Ok so I'll start by trying to describe the symptoms I'm having. Rough idle when at operating temp (85ish degrees) feels down on power. Sometimes it feels like it pulls ok, other times pretty damn gutless. Slight rattle on when letting off the throttle (only last about a second) I had all these problems with my old engine, it had low comp on two cylinders. Put in a rebuilt engine about 1700kms ago, and nothing has changed. Doesn't run any better than with the old engine. So on the positive side I guess that rules out the engine itself what I've done so far; new injector connectors, injectors cleaned while swapping upper plenum onto new engine (the new engine was complete from lower plenum to sump, all bolt on's and upper plenum etc all swapped over from old engine) series 2 ptu, new o2's, probably more things that I can't think of right now. Only aftermarket bits are a gfb underdrive crank pulley and temp gauge. It's really got me stumped and it's drivin me bloody nuts! i don't know of any zed mechanics in my area, but I'm in Wollongong this week for tafe, so i'm thinking of taking it to bezerkly automotive to get it checked out. But before swapping out the old engine I took it to Craig hall in Canberra as well as tuggeranong auto electrics, Craig hall said they couldn't figure it out, and the auto electrician said it was running fine! When I got the car early last year it had a slight miss but still pulled hard and strong. Nowdays my tired old r31 goes harder any advice on what to look into would be much appreciated. Cheers, John
what type/brand of O2s did u use? i had a similiar fault, fitted new o2s to find even though they said for z32s they were no good, so i ended up getting bosche o2s and problem fixed
If you are ruling out engine & sometimes it's okay, other times it's gutless and there's a rattle; then that leaves drivetrain... So, clutch slipping under heavy load.
No mate. I think I would notice the clutch slipping. It's definatley not. The rattle is there everytime I take my foot off the throttle. When I said I can rule out the engine itself, I meant ruling out a worn engine. As in low comp etc.
x 2. Try to either buy or borrow the following: AFM ECU Did u inspect your exhaust? No chance a cat/resonator/muffler has collapsed? Hence the rattle? Get the fuel filter replaced Check flow from the fuel pump (Most tuners can check this) Injectors flow tested? Checked TPS? - Check with Conzult if u can? Also check ur cas bolts are done up properly as the timing can wonder if they are loose. Checked timing lately? Defo check the exhaust tho...
Injectors have been cleaned, not flow tested as the guy said he couldn't do it. Tps is set to .46v I set the timing to 15btdc. The cas bolts are tight. Haven't inspected the exhaust or fuel pressure/flow. Fuel filter is new (changed it last week) anyone in Canberra have a spare ecu and/or afm?
Plugs have been recently replaced with Ngk iridiums (or platinums, not sure) dampner and fpr I'm not sure if I can test?
Stock front pipes on the exhaust? A wreck I bought recently had one of the cats totally collapsed. Bits of ceramic were rattling around not to mention sapping plenty of power as flow was severely impaired. With the dampener and FPR, borrowing a known good set would rule them out...
Yeh pretty sure the exhaust is stock atleast pre cat. I'll check out the guts of the cats and try to source afm, ecu, dampner and fpr to test. The other day when I replaced the fuel filter, I pulled the fuel pump relay, ran the car till it stalled, cranked it over for 10-20 seconds to make sure there was no more fuel, took the fuel cap off. When I pulled of the fuel line (engine side of the filter) there was still a crazy amount of pressure. Sprayed fuel everywhere! Copped a heap right in the face is that normal? Or could point to something being wrong with my fuel system?
rattle The rattle could be your intake CAM gears at the front of the engine. When they go bad they either leak oil or develop a rattle on deceleration. To test this, disconnect the VTC solenoids at the back on the engine and if the rattle goes away on deceleration, you have found your problem.
I don't know how all the vct etc works. But what's the chances that the intake cam gears would be stuffing up on both of the engines? The rebuilt motor came with vct solenoids attached.
Its not the solenoids.... Its the gears at the front that make the noise. Did the new motor come with its own set of CAM gears, or did you reuse the old ones from your old engine? You disconnect the solenoids because that prevents the VTC system from engaging, which causes the rattle inside the CAM gear.
