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-   S Chassis (#/f/forumdisplay.php?f=97)
-   -   240sx bogging (#/f/showthread.php?t=457371)

KiLLeR2001 07-10-2012 05:26 PM

You need a dedicated fuel pressure gauge, fuel pressure will change after the car is warmed up. You'll especially want to see what your fuel pressure is reading around the problem RPM range. I'm not so concerned with the fuel pump but more so the connections / wiring for the fuel pump. A loose ground, wires with high resistance, will cause fueling issues for sure.

tman6500 07-10-2012 06:01 PM

thanks for the help will check it out tomorrow and post the results.

tman6500 07-11-2012 03:03 AM

Driving it around today it might not be rpm or throttle position its different for every gear and sometimes just goes limp in first from a stop

tman6500 07-11-2012 04:57 PM

Do you mean the ground on the fuel pump like taking it out again? or is there another ground outside the tank?

tman6500 07-12-2012 03:32 PM

The tps is set to .73 closed 4.23 wot

KiLLeR2001 07-12-2012 03:34 PM

Not good. You'll want it at 0.45 closed.

tman6500 07-12-2012 04:14 PM

So to change the voltage you loosen the two screws and move the tps unit?

KiLLeR2001 07-12-2012 04:16 PM

Yes, make sure you test the entire range of motion as well. Move it and make sure the voltage continues to go up, if it dips down randomly or cuts out, you may need a new TPS.

tman6500 07-13-2012 10:20 AM

Closed its .45 wot 3.97

KiLLeR2001 07-13-2012 10:28 AM

WOT seems a little low, it should be around 4.45 - 4.55v.

Here's a good article: KA24DE : Checking TPS and adjusting idle : Nissan Articles

tman6500 07-13-2012 11:58 AM

set the wot to 4.5 and then closed was .97 now its set to .48 wot 4.04 best i could get it could it be bad it like a month old? It helped but still going it. Going up hill makes it bogs worse.

tman6500 07-13-2012 02:44 PM

Going to hook up a fuel pressure gauge next.

Nizzan4u2nv 07-13-2012 02:53 PM

Try swapping in a working ECU.

tman6500 07-21-2012 08:57 AM

Well i gave up and a shop now has had it for about about 5 days no luck.

emack240StL 07-25-2012 01:26 PM

Any word from the shop yet? I think mine is having the same problem that you are describing. I was happening earlier this year, I switched out the mass airflow meter, and the spark plugs and the problem almost completely went away, but now its getting worse again. I'm goning to start testing the advice from this feed, and see what works, but let me know what you learn from the shop.

tman6500 07-25-2012 04:30 PM

They still have it cant find anything yet

tman6500 07-26-2012 01:32 PM

Shop called and they ran out of ideas. Great lol now what

emack240StL 07-27-2012 02:13 PM

I've been doing my research, I havn't had time to start palying with it yet, but one thing I have found that seems to give the same symptoms as we are experienceing is the EGR unit. It can go faulty, or get clogged and cause hessitations. The EGR and EGRV can be cleaned replaced or removed to fix the problem. Like i said i havnt tested it yet but you might want to try it, seems like its getting good results...

tman6500 07-30-2012 02:44 PM

Checked the egr valve you can get your hand under it and push up on it and if the engine starts to idle bad (which mine did) then the egr valve is working.

Butcher240sx 07-30-2012 04:01 PM

Did you ever try another ecu?

tman6500 07-31-2012 09:39 AM

Couldnt get my hands on one to just swap. Might have to just buy one

OutlawLui 07-31-2012 10:02 AM

Same thing with mine , it was a bad maf plug connection.

Thank god for safe mode

So i cut it off and did this
http://i278.photobucket.com/albums/k...k/smallmaf.jpg

Like a baws. now it runs perfect

tman6500 08-01-2012 01:23 PM

Ya I was thinking about the same thing but didnt because i thought it would have given a code. I will have to steal or idea and give it a try thanks for your help.

emack240StL 08-01-2012 02:20 PM

I just noticed last night that the air temp sensor on the intake just past the filter was missing the wires/pug that connects to the plug that goes to the ecu. i have the part on order and i'll let you know if that fixes my problem any. if you have and aftermarket intake u might want to make sure that yours isn't like this too. im thinking that when my maf went bad, the shop might have accidently knocked the wires of the sensor and it got lost somewhere and thats why only half of the problem got fixed the first time around in my case

tman6500 08-09-2012 02:30 PM

Well bought a used ECU and no luck. Also hooked the MAF connecter right to the MAF nothing drove the car around don't see any difference. Wow this is crazy there most just be a loose wire or half broken wire sending a bad signal or something.

Butcher240sx 08-09-2012 02:37 PM

Start de looming the harness. Wiggle test the connectors with a ohm meter to check for bad connections. I'd start with the Maf and work back. There is a gremelin in there somewhere.

falling angel 08-10-2012 09:06 PM

One thing I haven't seen you check, the tps voltage. Does it go up smoothly all the way from closed to full open? I've had this problem, right at quarter throttle the voltage dropped then came back near 3/4 throttle.

tman6500 08-12-2012 07:46 AM

Set the tps to .48 4.04 with the new on didnt see anything jumping in volts.

CraftHell 08-14-2012 12:50 PM

Im having the same exact issue wtf..

tman by any chance is yours manual or auto?

tman6500 08-14-2012 03:40 PM

My car is manual


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