SR20DET problems.

[Hatchman]

Some of you may remember my wont start thread if you do I've made progress since then.It now starts but only stays running if you unplug the mafs and put it into limp mode and wont rev past 2500 rpm (Or whatever it is my tach does not work).I've replaced the mafs also so its probebly not that,anyways I'm open to suggestions.

[Justin35ll]

I was gonna say replace maf, but if you already did and that didn't work I'm not sure.

[Hatchman]

Yeah thats what I thought it was too so I replaced it and it did the same thing, it was enough to make me want to go wrestle an aligator.But seriously if anybody has any ideas dont be afraid to speak up.


Modified by Hatchman at 12:43 PM 11/15/2008

[va240dude]

ECM possibly? Sometimes its worth a swap just to see...

[Hatchman]

I swapped it out with one out of a running sr20 swap and it did the same thing .

[Hatchman]

Also one of the two little ground bolts on the intake manifold is broken off so I had to ground both of them off the one remaining bolt.Would this cause problems and does anybody know what these are for, one person said one was for the CAS and the other is for various sensors.Sorry for all the questions I'm just anxious.
Modified by Hatchman at 11:41 AM 11/6/2008

[Hatchman]

Bump

[Hatchman]

Anybody have anymore ideas?

[javi-air]

check to see if the wires for the maf arnt burned or if they r wired wrong... i had a ca18det and thats what happen... the wires were wrong om the maf

[skaterfromvt]

check for ecu codes...anything?

when you plugged the other ecu into your vehicle and it didnt work...did you plug it back into the other vehicle after to see if it still worked..

the reason i ask is...it is possilbe that the wiring to your MAF could possible be grounded out or 2 wires could be touching if this is the case..then the ecu would short out...

if the ecu is fried when you pull the cover it is repairable (sometimes) by a place in PA... best1tuning.com

[Hatchman]

We swapped the whole wiring harness and ECU and it still refused to idle.I've been reading some old threads and some people have had problems with MAFS turbulance from the MAFS being to close to the turbo but it dosen't seem like its close enough to the turbo to cause problems,or I could be a total jackass and not know anything.I can't get a picture of it right away because it is at a shop a few miles away and I have no car.Oh yeah the other car still starts and my ECU throws a code 55.

[Hatchman]

Anybody?

[mjmmx6]

think maybe a vacuum issue or fuel issue?

[WestTxSR20Tuner]

I have the exact same issue. I pulled my harness off and triple checked all the wiring using the FAQ on frsport.com. I have tried two SR20 MAfs, a KA20 MAF, and I now have a Z32 MAF wired on there. Could it be we did not set CAS properly?

[skaterfromvt]

clean the idle air control valve...

[Hatchman]

I'm pretty sure I installed my CAS correctly I did it the way the drifting.com install dvd says to,unplug your MAFS and see if it runs better mabye we can help each other out.I think my vacuum and fuel lines are hooked up correctly I just copyed the other 240sx and I'm pretty sure I dont think I have any vacuum leaks.How do you clean the idle air control valve, just spray some carb cleaner in the the little tube coming from above the throttle body?It runs just fine with the MAFS unplugged though I love these smiley faces


Modified by Hatchman at 10:01 PM 11/18/2008

[boro drift]

So you have your cas installed correctly, did you set the timing?

[Hatchman]

Yeah second notch to the left, valve cover popped off dots on the timing gears lined up the whole shebang.I researched like crazy when I did it so I wouldnt screw it up

[boro drift]

I mean did you set the initial timing with a timing light and with the engine running?

[skaterfromvt]

if it idles fine with your maf unplugged then your maf is probally wired wrong or has shot the bed....try replacing it with one that u know works!

[Hatchman]

I didnt set it with the timing light but I adjusted the timing by twisting the CAS around and getting it into the sweet spot.I'm probably going to get told to search but what does shot the bed mean.Are you talking about swapping the MAFS or rewiring the MAFS.Sorry if this dosent make sense I had surgery today and I'm a litlle loopy

[redsx13]

Some of you may remember my wont start thread if you do I've made progress since then.It now starts but only stays running if you unplug the mafs and put it into limp mode and wont rev past 2500 rpm (Or whatever it is my tach does not work).I've replaced the mafs also so its probebly not that,anyways I'm open to suggestions.

