S14 SR20DET will not run/stay running/runs like total crap

[95KA-Turbo]

Ok,

To start off I did search and could not find anything specific. I did this swap back in May of 08. I had a few hick-ups at the beginning but worked everything out. I've had zero problems with the swap since the initial issues (July 08) - I DD this car and have done several drift events with no issues.

I'm running a stock SMIC, HKS air filter, stock bypass valve, unknown jdm tubular turbo manifold, manual boost controller (set at 10psi), 3" elbow/downpipe/cat, Trust DD exhaust, OEM silvia fuel pump and MAF.

From the first hick-ups I had with the motor I replaced the coil packs and fuel filter (circa May-June 08).

My current situation started a week or so ago when my car started cutting out/bogging randomly while driving (WOT, idling, cruising on interstate, and normal city driving all included). It felt like a fuel cut, and was not dependent on the direction I was turning or anything. It would also occur at different RPM ranges, nothing specific. I assumed my fuel pump was going out/a connection was lose or something.

Kind of a side story - a couple of days ago I tried a different ECU for a member on here to rule out his ECU being the reason his car was not running. The ECU worked great and I drove around the block/hit full boost, pulled back in the drive way, unplugged his ECU and plugged mine in. I did not drive the car until the next day.

The next day I go to move my car because I was going to roll my friend's fenders. My car started up just fine but was idling a little high (it was much colder out then the day before though). I put it in reverse and started backing out and it died as if I stalled (not enough gas). I start it back up and rev it really high and it just cuts off. I go through this process for a minute or so and get the car to run enough to get out of the driveway.

I can get the car to somewhat idle if I rev it up fairly high (2k-2500) - and that is only some times. Most of the time it will basically shut off/bog/hick-up when I give it gas.

I ended up getting it up to temperature and it was behaving mildly better, but if I hold the throttle constant the RPM does not match my foot (it will bounce around a little bit and sometimes sound like it does when you unplug the MAF and try to rev over 2500 - it sounds a lot like 2-step. I want to be clear this is not the same common symptom as a bad MAF - as I did unplug the MAF and it ran MUCH worse and would not let me rev over 2500 (ruling that out as far as I know).

Convinced it was my fuel pump, today I ripped my fuel pump out and put my stock KA one back in - because I know for sure it was working when I took it out and I know it should start and idle the motor just fine. I did all of that and it still has the same symptoms. I put the silvia pump back in the tank and have been scratching my head.

I don't believe this is an ignition problem, but I am going to borrow my friends known working ignitor chip and coil packs tomorrow to 100% rule those out. I am going to check my IACV and TPS tomorrow as well - but I'm not thinking those would just randomly shit on me like that as they're in very good condition.

I am open to all suggestions, all of my couplers are fine and have been for the past 6 months so I don't know why I'd have a vacuum leak out of no where. The manual boost controller would not effect idle at all, or non-boost situations so I don't see how that could be it. I just changed my oil about a week ago - it was after the original symptoms occurred though and my old oil looked normal.

The only thing I am unsure of is my fuel pressure as I don't have a gauge and none of my friends do either. I'm going to attempt to get a hold of one tomorrow and see if maybe my factory FPR died on me - I'm really not sure if that's common and haven't really ever heard of that happening.

Thanks in advance, please ask questions if it will help you give me answers - sorry for writing so much, but I want to make sure I am thorough in my descriptions!

[devonkyle77]

shit man...

[fliprayzin240sx]

If its not the maf, i'd look into the o2 sensor or the water temp sensor next. Sounds like its bogging due to extra fuel getting dumped into it.

[95KA-Turbo]

I went out to work on it today and it started right up and was running OK. It is probably 20 degrees warmer today then it was yesterday though (the great weather patterns of southern VA).

