help me!! im stumped on why car wont rev to 4k

[marsh63]

i just got this new 1990 eagle talon non turbo as my daily driver. the car has 150 lbs of compression in each cylinder. the timing is dead on.

when i got it the car will not go above 4k and has a 500 rpm idle surge. while sittin still with no load i can rev the car sometimes past 4k. it feels like i have a rev limiter.

so far i have taken from my other talon the had non of these problems.

alternator.
transistor
i tested the car with my coil from my good talon
the idle thing on the tb that has the one wire going to it

things i did to try other possible things

i cleaned everything
checked the mass air flow sensor
new O2 sensor
new wires
new oil
checked for vacuum leaks.
blocked off egr since it was stuck open when i got the car
i checked the ecu and non of the caps are leaking.


so right no i am completely stumped. so if anyone has anyother sugestions please tell me.

oh when i unplug the tps and the idle thing the car will not have idle surge but it still wont rev. when i unplug the iac the car will sometimes do the same but most of the time die.

please tell me something!!! will the tb parts from a turbo talon work on a n/t?

only way how to get above 4000 rpm when there is load and it only works if you do it this way for the car is to go in thrid and then drop into 2nd once your at about 3600 rpms in 3rd. and then i can run it all the way to redline. (i know this is not good for the car).

 

[DJYoshaBYD]

check your fuel pressure.. It almost sounds like your fuel pump is cutting out..

 

[marsh63]

forgot to tell you guys that the car is running really rich. it ran rich befor i put the new o2 sensor on too.

 

[DJYoshaBYD]

then there is something wrong with your firing system.. how do you know it is running rich when you are trying to rev that high? Are you watching it with a cheap gauge? A wideband? Scanner? Do you just smell gas? maybe you have clogged injectors, fuel filter, line, etc.. If its not your fuel system, then it has to be spark.. test your coil packs, as well..

rull of thumb for testing this type of stuff.. check 1>spark 2>fuel 3>air (usually a given, unless a squirrel got sucked up in your cai.. haha ).. some people (like boosted car drivers) check boost leaks and vac leaks first, which is what you should do.. but for NA, its a lil different.. This is just how I was taught though..

 

[DSM4me44]

Check to make sure you have the right plug wires running to the right plugs. I switch the order of the wires one time and that was bad news.

 

[Noogabox]

I am pretty sure you are having a misfire, however the misfire my just be a symptom of another issue. For example a O@ goes out like everyone says and the spark has trouble jumping the gap with the air fuel mix soo rich. I had it happen. The over rich fuel fouls plugs and they start to misfire around 3500 rpm. Copper plugs are horrible about fouling on turbo cars. I would check your plugs. I bet they are black with maybe a little white on the electrode. This is a sure sign of ignition problem. If its running too rich, no matter how many times you change the plugs they will foul agian! Check you air fuel issue, normally o2 sensors are to blame. Once thats fixed, replace your plugs with iridium IX or your favorite double platinum!

option 2: In more rare cases the spark plug wires need to be replace and coil. If these have note been done and your car has more than 100,000 miles be sure and change them out. Factory recomends they are replaces at 80,000 miles for preventative maintenance anyways.

Codename: Upgrade, Xbox 360 Talon

 

[marsh63]

i know its running rich cause of the plugs are black and there is black smoke and a definite smell of gas. the car works the best when i am not running the mas plugged in. or the idle thing on top of the tb with the one wire running to it. still has a fuel cut but its much better.

the fuel system is working fine and the coil pack is fine to. idk what it is i think im going to replace the mas .

 

[srumel]

Do you have a logger/checked for stored codes?

I'd lean more towards, like you said, a MAS issue or maybe the TPS. It could also be that the CAS is out of adjustment; check your base timing if you haven't already.

On a side note, I'm pretty sure that 150psi is pretty low for an N/A model, but as long as they are pretty consistent from cylinder to cylinder then you are probably ok.

 

[DJYoshaBYD]

you need to adjust the cas, tps, and biss.. maybe a clogged fpr causing too much pressure in the system? Did you check the injectors for leaks? that will make your car run rich as all hell..

Once you do the timing and tps adjustments, then you need to look at fuel... there has to be something either letting too much in or forcing too much in...

 

[ROOKIE1]

First off the car runs better when the mas is not plugged in . Stated by OP , start there . Get one that works . It will richen up the car . Because it is not metering the air properly. Also why it won't rev past 4k , its drowning .

 

[marsh63]

well i have adjusted the tb and now it has about a 300 rpm surge and i have all the sensors but the mass plugged in. i can now rev past 4k and it just chugs a little bit. im going to get a new mas here in like the next week.

 

[yesItsdsm]

I had this same problem with my NT 4g63.. turned out to be the ECU. Yank it out and check for leaky capacitors.

 

[yesItsdsm]

I'm almost 100 percent positive that's your problem.

 

[silver bullit]

Ecu #1
maf #2
Complete check of all the stuff on your motor, sensors wires, hoses ec #3

 

[BoostedinSoFla]

I call plug wires..

 

[debbie]

for my money i think it is your mass let us know dude so if this happens to enyone else we can fix it

 

[92awddsm]

I had this same problem with my NT 4g63.. turned out to be the ECU. Yank it out and check for leaky capacitors.

Ecu #1
maf #2
Complete check of all the stuff on your motor, sensors wires, hoses ec #3

He already stated that he has removed and inspected the ecu. No signs of leaking caps or damage.

Have you tried replacing the coolant temp sensor?

 

[marsh63]

im going to get a new mass air flow sensor this week and plug it in. ill take the temp sensor from my other talon off and see if that helps this talon tonight.

before i unhooked the maf sensor the car had no cel but when i un hooked it i now have a cel but thats normal i guess since im not running a vital sensor right now. i guess on monday ill be going out to the junk yard to get some new stuff.

thanks for the help so far.

but right now i think its a combo of my mas sensor and the little one wire sensor on my tb thats on top of the tb. (i tride using the one from my other talon but it had idle surge to a little.)

 

[marsh63]

ok well i got another maf sensor. i checked my fuel pressure. i replaced my iac and tps and the little sensor on the tb for the throttle. i cleaned the tb and replaced my coolant sensor and now the car runs like crap. what else can it be. i checked the coil and tested it with my other car and it was fine.

2 of the plugs are real rich and the other 2 are rich but the middle electrodes are burnt. (white)

once and a whill i can get it to rev up to redline but most of the time it now has a rev limiter at like 2 k