92 FJ80 starts then dies then starts then dies...you get the idea (1 Viewer)

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Oct 1, 2017
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Kentucky
:rolleyes: Ok I searched the forum and found a thread to check the EFI relays and fuses and replaced all with new put a new EFI relay in. this all started a cpl weeks ago, had never had the first problem with starting & running like a sewing machine. I've looked on the inter-web for locations of fuel pump relay and found where it should be, drivers side near the firewall but guess what nothing there nor looks as though was ever there, am i missing something? could it be in the kick panel area there are several ?
Its really strange sometime it fires right up and runs as always then stops like i turned the key off, CEL comes on with key on as it should so I'm pretty sure ECM is getting power. so what you think? whats to check next?
 
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The fuel pump is fired from the starter circuit when you crank the starter. When you release the key from the START position after the engine fires, the flap in the AFM opens and fires the secondary fuel pump circuit which continues to run the fuel pump.

So, if she fires up and dies shortly after releasing the key from the START position:
The AFM flap isn't moving freely.
OR
You have a tear in the intake plenum downstream of the AFM allowing too much air to bypass the AFM keeping the flap closed.
OR
There is an issue with the fuel pump logic circuit.

DO NOT REMOVE THE 2 PHILLIPS SCREWS ON THE AFM HOUSING THAT HOLD THE CONNECTOR IN PLACE.

Toyota calls the fuel pump relay a "circuit opening relay" on the FJ80. It is located in the driver's side kick panel.

Relay block Left Kick.jpg


Before messing around with relays and logic circuits, I would make certain that the mechanicals are correct first.

DO NOT REMOVE THE 2 PHILLIPS SCREWS ON THE AFM HOUSING THAT HOLD THE CONNECTOR IN PLACE.
That is NOT how the connector comes apart. There is a small spring clip that gets moved up on the connector shell.
 
Last edited:
Joined
Oct 1, 2017
Messages
10
Location
Kentucky
The fuel pump is fired from the starter circuit when you crank the starter. When you release the key from the START position after the engine fires, the flap in the AFM opens and fires the secondary fuel pump circuit which continues to run the fuel pump.

So, if she fires up and dies shortly after releasing the key from the START position:
The AFM flap isn't moving freely.
OR
You have a tear in the intake plenum downstream of the AFM allowing too much air to bypass the AFM keeping the flap closed.
OR
There is an issue with the fuel pump logic circuit.

DO NOT REMOVE THE 2 PHILLIPS SCREWS ON THE AFM HOUSING THAT HOLD THE CONNECTOR IN PLACE.

Toyota calls the fuel pump relay a "circuit opening relay" on the FJ80. It is located in the driver's side kick panel.

View attachment 2193669

Before messing around with relays and logic circuits, I would make certain that the mechanicals are correct first.

DO NOT REMOVE THE 2 PHILLIPS SCREWS ON THE AFM HOUSING THAT HOLD THE CONNECTOR IN PLACE.
That is NOT how the connector comes apart. There is a small spring clip that gets moved up on the connector shell.
 
Last edited:
Joined
Oct 1, 2017
Messages
10
Location
Kentucky
Good info, I'll check the plenum and AFM. Good to know that I'm not crazy and blind that I couldn't find the fuel pump relay in the engine bay, i thought i maybe I was missing something...now i can put all the stuff I took off looking for the damn thing back. I've already replaced the EFI relay and reworked the wiring to it with a heavier gauge wire, however i notice the boots that surround the plugs to the various sensors are all very dried out and cracked some completely gone, wires look old and some wire insulation is pretty hard. I replaced the worse ones but didn't seem to make a great difference. It's such a bazaar problem because sometimes it starts and runs fine, then right out of the blue dies and wont restart.
 
Joined
Oct 1, 2017
Messages
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Location
Kentucky
Well finally got time to work on my stuff again, went though the list of things to check didn't really see or find serious problems checked and replaced a cpl relays EFI (under hood) and Main (kick panel) circuit opening relay sounds like it kicking will replace it when it comes in.
Dug in to the harness under the hood because it's looking pretty ragged from age and heat pulled the manifold and F%$@#'n EGR stuff off finished a complete de-smog and found several wires clearly burnt through and several more bare of insulation from where they had rested on the smog tube under the intake. Have repaired all that now and re-insulated the harness and treated it to a generous layer of high heat insulation care of Jeggs. Hopefully finish up the re-assembly today and keep your fingers crossed she'll start and run as normal.
IMG_3089.JPG
IMG_3090.JPG
 
Joined
Oct 1, 2017
Messages
10
Location
Kentucky
Another update...still no love :confused: checked all of the diagnostics once again (thanks @jonheld) after repairing the harness under the manifold everything seemed to test out OK. but still no spark, so checked the coil with my meter it wouldn't register on the scale 00.0 when i tested the secondary it was 9.2 So i checked the pickups in the dist and found yet another wire with literally no strand connection on the harness to the ECM the Lg/w lead insulation was hard and cracked right at the connector had maybe a strand or two making contact so if it was getting a signal thru it coundn't have been much of one. I fixed the connection with a Packard style 3 pin (similar to older GM connectors) so now I have Lg/w, Lg/r & Lg/bl in the Packard plug but i see the color scheme i snot carried to the dist side with yellow, white & red on the dist side. Anyone know the color sceme I hooked them up as they where but just in case i got something wrong...I'm old so don't judge...now I wait patiently for my new coil to arrive and try this one more time :deadhorse:
 

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