90 All-Trac Check Engine Light Not Coming On..No Start

My check engine light will not come on at any time. With the key in the ON position it should illuminate. The car will crank but not start. It stumbles a little if I crank it with some starter fluid. I swapped in another ECU and the problems persists. I also swapped in EFI and fuel pump relays and still the check engine light will not come on. I am in the process of replacing the fuel pump now but am afraid the car will not start for the same reason that there is no check enging light. So the question here is....

What might be causing the check engine light to not come on when I turn the key to the ON/ACC position?
 
Did this situation just happen suddenly for you? Or were there symptoms before it got to where you are now? Or did you buy the car recently with this problem?

The EFI system has a fuse also - may want to check if that fuse is blown.

Do you have the all the service manuals with wiring diagrams?
 
The car ran fine for the last time in 2017. It then sat for a year. Then, I tried to start it and it ran poorly and stumbled as if it was starved for fuel. The car sat in the car-port as it does now.

As for the situation I have now with the no check engine light, this just happened when I tried to get the car going yesterday.

I have checked the IG fuses and the EFI fuse and put in a spare EFI relay that, following the Toyota Service Repair Manual for the 1990 All-Trac, proved the relay was OK. I also have the Toyota Electrical Manual for this car.

With the ignition in the ON position, the car has 12V at the fuel pump harness, but I do not hear the pump.

The diagnostic port under the hood gets 12V at the B+ with ignition ON and the Fp slot gets around 10.5V while cranking.

At this time, the simple explanation may be correct;

1. The fuel pump failed after letting the car sit for so long.

2. The light bulb for the CHECK engine light coincedentally has burned out.

I have the fuel tank 1/2 of the way out now. I removed all the 10mm bolts holding the plastic cover for the tank but the cover is bound up on the side right by the filler neck. I think that by removing the 10mm bolt in the wheel well just behind the rear driver side tire will allow me to remove what the TSRM refers to as the fuel inlet pipe protector.

So, the plan is to inspect inside of the tank and get it cleaned up and sealed if neccessary. Then I will install my new Denso fuel pump with stainer. This will likely get the car going.

Then I plan on removing the guage cluster to replace the capacitors on my slow tachometer and also put in a new light bulb for the CHECK engine light.

I'll post back when I get it going but feel free to chime in if you think it may help.

Thanks Guys.

Any tips from here are appreciated. For instance, must the car be raised up to fully remove the fuel tank?
 
Only note I have is that the fuel pump wiring harness should not have 12V with the ignition key in the ON position. This car has a safety feature that does not provide power to the fuel pump unless the ignition is in the start position or the engine is running. So this part, if what you say is true, is a problem in the control circuit somewhere.

I would have brought a temporary separate 12V wire from the battery to the +12V terminal on the fuel pump wiring harness to check for pump operation before going through the difficulty of removing the tank. It's possible your pump is fine.
 
underscore":2q11p5sg said:
Bridging B+ and FP in the diagnostic box is a lot easier.
But not the same. OP said car was sitting for a long time. Possible mice/rats bit through a wire somewhere. Wiring has to be all good to do the B+ & FP jumper. I was looking to bypass all except the fuel pump to see if the pump worked first, then work back (if the OP is right in that the fuel pump doesn't work when trying to start the car).
 

underscore

Well-known member
That's a very good point, though I'd still try the jumper first since it's so easy.

Also maybe a dumb question, but it does have gas in the tank right?
 
93celicaconv":3nejs1fp said:
Only note I have is that the fuel pump wiring harness should not have 12V with the ignition key in the ON position. This car has a safety feature that does not provide power to the fuel pump unless the ignition is in the start position or the engine is running. So this part, if what you say is true, is a problem in the control circuit somewhere.

I would have brought a temporary separate 12V wire from the battery to the +12V terminal on the fuel pump wiring harness to check for pump operation before going through the difficulty of removing the tank. It's possible your pump is fine.
93celicaconv is right about there is not supposed to be 12V at the fuel pump with the key in the ON postion. I had a jumper bridging the B+ to Fp so that is why there was 12V at the pump harness. Upon removing the jumper, there is no voltage which is normal.

I have since run wires directly from the battery to the fuel pump plug and the pump still does not move or make a sound.

There is about 3 gallons of fuel in the tank. I am going to syphon that out and then proceed to removing the tank. I am going back out to the car right now---about 9am here in San Antonio. I really have to get this car going before we start work on a retaining wall at 6pm tonight. The car is now sitting in what will be workspace.


