92 Talon TSI Misfire *Help Appreciated*

[Hestman]

Okay so when I got the car it ran great. Started running really crappy and barely running turned out to be a boost leak. Since ive had it ive replaced the alternator, 02 sensor, fuel pump (Walboro 255lph), Spark plugs (NGK 7's gapped to .028)

Car started misfiring and lower rpms and would idle rough. When I would floor it It would sputter then after about 3.5k rpms the misfire would go away and it would haul all the way to red line. Now It wont even do that. I pulled each plug wire off the plug and started the car i had spark going from the plug wire to the valve cover on each wire. I tried testing the coil with my DMM. On the 3 pin connecter i got .8 oms between 3 and 2 and again between 3 and 1. Thats what the book said to do. When I look inside the place where the plug wires connect to the coil i can see the shiney metal piece on each one except the first one. (Cylinder 4 coil) I ordered a coil from autozone it will be here tomorrow. When I tested the ohms between 4 and 1 my dmm kept jumping around (Probably because the electrical connector is missing?) and When I tested the ohms between 2 and 3 Im pretty sure i got 14.3 ohms which was in the approved range.

I'm wondering If the spark I see going from plug four to the valve cover is maybe not enough to burn the mixture completely bc of the OHM reading I got between 4-1 on the coil pack itself. (It jumped around irratically couldnt get a solid test)

I failed echeck too btw I scored 938 on my HC and only 280 is allowable i think.

Any help on anything else I can check while I wait on the coil tomorrow would be greatly appreciated. If I can fix it and save my self 113$ I would really be happy. Thanks for taking your time to read this. Heston

 

[tsi209]

Hey bro I had the same thing on my 92 tsi and I found it to be my ecu and my charcoal canister had a big hole from my battery acid. Changed both and now my car pulls hard again.

 

[izzone913]

+1 on ecu. Mine wouldnt go above 2k but I put another ecu in and bam perfect. It seems to me if you start out with a good/rebuilt ecu you spend alot less becuase your not spending it on sensors etc only to find out its ecu.

 

[Hestman]

Well the car had a rebuilt ECU in it. Im meeting with the guy i got the car off of this weekend. I wish I had the craigslist add to show you guys. And pretty much ALL of the emissions were deleted. NO IAC no EGR and also no power steering no ac. He deleted basically everything. (He's sponsored by buschur racing has a 9 sec evo) The car was done right.

Update: Got new plug wires. the car pulls at 3k rpms now as apposed to 3.5k making me think more that my coil is just week or something bc what little spark it is putting out went through a better wire. Also I have a wideband 02 sensor. Used to idle at 14.7 now it idles at 15.3 Maybe the sensor is picking up on more 02 because of not combusting? I dunno. Coil tomorrow then ill post what happenes.

 

[MichaelSuch]

The 255 lph fuel pump is most likely overruning the stock FPR

 

[Hestman]

The 255 lph fuel pump is most likely overruning the stock FPR

I have an aeromotive adjustable FPR. Its all nice looking with a cool gauge on the front. It came with the car. The walboro 255lph came with the car too but not installed. I installed it 2 months ago when I bought the car, Has been running great until a couple days ago. I should have included that in my post earlier but thanks for your reply. Any other suggestions?

I replaced the coil. Still misfires. So far ive replaced the plugs, wires, and the 4-1 coil. Any other suggestions?

Also Did a compression test. Didnt have the throttle pressed in dont know what kind of a difference it would make but i got

Cylinder #1 - 130psi

Cylinder #2 - 130psi

Cylinder #3 - 135psi

Cylinder #4 - 150psi

Did a boost leak test. Built a tester with a valve stem, plumbing coupler, and the pvc cap. Filled it up had a bas SWOOOSH right at the throttle body. Sprayed soap on it and BAM Huge bubble. It didnt hole 10psi for 2 seconds it was leaking so bad. Im guessing this is my problem. Ill get the gasket after the holidays and let you guys know if it did the trick. Thank you for your replies. Heston

 

[Hestman]

Well I took out the old gasket and put in the new one and its leaking on the same spot. I did it really fast though and didnt clean the surfaces so tomorrow im going to take it apart use a brillo pad on both metal surfaces then use some sealant in between the parts on each side of the gasket. Put it all back together and let it sit for a few hours then try again. I hope this helps

 

[92_talonGsXt]

check the power transistor

 

[Hestman]

Well Im going to try and fix my vacuum leak before I do anything else. I found a tech article on VFAQ.

http://www.vfaq.com/index-main.html

I Had a bad leak and made a huge bubble and the top of the throttle body to the intake manifold. Im hoping its not the shaft seals as they look hard to replace....... fml

 

[Hestman]

Well I rebuilt the throttle body with the O ring type rebuild on the VFAQ. I hooked pressure up to it and No leak at the throttle body anymore. Still Have one coming from it seems the Lower hose on the intercooler. Im by myself and only have an air tank so I cant watch my boost gauge to make sure it goes to high, pump the system with air, and listen for the leak all at once.

Just to see if I fixed the misfire though because It was sealing better than before I put everything back together and It still misfired and idled rough.

Maybe I should swap the new coil I just got with the other one and see if this helps? Would that vacuum leak cause it to idle like that? Im stumped here and I could really use some help.

