Caravan 2.5 TBI

[Ted]

Hello All:

I have a 1990 Caravan 2.5 TBI that was running great before I put in
the garage for major front suspension refurb where it sat for almost 2
months. When I finished the work and took it out for a test spin, the
engine bogged down really bad as long as it was cold and black sooty
stuff blew out of tail pipe. Had to really baby the throttle to get
it up to speed or just put it to the floor. When it warmed up, ran
MUCH better, no soot out the tailpipe, but I could tell that it wasn't
running at its full potential. Gas mileage went down from about 22
mpg to 14 mpg.
Last night, I pulled the air cleaner off while the engine was running
and fuel was squirting straight up out of the fuel regulator in a
steady stream. Now I don't know anything about these injection fuel
systems, but that just doesn't look right to me, OR safe. Am I right?
If it is not correct, what would cause this problem, is it as simple
as replacing the regulator, or is there external sensors making the
regulator do this?
TIA for your help.

Ted

 

[Dave Gower]

Last night, I pulled the air cleaner off while the engine was running
and fuel was squirting straight up out of the fuel regulator in a
steady stream. Now I don't know anything about these injection fuel
systems, but that just doesn't look right to me, OR safe. Am I right?

You are very right on both counts. Sounds like a stuck injector (I presume
that's what you mean when you say "regulator". I forget the price but
they're not expensive. Don't drive it until it's fixed.

 

[Ted]

You are very right on both counts. Sounds like a stuck injector (I presume
that's what you mean when you say "regulator". I forget the price but
they're not expensive. Don't drive it until it's fixed.

The 2.5 TBI has a fuel pressure regulator mounted on top of the
throttle body in front of the injector. It keeps the fuel pressure
constant at 14.5 psi. I replaced it, and it now runs like a top.
Thanks for the confirmation that the stream of fuel shooting straight
up was not correct.
Ted

 

[Daniel J. Stern]

The 2.5 TBI has a fuel pressure regulator mounted on top of the
throttle body in front of the injector. It keeps the fuel pressure
constant at 14.5 psi.

This information does *not* apply to all years ('86 to '95) of the
2.2/2.5 TBI. Different system pressures were used in early vs. late
applications - 14.5 is the "low" pressure system, and 35 (I believe, maybe
45) is the "high" pressure system. The fuel pump, fuel pressure regulator
and fuel injector are not interchangeable between low and high pressure
systems, so it's important to get the one that applies to your model year
vehicle.

DS