Suspected fuel delivery problem after engine rebuild... (1 Viewer)

[pilotuku]

I have a '94 and just finished an engine/tranny rebuild and today we tried to fire her up. Initially, I had no click, won't turn and won't start but there's power. I check for spark, nothing. There was no check engine light so I was told to check ECU harness. I unplugged and plug the connectors and still have no CEL.

I then switched and used a spare ECU (from an LX450) and I had check engine light and now I have spark.
Tried turning her over, it now turns and starts but dies immediately. I tried to help by spraying starting fluid, it turns and starts until the starting fluid is gone and then it stalls again. I tried to unplug and plug the ECU connectors and then tried starting it again.. It started without the help of starting fluid for about 10 seconds and then it died again.

At this point I'm thinking I have fuel delivery issues because it only starts with the help of starting fluid.

A few things I checked to narrow it down:
fuel pump - jumped B+ and FP on diagnostic box - good
MAF - plugged and good
fuel pump relay - checked and good
fuel pressure regulator - removed and cover the whole with my thumb and had someone started it - fuel squirted out - good
EFI relay - checked and good
fusible link - new and good
no alarm system to immobilize it
there's spark

My original computer box was working before the engine swap. Fuel injectors were working before engine swap.

Question:

How do I test if there is signal going to the injectors?
How do I know if the ECU box is good?
Although the plugs went in and all markings are the same, is the '94 ECU and '97 LX ECU the same? I'm no real scientist and this is the biggest job i did on my 80. So I am an expert youtube mechanic... Lol...

I can only work on her on weekends and I'm running out of time and I have a planned trip to California to Yellowstone with my kids on the 23rd and been planning this for a year.... If not, we're taking the mini van - LOL...

Thank you for your time...

John

 

[ceylonfj40nut]

Not trying to be a smart@ass here. The FSM has all the diagnostics laid out.

 

[jonheld]

I had no click, won't turn and won't start but there's power. I check for spark, nothing. There was no check engine light so I was told to check ECU harness. I unplugged and plug the connectors and still have no CEL.

No click, no crank has NOTHING to do with the ECU.
And how could you check for spark if the engine wasn't cranking??

The logic for the starter circuit is: FL AM1/Fuse AM1/ignition switch/neutral start switch/starter solenoid. Nothing else effects that circuit.
The motor side of the starter is connected directly to the battery positive terminal.

An OBD2 ECU will not work with an OBD1 vehicle.

 

[bigredmachine]

no crank no start could be a grounding issues, double check the harness ground points and go form there. you could check the injectors with either a noid light or use a mechanics stethoscope to try to hear the injectors while cranking.

 

[pilotuku]

Not trying to be a smart@ass here. The FSM has all the diagnostics laid out.

And a copy of FSM I have doesn’t have that. Ugghhhh. Pages were pulled out. A lot.

As Jon said, the ECU I tried is not compatible to my OBD1 truck.

 

[pilotuku]

No click, no crank has NOTHING to do with the ECU.
And how could you check for spark if the engine wasn't cranking??

The logic for the starter circuit is: FL AM1/Fuse AM1/ignition switch/neutral start switch/starter solenoid. Nothing else effects that circuit.
The motor side of the starter is connected directly to the battery positive terminal.

An OBD2 ECU will not work with an OBD1 vehicle.

I guess I’ll be looking for a 93/94 ECU. A friend will be dropping by with his 93 and will try his… I saw a company that re programs ECU. I wonder if that’s worth a try or just buy another used one…

 

[JoeW]

94 is a vane air flow right? Is your intake tube on and connected from the throttle body to the vafm?

 

[BILT4ME]

Did you remove the two screws on the VAF and tug on the harness?

What you are describing points to the VAF.

 

[jonheld]

FSM - 1994 FZJ80 EWD

1994 FZJ80 Electronic Wiring Diagram (schematics). This file is bookmarked exactly the way the hardcover version is laid out. You're welcome.

forum.ih8mud.com

FSM - 1993-1994 FZJ-80 Updated and Combined FSM

IF YOU ARE HAPPY WITH THIS FSM PLEASE RATE THIS RESOURCE 5 STARS! Revision 05 has been uploaded, check out the update I posted detailing the new features added. The previous version of the 93-94 FSM had confusing file names, ridiculously...

forum.ih8mud.com

 

[pilotuku]

I just tried my friend’s 93 ecu on mine, it gives me the same response. Just crank no start.
I tried my 94 ecu on his truck, it started just fine. I think this eliminates my ecu box problem. Time to look for something else.
Thank you @jonheld for the FSM link. I will go through it and look for solutions.
@JoeW @BILT4ME i have an MAF

 

[JoeW]

And your intake hose is connected? How are you getting starting fluid into the engine? Also, are you sure it's not 180 out since you just rebuilt it.

 

[BILT4ME]

I just tried my friend’s 93 ecu on mine, it gives me the same response. Just crank no start.
I tried my 94 ecu on his truck, it started just fine. I think this eliminates my ecu box problem. Time to look for something else.
Thank you @jonheld for the FSM link. I will go through it and look for solutions.
@JoeW @BILT4ME i have an MAF

AFM/VAF whatever. If it's a 94 it's not a MAF.

Did you yank on the harness?

 

[shocktower]

I know this is simple, but have you replaced the fusable link

 

[pilotuku]

Well after taking all options, she fired up!

I tried my friends ‘93 and took his ecu out but it won’t work on my truck and was giving me the same response as if I was using my own ecu. But my ecu worked on his just fine.

So ECU issue is eliminated.

After going through the relays again, found out that the connector of the EFI relay does not give me ground.

I wired the ground pin directly to the battery and plugged the EFI relay and it fired up no issues.

I checked my body and engine grounds and they are solid.

Now I have to follow this brown wire upstream and figure out why I’m not getting ground.

Finally heard her purring and I’m relieved!

Thanks everyone for the input. All your tips are solid, I was just all over the place. It’s my first engine swap and I’m just a novice YouTube mechanic.

Thank you @jonheld for the the link to the FSM. The version I have had a lot of missing info. Especially the electrical part of it!

 

[jonheld]

That should be ground point EB. Left side inner fender towards the front.

 

[pilotuku]

That should be ground point EB. Left side inner fender towards the front.

I wonder if it messed it up when I degreased the engine bay and rinse it with low pressure water...

Oh well...

I'll check on it when I get home.