Hestation?

[drzsnapj]

hello everyone, i have a few issues that are driving me insane (s13 redtop) hopefully nico can help me out:1. between 2600-3000rpm i feel this hesitation feeling like the engine is struggling to go, as if it wants to stall almost, but before and after that range it feels fine. some days it is not that bad but others days it's terrible.

2. the engine is running rich, its not blowing black smoke, but i can smell the gas from the tailpipe, and i have backfire. what can cause the car to be running rich?

3.after the car has been warmed up the engine idle would be sometimes at 900rpm and other times at 1300rpm, any ideas what it can be?

any help would be appreciated

[seanman]

do you have a none oem fuel setup? such as a walbro 255 fuel pump? anything to boost your fuel pressure would put alot of strain on the stock fpr causing over supply of fuel

[Sileighty_85]

Check ECU for Codes

[kainvamp]

yowza^both mine were like that till i tuned em with afc's. You should probably have it tuned casue im pretty sure most sr swaps will just run rich to begin with. but i agree the fpr should be upgraded too if your running a high pressure fuel pump

[drzsnapj]

im not running any upgraded fuel pump. i checked my ecu for codes and all it did was light up red for about 10sec. and then went off. i had the car runiing for about 5 min. and it never came back on. maybe im doing it wrong

[Sileighty_85]

im not running any upgraded fuel pump. i checked my ecu for codes and all it did was light up red for about 10sec. and then went off. i had the car runiing for about 5 min. and it never came back on. maybe im doing it wrong

*Quoted from Kazuo on Zilvia*- this is general for 89-98 Nissan but most apply to the SR20 motor.- to set car into diag. mode, with the key in the "ON" position, turn potentometer screw on ECU fully clockwise, then turn it fully counterclockwise. The LED on the ECU will begin to flash.- first digit = LONG blink; second digit = SHORT blink (ex: 1... 1... 1... 1... then 1-1-1 equals 43 = TPS)

Error Codes Biatch11 Crank Angle Sensor/Camshaft Position Sensor. 12 Air Flow Meter/Mass Air Flow Sensor. 13 Engine Coolant Temperature Sensor. 14 Vehicle Speed Sensor. 21 Ignition Signal. 22 Fuel Pump. 23 Idle Switch. 24 Throttle Valve Switch. 25 Idle Speed Control Valve. 28 Cooling Fan Circuit. 31 ECM. 32 EGR Function. 33 Heated Oxygen Sensor. 34 Knock Sensor. 35 Exhaust Gas Temperature Sensor. 36 EGR Control-Back Pressure Transducer. 37 Knock Sensor. 38 Right hand bank Closed Loop (B2). 41 Intake Air Temperature Sensor. 42 Fuel Temperature Sensor. 43 Throttle Position Sensor. 45 Injector Leak. 47 Crankshaft Position Sensor. 51 Injector Circuit. 53 Oxygen Sensor. 54 A/T Control. 55 No Malfunction. 63 No. 6 Cylinder Misfire. 64 No. 5 Cylinder Misfire. 65 No. 4 Cylinder Misfire. 66 No. 3 Cylinder Misfire. 67 No. 2 Cylinder Misfire. 68 No. 1 Cylinder Misfire. 71 Random Misfire. 72 TWC Function right hand bank. 73 TWC Function right hand bank. 76 Fuel Injection System Function right hand bank. 77 Rear Heated Oxygen Sensor Circuit. 82 Crankshaft Position Sensor. 84 A/T Diagnosis Communication Line. 85 VTC Solenoid Valve Circuit. 86 Fuel Injection System Function right hand bank. 87 Canister Control Solenoid Valve Circuit. 91 Front Heated Oxygen Sensor Heater Circuit right hand bank. 94 TCC Solenoid Valve. 95 Crankshaft Position Sensor. 98 Engine Coolant Temperature Sensor. 101 Front Heated Oxygen Sensor Heater Circuit right hand bank. 103 Park/Neutral Position Switch Circuit. 105 EGR and EGR Canister Control Solenoid Valve Circuit. 108 Canister Purge Control Valve Circuit.

[hks240sr20]

I would check the fuel pump to make sure thats operating properly, get a fuel pressure gauge so you know if your regualtor is working and could possibly be a maf problem

[drzsnapj]

cool thanks guys i will check for codes today, and will try to get a fuel pressure gauge(what should my pressure be at? i have a stock pump)

i had a boost leak before this problem, so i did a boost pressure test and found a small leak on one of my cold pipes, but would that cause the car to hesitate?

