Engine runs in startermode

old cars do this, all do mostly , that old.
year and engine told a wise post that.(but A/T or M/T trans box?)
2wd/4wd?
first let me ID that real fuse name.
what is fuse amp rating, (and have many spares for testing?)
still have users guide in the glove box and see fuse page for proper names of fuses.?
so the fuse that blows is 15amps under hood, relay box 2 it is called.
if yes I have answers, that fuse EFI is fuse #2
fuse 1 is charge fuse 3 is HAZ-horn'
so yes I have the schematic for that F2 feed buss.
feeds blk/grn wire to....ECU direct and ECU indirect via EFI main relay to ECU. and via fuelpump relay to fuel pump.
so is 2 things, really ECU and pump.
the ECU are know to have bad shorted capators inside, 20 year design life (easy fix really)
but the tricky part is if you unplug the ECU the pump is offline see?
so to find the short with spare fuse
at rear of car unplug the fuel and now the EFI 15 amp fuse does not blow the pump is bad and is common.
the pump has brushes inside that old they mangle up and short.
if fuse blows, the ECU is shorted inside.
bad caps sure. super common that,
cardone1 may have spare ECU rebuilt here
let me see, (not sold direct but via all car parts stores)

here they are based on drive line, 2wd 4wd and more.
It is plug and play, no programming needed or done.

https://www.cardone.com/search.php?search_query=%22VKOI3~%22&year=1989&make=TOYOTA&model=PICKUP&Part%20Type=Engine%20Control%20Module&sort=relevance


find the PN the find it for sale at any store googled.
in hurry USA go to NAPA and ask them to get it. by number seen ab ove.
they used do send in repair if out of stock, ask them CARDONE

any of these immobiliser/fuel pump/ecu /
needs a diagnostic tool to find the cause

the car still cranks but some immobilizers cut fuel and spark

Have you run basic tests? Spark at plugs? Correct fuel pressure at key on? Compression?

images for Fuel pump relay location on gmc 7500

GM Fuel Pump Relay Testing - YouTube

? 27:40
https://www.youtube.com/watch?v=McnXLcJNVfI
Mar 14, 2012 - Uploaded by ScannerDanner
How to manually jump a fuel pump from the fuse box ... Is this the same on the 2003 cavalier chevy? ... I go through fuel pumprelays often on my 99 GMC Yukon Denali. ... Finally, fuel pressure totally drains after motor turns off. ... run right, it would sputter when you hit the gas and finally just would not start.Missing: 7500

Sure sounds like one of the wire terminal connectors under the fuse panel where the relay plugs in may have a problem, being loose, or wire strands broken at the connector. You might check that. Also, one of those relay terminals would be a ground for the coil side of the relay. Maybe the ground is not solidly connected, either at the relay terminal or at its grounding source on the frame or engine, I don't know where.

Hello, You might try a Relay that controls the PCM or ECU. They would be in the Powerbox where the fuelpump Relay is. Some of the Relays are identical so you could buy 1 and it would be a backup part for several.

You should also look at the other things the Ignition switch turns on in the Run position. Does the radio work, the fan motor, or turn signals? If they do not work look at replacing your Ignition switch.

The PCM and ECU get their power indirectly from the Ignition switch. When all have power they will connect to the fuelpump Relay. Since you said you checked the Relays, I am taking that to mean you checked the fuelpump Relay only. Many times people do not know that there are several relays which all need to connect to get the fuelpump to run. When you determine the Ignition switch is good, then the ECU and PCM relays should be getting power. Have you tested the fuelpressure Regulator? It needs to demand fuel from the pump.

The fuelpump relay depends on the ECU or PCM relays to work. One of the 2 relays may be bad and preventing the fuelpump relay from working. When you get to trouble shooting the terminals you can get wiring diagrams online or the info may be in a book at the Autoparts store.

One of the benefits of using a Dealer with the hardest problems is the tools they have. They have machines with connectors that match every wiring connector inside your car. If one section is unplugged they can test the wire loom section by section until the problem is found.

I hope you have found my solution to be very helpful and that I have brought up a few new areas to try. If trying different parts does not help, you are left with a wire by wire battle to fix this and the Dealers' better tools may make more sense.

Change your fuel filter. Check your fuel pump pressure.

when the car won't start. turn ignition switch off . remove gas cap and have someone turn ignition switch on without cranking the engine.listen for a hissing sound that should last for around 3 to 4 seconds, If you don't hear it the most likely problem is the fuel pump. you can further confirm this by checking voltage at the fuel pump by repeating the first step . There should be 12 volt supply for a few seconds when ignition is turned on.If voltage is present and no sound ,replace fuel pump and raplace fuel filter. Fuel pump is in gas tank. this is a very dangerous operation and suggest you bring it to a mechanic.If there is no voltage ,check the electrical plug to fuelpump as to my experience a lot of unsolved intermittent fuel pump problems could be traced to this plug.The other cause could be fuelpump relay or ECU.

It could, once the engine is running it then keeps the fuelpump running with the oil preasure switch and if the oil preasure drops it can stop the pump,but should start back up unless theres a bad fuelpump relay,

check for compression it should start if it has spark and fuel nothing but compression stopping it