Ok so I don't usually post on these sites, that being said i have literally spent weeks googling and reading over every single forum post or just anything i can find to check to get this this running right again...

Its a D16Z6 which was in a 95 Civic until i totaled the body and put the Z6 into my 98 civic chassis that used to have a Y8 in it but had a blown head gasket.
Its running a p28 in OBD1. (the ecu that came with this motor in the 95)
Jumper harness on the ECU and Distributor to be able to use stock 98 harness and the Z6 dizzy that came on the motor.
I am getting NO CODES.
I got the motor swapped in and ended up having to take a 2yr vacation and wasnt able to get it 100% running at the time (this was 4 years go now) Now that i have had time to do it ive been trying to get this thing running to no avail. It starts and idles ok but when the throttle is pressed it bogs down at 3000-3500 rpm and if i dont let off the throttle plate it will stall out and die. I can rev it up a few times but eventually it will bog out at all rpm's, as in it wont rev up at all what-so-ever past idle without choking and stalling.
I was thinking TPS but after testing the original one i didnt see any problems but happened to have a new TPS here so i put it on and calibrated it to .49v closed throttle and 4.5v WOT.
Replaced fuel filter, coil (old one went bad randomly), it has fresh fuel in the tank, cap rotor and plugs were new when i did the swap but i have a new set of plugs and wires coming. I checked ALL grounds under the hood and cleaned the terminals/scraped the paint under them.
I have checked mechanical and ignition timing with a timing light and it is spot on 16* at 750ish idle. I pulled the exhaust and checked for blockages and didnt find anything. It has a new O2 sensor before the cat also. I tested the MAP sensor and TPS sensor at the ecu and was getting correct numbers there.
The car idles nice and rev's nice when i can get it to rev but when it does rev eventually it will bog like fuel is being cut or something by the ecu.
So today i went to autozone and rented a fuel pressure regulator and got 72-74psi measuring from the top of the filter, it should be like 38-42 or something like that, could crazy high fuel pressure be causing these issues and what could cause way high fuel pressure like that? I have the FPR from the Y8 that doesnt quite fit but i have modified it to fit on the Z6 rail and i get the same reading. Could it be something in the return line causing low flow and spiking the rail pressure? or do i have 2 bad FPR's? I just dont get it, i have been working on this for weeks and cant seem to figure it out, anyone have any ideas?

I am not an ASE Certified mechanic but i am not a complete noob either. Any ideas on what to try or check would be greatly appreciated.
Thanks in advance
-Frank

 

It's not going to run right with the fuel pressure that high. The fuel pressure regulator works by bleeding excess fuel back to the tank, so if the line is blocked that will happen. Test by removing the gas cap then disconnect the return line from the regulator and try to blow air into the tank through the return line. This path should be quite free since there are no valves or anything in the line.

Also it is possible to have a blockage between the pressure test point on the fuel filter and the fuel rail. This will cause high pressure at the filter, yet the engine starves for gas. The copper washers on the banjo fittings can be wrong or distorted and blocking the fuel path.

Make sure you're checking timing with the test jumper in place (the CEL should be on steady during the test to tell you the jumper is in place but no codes). A very common reason to not rev over 3500 is having the cam timing wrong. But in that case it will stay running reasonably smooth at lower rpm.

The coil is prone to blow out from firing into an open circuit (crank or run with a spark wire disconnected) so don't do that. Always unplug the low voltage wires at the distributor before cranking with the spark plugs out for a compression test (which would be a good idea here to baseline the engine). Do cylinder drop tests by disconnecting the fuel injectors one at a time, not the spark plugs.

 

Yeah i was thinking the same thing too so i checked the fuel hose going from filter top to rail and replaced the crush washers on the rail with OEM honda crush washers and the fuel filter i just put on came with new crush washers for there too so i dont think that is the problem. I blew air through the return into the tank and everything seemed fine to me...

I did check the ignition timing with the jumper connected as per the FSM and ive reset the ecu prolly 20 times since tinkering around with it.

This whole thing has me stumped as to what could be causing such high fuel pressure...

 

If you are using the intake manifold from the Z6 instead of the Y8, then you will need to be using the fuel feed line between the fuel filter and the rail from the '95 Civic chassis instead of the one in the '98 Chassis. Fuel pressure is high because it is not getting into the rail except for a trickle... re-install the original Z6 FPR and swap the fuel feed lines. Make sure you use the proper washers on both sides of the banjo fitting at the rail... the larger spiked washer goes toward the fuel pulse dampener that bolts on to the end of the inlet side of the fuel rail. Good chance this solves your issues.

 

Yeah, i m using the Z6 intake manifold so i am using the Z6 fuel line from filter to rail and the Z6 FPR, I just double checked the crush washers on the filter and rail and they are perfect. The big spikey one is between the Pulsation Damper and the rail banjo and i put a new OEM Honda crush washer between the banjo and the rail itself but its still doing the same thing. 72-74psi and it bogs down or hesitates with some throttle. This thing is completly undrivable in the shape its in now... I can get it to move but it bucks and jerks around and shakes and i can barely get out of 1st gear into second, this motor before the swap pulled HARD as hell and now i can barely get it to rev up past idle.

 

Did you make sure that the large opening banjo fitting is on the fuel rail end and facing the pulse dampener ?

 

I just went out and checked, the large opening side has the larger spikey washer held on by the pulsation damper. Today wasas I was trying to troubleshoot this cars issue I noticed if I prime the fuel pump twice it shoots up to 60ish psi then drops pressure fast, it should hold pressure for a while shouldn't it? Could it be a bad check valve in the pump or a leaking injector? That pressure as well as being stupid high shouldn't just drop that fast should it?

 

Opps posted in the wrong thread by mistake.