[drzsnapj]

im not running any upgraded fuel pump. i checked my ecu for codes and all it did was light up red for about 10sec. and then went off. i had the car runiing for about 5 min. and it never came back on. maybe im doing it wrong

[drzsnapj]

so i checked for codes and it gave a 55 code (No Malfunction), i still have to check my fuel pressure.

i searched hesitation here on nico and some guy had similar issues like mine and he disconnected his o2 sensor and hestation stopped, so i did the same and it stopped but not much.

then my friend noticed that my fuel pump sounds like a loud stuck window motor (if that makes any sense) so i have to wait on the fuel pressure test to verify if it is bad or not.

does anyone know where it should be at?

my friend also said he experianced the same problems on his N/A SOHC and that he solved it by taking off the vacuum line that goes to the FPR capping the other end of the vacuum source leaving the FPR open. so we tried it on my car the same way he did his and 2 things happened:1. the hesitation seemed to have stopped, but sometimes it could still be felt but not as much.2. the car idled alot smoother, steady at 1200 rpm, i adjusted the idle to 850 rpm and it was still idling smooth.

so could all this possibly mean my FPR is bad? or could it still be something else?

thanks for the responds guys

[Sileighty_85]

if you can hear your fuel pump whining from the out side of your car then you fuel pump is crappin out or your fuel filter sock is clogged

[drzsnapj]

is it bad if i drive the car around with FPR not hooked up to a vacuum source?

[Sileighty_85]

well you need a Walbro 255 fuel pump

whenever you up the boost the KA fuel pump will not support the SR

your fuel pump is dying and putting out low pressureby pulling the Vac line off you closed the FPR so you are getting more pressure at the Inj. which is why your idle is better.

Replace the fuel pump, and install a Z32 Fuel filter if you have not already

[drzsnapj]

okay so remember how i said i was driving the car with the FPR open, well i put the vac source back in and it stayed idling at 850 rpm for about 2 min. and then it gradually started to creep down to 550 rpm. so i think my FPR is done for. am i right?

[Sileighty_85]

Your FPR is closed when you pull the Vac source off of it, so you get more fuel pressure.

If your Fuel pump is whining really loud then it dying or the Sock is clogged

So it sounds like itd your fuel pump and you need to replace it anyway since you have an SR in there

[drzsnapj]

Okay so I just check the fuel tank and there looks like there is a Walbro 255 pump in there. Maybe its gone bad or something

[drzsnapj]

okay so i fixed the fuel pump problem, the fuse was bad, but my hestation is still there. I noticed a few things about my jerking car!!!!!!!!!":

1. when in cold start up, i let it warm up (everytime, anytime of the day, i never run it cold) and the first 15-30min. of driving the jerking is horrible, after that those 15-30 min. it stops but it can still be felt between that range (2700-3000rpm)

2. i have my greddy turbo timer set to display the voltage, so when i slow down to stop at a stop light the voltage drops all the way down to 11.9 volts , and my rpm's drops to about 500rpm.

3. also when i put it 5 gear the jerking/hesitation is felt through 2-3000 rpm range.

its driving me nuts and dont wanna buy parts without knowing for sure what is the problem. Im leaning towards a MAF or a TPS malfuction. any idea guys/

oh yea if it helps i have a N62 computer, and a blacktop harness, redtop sr

[blackhole1]

could be a number of things, check to see why you blew a fuse, check for electrical shorts and grounds, check for spark in all cylinders, also check to see if all injectors are working,check the coil packs. most people that do the sr swaps over look changing out the pcv and coolant temp sensor. Check the plugs and their gap. like i said could be any of this crap, had a similar problem with my sr and it turned out to be a bad injector. it also would'nt hurt to clean the maf check voltage just to be sure recheck all your hose connections and good luck. if all fail drop it off at Carisma they are located in longwood.

[drzsnapj]

it wasn't a bad fuse i had a kill switch to the fuel pump and the switch went bad, so i just put the fuse in directly. i just check the ecu for codes again (BTW IT IS A #63 ECU NOT A #62) and i got a 55 code which is no malfuction. i wanna check all of my sensors but i dont know the specs, does anyone know the spec for the sensors?

i really wanna get this pandora box fixed already, its my one and only dd.

thanks in advance guys for the help.

[90_240sxx]

check your timing. advance it a little and see if that helps

[LovesBigTurbos]

i say misfire could be causing hesitation check plugs and wires!!