new engine, wont rev over 4k, sounds like its missing, running rich too

[TargeT]

I pulled a set of plugs this weekend, they were all real black 'n nasty looking, the car "idles" but it sounds like its missing every once in a while. b4 the 6bolt swap everything ran perfect, i do have a GM MAFT, could it be that my MAFT is bad & i'm in a closed loop?

the car idles but wont rev above 4k with out missing bad 'n blowing tons of black smoke stock ECU (cuz my dsmlink one took a crap onme) and 660 injectors..

 

[xxeclipsedxx]

I had the same problem. it could be a few different things but the problem with mine was where i spliced the A/F guage to the ecu. i didnt do it properly the first time and one of the connections, probably the heater wire, was loose. but like yours it wouldnt rev, heavy black smoke, and sounded like it was missing. if you have a AF guage check the connections. if its good you may need a new o2 sensor.

 

[Talesin]

660 injectors and no way of controlling them? Black gunk? Damn, you're running super rich, dude. Pop in 450s or get DSMLink again, or a VPC.

Er, I take that back. Did you calibrate your MAF-T for the 660s, or were you compensating for them in DSMLink? It sounds like the latter. You should dig out your MAF-T manual and go through the settings, make SURE it's set to work with 660s.

Just had something like this happen on my 1Ga too... had the UICP pop its clamp. Check all of your intercooler piping, and do a boost leak test, if the settings on the MAF-T are right. (And don't just assume they are, CHECK IT.)

 

[TargeT]

Hmm, intresting my A/F gauge is currently disconnected, i didn't think that that would cause the ECU to not see the front 02, but then again, i didn't wire it in soi have no clue how its run, that could be my issue.

the MAF-T is in and wired correctly (worked before the engine swap) but after the eletrical "issues" i had i was begining to think that my MAF-T got fried also

I'll check into the A/F gauge and see if hooking that up helps, the thing that worrys me about the maft was when i adjusted it it seemed to make no difference

oh well I sent my ECU off to get repaired so hopfuly it will be back next week and i can finaly tell what the hell is going on.

I'm so tired of having my "daily driver" be a lawn ordiment,, people are starting to laugh at it

 

[Jacie]

I have the same problem

 

[93blacktsi]

okay my car has a bad misfire above 4k.so far i have changed the coil packs, power transitor, plugs, wires, fuel filter.did a commpression test and it was 160 in all clyinders. im running out of ideas now.my logger is broke so thats no help.the last log i did my injector duty was 70%, my o2 volts jumped between .5 and .9
and when it started braking up the knock count would jump up to 20 and it would pull timing bad.

 

[EagleTalon1993]

I know it sounds strange but have you checked your ignition timing ? if it's too far advanced when you hit the higher rpm range it could be pre-ignition causing the knock count to rise and the bad timing issue.

Thats my two cents worth

 

[93blacktsi]

ya know i actully havent checked that yet.i gotta go get my timing light from my friends house

 

[trevor81490]

I had the very same problem when I first got my car, and like you i counl not figure it out, it ended up being the spark plugs, the were not the right ones for my car, they were too short and were not far enough in the combustion chamber. Try changing them to an NGK, i do not trust anything else, and do not go with the platinum if yours is turbocharged its just a waste, and make sure to gap them properly. Hope this helps.

 

[93blacktsi]

i have ngk plugs in there that was the frist thing i did they are gapped a .28

 

[habitatguy187]

Have you checked the ecu? Turned out to be my problem.

89-94 Capacitor Replacement

Also how much boost are you trying to run? Are you still on stock fuel system? Does this only happen when in boost or anytime over 4k?

 

[92awddsm]

Like already stated, check your ecu for leaking caps.

I have been having the same problem lately. Went out earlier today and found that there was a fuel pressure leak between the pump and the sending unit assembly. Car had enough fuel pressure to run and drive but not enough to keep up once I got into boost.

 

[habitatguy187]

Car had enough fuel pressure to run and drive but not enough to keep up once I got into boost.

+1

I've also heard of it being caused by a dying fuel pump, bad stock fuel pump wiring, or a dying alternator that can't keep up under boost.

 

[93blacktsi]

car has a new 190 fuel pump rewired.im running the stock wastegate on the 16 which is are 10-12 psi.im actully thinking the alt. maybe going out becuse sometimes the volts will drop down around 12 or so at idle

 

[92awddsm]

car has a new 190 fuel pump rewired.im running the stock wastegate on the 16 which is are 10-12 psi.im actully thinking the alt. maybe going out becuse sometimes the volts will drop down around 12 or so at idle

If its new, it is a good possibility that the o-ring is cocked around the top of the fuel pump. I would pull it back out and check.

 

[93blacktsi]

back from the dead.car still has this problem i have changed coil packs, power transitor, ground wires, pulled fuel pump double check everythig all is good, inj. restior pack.this problem wont go away voltage is good while driving according to mmcd.im tring a know good ecu tommorw.i will report back.

 

[Fast-Orange]

use a multimeter set it to volts toutch the red lead to your + batt terminal and your black lead to your - terminal with the car idling is your voltage 14.00 to 14.67? if good then put load on your system turn your ac, fan, lights lots of things n to put load on it keep it all on and retest is is still withen that range? if not your alt is bad

 

[93blacktsi]

did that man

 

[Fast-Orange]

your running a 16G what are you boosting at? are you still running stock injectors and fuel set up? 70% duty cycle is damn near maxed out you could be hitting fuel cut, acutally i almost guarantee it i think your experiencing detonation your leaning out which raises cylinder temps are you causing your knock count to jump up and pull timing to try and prevent detonation

sorry missed that your running a 190 but regarless 70% duty cyle is pretty much maxed out

 

[93blacktsi]

the 16 is running of the stock wastegate.the car ran fine then one day stared missing like this is not fuel cut.injector duty is around 70% but that is not to high i wont go over 80.after change all said parts the knock count is down around 5 and its still pulling timing.i will try to get somelogging done this weekend but, i dont like really beating on it when its running like this.

 

[Fast-Orange]

so is it running at 8 or 14 psi then? which WG?
whats your fuel pressure set at?
if those are your stock injectors 70% may be all they can handle now, do they stay at 70% all of the time?
what is your o2 reading durring all this?

 

[GSTRyder]

okay my car has a bad misfire above 4k.so far i have changed the coil packs, power transitor, plugs, wires, fuel filter.did a commpression test and it was 160 in all clyinders. im running out of ideas now.my logger is broke so thats no help.the last log i did my injector duty was 70%, my o2 volts jumped between .5 and .9
and when it started braking up the knock count would jump up to 20 and it would pull timing bad.

And it runs fine at idle with no check engine light? Check to make sure your main ecm lead under the fuel rail is completely pushed down and locked. Check fuses

 

[93blacktsi]

fast orange i will work on some new logs.and the car idle fines and no cel