80 Series Crank No Start

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smallv8

smallv8

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Joined
Feb 20, 2006
Threads
5
Messages
71
Location
Buffalo
Hi guys,
Posting here cause im perplexed. Owned several 40's, 60's and now an 80 series. Purchased a year ago with 234,xxx, just rolled 264,xxx no issues til last week. She was running a little rough figured had to do tune up, went to jobsite and she died, crank no start.

Pulled rear seats, tested voltage at fuel pump 5v. Pulled original fuel pump, changed, tested 12v, return line flow back no issues; crank no start.

Did denso cap rotor plugs gapped; crank no start.

Checked efi relay; have check engine light crank no start. (Even swapped as well)

Changed fuel filter (again) crank no start

Changed circuit opening relay; crank no start

Timing has not been adjusted, marked and advanced wanted to fire; crank no start. Retarded, crank no start. Set back to mark.

Tested all continuity to manual. Pinned out maf for ohm resistance, all by the book.

Been wrenching on cruisers for over 30 years. This one has really got me.

1. Yes fusible link is good (have amp light on start up)
2. New (car quest premium) fuel pump is in and pumping to pressure (original works as well just louder)
3. Truck is NOT desmogged all original minus desert 4core rad

Ive been working on fj's for over 30 years and this one is leaving me defeated.

Any help? Am i missing something?

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I assume you have checked for Good spark and compression? If that checks out then fuel . check fuel pressure with a gauge per fsm make sure pmp is turning on and giving enough pressure. The AFM has a vacuum operated flapper door. That has to move open in order to turn the fuel pump on I had a 22re do that to me once due to a cracked intake tube . If all that checks out you will know winch 1 of the trinity you don't have Fuel,Air, Fire. Once you know that you can go down the correct rabbit hole. Have you tired giving it a shot of starter fluid down the intake to see if it sparks off? quick way to check if it's a fuel issue.. good luck these really suck sometimes to find.. I will also use a remote start switch so I can manually operate the starter just to rule out any elec issue between starter and key . More for piece of mind to make sure 100% it isn't wiring . More times than not ,your going to find this by knowing whats not broken
 
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raisinhell2 said:
I assume you have checked for Good spark and compression? If that checks out then fuel . check fuel pressure with a gauge per fsm make sure pmp is turning on and giving enough pressure. The AFM has a vacuum operated flapper door. That has to move open in order to turn the fuel pump on I had a 22re do that to me once due to a cracked intake tube . If all that checks out you will know winch 1 of the trinity you don't have Fuel,Air, Fire. Once you know that you can go down the correct rabbit hole. Have you tired giving it a shot of starter fluid down the intake to see if it sparks off? quick way to check if it's a fuel issue.. good luck these really suck sometimes to find.. I will also use a remote start switch so I can manually operate the starter just to rule out any elec issue between starter and key . More for piece of mind to make sure 100% it isn't wiring . More times than not ,your going to find this by knowing whats not broken
Click to expand...
Yes fuel pressure is good at rail, plenty of spark on all 6 ht leads, the maf is questionable, i ordered a new one waiting for it to arrive, ive read that maf causes fuel pump to shut down. I did test resistance when i pinned it out and was within spec still think its culprit. Tried ether after maf and she wants to fire, but stalls.
 
smallv8 said:
Yes fuel pressure is good at rail, plenty of spark on all 6 ht leads, the maf is questionable, i ordered a new one waiting for it to arrive, ive read that maf causes fuel pump to shut down. I did test resistance when i pinned it out and was within spec still think its culprit. Tried ether after maf and she wants to fire, but stalls.
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She has been running really rough when starting in am for last month or so, all roads are pointing at maf. Thanks again for your help!
 
smallv8 said:
I did test resistance when i pinned it out and was within spec still think its culprit.
Click to expand...
Below is from the Toyota FSM and EWD.
The flap switch (pins 1/2) of the AFM runs the fuel pump along with the circuit opening relay after you release the key from the start position once the motor starts sucking air.
If all the readings check out on the AFM according to the documents below, you may have an issue with the circuit opening relay.
Please read the last page on this document regarding fuel pump operation:

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jonheld said:
Below is from the Toyota FSM and EWD.
The flap switch (pins 1/2) of the AFM runs the fuel pump along with the circuit opening relay after you release the key from the start position once the motor starts sucking air.
If all the readings check out on the AFM according to the documents below, you may have an issue with the circuit opening relay.
Please read the last page on this document regarding fuel pump operation:

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Click to expand...
Thank you!
 
jonheld said:
Below is from the Toyota FSM and EWD.
The flap switch (pins 1/2) of the AFM runs the fuel pump along with the circuit opening relay after you release the key from the start position once the motor starts sucking air.
If all the readings check out on the AFM according to the documents below, you may have an issue with the circuit opening relay.
Please read the last page on this document regarding fuel pump operation:

View attachment 4134583
View attachment 4134584
View attachment 4134589
Click to expand...
Fully closed spec is 200-600; fully open spec is 20-1200, Im w/in tolerances. Circuit opening relay by kick panel is good, tested and changed with new one.

