84 Van dies just after starting

[84George]

Hello all! First off thanks for having me!

So my Van is an 84 3y-ec with 123k miles. Its been immobile for a year. As of right now she will start just fine and run for 5 seconds before she cuts out. No sputters... just dies. If i push the gas she dies as soon as i do. ran fine until the fuel pump went out. Had it towed into a shop. Shop replaced the fuel pump and in the process shorted something out. I then had it towed to Toyota for further diagnosis. Toyota replaced the MAF and efi coolant sensor. I’ve now got some spare time and will be moving forward solo. Toyota recommend replacing the distributor however I’m definitely getting spark on all cylinders because it runs normal until it dies. I suspect there is a loss of fuel or spark. I have yet to determine which however suspect its fuel related because the initial diagnosis was the fuel pump. Any help or guidance would be awesome!

Also if anyone has a service manual pdf I could use that would be greatly appreciated!
Thanks for your consideration and time!

[Burntboot]

Welcome to the party.
I dont know anything about 1st Gen's but as no one has responded yet ...

It should be easy enough to check for spark, once it dies pull #1 spark plug wire, install a known good spark plug, ground the electrode and crank the engine over, it should snap brightly as it sparks.
If you have spark, its time to dig into the fuel system.

I would start with checking for fuel pressure, try this thread:
Testing fuel system / replacing fuel pressure regulator

One thing that isnt clear to me is the timeline, was the year of non-use before or after the attempted repairs?
How was the fuel pump failure diagnosed? ( I have seen people replace pumps based on assumption, not actual testing, hence the ask)

Fuel that sits in a tank for long periods tends to break down (ethanol fuel has a "shelf life" of approx 3 months) just for fun, have a read thru this thread:

Fuel gauge not working?

Page 2 is where it will get interesting for you and might yield some insights

Cheers

[84George]

Burntboot! Thank you responding. Other than fluid services and details I’m a very novice mechanic so having someone to bounce ideas off of is a confidence booster.

I purchased the Van in August of 21 at 89k miles and in August of 22 was driving down the highway when the engine sputtered out. One strange thing was that when the engine sputtered out the fuel gauge was reading a half tank, the registered empty then shot all the way to reading a full tank. The van then cranked with zero start so I had it towed to a shop. Shop diagnosed the fuel pump. The gas was added just days prior and was BP 93. I drive a bit for work and try to get my gas at busy places so there’s presumably always fresh gas.

Three days ago after work I added a can of seafoam and started the van about ten times trying to work it through the lines and injectors. Let it sit for a night then two days ago pulled the fuel filter and the gas that poured out was super dark grey/blue. I changed the filter and on the first start the van ran for a solid minute! Hallelujah! Then died… then ran for 20 secs… then was back to 5 seconds of running before dying. However now when it dies it’s a hard jarring sputter whereas before it would cut out quickly as if someone pulled the plug on it. No amount of foot on the gas pedal saves it. So I then thought “the tank must be dirty! Drop it and clean it.” So I drained the tank(gas looked fine) dropped it and the tank needed nothing. looks brand new inside and the fuel pump is also noticeably new. The mechanics who installed it did cut wires from the pump and sensor then electrical taped them back together. Presumably because they couldn’t figure out how to unplug them.

my plan today is to reinstall the tank and try your spark plug suggestion.

[Burntboot]

Good news that its clean inside.

Those wires need to be fixed properly before you put the tank back in (solder and shrink).
I would also recommend slowing down a bit, the more things you disturb the more variables you introduce which can complicate diagnosis.

It could well be a contaminated fuel issue or it could be electrical.
There is a lot of components to the fuel system (mechanical and electrical) and you'll want to work thru all the systems.
The more things you can evaluate and eliminate, the closer you will get to a solution.

Be gentle with your motor, you really want to avoid " hard jarring sputter" type events, that can do damage.


In reality you need a manual and someone who can offer better guidance.
Hopefully Mark H will drop by, he is extremely knowledgeable in these matters.
Good luck.

[Burntboot]

And given that it tries to run, it sounds like spark isnt the problem, stay with the fuel system until you can rule it out.

[84George]

Hey Burntboot.

So apparently the wires were not severed but are in a bad way. I think I should cut them, solder them and shrink wrap them. I’d never soldered before so I took some scrap wire and have been practicing. Seems like something I can handle.

I’m also going to buy the manual tonight. Seems like there are a few options and I’m wondering if you could offer some direction on which may be the simplest to understand. I’ve begun taking photos and will soon be gone uploading them so you guys can peep the problems and progress. Bare with me while I learn this process!

Thank you!

[84George]

So I took fuel pump/fuel sensor harness off the Van and tested each wire and connector with a meter. Everything checked out. Got those babies lookin nice with some solder and heat shrink. Put the tank back on. Added 3gals of 93 with some Techron and it’s back to run for 5 secs and then immediately die. At least it didn’t sputter this time. I only tried starting it twice this go round to avoid further damage.

[Burntboot]

Those wires look a lot happier now and while it didn't solve your issue, at least you have eliminated one variable.

I forgot to ask previously, have you checked for stored codes?
That would usually be step #1 for any problem you encounter, always best to start with the easiest things and go for there.

[84George]

Ya checking the list of possible issues off the list is very satisfying.

Today I ordered the OEM repair manual and wiring diagram booklet as well. Should be here in a week. I also bought an OBD1 reader then realized I do not have the proper adapter. Then began to wonder if there is even a plug for it or if I’m to read the check engine blinks?

[originalkwyjibo]

This should get you through the diagnostic codes.
https://www.toyotavantech.com/forum/...vice-Connector

[MarkH]

I don't know if you ever solved your issue, but yesterday, I had the same issue. I had some vacuum leaks in the intake manifold and some sheared-off exhaust studs so I figured I'd remove the intake/exhaust manifolds and replace the gaskets. When I got it all back together yesterday and tried to start it, it would run great for about 2 seconds and then die. After poking around for a bit, I found the issue. One of the large vacuum hoses that goes under the intake manifold had become disconnected, creating a large vacuum leak. It would start fine because of the extra fuel from the cold start injector, but then immediately die since the mix was way too lean. I only thought this might be similar to your issue since you said the shop replaced the MAF sensor which may have resulted in one of the vacuum lines around that area getting disconnected. With mine, the end of that big vacuum line is hard to see without looking under the intake manifold with a flashlight, so it would be easy to miss.

[MarkH]

Oh, and by the way, this issue didn't generate any diagnostic codes on my '85 1st gen van.

[MarkH]

This hose circled in red is the hard-to-see one that was disconnected in my van. It comes right off the intake manifold and is a large-diameter hose so if it is disconnected, it is a massive vacuum leak that would prevent the engine from idling.