EuroDat

Congrats on the quick fix. You are lucky to have a Bosch 0 322 514 127 Fiat relay handy. These dual units are getting harder to find since Bosch stopped making them around 2020. Something I found years ago. If you are looking for a Bosch 0 322 514 120, try Beck Arnley 203-0053. It's a Bosch relay, but they just took it out of the Bosch box and put in a Beck Arnley box. It is also hard to find, but the more options increase your chances of finding one.

Mine will hold more than 1.5bar pressure for a least 2 weeks. It took me a while to get it that far, but replacing the check valve on the fuel pump was my eureka moment.

When you change multiple things and something goes wrong it will always be a challenge with fault finding. If this problem wasn't there when I started, I would be changing things back one at a time to try and locate the cause of the problem. The question is: Can you change back or are you past the point of return? You already swapped the TIU and tried other coils with no improvement so the problem doesn't seem to be related to those units. I'm interested in the Volvo IACV thingy. I probably should read through the other thread, but I'm feeling a little lazy so I'll just ask. How does the Volvo system know where the idle is? The timing light seems to indicate no issue with spark, but could it be interfering with the ECU and fuel management? I don't think your problem is fuel delivery. You can have a blockage in the injectors and that will cause fuel starvation. If it's a blockage in the fuel system, then it will be after the fuel guage.

It's hard to believe a 125amp fuse blows by swapping the reluctor wires, but there must be some relation if that is the only change you made before the fuse blow. I had similar problems with not revving past 2500rpm. Mine would rev cleanly to 2500rpm and then sputter around 2500rpm. It wasn't a hunt, more erratic running. I'm doing this from memory, since it is some years back. Like you noticed, I accidently swapped the green and red wires on the HEI terminals when I quickly fittrd it for testing. When I changed them back, the promlem was gone. FUEL: I don't think you have problems with fuel flow. If that was the case, you would loose fuel pressure. Pressure and fuel are very much related. You can have pressure with a restricted line, but when the injectors open for more fuel, the supply (flow) can't keep up and the pressure will drop. If your pressure is stable, then your fuel delivery is good. These old ECU's don't read fuel pressure. Bosch (and Hitachi) solved this by creating a constant pressure differential over the injector tip and using a Fuel Pressure Regulator with vacuum assist. Remember fuel pressure will follow the to vacuum in the manifold so I think it will vary a little with this problem. If you add a vacuum gauge next to the fuel gauge, they should work in unison. IGNITION: If you are using a 12volt coil then the ballast is not helping. It will reduce the voltage to the coil and cranking voltage is already reduce due to the high current draw from the starter. That was the whole reason for the lower voltage coils. During starting they would bypass the resistor and the coil would get battery voltage to help starting. Do you know the history of the Volvo coil? Could it be failing? Do you have another coil to test and see if that reacts differently? I'm still trying to get my head around your 125amp fuse blowing. It can't be going through the HEI. Nothing in the HEI can handle such high current draw. It must be a high labouring starter drawing so much current, but what could be creating such a resistance/load on the starter? Pre-ignition or timing firing way to early. You would think it would cause backfire. The motor is turning? I hope I'm helping and not adding to your problems. Chas

Shouldn't you be looking for thr PR4052? The PR124 is the aftermarket for the 280Z 74-77. Both are 2.5bar spec.

Hi Zed Head, The wires were switched accidently during testing. I'll take a new photo and update the Tech sheet. Funny thing, looking through my photos and I can't find that photo anywher. Must have deleted it. Here is where my dyslexie kick in and it all when south for a moment..... I did start on the correct side and after running the engine which would not rev over 2500rpm, I corrected it and back on track.

Hi, I accidently swithed the wires when I quickly connected the TIU for a photo. I noticed it a year or two later, but funny no one else has made a note of it until now. The wiring for the HEI is correct. Trust me, when I was first testing it would not rev over 2500rpm. That was because I connected the two red - green wires on the TIU backwards Working from left to right, looking at the TIU with the wires coming out from under the TIU. B - Black wire: HEI Ground. Very important. BW - Black/White wire: HEI B (battery) BW - Black/White wire: Not used. L - Blue wire: HEI C (Coil trigger "-") R - Red wire: HEI W (reluctor input) G - Green wire: HEI G (reluctor input) You can set up the HEI next to the coil if you want. Just disconnect all the wires from the TIU. You can then use the power to the coil to HEI B and the HEI C terminal can connect to the coil negative. The blue wire on the coil negative will still need to be connected for the tacho to function. Make sure you ground the HEI well. PS: Agree with you on the terminal layout in the electrical schema. I try to find a terminal that is not full. Say it has 7 wires in a 8 pin plug, then I can figure out which direction I need to look at it.

I'm getting the same error. Probably the EU authorities "protecting" us from learning too much.....

I havd been following this thread and a little suprised no one has commented yet. It is an interesting mod you're attempting and I hope it delivers the results you are looking for. Great detail and plenty of photos so others can follow. Slowly buy surely these parts (AAR for example) are getting harder to find and a possibld update to later more available parts is more than welcome.

Yes the plated version is the 240Z version. The other one is a 280Z. I think there are 3 basic models of the S30 horns and probably more finer differences in the 3. The left horn in you photo is the later 280Z version. The single metal strip bolts to the bumper shock. The right horn is from the 240Z. There is also a variant on the 240Z version, I think it came in the 260Z and maybe the later 240Z. The have the same mounting bolt pattern as the 240Z, but the bracket connects to a single bolt on the back of the horn like the 280Z. See photo.

Let see, an engine in another Z, a couple of 280ZX turbo motors and a V07 crank lying around. You know they have therapy for that kind of behavior🤣 No real experience with either option, but I'm leaning towards the turbo camp. Turbo with an aftermarket MS ecu or similar to aid in tuning. I'm also quite happy to sit on the fence and watch this develop.

Ill have a look for the old one. I had one original still in good condition to copy from. If I can find it I can get some copies done, but it will take a couple of weeks because our machinist is on holiday, and we "untrained" engineers are not allowed to play in his workshop😁

Mine dit the same thing, and I DON'T drive it hard. Ended up making them out of HDPE from work. They have been in the car since 2014. The instructions look exactly like the ones I have in my map and I ordered them from MSA.

The variable resistor on the coolant temp circuit will richen your mixture. These old analog systems are known to lean out over time. Probably not what you are looking for to pas your emissions test, but it's fun to play with and I think it's the only form of tuning you have on these old efi systems even if it's just restoring original settings.

Hi Paul, I would bypass the resistor or bridge it over if you are looking for the original look. I bridged mine in the photos. The condensor should not be an issue, it's more a noise supressor than anything else. Like Zed Head said. It could be a heat issue. You could try and mount the HEI module with the heat sink plate next to the coil. Then you have the shortest circuit to the coil and good grounds in the area. Once you know it works, then you can more to fitting the module in the original position. The HEI will get hot, and the flame thrower in no exception, but heat is not a good thing in these units. The high resistance the resisitor is generating will not let the HEI function as it was designed. Not helping. Btw: My TIU was overheating when failing. Like yours it would leave me stranded on the side of the road. A quick spray with very cold circuit cleaner would bring it back to life almost instantly. A passenger (my wife) could spray it and the engine would come back on after a second or two.