duowing

Alright guys I really need help, I've tried so many things I just don't know where to go with this anymore. This thing gets work done then just sits because I can't seem to make progress. Quick recap.

Motor is from my old 280ZXT which used to run really good and only had 99k miles on it. Converted it to Z31 ECU/MAF setup and still ran great. Pulled the engine put a P90 solid lifter head on, new oil pump, timing chain, tensioner, new gaskets, N42 egr-less manifold, relocated PCV valve, etc. Walbro 255lph pump, or possibly an ebay rip off pump(not sure) aftermarket rising rate FPR, Pallnet fuel rail, etc.

Anyway this all went into my 76' 280Z and I've never gotten it to run right, the car will start and run, and idle just not very well. Cold starts aren't easy, once warm the car will fire immediately. I have low vacuum like 15inHG of vaccum at idle and the needle doesn't sit steady it waivers. I've checked timing and it's spot on. I'm running an 88' Z31 NA ECU with Nistune. Air regulator works as it should, all the injectors are firing, the injectors aren't clogged and all have a very similar unobstructed spray pattern. Just put in new plugs, new O2 sensor, new PCV valve. I have a Blaster II coil and a remanned IC unit that's been in the car for a while. I may still have some vacuum leaks and that could be the problem I fixed alot of vaccum leaks, but still made no difference. Thought the Intake Manifold gasket may be leaking, pulled the manifolds and redid that.

Idle seems to be a little lean, the car will rev up and drive, I'm not sure if it will reliably drive though. It's sporting an N/A "A" cam. I don't know if this will affect idle much on the turbo motor? I wouldn't think it would be that drastic. Also my fuel pressure gauge on the rail, the needle flicks wildly when running, but doesn't vibrate or shake during the priming sequence. I removed the factory dampener from the car, but I don't know if this will cause what I'm seeing. For a while before I even had the aftermarket FPR or even put in a different pump the needle would stay really steady, then eventually it just started fluttering wildly. At one point on the current setup for some reason the needle decided to sit really smooth in the gauge, and I've never seen it do that again. Could this be an indication of a wiring issue with the pump? The Fuel Pump relay seems to definitely be getting warm/hot I don't know if this is normal or not.

At one point when everything was reinstalled and I first got the car running way back when, I could not set the timing properly no matter what I did. The Oil pump had to be pulled and re aligned, now I can set the timing properly, but could the oil pump still be off a tooth causing an ignition issue?

Z31 ECU only gives codes for Fuel Pump, Fuel Temp Sensor, and Knock sensor, the fuel pump code will always be there since it doesn't get wired up exactly the way the Z31 has it.

As for vacuum leaks at one point I removed the whole intake boot and pressure tested that separately along with the J-pipe and found no leaks there. I then capped off the intake at the turbo, left the J-pipe on and then capped off my exhaust at my downpipe and used an air tank to pressurize my motor to look for leaks, I found several leaks here and there that I fixed. Eventually I got to the point where I could pressurize the system and get it up to 5 psi, I didn't risk going over that, but it would still bleed off. This is why I pulled the manifolds thinking there was a problem there.

I just need some advice on where to go next. Maybe it's my wiring, or maybe I need to start replacing more of the ignition system?

NismoPick

Sup dude! I've been wondering if you scrapped this project...

Have you considered a bad ecu tune? Also, I know I've stated this before, but I have never been able to get an L28ET to idle properly w/ an N42 intake.

I would check and re-check your loaded tune from Nistune... or maybe the ecu has developed a problem?

Also check the tps (I ripped mine apart to see the contact points), and the MAF (make sure the wire is clean & completing the burn off cycle... which it's not doing on it's own w/o the 280zx speed sensor).

duowing

There's been times where I've wanted to scrap this project... I sold my 87' Z31T back in November and I'm really aching to drive a Z again.

Anyway I've considered a bad ECU, but I was using these ECUs I have with no Issues in my Z31T a while back. I also have two MAF's I've tried which have managed to provide the same results. The thing has a hard time on cold starts, but once warm will start up with no issues, it seems to rev up with little to no issue, but coming down from that it seems to vary sometimes it's smooth, sometimes it acts like it wants to die.

As I mentioned should the Fuel Pump Relay be getting warm-hot while running? I think I also need to adjust down my FRP, I'm running 35-closer to 40psi at idle right now. I finished getting everything back together after doing the manifold gasket and I started the car up with the timing way off since I had pulled the distributor. It was running really bad but got running, set the timing, turned the car off and tightened down the distributor. After restarting it the car started up and for a couple minutes sounded perfect. It was idling fairly smooth, revving up and dropping off really smoothly, I looked at my vacuum gauge and it was showing 19inHG of vacuum, but I also noticed that my gauge started acting up like it was broken it was just sitting at weird numbers, etc. Then a little later it started working correctly again. After that short burst of running perfect the car went back to what it normally does.