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raisinhell2 said:
Have you tired giving it a shot of starter fluid down the intake to see if it sparks off?
Click to expand...

Have you tried this?

smallv8 said:
Ordered new maf, think air is the issue
Click to expand...

If your maf is bad then you'd be missing fuel, not air. I know you said you had good fuel pressure but it's so easy to validate compression, spark, air, and timing with a little shot of starting fluid
 
60 toy ota said:
Have you tried this?



If your maf is bad then you'd be missing fuel, not air. I know you said you had good fuel pressure but it's so easy to validate compression, spark, air, and timing with a little shot of starting fluid
Click to expand...
Shot of starting fluid after maf and she fires roughly and dies
 
smallv8 said:
Shot of starting fluid after maf and she fires roughly and dies
Click to expand...
Definitely chasing a fuel issue , Or a AFM not providing signal to the ecu for fuel. Ive seen the wiring on the plugs break inside the plug and or corrected . I would chase your wiring from the AFM to the ecu.. Plus make sure the fuel pump is turning on when the flapper opens. My bet is on a wiring issue broken wire or a bad ground .. You rig has a air flow meter AFM not a map just so you know
 
raisinhell2 said:
Definitely chasing a fuel issue , Or a AFM not providing signal to the ecu for fuel. Ive seen the wiring on the plugs break inside the plug and or corrected . I would chase your wiring from the AFM to the ecu.. Plus make sure the fuel pump is turning on when the flapper opens. My bet is on a wiring issue broken wire or a bad ground .. You rig has a air flow meter AFM not a map just so you know
Click to expand...
On a OBD1 80 Series, the ECU does not control the fuel pump.
The FP is run from the circuit opening relay which has 2 coils.
The first coil is fired from the starter circuit.
The second coil is fired by the flap switch in the AFM.
 
raisinhell2 said:
Definitely chasing a fuel issue , Or a AFM not providing signal to the ecu for fuel. Ive seen the wiring on the plugs break inside the plug and or corrected . I would chase your wiring from the AFM to the ecu.. Plus make sure the fuel pump is turning on when the flapper opens. My bet is on a wiring issue broken wire or a bad ground .. You rig has a air flow meter AFM not a map just so you know
Click to expand...
Ok thx ill check continuity from afm to ecu. Its been running rough last month which led me to think the fuel pump/filter were failing. Broken/loose wire and or bad ground at afm would yield similar situation.
 
jonheld said:
On a OBD1 80 Series, the ECU does not control the fuel pump.
The FP is run from the circuit opening relay which has 2 coils.
The first coil is fired from the starter circuit.
The second coil is fired by the flap switch in the AFM.
Click to expand...
Oh ok, so check continuity between circuit opening relay to afm per diagram
 
smallv8 said:
Oh ok, so check continuity between circuit opening relay to afm per diagram
Click to expand...
The COR gets an ignition hot +12 on pin 2 which also hits the second coil.
Pin 4 is the ground path of the second coil that runs to the switch in the AFM.
When the flap opens, the switch completes the ground path and the COR fires the fuel pump.

On a related issue, have you bypassed all FP logic by shorting pins 1 (FP)-8 (B+) in the diagnostic connector on the firewall?
That should fire the FP with the key in the ON position, bypassing the COR and associated logic.
 
jonheld said:
On a OBD1 80 Series, the ECU does not control the fuel pump.
The FP is run from the circuit opening relay which has 2 coils.
The first coil is fired from the starter circuit.
The second coil is fired by the flap switch in the AFM.
Click to expand...
You are correct. Last one I messed with was a 22re they use the same theory. I know I did something when I made the stand alone I think I has a broken wire in a plug that told the ECU (could have been the relay for the AFM) the flapper was open . and had the same issues . Getting old sucks.. now I'm going to have to look at my notes, drives me nut doing something then I can't remember what I did ha.
 
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