acceleration and idle problem

[alexrc]

Hey my 420a has a little problem I may say I don’t know if is the ecu or what , here it goes , my car wont idle still between 1,000 rpm and 2,000 rpm there’s a gap , wont idle on 1100 , 1500 , etc. , what’s wrong any ideas

95 rs
420a MT

 

[junkyarddsm]

by it wont ideal what do you mean like it dies or just runs really bad and lacks power?

 

[alexrc]

its like theres aire in the fuel system in those rpm , lack of power or no power at all cause it jumps to 2,000 rpm its weird . someone told me that the ecu was from a 1.8 talon let me give you the serial # just in case it helps


i send you a pic of the ecu , the one i got is the 646 ,


thx

 

[LiquidX]

So does it bounce between 1k and 2k at idle?

What are you doing to make it idle so high, are you reving the motor or is it doing it naturally? Do you have and CELs?

 

[alexrc]

i think u miss uderstud me , it idles fine at 900 , 1000 k , but when u try to get it to 1300 , 1500 , goes directly to 2,000 k

 

[LiquidX]

Is this just free reving or while driving? You need to clarify your posts so they are easy to understand.

 

[alexrc]

both free reving and driving

 

[LiquidX]

Let me get this clear.

While sitting at the stop light your idle is normal at 900rpm. As you procede to move forward you get to 1200rpm and the needle instantly jumps to 2000rpm. Does you engine noise go along with the rpms or does the engine noise stay the same and the needle just jumps up? Also when the needle jumps, does it hold steady at 1200 and then instantly moves to 2000 or more of a hesitant bouncing around movement on it's way to 2000rpm?

If you decel, does the needle instantly drop from 2000rpm or act funny in the "jump zone"?
Do you have problems anywhere else in the powerband?

 

[alexrc]

just like you said

a hesitant bouncing around movement on it's way to 2000rpm?

and


is like theres a hole in the fuel , theres no engine noise nothing , everything is perfect when it pass 2,000 k , is like it chokes , and then normal ,

 

[junkyarddsm]

sounds like you throttle poising sensor maybe bad and that would cause the computer to not know were its at when you start to give it throttle it sends the wrong amount of fuel can you tell if it smells like fuel really bad? O and to my knowledge a ecu will not work in a 2g eclipse and yours is for a 420a eclipse from the info you have posed.

 

[LD25Delta9]

Throttle poising sensor? Sending fuel? WTF It's a throttle POSITION sensor. And it just tells the ecu the position of the throttle plate. That, along with cam sensor position, crank position sensor, manifold absolute pressure, and intake air temperature, is how it calculates proper air/fuel ratios.

OP: Sounds like you have bad plugs, possibly bad wires, possibly water in the fuel. Your ECU is the 95 420 Ecu. They are known for their problems. If you have the capability, find a 96+ donor car at the junkyard and snatch the fuse box, wiring harness, and ecu. How rare are 2g NT's in your country?

 

[alexrc]

very rare , but i bought everything on ebay and with a friend ,if i put a 96 or 97 ecu why do i have to mess with the fuse box ?


and the plugs are new , i have msd coil pack 2

 

[NeMiZiS]

You know it kind of sounds like a slipping timing belt.
Does it ever just completely die?
I had a Talon a long time ago the would just jump RPMs in gaps like that.
But it was in the higher RPM range, at the time I didn't know too much about DSM's and I replaced the computer, the crank angle sensor and it still kept doing it.
(That is what I was told to do at the time)
But mine would die randomly and sometimes not start for days.
Then all of the sudden it would start right up.
After I took it to a shop they replaced the belt and said it had been slipping.
Might have been BS(from the mechanic) but I thought I'd throw it out there.

 

[alexrc]

hey ,

i'm my first guess was the tps , so i bought a tps , then the cam sensor , then as you said , i checked the timing and everything is a ok so is a bit confusing but , as the guys tell me here might be the ecu , the car runs fine , starts fine , idles fine ,

thxxx