I think my next test is to take the old 280Z fuel pump, put the hose in a gas can of fresh gas, and hook it directly to the battery to see if I get any different results, in fuel pressure fluctuations, idle, etc. Would be a good way to tell me if there's something with my fuel lines, or wiring, maybe even the gas that's in there is a little too old.

http://www.youtube.com/watch?v=E5Zu9xJ45M0

http://www.youtube.com/watch?v=Fzs9gQaHoQk

Here are some videos I took a while back before I found a bunch of vacuum leaks. I thought for sure with how many vacuum leaks I found that it had to be the problem, yet it still didn't improve that much. Like I said about the oil pump/distributor timing, does that sound like that could be off if I'm able to set the timing properly with my timing light? I maybe need to recheck the valve adjustments again as well. Also like I mentioned I don't know if the N/A "A" cam would make any difference with a turbo motor. I am running the air regulator. Also I may need to readjust the throttle body stopper, that could be potentially be an issue. I remember having idle problems on the ZXT when I removed the AAC, VCV, etc and by adjusting the throttle body stop screw I was able to get it to idle pretty decently.

duowing

Well I went and adjusted down the fuel pressure on my regulator and adjusted the throttle stop screw. Idle has been brought down from about 900 to 750ish. This also gave me a little more vacuum, closer to 17inHG now. Just doing these little things the car seems to be idling smoother as well as a smoother rev up/fall off. I actually feel like it's getting closer. As far as the TPS goes I didn't really mess with it, but I do know that in Nistune when connected through USB there's a diagnostics window that will show the status of the TPS whether it's open or closed, and it seems to operate properly registering as being idle/off idle when it should be. It also does make a difference if I disconnect the TPS when the car is running.

duowing

One more thing I thought of, I currently have no air filter on the end of my MAF. Could this contribute to slightly lower vaccum as there would be essentially no restriction on the end of the intake piping?

duowing

Another quick question. I need to find out where exactly, but my fuel tank has a leak in it. I'm thinking that I either didn't put the sending unit back in correctly or the sending unit seal is shot. The tank leaks above a certain level. I want to say about halfway. I also noticed the little bit I've driven it I stopped real quick and then when I looked under I saw fuel on the ground. So it's leaking somewhere near the front of the tank. Do any of you have any explanations on how to make sure I put the sending unit back in right, and also what to use if the seal is infact shot? Also could a leak in the tank cause an issue with running. Maybe not building the right pressure or something?

NismoPick

I got nothin on that one... other than my S30 had a leaky return line hose right at the tank. The hose was toast, but it was some crazy special size on one side, and another size on the other, so I welded up a coupler and used two hoses.

Gotta get under there and trace where the leak is coming from.

What's up w/ the ecu pics on FB?

duowing

Yeah the leak is probably my next priority. The ECU pics were my two different Nistune ECUs that I have. The one I never completely finished putting together, mainly drilling out the diagnostics screw hole to place the USB connector for the ECU. The one I just put together is an 88 N/A ECU so I could map it out for the Turbo motor and still use the larger O2 sensor. I kinda want to get ahold of another 84-85 ECU and see if it runs the car any differently. Anyway I put the 88 in and hooked it up to my laptop, played around with the maps, adjusted the timing/idle/fuel maps to match the 87' Z31 since that's a little closer to the L28 since it still had the T3. Also still adjusted the idle timing from 15 to 20* before TDC and this actually helped my idle more, this brought idle speed up a bit more which again increased my vacuum reading. I'm getting about 17-18inHG of vacuum at idle as opposed to what it used to be. The fact that it's using the O2 sensor has actually greatly improved idle at operating temp. Rev up and fall off is way better with the changed maps/idle timing. The idle sound even with only having a downpipe off the turbo is a lot quieter/smoother now.

Although I'm thinking there's still an issue either with a vaccum leak or the fuel pressure because it still has a hard time starting and still idles poorly when cold. Once the O2 kicks in and everything gets to Operating Temp is when the car starts doing good. The fact that I'm getting really close to proper vacuum when warm but still just a little low is telling me it's gotta be a vacuum leak or something. Even the waver of the needle on my vaccum gauge has greatly been toned down when warm and all the sensors seem to be working to try and get the best idle.

ECU isn't throwing me any unusual codes. The typical Fuel Pump, Fuel Temp, and Knock codes. The TPS does work. I can hear a change in engine sound when I disconnect it. Plus I can actually watch the timing change with my timing light when I disconnect the TPS as the ECU now things it's off idle.