I drove it down the street and let it warm up all of the way. Got back in the drive way and was unplugging sensors, these are what I unplugged:

the brown and purple plugs on the IACV
the brown TPS plug

The brown IACV and TPS plugs made a difference in the idle but hte car still ran - I know unplugging the TPS will let the car run still. The only thing that somewhat bothers me is that there was no change with the purple plug being plugged in or unplugged.

Shortly after that it started running irregularly like before. It cut off a few times, I got it running and took a crappy cell phone video.

In the video I'm keeping my foot on the throttle and when it isn't messing up it is staying at 1200rpms. The audio quality is definitely not the greatest but you can get an idea what it is doing. The biggest thing is my foot is not moving - so the RPMs are jumping around all by themselves - about 5 seconds after the video ends it cuts off with my foot still on the throttle.

http://i25.photobucket.com/albums/c51/95KA-Turbo/th_0105091253.jpg (http://s25.photobucket.com/albums/c51/95KA-Turbo/?action=view&current=0105091253.flv)

I have the phone pointed at the open hood from the drivers seat.

[cotbu]

That's horrible... I'd check codes and then mechanical timing, then go from there.
I really can't tell but is your boost gauge bouncing around too? I'm also confused about the ecu swap... did it make it your car run better or ? Maybe your ecu is fubar...!

[95KA-Turbo]

My ECU is fine as far as I can tell. I only tried another ECU to check and see if that ECU was good for someone else - since my set up was running fine. I rechecked with that other ECU just to be sure my ECU didn't somehow shit on me and it acted the same.

I've got to get my friend come over and help me check for codes...last time I tried it I did it wrong because the codes I got didn't make any sense (they were nonexistent codes).

[95KA-Turbo]

I'm bumping this so Z U L8R can check this out....I hope you can help me!

[jeb]

what bov are you using an is it vented to the atmosphere or recirculated?

[95KA-Turbo]

It's the stock bypass valve and it is recirculated like it is supposed to be.

[Z U L8R]

:) i'm flattered

i just got an s14 with an rb20 dropped off at the shop doing something similar. i'll be checking it out tomorrow.

i've seen a lot of different shit cause a lot of the symptoms you're having in my day.

but if i had to go on a hunch and start diaging your car as if it were here, i'd be looking at your injectors, your injector o-rings, and the grommetts on the intake manifold that the fuel rail sits in.

then i would check for codes if no problems found in the injector area. if any codes are present besides 55 then i'd remedy those and continue

if you get code 55 then i'd look into a fuel related issue such as a fuel leak, inadequate fuel pressure, or not holding pressure.

all this after putting in a set of brand new ngk 3330's (BCPR7ES) gapped at .028

checking the fuel pressure and making sure it holds pressure is an important test i'd get out of the way. i've seen the little fuel hose that goes on top of the fuel pump where it connects to the sening unit assembly crack/rip cause people didn't use fuel injection hose and that cause these symptoms.

if i still didn't find the culprit at this point, and didn't get any codes i would check continuity from the maf black and white wires to the ecu, and check the black/white wire at the maf that it was getting ignition 12v power.

if still didn't find an issue, i would test the tps, and the resistances per/temperature on the coolant temp sensor as the fsm explains to test it.

do that stuff and let me know ur results.

Dave @ Lethal Injection Motorsports
770-343-9969

[95KA-Turbo]

Thanks a lot! It has been raining for the past two days so I've been unable to accomplish anything. I just wanted to clarify a few things so I could jump right on it tomorrow and get all of this stuff knocked out!

To check that stuff on the fuel rail I'm going to have to take the fuel rail off and look at each injector aren't I? I haven't done that on a S14 SR before...so I hope I don't have to remove my whole intake manifold for that.

The rest is pretty self explanatory, so I'll let you know what I find. I might go try and check the codes since I can do that in the car and not get rained on.

