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arcing by intake manifold and running rich

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kalium91

Probationary Member
9
0
Oct 2, 2010
aurora, Illinois
ok heres the deal. i have a 99 gst with a swapped built 6bolt in it and it starts and runs fine. i havent been driving it to often but iv been trying to solve this problem for a while now.
car starts and runs no problem but when i start it the afr stays at 14.7-14.8 and then steadily drops by .1 to about 12.8 then the car leans everything out because then it brings it back to 14.5 to 15.1ish but i can tell its running lean by how hot the engine gets so fast. i believe that 1 cylinder isent firing and its sending unburned gas into the exhaust making the car see a "rich" signal when its just one unburned cylinder then takes fuel away from all other cylinders(reads good. smell really rich). when i remove the injector connectors one at a time they all effect the engine equally. There is an arcing sound by the intake and i cant seam to find it. i looked in the dark for a spark with no luck. checked for a vacuum leak also and none were present. i also added an extra ground from the coil pack bracket to the firewall with no change. timing is 5 btdc

other problems it has is when im crusing at 70 after a few mins it will shutter real bad like a dead miss so i pull over and restart it and its fine till it cruises that fast again. i dont cruise that fast anymore because of that. tested my power transistor and its fine. car builds boost slowly and accelerates slowly. also when i pull each spark plug wire well running i can here it arcing so spark is getting to the plug (id assume) but i dont know how much spark is actually reaching the plug. only thing i can guess besides the arch sound(which would also be a problem) is a leaking injector thats making it run rich. i have a set of 550 low impedance rx 7 injectors that i can throw in to see if it will run right. anyone know the deadtime to set on those??

mods are a 6bolt swap with 272 hks cams and BC springs and retainers. 255 walbro. E316g. and stock injectors. ecmlink v3. more mods but dont really apply.

iv read a few other posts with the same problem but no solutions were posted. also had less detail then iv come to find with my problem.

http://www.dsmtuners.com/threads/electrical-arcing-sound-low-boost-and-rough-iddle.119764/

http://www.dsmtuners.com/threads/please-god-someone-tell-me-whats-wrong.109925/

please help if you have an idea or something i can test.
 
doing some more checking but im thinking that its my pcv making that "arcing" sound...:ohdamn: hopefully i can do this injector swap and fix my problems. :pray:
 
Coils/PTU can test juuuuust fine and still be bad. Its the nature of the beast. HEAT can cause failures intermittently. Bad plug wire? Injector wire? Id take a guess from what you say its the coil pack though. Mine tested fine and did similar shit, it was indeed bad.

cas wiring doesnt seem to be the culprit either from description.
 
thanks for the replys
hmm i have a few laying around so il swap on in but don't both cylinders normally go bad at the same time? and i double checked my cas wiring and connections. both are fine. its just weird to me that it gets so rich and then leans out in about 15 seconds all together. correct me if im wrong but if my ecu is in open loop(cold start) wouldent it not correct itself that fast? since the o2 sensor isent even heated or being used in open loop? how would it know its rich and then correct it?
 
Do you still have the FIAV? Do you have the fuel pressure solenoid still? These are a couple things used to help for the brief time upon startup that the front o2 is not cycling. To my knowledge, at least.
 
yes i do have a fuel pressure solenoid and the FIAV but the 1g throttle body. removed the pvc and the sounds was still there. it comes and goes randomly. my next step is to take out these coil packs and swap them out and check for any cracks or corrosion. and log my wide-band to the ecm with a narrow band simulation. its just weird because the wideband says its running a little lean (15 to 1 adverage) and it smells really rich.
 
Did switching out coil packs solve this? I just developed intermittent bad idle and checked it at night, the problem coincides with arcing that is visible between the towers of the passenger side coil pack. Smells rich as heck when it's happening.
 
I am going to assume that you will not get a response from the OP as their last activity was over a year ago.
 
Ah sorry. I actually saw that but didn't think it through.
Earlier today I PM'd someone from an eight year old thread on the off chance they could give me some pertinent info. They actually responded within an hour! Guess I was trying to double down.
 
If you see arching, why not swap it out to try and solve it? If it is arching and not producing proper spark to the plug, it may not be igniting all the fuel(Hence why you think it is running rich). Swap out the coil pack, you can find them cheap in the classifieds. If you can't find one, PM me as I have a couple extra.
 
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