SR20 Forum banner
1 - 20 of 37 Posts

·
rollin 4 deep with JoeD
Joined
·
1,410 Posts
Discussion Starter · #1 · (Edited)
Car runs much better! (WAS: Car runs like CRAP)

Here's the deal. I've recently swapped in a JDM high port motor in to my 96 200sx.

I've used the turbo pressure tester, and eliminated all of my leaks between the turbo and throttle body.

The car fires right up, no problem. Fast idle is great, and slowly comes down to warm idle, ~950rpm. MAF voltage is at approximately 1mV. I have set the timing to 13 degrees, base idle to 950, and Aermotive adjustable FPR to 4 bar with the vacuum line disconnected. This is all with the JWT ECU 4 bar 50lb MSD program.

So at this point the warm idle is great and solid, until I give it gas. The car revs up just fine, but when it comes back down to the idle rpm (around 950-1050) it starts to sputter, hesitate and often stalls.

It seems like the motor is just LOADING up on fuel when I give it gas, and it then has to much fuel at idle. WTF?! I HAVE a consult here at my house, so if any of you know what I should be doing with this thing to help me diagnose my problem, please let me know. The only codes registered are EGR temp sensor and EGR solenoid valve (I am running the JDM intake manifold). I DO have the EGR solenoid plugged in, with the vacuum lines going no where, should I unplug this?

Any help is greatly appreciated. BTW, I know my 02 sensor is fubared, but this shouldn't matter that much. In case it does, I have a new one on order.

Thanks,
 

·
Registered
Joined
·
329 Posts
Both of my EGR solenoids I plugged back in even with the JDM manifold but they never threw a CEL. Did you readjust your throttle position sensor when you swapped the motor? This sounds similar to a problem I had after the swap, it would rip up to redline but them stumble and hesitate when it went back down to idle. TPS voltage should be .44-.55 volts at idle and 4.5 at WOT.
 

·
BTCC VE Power
Joined
·
5,151 Posts
make sure you dont have an injector leaking... you can check by, priming the fuel pump by turn the key in the on position and turn it off... wait a little to let the fuel depressurize, it should but itll do it pretty fast if theres a leak.
 

·
Banned
Joined
·
2,587 Posts
I would check the TPS first, Frank. Make sure you check it with the car off/key in the on position.
 

·
rollin 4 deep with JoeD
Joined
·
1,410 Posts
Discussion Starter · #11 ·
Thanks for the tips guys.

TPS is at .46 at Idle, and timing at 13 degrees is within spec.

I also changed my Coolant Temp Sensor, but I still have the same problem.

The car passes the Consults Power Balance test on every cylinder though.

I will be playing with the MAF and injectors tonight. Seems like a problem with of thse bastards.

Thanks!
 

·
rollin 4 deep with JoeD
Joined
·
1,410 Posts
Discussion Starter · #13 · (Edited)
97SE-R C2 said:
It seems that everyone has trouble with the 4 bar 50lb program. I remember hearing that 50lber's are more sensitive to pressure change. I know Brent (Coach) ditch the 4bar 50lb for the same reason your experiencing. Good luck :(
Yeah I've shared my consult readings with JWT, and they also told me they are trying to pull the 50lb 4 bar program off the shelf.

But I JUST DONT GET IT. I mean this is the exact same ECU and injectors that worked FINE on my old motor (low port). The only difference is I now have a high port, and I had my injectors cleaned and flowed (they are all within 2% of each other and flow and atomize perfectly).

It just doesn't seem logical to me. My car used to hold an idle quite well with the 4 bar 50 lb program, so there HAS TO BE something else I am missing.

I will keep troubleshooting, and only resort to the 72lb injectors and program as a last measure. sigh...
 

·
Premium Member
Joined
·
5,202 Posts
cnynracer1 said:
Yeah I've shared my consult readings with JWT, and they also told me they are trying to pull the 50lb 4 bar program off the shelf.

But I JUST DONT GET IT. I mean this is the exact same ECU and injectors that worked FINE on my old motor (low port). The only difference is I now have a high port, and I had my injectors cleaned and flowed (they are all within 2% of each other and flow and atomize perfectly).

It just doesn't seem logical to me. My car used to hold an idle quite well with the 4 bar 50 lb program, so there HAS TO BE something else I am missing.

I will keep troubleshooting, and only resort to the 72lb injectors and program as a last measure. sigh...
Frank, I'll lend you my wideband tomarrow and you can see what its doing when you experiance the problem.