[Z U L8R]

it is a little pain to take the fuel rail off. you will have to remove the upper plenum since it's an s14 sr20, it's not that hard with a good swivel 12mm socket and/or wobbly extensions. but anyways,

1. put the new plugs in there, and hook up an inline fuel pressure guage inbetween your fuel filter and the fuel rail. it should hold pressure and pump up to 38-42psi. after about 5 minutes you may lose a little bit of pressure, post your pressure after 5 minutes of holding.

2. look at the grommets that the fuel rail sits into and make sure they look ok and you don't see any dampness or smell fuel. sometimes these deteriorate and cause hard to see/diag vacuum leaks. it's pretty rare but sometimes engine importers damage/bend the fuel rail by how they hook up the hoist to the motor when moving it around and the bent fuel rail doesn't seat in the grommets all the way because of that. that's what you're looking for.

3. check all the other shit i mentioned above like codes, the tps, the cts, etc, and if no problem is found

4. take upper plenum off, unbolt fuel rail from the intake manifold. with it raised slightly, prime the fuel pressure and see if you have any fuel leaking out of the bottom of it, while also keeping an eye on the pressure guage you have hooked up.

5. post back results

gl,
Dave

[95KA-Turbo]

Thank you very much!

I'm working on getting an in line FPG right now, so I can hopefully have that in an hour or so.

There was a break in the weather so I ran outside and started it up - it started up fine and was idling smooth, just high - around 1500 rpms. I gave it some gas and everything was seeming to operate smoothly. I popped the hood and looked around - everything was a little wet since it has been raining non-stop for 2 days, but I could smell a little bit of fuel if I put my face over the injectors - there was no visible pooling of fuel or anything though.

I drove it up and down the street, got it up to temperature (the idle had dropped to around 8-900rpms at this point), it was still idling fine and driving fine. I let it sit a little longer because I knew it would start acting up and when I was looking around in the engine bay it died. I started it back up and it would kind of surge from ~900rpms to ~1100rpms and die. I put my foot on the gas and held it at 2200 and it would drop down the bounce back, then drop, and finally die even with my foot still in the same position.

I will post back my results once I get the fuel pressure gauge!

[cotbu]

The surging maybe cts related...you problem really doesn't sound like fuel, to me at least.
G\L

[Z U L8R]

The surging maybe cts related...you problem really doesn't sound like fuel, to me at least.
G\L

the surging may be cts related which is why i asked him to check the resistances of it, but then you contradict yourself and say the problem doesn't sound fuel related...

well the coolant temp sensor is one of the references the ecu uses to determine fuel trim. it is there so the ecu knows if the motor is cold or warmed up to operating temperature so if it's cold it'll run rich (like a choke on a lawnmower or carbeurated engine), as the motor warms up it leans out and goes closed loop.

if his coolant temp sensor was bad and was his problem, it would be telling the ecu that the engine is a temperature it isn't which in most cases is way below freezing so the ecu responds with DUMPING FUEL....and that is how a bad CTS is a fuel related symptom.

any updates?

Dave

[cotbu]

Maybe I wasn't really clear there, I admit saying CTS maybe the problem and the problem doesn't sound fuel related.... I could have said it doesn't sound like a fuel delivery problem ,injectosr, ect. But technically that would be wrong to... correct? (I see CTS as electrical)

Ok, I'm saying, the surging problem is probably related to the CTS. Sorry Dave, for being unclear, I was just using my expertise to help diagnose it quick.

[95KA-Turbo]

Ok, I had a little hang up in getting the FPG, but I got it on there and got the car to run for 5 mins. The fuel pressure basically stayed right at 38psi, it moved up very slightly between 38 and 39, and when the car died it would go up to 40psi.

I changed my fuel filter in this process since I already had to get gas on me, haha.

I don't have the plugs in yet because I have to order them.


I've got to get my friend to bring over his nice multi tester and check out the CTS and what not.


During the process of letting it run for 5 mins I had to keep my foot on the gas to keep it from stalling - I was keeping it right at 2k and it sounded like 2-step...so I'm not really sure what that means.

