Sudden no-run situation

[Seth_O]

I DD my '93 and have never had any real issues with it. Today I started it up and backed out of my parking spot and it randomly died. Thats never happened before, but it fired right back up and got underway again. A few miles later the RPM's started fluctuating, small at first, then larger and larger until the RPM's petered out and it died again. It restarted no problem, but only went another 1/2 mile and died again. Again it restarted just fine, but then wouldn't move anymore. In gear, neutral or park it would idle for a few seconds then get real rough and die. If I hit the gas it just immediately dies.

Ive never seen anything like this. I thought maybe a bad fuel pump or filter, but it restarts every time no problem, so its getting fuel. I thought maybe a massive intake leak after the MAF, but nothing was immediately visible.

A pic of the walk of shame for folks that need to see it:

Open to ideas? Strange to me how it happened so suddenly, and so catastrophically.

 

[LINUS]

If you never changed the fuel filter, it couldn’t hurt - sure, it starts, but a bunch of crap can re-plug it.
-Cheap & easy if you never did it.

Others:

Vacuum lines (cracked/old)
Intake tube cracked / poor metering
Injectors residue / buildup

***downright a batch of bad gas / bottom of station tank & you bought some $3.99/gal water***

-Just the few easy looks off top my head - HTH

 

[Seth_O]

If you never changed the fuel filter, it couldn’t hurt - sure, it starts, but a bunch of crap can re-plug it.
-Cheap & easy if you never did it.

Others:

Vacuum lines (cracked/old)
Intake tube cracked / poor metering
Injectors residue / buildup

***downright a batch of bad gas / bottom of station tank & you bought some $3.99/gal water***

-Just the few easy looks off top my head - HTH

Cheers for chiming in. I replaced the fuel filter about 5 yrs and 50k ago? I was halfway through a tank of fuel from Sam's Club (Chevron is the provider.) I'll take a look at the vacuum lines and intake tube. It does sound like my head was in the right spot though: a fuel or vacuum issue is likely.

 

[nhall80]

I’ve known fuel filters in my old mustang to block up with debris and kill the engine, and then when the debris settled to the bottom the engine started and ran for a minute or two until the debris picked back up. Not sure that’s your problem but as was suggested, it’s a simple place to start…

 

[LINUS]

I’ve known fuel filters in my old mustang to block up with debris and kill the engine, and then when the debris settled to the bottom the engine started and ran for a minute or two until the debris picked back up. Not sure that’s your problem but as was suggested, it’s a simple place to start…

Same experience w/ problematic fuel delivery & fuel filters.

Enough fuel sneaks by to idle, but when you really put a draw & need to move volume, the sediment rides back up & chokes the delivery.


@Seth_O - might check the accordions of the intake to start, see if it’s cracked - if you have a 50K on the filter, I’d start by eyeballing that 28yo intake & the vac tubes, but if they all look good then the fuel filter is the cheapest part / easiest to rule out.

You really need to pull the intake tube & look it over completely - lots of cracking likes to hide underside in the flex ribs, close to the throttlebody / valve cover heat rising.

GL!

 

[clx16]

Just because the fuel pump is pumping doesnt mean it is pumping well or providing enough pressure.

 

[MickeyB]

I DD my '93 and have never had any real issues with it. Today I started it up and backed out of my parking spot and it randomly died. Thats never happened before, but it fired right back up and got underway again. A few miles later the RPM's started fluctuating, small at first, then larger and larger until the RPM's petered out and it died again. It restarted no problem, but only went another 1/2 mile and died again. Again it restarted just fine, but then wouldn't move anymore. In gear, neutral or park it would idle for a few seconds then get real rough and die. If I hit the gas it just immediately dies.

Ive never seen anything like this. I thought maybe a bad fuel pump or filter, but it restarts every time no problem, so its getting fuel. I thought maybe a massive intake leak after the MAF, but nothing was immediately visible.

A pic of the walk of shame for folks that need to see it:

View attachment 2768604

Open to ideas? Strange to me how it happened so suddenly, and so catastrophically.

How many miles? How old is the intake tube, fuel pump? Also have you have the head cover gasket leaking oil?

 

[Seth_O]

How many miles? How old is the intake tube, fuel pump? Also have you have the head cover gasket leaking oil?

~320k on the odometer. Intake tube is (to my knowledge) original. Fuel pump as well, although the fuel filter was replaced ~50k/5yrs ago when i did the HG. No oil leaks that I know of.

 

[MickeyB]

~320k on the odometer. Intake tube is (to my knowledge) original. Fuel pump as well, although the fuel filter was replaced ~50k/5yrs ago when i did the HG. No oil leaks that I know of.

So with that couple things. I would put on a new intake hose, since yours is pretty old. The other item to inspect which is pretty easy are the fuel pump terminals inside the engine bay fuse box. Pull the fuse on the fuel pump and check for corrosion or loose connection. In my 94 LC the engine would cut of intermittently. I ended up replacing the fuel pump and the relays that did not fix the issue so took it Toyota. They wiggled the fuse for the fuel pump in the engine bay and truck would die. Luckily mechanic was old school and told me it was pretty common problem on the LC that the terminals would corrode and loose connectivity. Also he said they used to small of wire for the current that was going through so it would get really hot and cause issues. They replaced the terminals and no issues since.

