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Peter Bagley
Peter Bagley, Auto Service Technician
Category: Toyota
Satisfied Customers: 814
Experience:  master tech at Toyota dealer
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95 toy 4 runner I've replaced both relays and bench tested

Customer Question

Customer: 95 toy 4 runner I've replaced both relays and bench tested the pump but the truck wont turn the fuel pump on. JA: How many miles are on the car? Has the car been starting normally? Customer: 200,000 rough miles this part of CA is a third world area JA: Are you fixing your 9-5 yourself? What have you tried so far? Customer: As I said I bench tested the f.p. for 45 psi and replaced the under hood relay with a known good relay and the paid 140.00 for the in dash relay with no change. Someone told me to replace the computer but before I do that I need to look for something that computer needs to see to start. I know gm and ford need to see oil pressure and good temp to start. JA: Anything else you want the mechanic to know before I connect you? Customer: I can't afford his time

Submitted: 1 month ago.
Category: Toyota
Expert:  sprinkles08 replied 1 month ago.

Hello and welcome to JustAnswer!

There are several things that can prevent the fuel pump from running. It could simply be a blown fuse, there may be a wiring issue, and it's definitely possible that the problem could be the engine controller.

Have you checked fuses?

Have you checked for spark?

Customer: replied 1 month ago.
Mileage is probably in the 200,000 area
When I first took the job I was able to get the vehicle to run for 30 seconds then fuel pressure went out and it died. I used an idiot light to determine that there was power at both parts of the fuel pump relay in the under hood relay center. I could not locate the inline fuse but I did try to use my electrical leads to power the pump. I was able to deliver 45 psi to the engine but it still didn't start. I have not checked spark yet because It ran. I suspect the computer because I don't think it is engaging the fuel injectors.
I know from my years as an auto tech that there are sensors that the computer checks before it will start in closed loop in many obd 1 cars, but I'm not familiar with the start protocols of Toyota. Also this vehicle is really beat up. It is used to climb up and down a very rough road every day vibration damage is a serious consideration.
Expert:  sprinkles08 replied 1 month ago.

Have you checked fuses?

Have you checked for spark?

Customer: replied 1 month ago.
The customer is not willing to pay for the conversation. Again I am a college trained 20 year vet of the auto industry. You can't be to technical. The only things I don't have is an obd1 interrogatory computer. The obd 1 system is pretty useless any way and All data had little or no info on this particular car. I can't understand why Toyota put their relays / fuses et all in so many places. I just need to know what sensors to test before I make the 260.00 dollar commitment to a new computer.
Customer: replied 1 month ago.
I'm sorry I will have to continue this conversation tomorrow, after I was finally able to reach a spark plug and put my tester on it the battery died (it's probably a bad battery). Also I can't find the interior fuse block I've torn the stupid dash assembly apart but all I found were some relays hanging from the wire loom on the drivers side and the computer and havc system on the passenger side. The fuses in the engine compartment are all functioning. I know that gm put the fuse block in the center console for that short lived small car ( I forget the name) Is this one someplace special?
Expert:  Peter Bagley replied 1 month ago.

Hello and welcome to just answer, my name is ***** ***** master tech here to try and help. I cannot see or hear your vehicle so I rely on your patience and input to my questions so I can help you better. I read your notes and it seems we need to take this one step at a time. First we have to determine if you have spark and fuel pressure or lost one or the other or both.Then we need to keep it simple and attack one problem at a time.Toyota tells us [ KEEP IT SIMPLE STUPID] So first off, do you have a scanner that can read any codes and monitor any inputs?

Customer: replied 1 month ago.
Thank you the wire loom for the computer had been jostled loose (never saw this before, apparently a previous repair had broken the locking tab, or the road damaged it with heavy vibration) So I pushed it in and wire tied it to the unit, now it starts and runs.
Also I disabled an aftermarket security system. Thank you for your time. I guess you need to close this and figure out the bill.S
Expert:  Peter Bagley replied 1 month ago.

aftermarket security systems are a nightmare , not worth the money. Good hunting I will recommend a refund as you found the issue so thanx for trying us and remember us in the future