Okay new update. The rpms doesnt matter to whats causing this. Once I reach +10 psi The car quits misfiring and pulls like it used to. Any suggestions? I know someone out there has had to have this happen to them before

 

[habitatguy187]

I would pull your plugs and see how they look. I'm guessing that you're either getting too much fuel (black plugs) or running lean (white plugs)

 

[white92talontsi]

sounds similar to an issue that i had and turned out to be trash in the fuel system.

 

[atips1]

I would run some fuel injector, or fuel system cleaner through it. I don't think a vacuum leak would make it misfire horribly. I know I was having problems with misfires, but that's because I have a 6bolt swap and ECMLink which tends to cause that problem, so like the other people said, it could also be the ECU.

 

[Hestman]

Well I Fixed it!! I was pulling the injectors off while the car was running and I pulled out the number 4 injector and the car idled the exact same. My friend was over and wanted to do a compression test again to double check me and when i pulled the plug out the arm on the spark plug was pushed down against the electrode. So I put one of the old plugs back in and it was fine. I replaced the spark plugs at the same time I did my throttle body gasket maybe thats why I didnt notice a difference? Anyways The car runs great now but the throttle plate sticks a little bit since I was kinda rough with it taking it out and it idles at 1500 rpms unless i tap the gas and let off really fast. I am thinking about taking it back out and trying to sand It down. Any suggestions on that?

Thank you all by the way I really appreciate your help. Also I had a bunch of tiny pin holes in the IC where the hoses connect. I put some JB weld instant dry on there (For now until I order the VFR fmic kit on sale!) and it holds great now. I Get into boost alot sooner and the car feels alot better.

 

[StreetThisDSM]

Well I Fixed it!! I was pulling the injectors off while the car was running and I pulled out the number 4 injector and the car idled the exact same. My friend was over and wanted to do a compression test again to double check me and when i pulled the plug out the arm on the spark plug was pushed down against the electrode. So I put one of the old plugs back in and it was fine. I replaced the spark plugs at the same time I did my throttle body gasket maybe thats why I didnt notice a difference? Anyways The car runs great now but the throttle plate sticks a little bit since I was kinda rough with it taking it out and it idles at 1500 rpms unless i tap the gas and let off really fast. I am thinking about taking it back out and trying to sand It down. Any suggestions on that?

Thank you all by the way I really appreciate your help. Also I had a bunch of tiny pin holes in the IC where the hoses connect. I put some JB weld instant dry on there (For now until I order the VFR fmic kit on sale!) and it holds great now. I Get into boost alot sooner and the car feels alot better.

Glad it is running better

 

[RT-AWD]

Its running rich (too much fuel), have you compensated for the 255 fuel pump? that's a lot more fuel then stock. You need a SAFC or find out if you have an eprom ecu and get a tune via chip, then the car will run right.

 

[StreetThisDSM]

Its running rich (too much fuel), have you compensated for the 255 fuel pump? that's a lot more fuel then stock. You need a SAFC or find out if you have an eprom ecu and get a tune via chip, then the car will run right.

The issue is fixed.

He isn't running to rich. The car holds a solid 15 lbs all the way to redline with no creep issues. Wideband shows high high 9's to low 10's at WOT on 93 pump. Perfect for a car without many supporting mods and no tuning capabilities yet. It is a very safe tune right now.

The car is a Non-Eprom. He plans to get ECMlink v3 over the winter. I will help tune the car.

 

[Artago]

Well I Fixed it!! I was pulling the injectors off while the car was running and I pulled out the number 4 injector and the car idled the exact same. My friend was over and wanted to do a compression test again to double check me and when i pulled the plug out the arm on the spark plug was pushed down against the electrode. So I put one of the old plugs back in and it was fine. I replaced the spark plugs at the same time I did my throttle body gasket maybe thats why I didnt notice a difference?

So was it the injectors or the plugs?

 

[StreetThisDSM]

So was it the injectors or the plugs?

It was a combination of a boost leak at the inlet/outlet of the sidemount i/c and cylinder #4 spark plug had a gap of .000 ha. He must of dropped the plug in a little to hard and the tip of it caught the tread in the head and smashed it shut.

 

[Hestman]

Oh and I found somwehere on the internet if you loosen the throttle plate screws and let the throttle snap a few times it will help allign the throttle plate. It brought the idle down to around 900 when cold and around 1050 when warmed up. As stated I plan to get the car Tuned after the winter. Thanks ALOT to streetthisdsm. I like my first dsm so far and cant wait to take echeck and get my plates so I can get my 3in test pipe back on and get rid of the 2.5in cat thats on there now

 

[white92talontsi]

Oh and I found somwehere on the internet if you loosen the throttle plate screws and let the throttle snap a few times it will help allign the throttle plate. It brought the idle down to around 900 when cold and around 1050 when warmed up. As stated I plan to get the car Tuned after the winter. Thanks ALOT to streetthisdsm. I like my first dsm so far and cant wait to take echeck and get my plates so I can get my 3in test pipe back on and get rid of the 2.5in cat thats on there now

When I rebuilt my TB it was doing the same thing. All It was is that I needed to get the spring tighter. I believe I went 3 turns with it and it fixed my high idle problems.

 

[Hestman]

Yeah well i get impatient sometimes and i was "Tapping" the plate to get it out. Im not sure if i could have bent the throttle plate shaft by pressing too hard with the phillips so i didnt strip them. Ill be looking for an upgraded throttle body soon. I seen a nice rebuilt one for 165 somewhere on the internet.