Next task is to remove the Fuel Tank Protector(FTP) but first I am TRYING to remove the Fuel Inlet Pipe Protector (FIPP). I am stuck here at the FIPP.

I will report back soon.
 
Here is a top tip for removing the Fuel Inlet Pump Protector;

Remove the 2nd of two bolts BEFORE you try to wrestle it free from the wheel well. The 2nd bolt is located relative to the rim/tire at the 1 o'clock position and couple of inches down.
 
Update.

The tank is off. Another tip; DO NOT try to use the SAE equivalent flare wrench for the fuel tank line. I tried with an SAE flare wrench and felt it slip slightly. I immediately stopped. As stated by alltrac.net user tw2, use a 14mm flare wrench. I just bought one from AutoZone for $8.99.
 
Update. The tank is being rinsed with soapy water. I will do this until there is zero debris in the rinse water. Then, I will do a final rinse to remove the soap suds, drain it, and use a liberal amount of WD-40 to prevent flash rust inside the tank.
 
After hours of rinsing, the water rinsing the fuel tank is now clear of debris. I am going to leave it full of water overnight then rinse some more tomorrow and then do the WD-40 step.
 
And, to answer one of my questions, the car does not need to be raised at all to remove the fuel tank. However, I would raise the car up if I had to do it again.
 

Roreri

Active member
You really got after this--hat's off to you! I guess you found a solution to where it's sitting vis a vis your wall project?

The fuel filter is up front, on the driver's side (for US allTracs) relatively near the firewall. You don't have to remove a bunch of stuff, but I gave up trying to get the bottom nut loose because I couldn't get leverage on it and ended up having a mechanic do it.
 
Roreri":11wu5rse said:
The fuel filter is up front, on the driver's side (for US allTracs) relatively near the firewall. You don't have to remove a bunch of stuff, but I gave up trying to get the bottom nut loose because I couldn't get leverage on it and ended up having a mechanic do it.
That's right. If you remove the left front wheel, you will be able to see the fuel line going up to the bottom of the fuel filter. Changed two of those this spring - with a mechanic's help. That flare fitting design was a poor one for that application by Toyota. When the nut is tightened originally, the compression causes it to lock onto the tube - and time has a way to make the lock far more secure. If not handled very carefully, the fuel line can easily be damaged. So be careful, and get the right tools. Now would be a good time to change that fuel filter, or maybe after you have the rear tank stuff completed and ran the engine for a few miles (so that the debris knocked loose in the fuel lines and inside the tank tubes/hoses can get into the old filter rather than your new one).
 
Well, we are working around the All-Trac while rebuilding that retaining wall. The car can at least be rolled in neutral since I was able to free the sticky / sticking / stuck clutch by pumping the clutch pedal 100+ times to get pedal pressure, then with an engaged (not fully) e-brake, in 1st gear and the clutch petal to the floor, I cranked the motor with a couple of starter bumps and the clutch broke free.

I think that it may be wise to NOT fully engage the e-brake while doing this because as you crank the car, the e-brake will slip a little bit which is alot better than breaking a tooth in the flyweel or starter.

Otherwise, with the clutch sticking, if the car were to be rolled, the whole drive train would also be rolling. This happened on my father's 64 Corvair (twice). And, also on my brother's 64 Corvair Spyder while the tow truck was pulling it, I had the shifter set to neutral but with the clutch stuck it was as if was in gear.

Another TOP TIP to all;

If you have to let your car sit for more than, say around 6 months or so, at least pump the clutch pedal in order to prevent the clutch from sticking. The longer the car sits, the harder it becomes to "unstick" the clutch. If someone does this, make sure there is room in front of the car because it may lurch forward the same way it would if you try to start the car in gear without the clutch pedal to the floor.
 
Update.

I removed the fuel pump from the tank. There is still much corrosion on the pump bracket which I will clean up and spray with WD-40 until reinstallation.

Here is where I have some issues;

All three wires that connect to the fuel pump are detached. This probably happened during the rinsing of the tank as I was using a trigger/sprayer with the garden hose and that was likely to much pressure.

But, those wires were probably compromised anyway and new wires likely would have withstood such water pressure.

I have to now spice in new wires with eyelets so that they may be able to properly connect to the new fuel pump.

1. What guage wires should I use?
2. Are there some wires that already come with eyelets?
3. To prevent corrosion, do the wires and the insulation on the wires as well as the metal eyelets have to be rated for fuel usage?
 
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