Issue starting 87 4Runner

[ccoker]

We have an 87 4runner we use as a hunting truck that we had issues with over the weekend.

It wouldn't start this weekend, acting like it was not getting any gas.

A few years ago that happened and discovered that the EFI relay was unplugged, I reinserted and it started right up.

So, I assumed that that was the issue and so I reseated it a few times to no avail, I tapped on it a few times, nothing.

I removed the cover over the fuel pump and reseated the plug at going to the fuel pump a few times and tried it again.. it starts..
Cool, figured it was good to go and it ran that evening fine, restarted a few times, all good.

Next morning, it wouldn't start.
crap..

I messed with the EFI relay, cleaned the contacts, cleaned the contacts at the fuel pump, no go..

I should mention the battery is 4 years old and required a jump start the first evening.

We try jumping it again and we never get it to start..
I put a test light on the plug going to the fuel pump with the key on and it won't light up and so I assumed that the EFI relay must be dead...

I buy a new EFI relay, put it in and it won't start but the battery is weak, jump it, try starting it a few times and it runs fine the rest of the evening, turning it on and off a few times.

The next morning, it won't start again.

I call a mechanic buddy and discussed.
He informs me that it the fuel pump with only get voltage when you turn the key on for 1-15 seconds and so we test and sure enough it is lighting up. He told me to bang on the fuel pump while trying to start it, we did this (while the battery was being jumped) and it starts right up.

So, I think the fuel pump needs to be replaced but I wonder if the weak battery (coming on 5 years) could play a part in it as well..

Thoughts?

Oh, the truck is on our hunting property and hour and a 1/2 away so I can't really go check anything right now.. just looking for advice ..

We WILL be be replacing the battery for sure and will probably be replacing the fuel pump..

Thoughts?

 

[MacGyver1979]

test the battery. check the battery connections. if the battery and connections are good remove the terminals and see if any voltage is drawing. I wouldn't buy any parts before doing all this

 

[RAD4Runner]

...It wouldn't start this weekend, acting like it was not getting any gas.

Meaning starter cranks energetically, but you do not her/feel the "VROOM"?

I presume you already tested for spark?

I should mention the battery is 4 years old and required a jump start the first evening.

If battery can make starter turn energetically, it has more energy that necessary to run the fuel pump. No need to jump to start the fuel pump.

However, at 4 years, many batteries start to go bad. Have battery load-tested. Quick check is with engine OFF, measure voltage at battery posts. Turn high-beams on. Good battery should maintain at least 11 volts or around there.

Also, don't relay on a line tester. Get a volt-meter. Harbor Freight is your friend.

I buy a new EFI relay, put it in and it won't start but the battery is weak, jump it, try starting it a few times and it runs fine the rest of the evening, turning it on and off a few times.The next morning, it won't start again.

Don't throw parts, money and time at a problem. Don't replace parts unless you have verified it is the defective part and replacing it would solve the problem.

...the fuel pump with only get voltage when you turn the key on for 1-15 seconds

Wrong. The fuel pump gets voltage as soon as you out ignition key in "Start" position. See How Circuit-Opening Relay Works post.

He told me to bang on the fuel pump while trying to start it, we did this (while the battery was being jumped) and it starts right up.

Does not sound typical but IF this consistently fixes the problem, pump could be mechanically getting stuck, debris could be blocking flow, etc.

 

[wallytoo]

Does not sound typical but IF this consistently fixes the problem, pump could be mechanically getting stuck, debris could be blocking flow, etc.

that DOES sound typical for a failing fuel pump - intermittent operation, and banging it will get it to run. exactly what i experienced. anywhere from two hours or two weeks could pass in between episodes where it wouldn't work, manifested mostly by a "no-start" condition, as opposed to failure while running. eventually, it failed altogether, and i replaced it on the side of the road with the new one i had with me (a very cold day in january, 10 degrees).

 

[RAD4Runner]

... eventually, it failed altogether, and i replaced it on the side of the road with the new one i had with me (a very cold day in january, 10 degrees).

BRRR!!!
Speaking of bad fuel pump, so we do not get stranded, I wonder if there's a good time to replace fuel pump as a preventive measure- just like we replace timing belts in other vehicles.

Fellow members,
May we know at what mileage your fuel pump failed on you, if applicable?

TIA

 

[wallytoo]

failed at 110,010 miles. i suspect age played a more pivotal role in its demise, given that it had an original date stamp (1986). hard to be upset at getting nearly 30 years out of the pump.

 

[wallytoo]

BRRR!!!
I wonder if there's a good time to replace fuel pump

i don't recommend january, on the side of the road, in new england.

 

[airdreams1]

i don't recommend january, on the side of the road, in new england.

LOL
Way back when cell phones were as big & heavy as a starter, I had to do a CV in the dead of winter @ 1am in the morning wile laying on compact snow & ice. temp was in the teens & had a wind chill to boot...... Not fun at all! But I was too broke to get it sooner than I did (on the way to work, the night before it went out.)

 

[KidVermicious]

BRRR!!!
Speaking of bad fuel pump, so we do not get stranded, I wonder if there's a good time to replace fuel pump as a preventive measure- just like we replace timing belts in other vehicles.

Fellow members,
May we know at what mileage your fuel pump failed on you, if applicable?

TIA

The OEM pump in The Bastard died at around 240-something miles, I don't know if it was original. The cheap Rockauto pump I replaced it with died after sitting for several months (250-something miles) and the cheap Amazon pump I replaced that with failed on me after sitting for two weeks. My conclusion is that paying the extra for Denso is mandatory because these cheap-ass fuel pumps really don't like to sit.

 

[RAD4Runner]

failed at 110,010 miles...

...around 240-something miles...

Thanks, guys! Yeah I like OEM for things that make truck run, stop or turn, and stay upright

But I was too broke to get it sooner than I did (on the way to work, the night before it went out.)

I forgot to ask, Did any have any indication that pump was about to give up? (Like sputtering, hard-starts, etc) Or it simply just stopped working?

LOL Way back when cell phones were as big & heavy as a starter,

Like this? LOL!

 

[wallytoo]

sure, it started to not work when trying to start the engine. with the key turned to start, seatbelt plugged in, and clutch out (not in), the fuel pump should work. when having hard starts, where it seemed to almost catch, or catch briefly and immediately die, i suspected the pump. i'd then do the turn to start/clutch out to see if i could hear the pump, and almost every time, i couldn't.

i then used the jumper in the diagnostic box (paper clip) to make the pump run anytime the ignition was on, so i could "bang the tank" or pull the cover from under the seat and bang on the top of the pump directly. those things would usually get the pump to immediately operate. however, at that point, it's only a matter of time before it fails for good. i seem to recall getting perhaps two months out of it, with intermittent failure, before it quit completely.

 

[RAD4Runner]

Tnx, Wallytoo.
Good to know there's a warning, because we don't really want to replace things just because they're old. Some old parts may be better than new ones.