[Z U L8R]

can you borrow a buddy's mass air flow sensor?

try to get it to act up, once it's acting up, swap mafs and go from there. gl

Dave

[95KA-Turbo]

I trouble shot my "Engine Coolant Temperature Sensor" via the FSM (EC-116 and EC-201). The actual sensor itself checked out alright and terminal G on the large plug located near the IACV (F27) but terminal F is not showing continuity, so I've got to look more into that.


When I was warming it up to check the plugs out it would actually idle OK, but if I gave it gas it would break up and sound like 2 step once I got to 2000rpms...higher then that (3k for example) and it would sound like 2 step then drop down to 2k again, the pop back up to where I had the gas held to and die.


The closest guy to me with a S14 SR is 1.5 hours away, but he should be coming down here tomorrow so I'll see if he can bring me is MAF.


I had almost convinced myself it was my CTS so now I'm more pissed then I was before, haha.

[Z U L8R]

soon as you mentioned the 3k rpm rev limit, it goes into try known good maf

Dave

[Monooxide]

I popped the hood and looked around - everything was a little wet since it has been raining non-stop for 2 days, but I could smell a little bit of fuel if I put my face over the injectors - there was no visible pooling of fuel or anything though.

Did you check for a vacuum/boost leak at the injector bungs? This would most definitely cause a high idle and driveability issues as you're pulling in air that the MAF isn't reading.

You shouldn't smell fuel there unless you by chance spilled it there.

[95KA-Turbo]

soon as you mentioned the 3k rpm rev limit, it goes into try known good maf

Dave

It will rev past that, it just basically runs like shit above 2k...and will cut off at idle randomly.


I'm going to have some of my friends help me with it tomorrow - the third day of smelling gas fumes in high quantities is not good for my decision making skills, haha. I've got to muck with the fuel system again tomorrow because I must have not screwed one of the fittings on the fuel pressure gauge in enough because it has a small leak there. :rl: .


I will check on all of that stuff though, maybe get a better idea of what is going on....at this point I REALLY hope it is my MAF...but I'm not sure where I'm going to get another one. I may have to grab a SAFC and go Z32 maf...which I guess will let me get some bigger injectors too, haha.

[95KA-Turbo]

I got to try out another MAF today, and that definitely is not the problem. I am thinking maybe there was a loose connection in my harness that got loosened even more when I undid the harness from my ECU and put it back on the other one - or perhaps I pinched a wire somewhere. I'm going to go through all of it with a fine toothed comb tomorrow and hopefully resolve my issue.

Otherwise I'm clueless as to what it could be.

[slider2828]

My questions is why would you smell fuel in the engine bay? DO you still smell it? If so check your plugs, see any of them have any weird discoloration?

Also did you check your injectors for impedence as well? If you smell gas, did you pinch any of the o-rings when you might have fiddled around with your injectors?

[95KA-Turbo]

I've never messed with the injectors ever. I can hear each one of them tapping - so I guess I just need to get a really good flash light and check out each of the grommets thoroughly - I don't see anything by inspecting them under normal day light - a few of them in are in the shade though.

I did just go through my ECU harness though and resoldered all of the imperfect looking wires - there was only one. I redid the tape job on some of the wires where it was loose/kind of coming off. It didn't solve my problem - and I even shook the whole harness and it didn't effect anything.

It is idling pretty high - around 1500-1800 when first started. I am pretty sure on a cold start it should be idling around 1100-1200, so I used the IACV screw and lowered it to that.

My coil pack harness ground was a little loose so I tightened that, I checked to make sure nothing was melted over in that area - everything looked fine.


I'm really scratching my head on this. The FSM says to listen for ticking on each injector and monitor the fuel pressure while unplugging each injector harness one at a time and if the motor doesn't decel/change idle then the coil pack needs to be checked for spark.