Time to plug off the exhaust/intake again, and start pressurizing the motor again and keep looking for leaks. It was still bleeding off last time I checked, but there were some things that I didn't think would be an issue. I think the hoses that connect to my home depot ball valve/air regulator tester might be leaking a little. Need to replace the hose from the motor to the PCV valve. Maybe I should take the plug out where the old PCV used to be and teflon tape it and reinstall that too.

duowing

By the way have you ever had to replace that coupler from the Turbo to J-pipe? Can you just get another piece of rubber hose and throw it on there and just reuse that metal shield/clamp piece? The one I have on there still seems to be in decent condition. Although the clamp on the turbo side of it seemed to be a little loose.

NismoPick

I'm running an IC on my 280ZXT. On my other L28ET's, all the couplers were in good shape. If one needed to be replaced, it would be less of a hassle to fab up a better j-pipe from some mandrel bends.

duowing

I figured you weren't using the stock thing. I don't plan to stick with it. I'm planning to pipe an intercooler once this thing gets running right. You still have some sort of coupler to connect the piping to the turbo though, right?

Another thing I was wondering is in your car, I'm assuming you use an aftermarket FPR as well. Does yours hold pressure? Mine seems to just drop off after the priming sequence. I could see that possibly being an issue in making the car a little harder to start from cold. As a test I one time crimped the line before the FPR and real quick bumped the key then turned it off to see if it would hold pressure between the pump and the FPR and there was no problem there. So it has to be the FPR. I've seen other people say that alot of the aftermarket FPRs don't seem to hold pressure well off very well.

Also I still haven't messed with hooking up the old fuel pump yet. Do you have a damper in your system? I'm just wondering if the needle vibrating like that is normal.

I was trying to remove the NPT plug I put in the stock N42 PCV hole, but that didn't go too well. Might have to bust out the vice grips. I used that brush on pipe thread sealer, it's probably fine, but I'm not sure. Right now I'm just trying to find anything that might be loose or leaking. It was odd to see that coupler to the turbo seemed kind of loose, I'm pretty sure I remember tightening that before.

NismoPick

EDIT... yeah, my cheap ebay fpr doesn't hold pressure when the pump stops, so I just let the fuel pump prime before starting.

oh woops... I was thinking about the j-pipe to throttle body coupler... that one is the "hard to replace" one. The turbo out is just a standard silicone coupler. I was using a FEDERAL blue hose until I found a thinner one at a junk yard (I think from a Volvo or Saab?).

JSM

Nismo, why did you have problems w/ using the N42 and turbo? Did you mean turbo and Z31 setup or just turbo by itself?

duowing

Went to mess with my car today a bit to see if I could track down any more vacuum leaks or anything. My car is holding pressure really well, but what is annoying is it's leaking what looks like around the exhaust gasket right above the number 1 and number 6 runners. Hopefully I can just tighten the nuts on the studs a bit more. I also don't have the original giant washers, I found some larger washers and doubled them up. Other than this it seems like nothing on the intake side is leaking. It's doing better than the last time I checked. Seems like removing my home depot ball valve, and tightening that clamp from the turbo outlet to j-pipe seemed to help. Pressure was bleeding off very slowly from the couple of exhaust leaks. So next up is to do what I keep putting off, testing how the car runs with the old pump hooked up to see if there's any wiring issues/issues with the old fuel lines. Also and looking for possibly anymore electrical issues that could be causing problems.

On another note, I noticed if I flip the lights on so I can get the dash lights, there's a harness connector right under the steering wheel, I think it runs into that same switch, but right there the wires/connector are getting pretty warm/hot. Is there something I can take apart and clean? I'm just wondering if there's other little electrical issues like this in the old harness that can possibly cause interference/issues with my ZXT harness?

Oh I also meant to add that my cold starts have been alot better, I do still have to crank a bit and it doesn't just catch and start, kinda of sputters to life a bit. I'm thinking that's do to the fact that the fuel system doesn't seem to hold pressure, but once it comes to life it seems good, although last time I ran it, the car would rev fine up to 3500 then hit a wall. Once warm it seemed good to go.

duowing

I fixed what I think may have been one more small vaccum leak. Adjusted the throttle body stop screw to be open a little more. Messed around with Nistune a little. Car still had a rough start up cold, but once it started it seemed to be doing pretty good, seemed to be revving freely. Nistune was showing O2 voltage bouncing around as it should be, everything seemed to be really smooth especially when warm. The car was revving up super fast and on the drop off it would come down and not sound like it was going to die, would just rev down and settle.

Like I said I then went and adjusted the throttle body stop screw to be open a little more which brought my idle up a bit. It was pretty low, readjusted the TPS so hopefully that should help throttle response a bit. This time on cold it didn't seem to be stopping at 3500RPM. Although if I slowly revved it up or held it near 2000 I was noticing a miss right around there, but it would rev past there fine.

