Noz

Oh, I have actually read through your issues, here: http://www.300zx.co.uk/forums/showthread.php?178668-Detonation-issues-have-I-found-the-answer&p=1839135#post1839135 You've covered quite a lot of the points I suggested in the previous post, nice one :) Right. How do you know it's actually detonating? As far as I'm aware, you've not monitored knock using suitable equipment (det cans and aftermarket knock analyser), and you're simply going on the OEM knock sensor. They're not very clever components, so if I may suggest you take it to a reputable dyno operator (he doesn't need to be a Zed specialist) and ask him to monitor knock levels with the appropriate equipment. A Zed dropping into safety boost does not mean the engine is knocking. If you can't take it to a dyno, one thing you can do yourself is reduce the base timing by 10° and see if it still drops into safety boost. Not a definitive test, mind. Are you running a standard OEM ECU?

I've not read everything about your issues (not the crack smoking, the detonation), so apologies in advance if I repeat something as the follwing is just a general checklist. If you're detonating, then it will be due to one or more the following issues: Spark plug rating too hot Incorrect base timing Faulty CAS Fuel delivery issue (eg. weak pump, blocked injectors) Low grade fuel Carbon build up on piston crowns Compression too high (skimmed heads, NA engine) Lowered fuel RON due to oil ingestion Poorly mapped ECU (timing set too advanced; fuelling set too lean) Too much boost Intake charge temps too high Go through the above list. Discount what doesn't apply. Investigate what does. Get it on a dyno and monitor AFR & knock.

Well, I wouldn't put it that way exactly! MAF voltage output is not linear. It shares a polynomial relationship with the mass of air flowing through it. 4.16v is about right for 10.5psi* at 6k RPM under full load. I know this due to the thousands of log files I have recorded whilst mapping many Zeds both on the road and on the dyno. (Just in case anyone suggest I RTFM.... I already did ;)) *Edit: on stock turbos

Fair do's. If that's the case then it sounds like a different car :)

Check injectors with a long screwdriver held to your ear. Check plugs are sparking (ground them on the plenum). Swap coilpacks around to identify if it's coils or loom. Check connection on the PTU. Clean all connectors. Diagnostic check. Get it to a specialist. I think Lee Dent is closest to you.

I was being diplomatic. I know the reason why the first guy got rid, after it was for sale on Gumtree. All the best with it, as long as you're happy with it, that's all that counts :thumbup1:

Speak to Mark about it. There are reasons why it's been punted on by different people in quick succession.

If you dint mind me asking, did you buy it to keep or sell on?

Oh dear. I could tell you the likely reasons for that.... Best off giving Mark (Automodz) a call. Or subscribe so you can receive PMs :D Good luck!

Hello & welcome to the club. I know of the car, had a good look round it. It's been moved on quite a bit.

15%

:kiss:

^^This is me right now. Look what you've done :wack:

Pushing the pointy probes into the back of the connector. It doesn't matter, it's not important :D

I'll hopefully make it to Japfest. I've not been to Pod much this year :(

Douglas Adams was wrong. The answer is 15.

Hello & welcome :)

The manuals are a good set of instructions for a brand new completely stock 300ZX, but when it comes to a car that is 20+ years old and more than likely different to factory spec, they are simply a guideline. EF & EC-38 Idle timing 15°±2°. Nope, 15°±0°. It is imperative base timing is set at 15°. If you can't get it exactly on the 15° mark, make sure it sits just to the right, ie less than 15° and slightly retarded. Never higher, not on these cars, not in this country. AAC valve 15 - 40% (NA); 15 - 35% (Turbo). Nope, 15%. See post 6. Every Zed that needs the idle setting up I set it to 15%. I could set it to any %, but I always, without fail, set it to 15% for the specified target idle RPM. They idle perfectly like this, it is not a brand new component. No need to unplug the AAC valve, disrupting a 20+ year old wiring loom is a bad idea.

:thumbup: You may have a vacuum leak, but that is separate from IACV setup. Perform a boost leak test. Then after any issues are resolved, recheck the IACV value & operation :)

Ahh. The mulitmeter was a birthday present! Lol, happy birthday!

Yeah, the probes are pointed for that exact purpose.

Try to refrain from driving it hard when you have a misfire. If it's a fuel delivery issue, "driving through" the problem is the worst thing you can do.

:blink: No. It doesn't mean that in the slightest. Read post 6 :laugh: 30% at warm idle means the IACV is working too hard to maintain the designated idle speed. I don't care what Z32wiki says, that is plain incorrect in practice. Unless you enjoy revs dropping low at every junction :wack: 15% 15% 15% In case there is any uncertainty.... 15%

Grim.

Just checking.... You didn't measure the impedance with the connector still in place did you?