Misfire at higher boost

[HawkesTSI96]

I have recently did a compression test on my motor ( Okay numbers 150-160 through all cylinders.) before compression test running 18 psi on engine no problem. after compression test I plug everything back in. while driving at higher boost it misfires and pops really bad. not like a fuel cutt but just misfires. prior to compression test and problem have replaced spark plugs and spark plug wires. i have double and tripple checked everything spark plugs are gapped at .032 and have been gapped at that while running 18 psi with no problem. when i turn down the boost to 12psi and have minimal to no problem i have still experianced it at lower booost. I have tried adjusting it up every psi and seems to start at 15psi. I have read to reduce spark plug gap to maybe help at higher psi, but i have not tried that yet. im jsut confused on why it would all of the sudden having a probelm at higher psi. I have not checked for a boost leak. or at least havent done a boost leak test. recently have replaced injectors as well. I am Going crazy I have been searching for information on this topic but have had no luck with what would cause this. and it was absolutely perfect before compression test. boost fine on 18 psi. also for some reason my wideband o2 sensor went bad right after this had happened not saying anyting related but strange. any advice or info on the subject would be much aprreciated. ( I am running a evo 16g turbo, walbro 190 fuel pump.)

 

[Chumpaumpalumpa]

How are all your grounds. I'd check those.... ALL of them. They give all sorts of little gremlins the little buggars. Also +1 on fuel filter and gap to 28

 

[HawkesTSI96]

plugs are gapped for sure. .28 and just have gone through all grounds everything is solid.. going to try fuel filter. and have ordered aftermarket FPR. soo we shall see.

 

[iceguru1114]

My goodness, man, this has really turned into a swapnostics goose chase. Did you ever go back to the setup you had prior to your compression test when things were running right? If not start there. I mean seriously, if you have the old plugs and wires you were using, put them back in to see where that gets you. Then make one change at a time until you isolate the issue. BTW, spark plugs and wires are two changes at a time, you need to take smaller steps to isolate the problem.

 

[HawkesTSI96]

issue comes and goes. so diagnosing issues is very difficult. its been about a week now where it has not happened. like I said strange issue I'm having. that comes and goes.

 

[HawkesTSI96]

so here is a log of the issue... Can someone please review and and let me know if this can tell them anything ?????? Issue is sputter spitting. misfire. This specific log shows 1st gear 2nd gear 3rd gear. having issue the whole way through. and comes out of it in 4th gear. this is a slow and easy log. not stomping on it at all. but problem usually occurs when getting on it extremely hard.. this problem has occurred for 2 years that I've had 5 different engines sense then. problem comes and goes. i can drive the car 50 miles with out it doing this a single time. and other days it does it constantly. It USUALLY goes crazy lean when happening. but I (think) . its happened while running rich as well.... its happened so much I'm seriously about to burn the car to the ground... anyone who looks over this and gives me any feed back. I Extremely appreciate it. Thank you!

More relative info. TC's engine coolant temp sensor is not working. I am pretty sure it has nothing to do with issue at hand. Because its been happening so long off and on. and this trouble code just recently came up because wiring harness broke on the plug. replaced plug in harness and still reading -74 degrees.. next step I'm checking for power at plug and then replacing sensor. PLEASE HELP

 

[mikehuntisitchy]

This may be a long shot, or not even make sense but I hope it does. When I had my bmw 335i, our weak fuel pumps would cause misfire when in high boost map. Maybe something a long those lines?

 

[HawkesTSI96]

Yes I've been doing tons of research.. I've had fuel pump problems in the past. I was leaning towards FPR or fuel pump. I plan to do a pump re wire kit and FPR see if that changes it. this made me a little more confident with you response. Thanks for the info will update when that has been all done.

 

[HawkesTSI96]

Just bought a rewire kit for the fuel pump. waiting for payday thursday to get the actual pump and FPR. just thought id keep everyone updated. Also sent a log to our local 4g63shop Dsm shop for the owner to possibly review the log if he has the time and see if he can tell me anything more with issue.. .

 

[HawkesTSI96]

also more relative info previous owner did a re wire kit.. I'm hoping this is a possible cause

 

[HawkesTSI96]

Rewired Fuel pump. just to put my mind at ease. problem still occurring . Tested Injector clips for higher resistance then normal and testing on my multimeter on 20m showed. .08 on all 4. just assume that is to spec. or around where it should be.. Ive tried looking for spec but shouldn't it be close to .00 or even .01 at the injector anyways?? can anyone help me find info on what is to spec