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Curious and annoying RB25DE Misfire / Lumpy running

749 views 3 replies 1 participant last post by  Nemeth72 
#1 · (Edited)
Hi All,

Had my GTS25 for 12 years now, serviced every year (only does 2-3K per year if lucky). Last service as well as the usual, i had the Timing belt and water pump replaced. All had been fine up until 2 weeks ago when i was on drive. I was cruising up the motorway at a steady 70mph (yes really...lol) when all of sudden it started to sound more like a old Subaru than a Skyline and i had some power loss.

I pulled off of the motorway and had a look but i couldn't see anything obvious. Managed to get it home and hit the forums. Suspecting a normal misfire type issue and starting with the obvious, i checked and tested the coil packs, they seemed ok, tested the coil pack loom, that was ok. Looked at the spark plugs (replaced last service and NGK platinum), they seemed ok, gap was ok, no fouling. cleaned up the coil packs and connection etc, sounded a little better, but still rough.

Then as a belt and bracers measure, bought and fitted new benchmark coilpacks and new plugs. Same result.

After more digging on forums i got a USB Consult cable and ECUtalk. Managed to log the data and checked against known voltages / ranges at idle and 2500rpm. The readings for the TPS, Timing, Air Flow, O2 sensor, injector pulse and AAC all seem to be within normal.

Car does run a bit better, however, it is still lumpy / missing.

So far i've

Replaced coils
Replaced Plugs
Tested coilpack loom continuity, all ok (original loom so may get a wiring specialist harness)
Tested ignition amplifier continuity, all ok
Cleaned connections for TPS, AAC, CAS, AFM, coilpack loom
Cleaned all earthing points
Checked the obvious pipes and hoses for leaks, none visible to the eye (maybe smoke test needed)
Ran ECUtalk and checked the voltages / ranges. These seem ok, but i am not an expert.

Car is going into garage tomorrow to get a compression check and to have the injectors tested.

Anyone out there have any other thoughts on what could potentially cause this issue?

** update **

Forgot to add, no fault codes showing*
 
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#3 ·
Well, had the car in the garage today. They ran a compression test and all cylinders are at 150+. Narrowed down the misfire to cylinder 3 and suspected a duff injector. This was confirmed by moving the injector from cylinder 3 to cylinder 1 and sure enough the misfire followed.

Now the only issue is getting hold of an injector for an RB25DE 🙈

The mechanic sent me a pic of the numbers on the injector, but they are extremely difficult to make out. Had a trawl through forums, they appear to be 270cc and possibly used in the 200sx and 300zx.
Has anyone any ideas on the actual part number?

Any help appreciated
 

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#4 ·
Ok, so for those interested. I did a crap load of cross referencing injector part numbers and found that injectors from the SR20DE (200sx etc) and the VG30DE (300zx i believe series 2) fit. I actually stumbled on some refurbed from a Almera GTi of all things (SR20DE). The one on the left is the old one from my car, the refurbed one from the Almera on the right. Specs are the same. Best of all, no Skyline Tax 🤣 just £75 for 4. Car sounds like a Skyline again and seems to run as before. Need to go on a longer run and give it a proper road test.

Nissan part number 16600-10Y00
0F655418 (i believe is a JECS part number)
 

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