robs junkyard 92 vr-4

[rob5625]

well here she is, junkyard found 92 vr-4. knew very little about these cars besides the fact i rarely ever see them on the road and that was just about all i needed to pull the trigger.


now ill be the first to admit i aint no good at the whole takin pics and notes and build thread thing, normally cause im too busy drinkin beers and turnin wrenches but at least i got some before and after shots

before


after


still lots of nooks n crannies to clean and more rusty bolts to replace (and when i say replace i mean attempt to remove, snap bolt, drill out and re-tap lol) but its comming along nicely.

i did get the original motor running but it wasnt healthy, further inspection found spun #1 and #2 rod bearings and the crank was toast. found rez selling parts on craigslist then it was time to get dirty. wasnt without challenges swapping in the partially complete 2g motor while using a lot of the 1g parts but all in all not too bad. big thanks to rez for hooking me up with the tools and engine.

[rob5625]

now im a metal fabricator by trade, have access to some pretty badass equiptment so let me know what you need for random welding/materials/custom fab ect. for example i found identical cracks in the same spot on the front manis of both engines. im thinking its not a coincidence so if you ever have your oem mani out take a look, see the crack, buy a 6 pack and head down to my shop. about a 10 min repair.


same goes for this kinda thing where i found a crossthreaded and broken starter housing, 15 min repair.


got some ideas bouncing around my head like a cover for the harness connectors on the intake mani and custom plug wire covers for the front valve cover (could put your name on it if you really wanted) just let me know what your thinking and we'll fart around with it.


oh ya, the original 1g block is just sitting in the corner at the shop if you need anything. crank and 2 rods are toast, rear valve cover im keeping as the 2g valve cover doesnt bolt up proper to my 1g timing cover and i plan on fixing that one day. bank 1 exhaust cam sprocket is also missing along with other randoms i had to swap onto the new motor

[TT Eric]

Nice!!

Eric

[rob5625]

I knew they would be small but I was still a little surprised. Heres a side by side with the turbo I run on the sentra. Thank god theres two of them! lol

[TT Eric]

Yeah I agree, the snails are small, it's hard to believe I do the power I do with only this x2:



Eric

[rob5625]

Now im gonna need some help to get her running right. It missfires under heavy load at low rpms. Definate lack of power and bliping the throttle at idle will cause it to backfire. It actually will cruise around ok but with a constant backfire during decel. Ive already gone through many of the basics but using my timing light on the plug wires I think I found the problem, not sure if its the cause or a side effect of another problem.

Only #1 & #3 have consistant steady spark, all other cylinders have spark but they are inconsistantly firing with random patterns and misses. Cylinders on matching coils dont have the same spark pattern either.
Now I dug up my notes from when I had the original motor running and found the exact same results on the same cylinders which tells me the problem must be with something I reused with the new motor.

Parts reused were ecu, ptu, plug wires, cas sensor, intake, tb, injectors, and turbos.
Ptu I checked out per fsm and seemed within spec, cas sensor can be eliminated if I just wire in the 2g cam/crank sensors (I left them installed but im using the 1g cas). Still have to give the ecu a visual inspection as well.
What else should I concentrate on that might cause intermittent and random spark output on some but not all cylinders?

[rez604]

welcome to the forum dude, you got that engine in there quick.

pull the ecu and replace the caps even if they look good. if you remember rob from the meet (white 91 vr4), had stumbling issues and we figured out in the end it was the injector drivers in his ecu even we replaced the caps. see if you can find a good spare to test with.

as for the ignition system
-you may have installed the CAS backwards (180deg out)
-replace your wires with a new oem set
-replace your coils with a new set (and hotwire them if you want)
-replace your ptu with new one if you can afford it in your budget
-you should be running copper sparkplugs bkr6e or bcp6es. gap them at 32"thous. do not run 7 heat range. plugs should be replaced every ~20ishkkm

as always I'm available for help if you need it, just throw me a text. good to see your car running!

PS get a data logger asap, they are a god send for these cars

[rob5625]

Yah definately need a data logger. Guess ive been spoiled for too long with obdII cars, I monitor/log all ecu parameters wirelessly with my phone in the sentra. Idle and timing adjustments, cylinder power testing, fuel pump, everything done with my phone lol

Fairly certain I swapped the cas properly as I still had the timing covers off at the time but I think what ill try first is wiring in the new motors cam/crank sensors temporarily and see what happens. Got an spare wideband I should install too. A bit of a mystery problem right now but considering the age and condition of some of these original parts I cant say im surprised.

