's are the plugs you want. Gapped to .028, not .28. The 7's are too cold for your mods and there is no need to run those on boost levels of 11-13 psi.

You stated in your original post that your "not running rich anymore." Were you experiencing this problem when you were running "rich?" Do you have anything to confirm that you are or are not? Or will the logging software that your getting be your first look at engine monitoring?

 

[joeyzaza]

I have no CEL. I wish I did, this would be easier.

I was running rich before, I had a horrible boost leak, and it was causing me to run rich, lots of black smoke when boosting. I had the problems then too, but it was a lot worse. After fixing the boost leaks, my new plugs look great, the old ones where black!!

I'm still waiting on the EVO Scan cable. I think I have the fuel filter hose on tight now, no more gas on it I got some new crush washers. Haven't had a chance to test the car yet. Ever since I changed the filter, about a week ago, the car has been idling higher. I wanted to try to adjust it, but the biss screw is stripped like no other. I'm ordering a new one of those.

I have only had the car for the summer. The last person only had it for a month, so I dont know much for its history.

 

[joeyzaza]

still waiting on evo scan... and its freaking snowing!! I will update this when I finally fix the problems, thanks all!

 

[joeyzaza]

Fixed the idle, my throttle spring was going bad, and not shutting the throttle all the way when off the gas.

I got the Evo Scan software, I'm not sure what I am looking for with that. The biggest thing I noticed is timing was reading at 33 when it backfired. Also O2 feedback trim went to -4.xxx.

My fuel filter no longer leaks.

The log was after the car was warm, I went WOT through first, then the car shifted into second and boom!

I hear a ticking noise that comes and goes from what seems to be an injector, I'm looking into this currently.

Anyone have any ideas what I should log to find a solution to this???

 

[Tarantula]

I have gotten backfires but its always due to a rich condition. Maybe check your FPR.

 

[joeyzaza]

I'm going to buy a fuel pressure gauge and check that monday. Its getting to cold to mess with cars here now, freakin michigan!!

 

[Tarantula]

Definately has to be a rich condition. Today i raised the boost a tad and I went a little rich around 5K and BOOM! backfire. It feels like the car hit a wall real quick Usually the peak cylinder pressure (5-5.5K RPM) area is where the backfire starts.
And me having all Stainless steel Exhaust makes it even more sensitive.

 

[joeyzaza]

I'm doing it at stock boost.

 

[Tarantula]

I still feel it may be the fuel. Maybe your stock FPR took a dump. It has to be fuel related. Is your fuel pressure solenoid still routed in with the intake manifold?

 

[joeyzaza]

Ya I'm pretty sure it is, I'm going to check it all out on Monday. I'll update then. Thanks

 

[19BLACKGST98]

I believe with Evo scan you need to subtract 10 from the timing reading. So when you said it read 33 it was actually at 23. Also make sure when you use evo scan that you deselect all of the stuff that you are not interested in because that program runs so slow as it is. I woldnt log more than 7 or 8 things at once if I were you.

 

[joeyzaza]

I think I fixed the problem. My alternator belt was squeeling, and I changed the belt. After changing it, it was still squeeling off and on. After finally getting it tight yesturday, the car seems to be boosting just fine. Could the loose belt cause not enough electricity to run the plugs, resulting in extra fuel not being burned off, then igniting in the exhaust. Any insight on this anyone??

I've only boosted through second, its icy here now so I can't really go WOT for very long.

 

[Tarantula]

Try it in third and forth. Thats where my backfires happen. Mostly in Forth. Second is much to fast.
It happens around 5K.

 

[gsxeclipse97]

So the evo scan does work on the 97's afterall? When i read about it they said that you needed a 98 for it to be useful. Well that makes since because you would be rich around 5k since the boost falls low in that area.