GTE running rough but no misfire cant figure out!!!

[7m_no_sht]

hey guys, i just built a fresh GTE and when i put it in the car and fire it up it is running rough, i set the timing to 10 degrees with the diag port shorted and still it changed nothing, i replaced the coils, nothing, replaced the ignighter, nothing, the plugs and wires are brand new NGKs and i cant figure out why its running rough, it backfires and while boosting it will almost hit fuel cut for a second then continue climbing RPMs. does anybody have any ideas?

 

[hvyman]

Have you checked for codes?

Any mods?

 

[planemos]

Check for leaks in the intake/intercooler piping. If your plugs are wet then you may need to change out the valve stem seals. Is it hard to start?

 

[IndigoMKII]

Have you checked mechanical timing? Do you have the FPU VSV hooked up correctly so the airflow is going in the right direction?

 

[jonahs_supra]

Have you checked mechanical timing?

yup check this

go through the basics:
do you have enough fuel pressure?
got good spark?
vaccum lines hooked up properly?
charge piping not leaking?
no leaks between afm and TB?

 

[7m_no_sht]

heres whats done to it, full rebuild, port/polish, compcam springs, al the IC pips are good, eliminated the charcoal canister and all the VSVs, we've done that on other 7Ms and havent had this problem, plugs and wires re brand new, i set the timing with a timing light but when i vaccume checked it said the timing was too advanced, i did the carb cleaner spray down on all vac lines, got nothing, its running a tad rich due to lex afm and 550s so its got plenty fuel, it did have some codes i believe they were 24 35 43 and 51

 

[IndigoMKII]

Okay, you need to erase the codes and check again to make sure those are current. So far you've got no IAT, no HAC and no IDL. The IDL is a miscalibrated TPS and IAT is the airflow meter.

 

[7m_no_sht]

yeah i tested both AFMs they tested good, how do i clear the codes?

 

[OfnaRcR4]

Disconnect battery or pull efi fuse for 10 or so mins.

 

[IndigoMKII]

Disconnect battery or pull efi fuse for 10 or so mins.

30 seconds on the EFI fuse is all that is required.

Don't forget this also wipes the stored data on the ecu so it has to 'learn' the engine again. Normally if you drive it around for 10 or so minutes it'll sort itself out.

 

[7m_no_sht]

ok cool ill try that when i get out of class, its a gray pin engine harness and edu on a yellow pin body so idk if that will cause any problems

 

[7m_no_sht]

nvm got it, that didnt work ether, the engine sounds ok when idling but it shakes alot and when you hit the gas it viberates to the point where you can feel it in the gas pedal and it sounds like it isnt firing right or something, could it be the cps?

 

[Backlash2032]

Fix what the ecu said was wrong...

Sent from my HTC Rezound using Tapatalk

 

[7m_no_sht]

it said its wrong because its not there

 

[Backlash2032]

So... Fix that. -_-

And besides. It won't throw a tps code unless the tps is hooked up.

Sent from my HTC Rezound using Tapatalk

 

[jetjock]

If people had to pay to post these kinds of threads wouldn't happen...

 

[planemos]

Yah this thread is all over the place lol. I remember when I had my car all apart once I forgot to plug in one of the main wire harness plugs inside the car. And it was running really rough without it plugged in.

 

[7m_no_sht]

If people had to pay to post these kinds of threads wouldn't happen...

FYI this post was my last resort, im no noob when it comes to this kind of stuff, iv gone over the entire engine, tested for vac leaks, checked timing with 2 different guns, different ignitors and coils nothing has worked, so if you feel like insulting this thread please keep it to yourself

 

[7m_no_sht]

the other night my brother and i decited to pull the plugs and we found that #1 was broken and #6 wasnt even firing, i replaced #1 and checked the ignition coil for #6 to see if it was firing, it was. so i replaced the plug wire which seemed to make it fire but after i replaced all of the plugs, #3 and #5 arent firing. at this point im lost, i checked the ohms on the CPS and it read 1.905 where i believe its supposed to be around 1.0-1.5 ohms. im going to replace that tomorrow and probably the ignition coils, ill post the results

 

[7m_no_sht]

correction, i wouldnt say they arent firing, but more like a very weak spark, if i pull the wire slightly out from the coil to where the spark will jump, the engine runs slightly rougher and when i pull it farther where the spark wont jump #3 and #5 dont change much compared to if i were to pull #2 completely