[Z U L8R]

when the idle is high you typically have a vacuum leak behind the throttle body, ie the intake manifold/plenum. check that out, if u wanna elilminate another thing, make sure the check valve on the brake booster vacuum line will only let vacuum suck on the booster and won't let any boost through to it.

post update

Dave

[95KA-Turbo]

when the idle is high you typically have a vacuum leak behind the throttle body, ie the intake manifold/plenum. check that out, if u wanna elilminate another thing, make sure the check valve on the brake booster vacuum line will only let vacuum suck on the booster and won't let any boost through to it.

post update

Dave

How would I check that? Is it just a matter of pulling the lines apart at the check valve and blowing through it or just undoing the line connected to the booster itself and make sure it has suction?

[ballinnmiami240sx]

yup.. its just a check valve. blow thru it.

stephen,

Can you list the things you have tried and know that are not the problem.

[slider2828]

Starting spray carb cleaner or brake cleaner around your fittings, see if it cuts or affects something. Testing your systems for leaks... My friend has the same problem, but he's an idiot cause he doesn't spend time on his car....

[KiLLeR2001]

Test for impedence (ohms) on your injectors. Should be ~11.5 for each of them. What does your exhaust fumes smell like?

[95KA-Turbo]

It has been cold as crap and I've been helping my roommate fix his truck - so at least one of us can drive, and since he has a job his truck took precedence, haha - so I haven't looked at the car other then swapping in another ignitor just to make 100% sure that isn't a problem.

Here's my list of things I've swapped out to check and see if they're the problem:

-Fuel Pump
-MAF
-Ignitor

Here are the things I've checked with the multimeter/per FSM:

-Coolant temp sensor
-Engine temp sensors
-IACV
-TPS


I have also...

-visually checked the injector O-rings for cracks and/or leaks
-listened to each injector with "appropriate tool"
-put an in line fuel pressure gauge on - pressure stays at 38psi
-checked grounds
-checked coil pack harness/ground
-checked ECU for broken/damaged wires
-did the jiggle test on my ECU harness


All of those things checked out - I'll check resistance on each of the injectors tomorrow (it's going to be in the fucking 20s out!!!!). I'll also try and look at the vacuum lines as best as possible, but it's going to be cold as shit so everything will most likely be inflexible and hard to maneuver around.


Any other ideas to check are greatly appreciated - I'm waiting for my friend's to come by and help me out on Saturday (hint hint Danny).

[slider2828]

Other than your car doesn't want to run cause its 20* outside... Could be the possibility. Lol.... But check those things first and get back to us

[95KA-Turbo]

I just got back in....

I was trying to get it to run long enough so I could unplug each injector and make sure the car responds appropriately (as described in the FSM) - but I could not get the injector clips off. I was squeezing them as hard as I could and jiggling them around and couldn't get it to come off. I am blaming that on the sub 30 degree temperatures outside right now.

The exhaust smells like fuel - which isn't really that much of a surprise as I have been trying to start it over and over and it only stays running for 5-10 seconds at a time. It ran for a min or so a few times but the exhaust still smelled like gas.

It is going to be over 30 tomorrow so I'm going to try and mess with it then, I think it is just too cold right now.

This is getting really old really fast.

[SILVIA_KIDs14.5]

boost leak any one had the same shit happen to me when i first got mine runing was running pig rich and idle was shit bogged when i slamed the gas down and the all the sudden would pick up wouldn't always do it but thats wut it sounds like you got would check that out good luck

[Z U L8R]

man, i figured you'd have it fixed by now.

you got any burnt/melted wires around the turbo area. like maybe the maf/o2 wires that run behind the head?

what kind of bov do you have? have you PULLED every intercooler pipe/coupler, inspected each clamp?

there really isn't that many things to these things...you should've found your culprit by now

gl man,
Dave

[nrmskate]

My guess would to try cleaning out the IACV, it can only help ad not hurt.

