S14 sr20det injector milliseconds??

DaVa · Mar 14th, 2008, 02:02 PM

Hey people, am a newbie here so bear wit me.

Have got a 94 s14 sr20det import, basically it idles really bad and is overfuelling
The car is totally standard with a standard ECU aswell (have tried 2 different ones)

Here is the list of things i have tried
2 different AFMs
2 lambdas
2 ECUs
Checked for air leaks by pressurising the intake system
Plug gaps checked
Replaced the coils
Replaced the injectors
Replaced the TPS
Replaced the idle control
Replaced the camshaft position sensor (it was slightly out before)
Replaced the fuel pressure reg with a sard one for temporary adjustment
Setup up the timing on the camshaft position sensor (it was slightly out before)
Checked the tps voltage before and after replacement and they read .43 on tickover and 4.5 at max rev position
Checked the voltage on the fuel pump
Checked wiring on lambda, afm, idle control valve and tps to the ecu
Blew down the fuel return pipe, all clear
Visualy check on vac pipes to match another s14 i have here.

Have checked the ECU part no and it matches that model number.

When the AFM is disconnected while the car is running it idles perfect but wont rev above 3500 (limp mode) as soon as it is connected again the car runs like crap on tickover but will clear if its is revved (though wont run correctly if the throttle is pressed and held still, it has to be kept moving. it also runs fine under load)

I have nissan datascan so got on the case, it came up with a few codes.. afm and tps, i reset the codes and they never came again (was me buggering about while the car was running) I went into the section that allows you to emulate what sensors etc do, i tried telling the ecu that the engine was running at 85 degrees to rule out the possibility that it maybe still on cold start and still no different. I turned off the fuel pump and the car ran fine for nearly 15 secs untill the fuel pressure dropped, i though i had it, so out came the fuel pressure guage, it was running at nearly 4 bar.....far too much, i took off the fuel pressure reg and temporarily plumbed in a sard one so i could mess with the pressure. I set it to 2.5 (2.9-3.0 with the vac off) and still no difference so i lowered it to 1 bar and it ran fine but as you could guess it would not rev.

I set the fuel pressure at 2.5 and looked at datascan again. I went into the gauges section, everything looked ok apart from the lambda, it was stuck at 32, it never changed if i put a new lambda in either, am guessing that it is too rich for the sensor to pick up. I went into preferences and added the injector ms gauge....bingo, it is running between 8.5 and 10 ms! Obviously me dropping the fuel pressure "sort of" corrected the amount of fuel thats being injected. As soon as i disconnect the afm to make it run good it sets the injector ms to around 2.8 (cant remember exact ms off the top of my head)

got any ideas ppl before i die of petrol fumes lol

Any help would be greatly appreciated.
Dave

**Asleep** · Mar 14th, 2008, 03:31 PM

what size injectors and which maf are you using and is the ecu stock?

DaVa · Mar 14th, 2008, 03:38 PM

Yeah all stock parts, the car isnt modded, standard injectors, swapped some from another s14 as well.

yup the AFM and ECU are all stock, checked the ECU part no on nissan fast and it all matches

**Asleep** · Mar 14th, 2008, 05:53 PM

who wired up the maf?
i ran into a problem when we wired up the cobra maf on my turbo altima. we crossed 2 wires and all it would do i belch smoke and dump fuel on my pistons.

DaVa · Mar 14th, 2008, 06:16 PM

yeah is a possibility, though datascan is picking up the airflow fine plus the wires havent been tampered with.
mad isnt it lol!!

**Asleep** · Mar 14th, 2008, 07:07 PM

ok do this, check the output voltage on the maf.
you have to check the wires as shown here

http://www.jimwolftechnology.com/wol...WIRINGINST.PDF

you dont want anything near 5 volts at idle on the reference wires.

DaVa · Mar 14th, 2008, 07:37 PM

ok will give it a go tomorrow. We have tried different afms so if the original was giving an incorrect voltage then it should have cured it. i'll check tomoz anyways. will let ya know.
Thanx

trmn8r · Mar 14th, 2008, 09:09 PM

Quote:

Originally Posted by DaVa

ok will give it a go tomorrow. We have tried different afms so if the original was giving an incorrect voltage then it should have cured it. i'll check tomoz anyways. will let ya know.
Thanx

i know you checked the tps but this car is acting just like my sr20det. it feels like it cuts out when at a steady rev. and when driving it it cuts out when its at 0psi. but when you give it boost it drives fine (load). i ended up replacing the tps and never had the problem since. i know you checked tps and the voltage sound right but i would definately look back towards that area, after all you did get a code for it. see if you can swap tps with the other car and see what happens.