As others have mentioned could be bad fuel, which I though what was going on with mine. However if you research bad fuel that’s never the case nowadays.

Fuel pump you can do a pressure check on, but if it’s the original pump I would just put in a new one for piece of mind. There not to expensive and you can get them from Rockauto. It was about a 2-3 hour job when I did it.

 

[MickeyB]

One more thing is it throwing any codes?

 

[Seth_O]

One more thing is it throwing any codes?

No codes

 

[MickeyB]

That makes me think fuel system. The system is straight forward and will not throw any codes. Trucks just die when something is not working. That’s what the Master Toyota tech told me.

 

[effjay80]

God that picture

 

[Seth_O]

I pulled the intake tube and it looks good, no cracks or holes at all. I checked the EFI fuse, relay and contacts. Everything is clean and good.

Now the motor barely fires over and then dies. I'm really leaning towards bad fuel/plugged filter. In thinking about it I realized this was the first ever tank of fuel I bought from the Kwik-e-serve instead of Sam's. That seems a likely culprit.

 

[Seth_O]

You know, this makes me really wish I had something to make this job simpler. If only there were something like a fuel filter relocator. Gosh that would make things better. Wouldn't it @NLXTACY?

 

[NLXTACY]

You know, this makes me really wish I had something to make this job simpler. If only there were something like a fuel filter relocator. Gosh that would make things better. Wouldn't it @NLXTACY?

I actually have a customer here that may push that project forward

 

[Irish Reiver]

In thinking about it I realized this was the first ever tank of fuel I bought from the Kwik-e-serve instead of Sam's. That seems a likely culprit.

If you think it is bad fuel (although I am not quite sure what that means) you could unscrew the drain plug and drop some in a clear jar. Water is denser than gas so the water should be at the bottom of the tank and thus in your jar.
If that shows up nothing then pop the inspection cover off the tank and look at the filter sock. You can also see if the tank is full of shlte. I can't imagine that the concept of bad fuel exists in the US but who knows.

 

[Seth_O]

If you think it is bad fuel (although I am not quite sure what that means) you could unscrew the drain plug and drop some in a clear jar. Water is denser than gas so the water should be at the bottom of the tank and thus in your jar.
If that shows up nothing then pop the inspection cover off the tank and look at the filter sock. You can also see if the tank is full of shlte. I can't imagine that the concept of bad fuel exists in the US but who knows.

All good steps to check.

I've heard that all the gasoline in the US comes from one of a only a few refineries, and it's all pretty much the same base quality and then the proprietary blends have additives (e.g. techron.)

That being said, some gas stations let their tanks get emptier than others, and could potentially pull junk or water off the bottom of their storage tank. Or you could buy gas right after it got stirred up by a refill maybe and suck a bunch of junk up into your tank.

At least those are the theories.....

 

[MickeyB]

All good steps to check.

I've heard that all the gasoline in the US comes from one of a only a few refineries, and it's all pretty much the same base quality and then the proprietary blends have additives (e.g. techron.)

That being said, some gas stations let their tanks get emptier than others, and could potentially pull junk or water off the bottom of their storage tank. Or you could buy gas right after it got stirred up by a refill maybe and suck a bunch of junk up into your tank.

At least those are the theories.....

All good steps to check.

I've heard that all the gasoline in the US comes from one of a only a few refineries, and it's all pretty much the same base quality and then the proprietary blends have additives (e.g. techron.)

That being said, some gas stations let their tanks get emptier than others, and could potentially pull junk or water off the bottom of their storage tank. Or you could buy gas right after it got stirred up by a refill maybe and suck a bunch of junk up into your tank.

At least those are the theories.....

Don’t worry it’s not the gas. When I changed my fuel pump the tank was spotless. Plus you have filter on the pump so none of that is going into the engine.

 

[LINUS]

Don’t worry it’s not the gas. When I changed my fuel pump the tank was spotless. Plus you have filter on the pump so none of that is going into the engine.

I was a refinery plant operator - the final product is good leaving the plant is water-free but a bad tank at a gas station is very real still in 2021.

Ethanol is a hygroscopic binder (why an occasional fill of it is good even in marine applications where ideally you want no alcohol fuel as the routine, picks up any fixed tank condensate).

— But if you live where temps fluctuate decently or any number of external factors of filling station tanks means water/soil can be present, from old unlined steel tanks that rust/leak groundwater & dirt to a simple worn seal on the filler port the tankers use to deliver from their truck to station tanks & you get a good rainstorm.

The fuel you put in your tank goes through a minimum of 3 tanks before you squeeze the nozzle - sediment is easily passed along.

Shine a flashlight in any small plastic gascan - you’ll easily see some particulate matter.

So I 100% disagree that “bad gas” is a thing of the past - to think otherwise is like thinking Taco Bell uses the exact same grade beef as Peter Luger’s steakhouse in NYC.