Gday everyone, been a while since I've posted. Been working a bit here and there on my NA Zed. I've been having some more issues with what sounded like a misfire. Also issues with a fuel line that had a dodgy clamp that kept rattling loose after a week or two of driving and leaking fuel (I started carrying a screwdriver and tightening it daily to prevent it leaking) As I've got what appears to be a vacuum leak somewhere still as well I've decided to try to replace hoses where I can, clamps that aren't any good anymore and any other somewhat not too expensive work at the same time. I diagnosed the misfire as a faulty connector or wire to a coil pack it seems possibly as wiggling the connector causes a misfire I think. I decided plenum pull was a good idea (in hindsight for my sanity I'm not sure it was) I've labelled every bolt and what not but holy hell there is a lot of hoses. The under plenum ones and the throttle body coolant lines and egr tubes my god.... Anyway whilst the plenum is off I wanted to show some pics. Especially of the "paper" gasket which looks and feel more like melted plastic, guessing this car has not had a plenum pull recently. I also want to know whilst its off what can i get rid of on the zed that I don't need, what deletes are recommended? It's possible some have already been done in a very half ass way as there are a few vacuum lines disconnected and blocked. I want to make this thing tidier and run a bit better or at least eliminate common problems. I thought there was a list of things to do on the tech section but I can't seem to find it. It's possible this 1990 zed has never had bits replaced and if the odometer is anything to go by the car has 300 000 km on it. I'm going to assume it's still the original injectors and coil packs. Pics to follow soon
https://www.youtube.com/watch?v=-9YRmixQlQk http://tech.aus300zx.com/Rear_Water_Hoses/NytWolf_waterhose_replacement.html
Under plenum and throttle body water bypass. Not needed in this country as our winters are very mild. Will make your life so much easier for future maintenance. Also think about maybe deleting some of the hardlines everywhere. It's actually quite easy to just run a long piece of a fuel hose to and from the fuel rail instead of through the hard lines and all those clamps. Doing so will bring the clamp count down to 4 instead of the 8 or so in the stock system. Same can be said with a lot of the vacuum lines.
Winter? xD I live in Darwin, our coldest temperature on record I believe is like 10.4 degrees in 1942..! Water bypass's it is! Also that'd be an awesome idea, never thought about deleting the hard lines.
Deletes FTW. Why not also get rid of the EGR, PRVR, AIVs while you're at it? Plenty of guides on these deletes in tech section. Highly recommended. Cleans up the rats nest of vacuum lines and they all do absolutely nothing especially with these cars being over 25 years old now.
Will do! Thanks for that, anything to make this thing nicer, easier to work on and easier to remove this plenum too next time. The amount of under plenum hoses is ridiculous. Question, is it worth getting my injectors tested somewhere local and if they are dodgy replace them too? Also is a water pump / timing belt service much easier with the upper plenum off? Or something that can be done a bit later?
Chances are if you don't know the history for the car, the insulators on the ends of the injectors are old and cracked. Getting them flow tested and recapped would certainly improve how it runs and the fuel efficiency. All the servicing that you need to do to the engine is easier with plenum off. Water pump is easy once all the front cam gear covers and things come off but the timing belt is a big job so decide if you want to do it all at once.
So I've started the bypass, all under plenum hoses and hard lines removed per the video/article above. I have all the connectors there and I haven't cut or drilled them out yet. Removed the PCV valves too, I've decided to delete as much as I can. I've been having some intermittent cooling issues when running the air-conditioning, temps would get up to 95. I can now see why, the coolant lines are filled with thick watery sludge. When the car is back on the road it's going to get some shop work done and I'll get them to flush the cooling system too i think, it looks nasty. Decided that I'll replace all accessible hoses too whilst plenum is off as there are lots aging and many cracked now. Also going to try do the O2 sensors as they are both faulty it seems.
I've had a look at the procedure for PCV removal, I may end up at this stage putting them back on for now because I don't know if I have the time, energy or money to change the set up that drastically. I may just stick with all the coolant deletes for now as well and leave the EGR intact because I don't see how I'm going to do that delete without the engine out!
While you have the plenum off. Remove & replace the two hoses that go to the heater core & any other coolant hoses you can see. Closely inspect the metal coolant pipes at the rear of the engine for corrosion. Pipes corrode from the inside, so an external inspection won't cut it. Check the condition of wiring & connectors, pay attention to earth connections. It may be worthwhile considering removing the lower plenum & changing the detonation sensor & sub harness........
To delete the PCV valves you remove the passenger side exhaust cam cover, remove the presses in fittings and then plug the holes either with a press in type plug or by drilling and tapping to take a pipe plug. Then use a threaded plug in each of the holes in the plenum. The easiest way to clean up the EGR is to cut the tubes off toward the back of the motor. You can cap them, or even leave them as the valve itself shouldnt open once the solenoid is disconnected.