Check your fuel lines to make sure their not corroded, pinched or cracked.

Again, spraying carb/brake cleaner on the vacuum lines will show you if it has any leaks or anything.

I may be mistaking, But I think you have to take the entire fuel rail off to take the injectors out.

[95KA-Turbo]

I think we've found the culpret, but I'm not 100% sure. My friend came down and helped me with it yesterday, but he didn't get down until after dark so we were working on it in the dark and the temperature was 26 degrees.

He rechecked everything I had checked and literally every sensor checks out fine and the coil packs check out fine, we couldn't find any vacuum leaks anywhere. We went through the harness and found a few more suspect connections so I've got to fix/replace those. I don't have any solder or anything so I was hoping one of my friends would be able to come by today and give me a hand with it - but now it's freezing rain/sleeting outside so I'm going to have to see if my friend can bring his pop up tent.

I'll keep you guys posted, I'm thinking this is more likely a wiring issue then a mechanical issue....at least I hope it is otherwise I have no fucking clue what it is.

[95KA-Turbo]

Ok, so short of redoing the entire wiring harness, I've resoldered every wire that moved even a little bit and the car started up and actually ran for 10-15 mins, got fully up to temperature and pulled on all of the intercooler pipes and tugged the shit out of the ECU and F-plug harnesses and the motor still ran the same.

However, when I give it throttle it still breaks up/bogs. I can rev through the whole RPM range and it will come back and idle fine most of the time. I can rev up to 3k, keep my foot there, and it will hold the RPMs for a few seconds- then cut out, drop back to 1k, then go back up to 3k.

And just to clarify, I've gone through all of the sensors and was actually able to unplug 2 of the 4 injectors (one at a time) and the motor lowered in idle/sounded like shit like it is supposed to.

[nrmskate]

Pull the codes from the ECU?

[slider2828]

Also try testing your coilpacks... Sounds like a coil pack ignitor issue.... Clean mafs of course...

[Autobacs]

OK allow me to jump in.

How do you figure out whether the igniter or the coilpack or both is the problem?

Any differences in symptoms of failure each one of them?

[slider2828]

I can rev up to 3k, keep my foot there, and it will hold the RPMs for a few seconds- then cut out, drop back to 1k, then go back up to 3k.

This sentence... I had the same thin happen to me.... Just check.... Not a big deal.... its a possible symptom...

FSM on how to check coilpack issue.

Easiest way to check ignitor is to get another.... Otherwise, there has been some ways to check without getting another one... Not sure.... Gotta Search

Symptoms are the same cause they are connected....

[95KA-Turbo]

I have a list of things I've swapped out at the top of the page (just mentioning that as a reference). In addition to swapping out the ignitor I also checked for spark on each coil pack as well as checked the harness for melted/messed up wires.


I tried to pull codes from the ECU but apparently my ECL either has the bulb pulled from it or is not wired in right for the swap :bash:.

[95KA-Turbo]

The problem is fixed, it was two things. One was a wire that came loose in my ECU harness and the other is the wires and plug itself was corroded on my MAF - a new plug and new wires fixed it all.

Thanks for the help everyone.



Also, just for reference. While you cannot use a SOHC KA MAF sensor on a S14 SR20 (with red WC ECU), you can use the plug if you just remove one of the wires on the plug. SOHC KA MAF plug is 4 pin and S14 SR20 (with red WC ECU) uses a 3 pin sensor but is the size of a 4 pin plug...so it fits perfectly.

[ballinnmiami240sx]

yeah!!!!!!!!!

[nixonsnow]

just question! is 11.1 ? ohm for stock s14 sr20det injectors baD?

[Slide13]

Ok I am having a very similar issue with an s14 sr20 with the NA ecu. Its got a working maf (F01) after reading your whole thread I have decided that my issue is wiring related to the cts? It runs fine but the idle jumps around. Going to investigate the wiring in a little bit