sr20det running badly

[scott240sx]

I just installed my sr20det and we have it where it will crank but will not rev past 4k, idles badly, and sputters at partial throttle. We have spark and fuel to each cylinder. There are no leaks in the intake any where. We tried a different tps and maf. I believe the timing is right. It is not starting very well. The guy who did the wiring double checked everything. We are stumped so I thought I would ask everyone here if they would have an idea. I have a 97 240sx with a 95 s13 sr20det that was once a auto but converted to manual before it was shipped. Everything was running right before shipped over here. I have tried searching for an answer but could not find one.

[smithers584]

have you checked your ecu for codes? do you know your fuel pressure? have you tested your 02 sensor per the FSM? how about are you coilpacks? download the FSM, and get a multi meter to test all the sensors to help you narrow it down quickly. By the way, welcome to the sr world where anything could cause any problems, no matter how logical it sounds. give us more info. are you sure are your charge pipes are hooked up and not leaking under load? are you using t bolt clamps?

[Nizzan4u2nv]

Sounds like a maf problem. Does it run the same with it plugged/unplugged? What is your maf voltage? Try regrounding the maf. Definitely check codes.

[scott240sx]

there are not lights on the ecu to check codes. when i unplug the maf it will not rev past 2500rpm. also what is the fsm. i do not know the fuel pressure. the coilpacks are getting power and the my friend who did the wiring checked one coilpack and was getting working right. i unplugged the coilpacks one by one and they work and i also did the same on the injectors. i'm not sure what tbolt clamps are but we sprayed carb cleaner on all the joints and they where good. we also bypassed the pipes and ran the motor just one pipe with the maf to see if there was a leak and it ran the same. my friend who did the wiring also works a the local importer and will try to bring another tps and maf to see if they are working right. i forgot to mention when we unplug the tps it will rev up higher than 4k but i forgot how high it would go.

[scott240sx]

i just read on another post about spark plug gap causing the car to run bad. I never checked the spark plugs, the gap should be like .36 right?

[scott240sx]

sorry i just found the right gap .036in. what is the best way to find tdc and all the other things to check the timing.

[smithers584]

i would gap them inbetween .028-.032, no bigger. FSM is the Factory Service Manual, you can download them at tons of sights, including this one. that will tell you everything you want to know. not sure why the tps revs so high unplugged, but when you unplug it just adjust the screw on the air idle control vavle, that is how you set your idle, which obviously sounds way out. you also should check your TPS voltage and see if it needs adjustment. try what Nissan4u2nv said, unplug the MAFS and see if its the same. he is right though, a bad maf ground or even a bad MAFS would definately cause shitty idle and starting, but should not allow your car to rev over 2400 rpms. what ecu do you have? check the number on it.

[scott240sx]

i regapped the plugs they were about .04 and a little higher. i put them at
.031 and i could not start it up. It would try to catch and I could smell gas coming from the exhaust. I would guess my timing is off. Since i cannot get it to start i am going to take the valve cover off and put it at tdc and check the timing that way. I don't know which numbers you are talking about on the ecu but there was a sticker with E6 in large print and to the right of the nissan symbol there was 237105F15 and below was A18 C81 G27. There was another spot for numbers but I could not read them. I think I got the other numbers right, I could barely read them. I will also try to get the maf ground checked this weekend. Someone is going to bring a different maf so help rule out everything

[smithers584]

ok E6 is from a 94-96 180sx blacktop automatic, so what SR do you have? if you have a redtop the pinning is different, so make sure that your wire guy knows that and has the correct diagrams. i am running a blacktop motor with a 62, redtop ecu and it can get a little tricky. if you have spark and fuel, the only thing left is timing. i can unplug any of my sensors other than that and still start my car, even maf and tps. so, check your CAS and your timing like you said, you could also check the knock sensor, if that is fucked up it will pull timing. you can shoot it with a meter, i think something like 550 ohms is optimal. gotta get back to work, let us know how this goes.

[scott240sx]

yea it is a 95 blacktop that was converted to manual before they shipped it over here

[scott240sx]

I just found out why it would not rev past 4k. If i have it in gear it will not rev high but if i put it in neutral it will rev all the way up. To get it run right i just need to regap the plugs and set the timing.

[scott240sx]

i think i found the problem. the knock sensor only had one wire going to it. tomorrow i will try to fix it. i will let you know if it is the problem.

[Nizzan4u2nv]

Theres no lights on the ecu because its probably the CEL that blinks not the led on the ecu.

