sputtering/fuel cut under boost

[mheidemanjr]

Ok ihave searched the topic and tryed thos suggtions such as plugs wires and boost leak. I do have small boost leak on the throttle body o rings but nothing major. The problme occurs over 3500 rpms and more than 20 percent throttle. If I ease the gas threw the rpm band ther is no issue but over 20 % and 6 psi it feels like fuel cut or missfiring real bad. I gusse in lookibg for things to look into or test out. Any thoughts? I have logged the problme alltho I can't post logs but when issue occurs you and see the spikes in all the graph bars looks like a outline of a moutain range up down up down and so on. A/f ratio is right around 11.1 air flow about 25_30 and timing between 8_11 depending on rpms

Update I changed plus to bpr7es gapped the to .28 , tested the coil 12.3 on secondary and 1.3 on secondary think that's 2 high?

 

[GreenGSXlover]

If you thoroughly believe there are no boost leaks, the next thing you should check is the ECU. Pull the ecu, remove the cover, and make sure the capacitors aren't leaking. The symptoms sound like a boost leak but leaky capacitors can cause the ecu to act up. I had a similar problem in a 1g. Hope this helps!

 

[Kyle d32a]

Are you running a larger than stock fuel pump on stock injectors? That could cause the problem.

 

[highlandgst]

do a leak down see if you have a vaccum leak . I had a split line on my MBC and it would do the same thing . I would check my vaccume lines before i did anything major else

 

[rush2252]

Ok ihave searched the topic and tryed thos suggtions such as plugs wires and boost leak. I do have small boost leak on the throttle body o rings but nothing major. The problme occurs over 3500 rpms and more than 20 percent throttle. If I ease the gas threw the rpm band ther is no issue but over 20 % and 6 psi it feels like fuel cut or missfiring real bad. I gusse in lookibg for things to look into or test out. Any thoughts? I have logged the problme alltho I can't post logs but when issue occurs you and see the spikes in all the graph bars looks like a outline of a moutain range up down up down and so on. A/f ratio is right around 11.1 air flow about 25_30 and timing between 8_11 depending on rpms

Update I changed plus to bpr7es gapped the to .28 , tested the coil 12.3 on secondary and 1.3 on secondary think that's 2 high?

Is this an auto or manual car? If auto might be sligth transmission slip. Try dielectric grease on the plug boots and coil boots as well, either that or new plug wires.

Also, double check your firing order from the coil, there are several diagrams on here and I notice you have a 95 model. The 2ga is differnt from 2gb IIRC.

...and lastly NOT to scare you but if you are capable perform a leakdown on the valvetrain. My 2g acted like this and I finally pulled the head for a HG job and noticed two ever-so-slightly bent intake valves when we did a leakdown.

 

[mheidemanjr]

Is this an auto or manual car? If auto might be sligth transmission slip. Try dielectric grease on the plug boots and coil boots as well, either that or new plug wires.

Also, double check your firing order from the coil, there are several diagrams on here and I notice you have a 95 model. The 2ga is differnt from 2gb IIRC.

...and lastly NOT to scare you but if you are capable perform a leakdown on the valvetrain. My 2g acted like this and I finally pulled the head for a HG job and noticed two ever-so-slightly bent intake valves when we did a leakdown.

Ok I was under the impression that the fireing order for all 2g 4g63's was 4 1 2 3 from left to right acorrding to my haynes manual can some one verify ther is a diffrense between 2ga and 2gb

Are you running a larger than stock fuel pump on stoc injectors? That could cause the problem.

I am runninh fic 850cc injectors with walbro 255 pump thers is no afpr tho could I have way to much fuel pressure? I do have a boost leak at the throttle body biss screw and o ring on thorttle shaft. Allso one at the j pipe gasket

Well after a whole nother day testing ecu injectors coil for the 5th time I decided to swap the plug wires that I just bought from autozone for some old ones I had lieing around garage and what do ya no the problem is gone. The wires wher 2 days old duralast may a$$. Thanx for the input fellas now I just gotta get a new throttle body and I will be all set.....for this week gotta love dsm

 

[JuGs]

OK sorry to res athis post but Im having almost the exact same issue. I have no boost leaks(but 1 on the thermastat housing) and i just replaced plugs and wired before I replied to this. Ecu is good just had link installed and ECMtuning convert my ecu and there was no bad caps. Bad o2? Temp sensor?

Don't know if this helps but its worse on cold starts. Once at temp it still spits/sputters but about half as bad from being cold.