I have a weird issue with my ignition timing under partial throttle.
I datalogged my timing using the EU and noticed that my timing was dropping down to anywhere between 0 degrees and 10 degrees advance anywhere between 7-60% throttle. I have no codes that would point to a problem with ignition timing. This problems is also intermittent. When this condition is present and I try and accelerate, the motor just makes a sputtering sound and a serious lack of power is evident. I'm leaning towards a bad CPS sensor (maybe both). I have no codes for them and I was wondering if anyone else had any suggestions. I dont have hard start problems. I dont have a knock sensor code. What could cause such a huge retard in timing considering that its happening anywhere from 7% to 60% throttle. I dont think its a misfire because acceleration, even though it's horribly slow, is smooth.

 

Does it only happen with the eu in place? If so, are you comfortable enough with wiring yet to leave the patch harness in place and jump the injector & coil pins, I'd like to rule out the patch harness, in particular one of the ground wires on it, or just interference in general. Also, I kept searching for you and dug up the rest of my wiring stuff, so I can tell you which wires on the 4-cylinder eu harness were used for inj&coil's 5 & 6 in & out.

Otherwise I would think it was a tps or maf issue ftr.

 

i agree. trouble shoot section by section. first rule out whether its the EU's doing or something else. test sensors with a voltmeter to verify its still putting out the correct voltages it should be.

 

I replaced the TPS and calibrated it and now it seems to run a lot stronger under light to moderate throttle. The only thing is I had to set the TPS to around 0.2V at idle.

I have this thread in the 4th gen section concerning ignition timing at idle with big cams.
http://forums.maxima.org/4th-generat...on-timing.html

Just wanted the input of those who are running aftermarket cams.

 

I have since removed the patch harness and wired everything directly to the main harness but I'm still getting the sputtering at part throttle and ignition timing dropping to low teens. I ruled out the KS buy hooking it up to the firewall. I swapped the 3.0 coils in place of the 3.5 to see if it was a coil issue and the symptoms are still present. The only thing left is MAF or ECM.
Could a dying maf present those symptoms without throwing a code or going into fail safe mode? The worst part is that the problem is intermittent and no codes...very frustrating.

 

It seems the ABS/TCS unit was responsible for the retarded timing. I had P1320 because of the EU (no resistors ) and the TCS module didnt like that and lit up the SLIP/TCS OFF lights. I unplugged the module all together and the car runs fine now. Any thoughts as to why it would cut fuel, indirectly retarding timing? I confirmed by plugging in the TCS unit again and the symptoms returned immediately. So right now I have no ABS/TCS but car runs fine

 

I wonder if that could also be a problem too... I have th ABS light on, on my swap. No EU thou. I'll found out today.. good info