Mike
 

·
70/30 Racing
Joined
·
11,372 Posts
injector leaking is not a problem with the MSDs, they are top feed.

you plugged up the hose going to the PCV valve to see if that was giving you problems?

when my O2 sensor wires got broken, my car did something very similiar to this, but only when cold, on C16.

did you gander at your plugs frank?
 

·
rollin 4 deep with JoeD
Joined
·
1,410 Posts
Discussion Starter · #16 ·
HotshtSR20 said:
injector leaking is not a problem with the MSDs, they are top feed.

you plugged up the hose going to the PCV valve to see if that was giving you problems?
Hose going to the PCV? Why would this be causing problems? It is a brand new PCV valve and the system is connected. Do you mean the breather filter on the valve cover? I still have this on temporarily, but I used to drive the car like this sometimes and it was OK.

HotshtSR20 said:
when my O2 sensor wires got broken, my car did something very similiar to this, but only when cold, on C16.

did you gander at your plugs frank?
O2 sensor is FRIED now, especially after they built the downpipe for it yesterday and killed it with more silicone. On the consult earlier this week, O2 sensor would not draw a code, now it does. But same result.

I did check out the plugs, expecting them to be black and coated with fuel, but to my surprise, they were quite dry and white. The electrode strap was whitish. Cylinder #2 plug did look a little rich, but only on one side.

I'll be replacing the O2 tonight and let you know how it goes.

BTW, Rockwood here has been tech support throughout the motor swap project, I bet his cell phone bill will have one page of my phone number, lol.
 

·
70/30 Racing
Joined
·
11,372 Posts
cnynracer1 said:
Hose going to the PCV? Why would this be causing problems? It is a brand new PCV valve and the system is connected. Do you mean the breather filter on the valve cover? I still have this on temporarily, but I used to drive the car like this sometimes and it was OK.

BTW, Rockwood here has been tech support throughout the motor swap project, I bet his cell phone bill will have one page of my phone number, lol.
you never know. new parts can be defective too meng. just plug the hose going to it, and test it meng.

yeah, more like 2 pages, mierda.
 

·
Registered
Joined
·
30 Posts
OMG!!! I pity you. I have the exact same problem as you and I have been trying to solve it for about 8 months unsuccessfully on my S14 Silvia. It will start fine and as long as I do not touch the throttle it will run fine for a long time. As soon as I hit the gas, it accelerates perfectly, but will not idle properly for crap and in about 10 seconds the plugs are fouled. It all happened after I changed cams, valvesprings, head gasket and turbo manifold. Never got it to run right after that. TPS voltage is 0.45 closed and about 4.3 open. MAF is reading 1.3-1.6V at "idle". I am using tomei 555cc injectors and a Z32 MAF and a Power FC which all worked fine before the above mentioned upgrades.

If anyone figures this one out, i will personally refer to them as God.

cnynracer1 said:
Here's the deal. I've recently swapped in a JDM high port motor in to my 96 200sx.

I've used the turbo pressure tester, and eliminated all of my leaks between the turbo and throttle body.

The car fires right up, no problem. Fast idle is great, and slowly comes down to warm idle, ~950rpm. MAF voltage is at approximately 1mV. I have set the timing to 13 degrees, base idle to 950, and Aermotive adjustable FPR to 4 bar with the vacuum line disconnected. This is all with the JWT ECU 4 bar 50lb MSD program.

So at this point the warm idle is great and solid, until I give it gas. The car revs up just fine, but when it comes back down to the idle rpm (around 950-1050) it starts to sputter, hesitate and often stalls.

It seems like the motor is just LOADING up on fuel when I give it gas, and it then has to much fuel at idle. WTF?! I HAVE a consult here at my house, so if any of you know what I should be doing with this thing to help me diagnose my problem, please let me know. The only codes registered are EGR temp sensor and EGR solenoid valve (I am running the JDM intake manifold). I DO have the EGR solenoid plugged in, with the vacuum lines going no where, should I unplug this?

Any help is greatly appreciated. BTW, I know my 02 sensor is fubared, but this shouldn't matter that much. In case it does, I have a new one on order.

Thanks,
 

·
Premium Member
Joined
·
3,409 Posts
You might want to try lowering your fuel pressure see if it makes a difference. Since your injectors are flowing more since cleaning. Might want to bump the timing up to 15 might run cleaner.
 
1 - 20 of 37 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top