Also found out that there is an O-ring needed for the fuel sending unit, I don't remember having an o-ring when reinstalling the sending unit into my tank. Ordered a new O-ring so that should take care of my tank leak once I get that. I'm thinking this thing may finally be hitting the road real soon to take it's maiden voyage.

NismoPick

w00t! 'Bout time!

duowing

Oh quick thing I thought of, what did you do for the carbon canister? I removed mine so I just have the metal line that comes from the back sitting open in the engine bay. Did you leave yours, or remove it? Can I just leave that metal line sitting open, or throw a little filter on it or something?

NismoPick

AutoZone has the lil cone filters for cold air intake vacuum & accessory ports. Clamp that on it. Technically it's the fuel tank evap line... One day I plan to reinstall the canister or at least tie it in to an oil catch can type unit.

Six_Shooter

It was kinda hard to follow when you made the changes to the set-up.

Did you add the FPR, Head, timing chain, and the rest of the parts in that list, and had it run fine in the donor car, or did you add/change these parts when you swapped it into this car?

If these parts were added or changed during the swap, then there is no base line to judge how the engine is running. Also if these changes were made during the swap and it was not ran this way in a way that seemed well, I would look at the cam timing, valve lash and everything else that goes along with the mechanicals of the engine related to cam timing to make sure it is all set correctly.

What is the FPR in question?

duowing

Looks like my car is leaking at either the fuel pump feed or the return line right at the tank. I'll have to mess with that, but like I suspected my sending unit had no O-ring on it. So that's now taken care of.

Also I was curious on two things, are the speedo cables the same for the automatic, and manual Z transmissions? I don't ever think I've heard of anyone having to change the cable. I picked one up from RockAuto for $9 vs. MSA selling it for $90.

Oh and what are your opinions on exhaust? Are there kits that will fit right where the MSA downpipe ends, or should I just take it to a shop and have them fab one up? Also what do you guys recommend as far as exhaust goes?

Six_Shooter

Speedo cables are the same.

I made my own exhaust, so I can't comment on any of the readily available ones.

NismoPick

Yeah, just take it to an exhaust shop... expect $200-$300. The S30 is really easy to fab...

https://www.zdriver.com/forums/showt...t=30516&page=2

duowing

My gas leak fun continues! Found out the hose was pretty much shot from the tank to the pump. Well replaced that and took a nice gasoline shower while doing it. So I think I'm done, but no! My tank is leaking around the barb that goes from the tank to the pump. Eventually I'm going to drop this tank and take it back to the place that cleaned/conditioned it since it's a lifetime warranty, but in the meantime. Time for some J-B Stick, or J-B weld. Either way this should help me. This also makes me wonder if this would be part of my running issue, with a leak right there, it'd be pulling fuel and air right along into my lines.

duowing

Finally drove the thing home. Could not bleed the clutch at all, so drove it without a clutch. The JB Waterweld seems to have done it's job quite well. Yanked the dash out, finished painting my floor pans. I'm waiting on a speedometer cable as the one from rockauto doesn't even work. New clutch master, slave, and hydraulic line are on the way.

When driving it, the car felt kinda slow, but it's hard to say for sure once I have the ability to use the clutch properly I'll have to take it out for a good actual drive and see how it feels. Last I checked my exhaust gasket seemed to be leaking around the 1st and 6th ports which annoys me. Any advice on this? I ran seafoam through it and there was no smoke coming out from around those ports, so maybe torquing the nuts around those ports a little more helped.

Also Nismo how did you mount the Z31 ECU in the 280Z? I see I can almost mount it up the way it sat in the 280ZXT, but it only seems to line up with one bolt hole and it does stick out a little far. I'll mess around with it though.

EDIT: I kinda see what you did, you put it above the little bracket on the driver's side. Looks like there's a bolt hole I could use there. I found that picture in your S30ZT Thread. Looks pretty good, gonna mess with doing that to mine.

duowing

Well I can now mount my ECU like you did Nismo. I had to cut out that upper bracket though that was used to originally hold the old 280Z EFI relays. Once that was removed the ECU sits in there so nicely, just like in the 280ZX. I cleaned up my floor pans a bit, got my HIDs from the HybridZ group buy installed, still haven't wired them yet. Waiting on some other parts as well.

I fixed my cracked center console and repainted it so it looks pretty decent now, not perfect, but that's alright. I also decided to get wild and see if I could manage to do some body work. I went ahead and fiberglassed those cutouts that you see when you remove the 280Z rear bumper as well as those 2 holes where the bumper shocks came through the rear of the car. Then I'm gonna work on using some body filler and seeing what I can do. I feel confident that I can get it to look pretty good. Part of me wants to have the car's paint and body work professionally done, but at the same time I feel like I'm doing everything else I'd rather try my hand and see what I can do with the body.