I've about had it with this truck. It was trying to leave me stranded in Steamboat a few weeks ago when the alternator went out (even though the one in there was <1 year and <8k miles old), and now this.

Ok, so yesterday I went out to start it like I do every morning that it is colder than 50* (rebuild engine, I like to let it warm up before driving). I go out 5 minutes later, and it's not running. Crank it over, but it won't fire. F* it, taking another car to work.

Get home 9 hours later, and it starts fine. I wait around and about 2 minutes in (I think when it went into closed loop) it starts running bad, and bogging down. I wait until I think it's about to stall, then I bring the revs up and it acts like nothings wrong. I let it return to idle, and it dies. Same thing, won't start.

Mess around with it again this morning. Here is what I have looked at so far:

The fuel pump relay clicks when the problem is present
The air meter moves freely, and the spring feels good to me.
Newer plugs, wires, cap, rotor (<8k miles ago). Still look good now.
No engine codes present.
The problem still exists when the coolant sensors are unplugged (was thinking one was bad telling the ECU the car was at high operating temp, which would make it stall).

Any thoughts? I'm seriously burnt out on this thing.


Thanks for your time.

 

any chance that you have a bad vacuum line on something that would open during closed loop? Doubt there is any vacuum lines big enough though to shut the engine down. only something the size of the PCV comes to mind. But I guess it's worth checking out.

 

I didn't specifically check vacuum lines, but I did notice the PCV hooked up on the valve cover. Possible it is unhooked at the other end, but like you said, I doubt it would cause this. It would at least try to fire. When I'm cranking, the engine doesn't even try to start.

 

yeah it would start then die if it were a vacuum leak.

What about your cold start time switch? Have you tested that?

While I am thinking about it, when it won't start, I believe you can jump the fuel pump test connector and try to start as well.

 

I have not, and don't know how to (although I'm sure it's in the service manual).

Where is the fuel pump test connector? I've got ~6 connectors under hood that it could be lol.

 

check the 4crawler website, I believe they have the locations.

 

Ok, it's still broken. Here is what I've found now:

I tried to see how long I could keep it running, but it still stalled on me, even though I had the pedal 1/2 way to the floor (the problem was getting progressively worse until it died)
I have 0v at the fuel pump when cranking before the problem arises (when it would start if the connector wasn't unplugged) and after his has stalled.
The problem is unaffected with the TPS disconnected
The problem is unaffected with the IAC hose disconnected (both with the open port plugged and unplugged)
It tries to run when I spray brake clean in the throttle body (telling me it's fuel related)
I unhooked the fuel line going to the cold start injector and cranked the enigne after it had stalled, and no fuel came out.

The fuel filter and fuel pump are ~15k miles old.

So, anyone got any thoughts? Anyone in Denver want to fix my problem? I'll buy pizza, beer, etc...

 

Do you know if the vented fuel cap on the tank is still working properly? I only ask because it sounds like a vapor lock. Need to confess here that I don't know if Toyota's are susceptible to vapor lock or not.

 

It's something to check, but I kinda doubt it. Most cars with the fuel pump in tank are very insusceptible of becoming vapor locked.

 

That's kind of what I figured but decided to throw it out there.

 

Anyone in the Denver area have a fuel pressure gauge with the longer banjo bolt attachment that I could borrow?

 

Anyone ^?

 

Just an idea, but have you checked the core relay ?, maybe its bad and after a couple of minutes it gets hot and looses power.

 

has he jumpered the fuel pump yet to see if it gets power then?

 

Where is the core relay?

I have yet to find a location to jump on an '86. I've got the shop manual for '87, but it's not there on an '86...

 

Top photo circled in red, bottom photo shows jumper.

http://www.4crawler.com/4x4/CheapTri...CheckConnector

 

The core relay is mounted in front of the computer, but just above it.

 

ok, just did some more messing around with it. I tried cranking without pushing the clutch pedal, and I heard a sound that I'm 95% sure was the fuel pump. I clicked it back and forth a few times, then the noise stopped. I started the truck, and it died after 2 seconds. Wouldn't restart. I tried shorting that connector, but all that did was make a relay behind the glove box click (I think this is the one that myyota is talking about). So, for sure the fuel pump, or should I check some other things first (I hate throwing a $140 fuel pump at it if it doesn't really need one...)

 

Anyone ^?

 

Is that the Core relay (the one behind the glove box)?