protege 5 no fuel after engine swap

OK I am at a loss, the fuel pump will not kick on. No prepressure build or when cranking.
car does crank.
things i have check:

all fuses with a test light.
pulled codes none.
checked fuel relay
replaced with one from another car that works, no change, put mine in second car works fine.
can manually activated. (took the top off the relay and can turn it on by grounding it out or physically pressing the solenoid.)
fuel pressure when manually activated relay 60psi at rail.
good fuel volume when manually activated
battery charged.
fuel gauge read 3/4
all dash lights are on
check engine light is on while key is on
no other signs of failure of any thing
pulled back seat to lightly tap on top of pump.(hoping something would flicker or give a sign)

checked fuel relay with another no change
i am lucky i have a second car to compare too, and swap parts.
only thing I have not check is ECU
the car ran great untill threw a rod 265,000 miles

any ideas as to what is causing this. the fuel relay looks like this

a b c
-- -- --
--
d

those represent the blades in the relay
power is in (a) and (c) when the key is on if ground is applied to (d) the relay clicks over and power is sent to (b) turning the pump on.

the control that grounds out fin (d) is not working dose anybody know what and where this is controlled?
at the ECU? I was thinking if this has a fuel pressure switch that is stuck or failed from sitting. is there a pressure sensor that tells the pump when to kick on and off?
or any other ideas as to what might be the cause?


Thanks in advance

Where'd the engine come from? What was the application that you removed it from?

"D" goes to pin 80 on the ECU, and only grounds when cranking or car being on.

http://mazdaspd.com/mspinout1.htm

check FP on that.

Also you can check continuity from pin D to pin 80 and check for near 0 ohms. Can also check from the DLC connector that's between the drivers side strut mount and drivers side hood bracket. Or you could just ground out pin 80 after disconnecting ECU connector or grounding out DLC pin.

http://www.mazdaspd.com/manual_files/01-14.pdf

Check page 01-14-18 for the DLC pinout.

As stated above it looks like you need to check the control side of your relay. For some reason it seems like your ecu is not grounding the control side - or the ground is not making it all the way to the fuel pump relay.

Wiring Diagram is going to be your friend in this situation. Need to figure out why the control circuit of the fuel pump relay is not functioning.

To me it sounds like a connector is loose or not connected from the engine swap.

Let's say that continuity exists from pin D to ECU pin 80, is there any way to test ECU to say 100% fried? What would be other symptoms of this? In my case, it looks like everything else works, CMP and CKP sensor read correct resistance across the sensor (the two sensors that provide the engine input to the ECU giving the OK to send fuel and spark). I haven't been able to check for spark just yet, but know that fuel system is exactly in the same condition as OP.

jwforeman said:

Let's say that continuity exists from pin D to ECU pin 80, is there any way to test ECU to say 100% fried? What would be other symptoms of this? In my case, it looks like everything else works, CMP and CKP sensor read correct resistance across the sensor (the two sensors that provide the engine input to the ECU giving the OK to send fuel and spark). I haven't been able to check for spark just yet, but know that fuel system is exactly in the same condition as OP.

Click to expand...

So there is continuity on the entire wire, but the ecu is not pulling pin 80 to ground? If I am reading right, that is what is happening in your case?

I don't know if you can condemn the ECU right away - you would have to see what it takes for the ecu to provide the ground on Pin 80(like the checks the ecu makes before turning on the fuel pump). You may need an advanced scan tool that can command the fuel pump on and off and see if the signal goes through the ecu and is Pin 80 Grounded at that point when manually commanded with the scan tool. I don't know the exact sensors and checks used before turning on the fuel pumps in these cars, but you have to make sure all of that is working first. Though if you have a scan tool capable of commanding the fuel pump on and off - that would probably be the best and easiest place to start - to see if pin 80 even gets a ground when the fuel pump is commanded on.

Correct, that is the case.

One other abnormality is there's a ground wire getting smoking hot. According to the 2002 Protg Wiring Diagram Supplement, this wire coming from chassis ground routes through wiring harness and joins another wire that is also attached to ground on the engine block, the other end of that wire says it goes to the neutral switch. Someone correct me if I'm wrong but any issues across that circuit wouldn't even allow the car to crank when trying to start. That being that case, I was trying to troubleshoot the fuel issue then this.

And speaking of fuel issue, anyone out there an ECU expert, perhaps knowing exactly what signals the ECU must see before ECU decides to send fuel? Those scanners sure don't come cheap and hopefully someone can come up with a list or required signals. I thought just CKP but of course I could be wrong.

May want to check that the engine ground in question has a clean and tight connection. Based on the wire getting super hot and the fact that you just changed this engine makes me think the ground may not be good. Seems like there maybe high resistance on that ground if the wire is getting hot.

This is a common issue on the 2nd gen rx7, 1 of the ground points on the engine gets corroded and loose over time, which causes all kinds of issues(one of the main grounds for the ecu). Once the ground is cleaned up, all is good usually.