240sx bogging

[KiLLeR2001]

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]

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

[tman6500]

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]

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

[tman6500]

The tps is set to .73 closed 4.23 wot

[KiLLeR2001]

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

[tman6500]

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

[KiLLeR2001]

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]

Closed its .45 wot 3.97

[KiLLeR2001]

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]

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]

Going to hook up a fuel pressure gauge next.

[Nizzan4u2nv]

Try swapping in a working ECU.

[tman6500]

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

[emack240StL]

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]

They still have it cant find anything yet

[tman6500]

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

[emack240StL]

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]

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]

Did you ever try another ecu?

[tman6500]

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

[OutlawLui]

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

Thank god for safe mode

So i cut it off and did this


Like a baws. now it runs perfect

[tman6500]

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]

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]

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]

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]

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]

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

[CraftHell]

Im having the same exact issue wtf..

tman by any chance is yours manual or auto?

[tman6500]

My car is manual