[smithers584]

ok well my knock sensor only has one wire going to it. it has two but only one is pinned on the connector to the sensor. i think that is because the sensor itself completes the circuit when bolted to the block (ground). someone please correct me if i am wrong, i havent found any good data to support this, but i cant find any data saying that there are supposed to be two wires there either.

[scott240sx]

dang it wasn't the knock sensor. back to where i was before. so far we have tried a good maf and checked for leaks several times. it is hard to start, at partial throttle it revs smoothly. but half to full throttle it sputters and still wont rev past 4k.

[jdm_s14_zenki]

are u sure ur smelling gas and not oil? did you check timing? should be stock at 15btdc. get a cheap timing light and check timing. your spark plugs should be gapped at .028-.032 depending. if your car ran good on .040 i think you have an ignition timing problem? your timing might be to retarded..

to find tdc, look at the crank pully from the top of the engine bay. theres a pin and a bunch of little line marks. 15btdc is the second mark from the LEFT! check it.

[scott240sx]

we got the car to run better but is still a little rough at idle and between 2k-3k can be a little rough under partial throttle and we still can't find out what is causing it not to rev past 4k

[rican_nick]

well me and a buddy have been helping scott240sx with this doozy of an issue.

quick rundown on where we are at.

Problem- Will NOT rev past 4k, at WOT the motor sits on 4k as if there was a ECU controlled Ignition/fuel limiter. Also having cold start issues.. takes 4-5 times to crank over. Car will hold idle now.

things we have done checked.

Motor Grounds- Good
new plugs- Gapped at .34 ish.. Will gap these down to about .30 which is what i ran on on my plugs stock boost.
Tried my Working maf - nothing
Timing is good now
No boost leaks that we have found
all connectors have been checked/cleaned
We have checked voltage at TPS/Maf/coil packs.. all check out fine
we have checked the 5th gear sensor to verify it hasnt gone haywire--this usually causes problems at 5k rpms though.. but we are running out of Ideas.

does anyone know of an ECU imposed limiter that would limit the motor to 4000rpm.

[rican_nick]

4000rpm's is the magic number..... never even heard of it.. but from searching on different boards others have had this issue.. but noone posts if they resolved the issue and/or what the resolution was.

[s13coupedrfter]

Try the coolant temp sensor, they can cause some weird shit like this to happen.

[rican_nick]

The coolant temp sensor was replaced with the one from te KA. The sensor it self appears to be working properly as it able to read the temp. but i do have another on a spare motor that I have so i'll give it a shot.

[jdm_s14_zenki]

try a different ecu, that may be the culprit?

[scott240sx]

tomorrow i am going to my local importer and try a different ecu tomorrow. as soon as i get it running right i will try to remember to post it so others that come across this same prob can have a reference.

[scott240sx]

i tried a different ecu but it acted the same. i was able to get a code off of it but what i got was 55, like that did me any good lol. tomorrow i am goin to try to get up early and replace my ka fuel pump with the s13 sr fuel pump. on the way home from work i almost boosted a 1 bar. that freaked me out because i know my car can't handle that yet.

[scott240sx]

oh i forgot to say that the sr came with a hks wastegate actuator

[scott240sx]

just replaced the fuel pump and there were no changes

[s13coupedrfter]

Check your grounds

[s13coupedrfter]

Sorry, I guess you already did that. I installed a grounding strap from the maf to frame and it helped stablize my idle a bit. Hope that will help GL

[scott240sx]

i have had a couple of people say the cat. if it isn't raining tomorrow i might take it out and break all the junk out of it to see if it helps. i just hope my car doesn't sound like crap. if it does i will just have to get the test pipe a little quicker than what i was going to do. s13coupedrfter you just reminded me that when i pick up my sr it had a bunch of ground wires on it. i wonder if the person who had it before did that to get the motor running right? i might just have to go pick up some ground wire and make my own grounding kit.

[TibDrifter]

check the maf,tps,ect for ground and power 5v. if those are good than work your way up to the ignitin system, swap out your coils, and ignitier. if all fails than get your wiring gone right, and ohh dont hog out your cat it has no way of effecting that 4k, and it cost 700$ for a replacement. good luck

[scott240sx]

ok today the guy who did the wiring checked all of the wiring and sensors. also we pressure checked the system and found on leak in the smic and someone is selling me one so i can fix that. we bypassed the intercooler and just ran the car n/a but still won't rev past 4k. could it be a bad sensor in the transmission?

[scott240sx]

sorry i haven't updated this but i finally fixed the car a couple months ago. the problem was in the wiring harness, not sure what it was i sent a new harness to phase2motortrend to have my harness done and it came back and ran perfectly