Over the last few days, when I drive less than 5 miles, then shut the Trooper off for a few minutes, it won't restart ('91 2.8 TBI V6). If it sits for more than an hour, it restarts no problem. If I try to restart immediately after shutting it off, no problem.

But...if it sits for 10 minutes to 1/2 hour or so, no start. <img src="/forums/images/graemlins/confused.gif" alt="" /> I had an appointment yesterday a couple miles from work, wound up having to walk back because it wouldn't restart. Got a ride back after work and it started just fine. <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

I haven't had time for a lot of trouble shooting yet, I did look at the distributor cap and rotor last night, they were a bit pitted, so cleaned them up (no help). I pulled a couple of the spark plugs, they had no discoloration or deposits.

When I did get it restarted, I noticed the injector pods (TBI, not MPFI) were leaking quite a bit (stream, not spray). Could the problem be vapor lock from the extra gas? Kind of seems to fit with it only happening when the engine is warm...it cranks like crazy, but doesn't even sound like it's trying to 'catch'. I tried removing the gas cap to depressurize the fuel system, but that didn't help either.

I have a replacement set of injectors already (waiting on the gasket set to install), but should I still be looking for other things? Ignition coil?

If it does sound like vapor lock, anybody have any tips to help start a vapor locked TBI engine until I get the injectors replaced?

Thanks,

Jay

It does kinda sound like vapor lock...you can try insulating the fuel line so the fuel doesn't boil after the engine is turned off.

But one other possibility to think about is an electrical contact problem, where expansion of the electrical components when warm is causing a connection to fail, until the parts cool and shrink back together again.

What about a possible fuel pump going bad? Same thing happened to my old 1986 Celica and is kind of happening to my current trooper. I haven't pulled it yet though. Just a thought.

- Jim

does a fuel pump start to get loud before it goes out?

kevan

Yeah, that was one of my thoughts also, I didn't dig out my book last night, I was going to run the resistance tests on the ignition components while it's in 'no-start' mode and see if they're different than when cold.



Wondered about that too, although the bad connector issue doesn't seem (from what I've read) to happen as often on the Troopers. How many folks out there have had fuel pump failures on the 1st Gen Troopers? Or corrosion at the pump connector block? I've only got 120K miles on mine...

Sigh, you have to love intermittent problems <img src="/forums/images/graemlins/pfft.gif" alt="" />

Keep 'em coming...

Thanks everyone,

Jay

Probably more important than the miles on your rig is the thirteen or fourteen years on your rig (and mine).

Happened again today...late back to work from lunch <img src="/forums/images/graemlins/frown.gif" alt="" />

Fiddled with numerous things, Murphy's Law, didn't have my multimeter or the time to check the ignition components like I intended. Might have been coincidental, but it finally restarted after I gave each injector a few taps.

So, I plan to replace the injectors this weekend. The Haynes manual also says warm restart problems can be due to the valves needing to be adjusted. How often (or ever) does anyone adjust their valves on the 2.8's?

There is no ticking (when it runs <img src="/forums/images/graemlins/pfft.gif" alt="" />), what are the symptoms of the valves needing adjustment? Hard starting when warm??? <img src="/forums/images/graemlins/lol.gif" alt="" />

Thanks,

Jay

The 2.8 has hydraulic lifters, so they "should" not ever need to be adjusted. I think that is the wrong tree to be barking up.

It's highly unlikely that you are vapor locking.
Fuel injected engines generally do not vapor lock. They can, but it's extremely rare.
Because of the fuel pressures being so high and the line under a constant pressure helps prevent vapor locking. Also, because of the high pressures and constant return flow of fuel from the system, that helps prevent vapor locking also. A Carb'd engine doesn' return fuel... once the 5 or 6 lbs of fuel pressure builds up and the float bowl is filled, the pump shuts off until the bowl needs filled again (when the pressure drops). A fuel injected engine is contanstly flowing fuel up to the rail or throttle body and returning the fuel back to the tank.
When you shut your engine off and go to crank it again, the fuel pump is going to force (upwards of 30 - 60lbs pressure)any fuel and "vapor" through the system and return it to the tank. You might experience some short bursts of cranking before it lights off, but it shouldn't prevent it from starting at all.

Come to think of it my 88 2.6L did this some and I changed out the fuel pump relay and it never did it again. The relay may be getting cooked and needs time to cool down!?!?maybe.


Madcat <img src="/forums/images/graemlins/kewl.gif" alt="" />