1.How long does it stay alive with the mafs plugged in?2.what happens when you try to rev it buyond 2500? (does it sound like a rev limiter or does it bog down. can you kill it by giving it more gas)3. why doesnt your tach work?4. what was wrong that caused it not to start?

[Hatchman]

1:When I have it plugged in and try to start it it starts then immedietly dies 2:When the MAFS is unplugged it revs up to 2500 and sounds like it hits the rev limiter3:Its an 89 240sx and I havent swapped in a 91-up tach yet4:My throttle body was chipped and I think the TPS was messed up so I got a new throttle body and my injectors were leaking so I put new o-rings in and swapped spark plugs cause the other ones were fouled by the leaky injectors

Oh yeah it starts up with the cold pipe dissconnected from the throttle body with the MAFS plugged up and it revs past 2500 rpms.

[skaterfromvt]

your turbo might have a leak where the manifold meets the turbo inlet...

maf...shot the bed..."sh*t the bed" = is junk...broke loli was suggesting that you unplug it and borrow a friends that u knows works and plug it in...

hmm its weird that it runs while the cold pipe is off the throttle and the maf is plugged in...maybe your front mount is way to big for the set up you have...

are you still running factory boost

was the ecu chipped?

[redsx13]

1:When I have it plugged in and try to start it it starts then immedietly dies 2:When the MAFS is unplugged it revs up to 2500 and sounds like it hits the rev limiter3:Its an 89 240sx and I havent swapped in a 91-up tach yet4:My throttle body was chipped and I think the TPS was messed up so I got a new throttle body and my injectors were leaking so I put new o-rings in and swapped spark plugs cause the other ones were fouled by the leaky injectors

Oh yeah it starts up with the cold pipe dissconnected from the throttle body with the MAFS plugged up and it revs past 2500 rpms.

the reason it sounds like it has a rev limiter at 2500 rpm's is because the maf is unplugged.

this is a long shot, but did u check to make shure your tps is good?just check the voltage coming outa the white wire with everything hooked up. it should be .5 volts at idle and a little under 5 at w.o.t

also, check the signal coming out of the white wire on the maf with it plugged in. have some one help you and check the volts while you start the car. you should be able too get some kind of a reading even though your car will only run for a few seconds. im not shure what kind of voltage you should be getting from your maf offhand but you can easily find out

let us know what you find

[skaterfromvt]

hey it if starts and stalls right out...that could be your Idle air control valve...

for example if your car is running and you pull that large vacuum line that runs to the idle air control valve while its running it will fight to stay running...check the vacuum line running to it and make sure its not pinched/fighting to get air...

you might have a bad iacv but try the maf thing and throttle body first b/c they might be a little cheaper...just a heads up

[Hatchman]

I'm probably going by the shop today so I'll check the turbo inlet and the vacuum lines and get them to check the voltage on the white wire on the MAFS and clean the IACV.I'm still running factory boost and I dont think my ECUs chipped cause I popped it open a while back and it all looked pretty stock.The shop that I have it at has two running sr20s and they have swapped out the MAFS,turbo,throttle body,coolent temp sensor,wiring harness,ecu and intercooler core from running sr20s and my old throttle body was the only part that made a difference in how it runs I hope that makes sense I'm still a little loopy.Oh and I have an xspower intercooler core and cxracing pipes and by the way don't get the spec gt intercooler kit on ebay if you want the pipes to fit because they don't on the other hand the cxracing pipes fit very well or at least they did for me.

[Hatchman]

Forgot they was closed today gotta wait till tomorrow

[WestTxSR20Tuner]

I swapped my IACV and TPS off a working motor and the car still does the same thing. Let me know what the shop finds.

[WestTxSR20Tuner]

I am going to try another CAS and barrow my friends tuned ECU to see if it makes a difference.