[rob5625]

so i wired in the 2g cam/crank sensors and nothing changed, gonna strike the cas sensor off the list for now. not 100% sure i ohm'd out the original ptu properly so its still high on the suspect list.

pulled the ecu today a found out a few things like its been pulled before and capasitors replaced. dunno when but either they started leaking again or the last person just did a shit messy job. no stink but definate goop situation going on. under a large pile of solder i found the tiny little ceramic capasitor c3, quite possible it was damaged by the last person and the lead (or pad) is completly missing on one end and im not sure it was functioning correctly the way it was. one more trip to the electronics store and it'll be ready for a retest.

now heres the interesting part...
appears at least one of the previous owners was some kinda baller cause its a mine's ecu. as far as i can tell its still the original north american ecu that i guess was shipped off to japan for the "chipping" cant find much info besides it was stupid expensive back in the day and most likely erased rev/speed limiters and remapped fuel tables for some extra ponies. not sure if its a good thing or not yet cause it adds another variable but maybe i can email mine's with the serial and program numbers to make sure its not a custom setup for different injectors or boost level. im a little surprised cause this car has so far been all stock, right down to the boost solenoid restrictor.

[rez604]

that ECU is beyond repair. just grab another one - either a 9966, 9965 or 9963. i guarantee you the microcontrollers on that thing are toast not to mention the other components.

66 is fed spec - uses 2 O2 sensors and doesn't care about emissions crap being removed
65 is cali spec - uses 4 O2 sensors and will throw CEL if you mess with emissions equipement
63 is fed spec 1993 when they switched over to cam/crank sensor - using this with the 91-92 CAS will give you a bit extra timing up top (which is actually sought after by some)

what you have there is a 9964 ecu, which is the JDM ecu, mapped for 96 octane (100RON). that's the same ecu as in my car. except that one has had it's injector drivers replaced by mines for leaner mapping up top. that's it, nothing else - no rev limit removers, no speed limit removers, nothing. the base 64 ecu has a higher timing map than the USDM ecus, our gas cannot handle it.

i've used all those ECMs and did some research back in the day when i was trying to fight my knock.

[rob5625]

Yah I just figured out it was a jdm ecu last night. The car is still using the fed spec harness and oem o2 sensor locations so I guess that means this ecu is only using the front bank exhaust for closed loop fuel trimming correct? Not the best scenario id think.

The ecu cleaned up real nice, replaced the standard 3 capasitors plus the messed up surface mount ceramic capasitor, got real excited about it all but the car ended up running just as bad as before. Re tested coils, ptu, plug wires and nothin Is out of spec. Also rotated the lower rad hose properly cause it was popping the shifter right out of 2nd,4th, and reverse lol

Thanks for the info on the mine's ecu, I couldn't find shit about It or what was modified on them. Now I wont feel so bad about getting rid of it.

[rob5625]

So I got a replacement ecu installed now (thanks eric) and shes running a lot better. I suspect it maybe due to it now reading both banks of o2 sensors? Anyways its still lacking power and will break up under high load/high rpm. Now getting code 41 for injectors every time I let it run for a while and this code never came up with the jdm ecu once.

So guess ill ohm check the injectors next, also found a schematic for a diy datalogging cable im gonna try... cause im cheap lol

[rob5625]

So resistance is an consistent 2.4ohms for all injectors, all injectors are getting proper voltage and ground continuity is good to the ecu. Now the redneck stethoscope test revealed #5 injector is not operating at all, confirmed by unplugging it at idle.

Im probably going to swap in the other ecu and see if #5 is still dead, then maybe swap #5 and #3 injectors and see if the problem follows injector or stays with the cylinder.

When swapping injectors from old motor to this one I numbered their original location and moved the rear banks to the front cause I had a suspicion that original #6 wasnt spraying proper and wanted easier access to it. Cant quite see the number I wrote on #5 but im fairly certain I did a strait back to front swap so that would make this the original #6

[rez604]

the JDM ecu uses the rear O2 sensor for trims (at the ecu level anyways, physically it is located after the downpipe merger in JDM cars)

while you're in there check the resistance of the injector wire harness (continuity). these cars are notorious for having the injector wire harness crack/split somewhere and make people chase their own tails with the 41 CEL. especially the rear harness that basically rests on the rear valve cover getting heat cycled constantly.

and if you haven't already, get evoscan. it is a god send for these cars. $57 for the cable + $20 for the software, countless hours of headaches saved. I can't tell you how many peoples problems i've solved within 10mins of doing a log. honestly i would have payed even $500 for that setup knowing how useful it is now.

[rob5625]

Did end up getting more testing done today. All harnesses check out good. Was also able to definately confirm that the injector from #6 (now in #5) is not working at all just like I originally suspected. Dropped it off at nw injector and they are goin to call me in the morning. They say "sometimes" an injector can be dirty enough to stick open or closed and if that is the case they can get it working again. If It is the case then ill pull the rest and have them serviced/balanced just like I should have done in the first place lol. Had no idea we had local drop off same day injector service for reasonable prices ($35/injector) but I guess the diesel scene around here has some perks for us gas huffers as well.

Ill have to note, although this motor hasnt been running proper I had no idea it was permanently running on 5 cylinders, still smooth as silk if you compared it to my sentra running one cylinder down... and I know cause its happened... quite a few times