90 Dodge Spirit - cold start & gas mileage

My daughter has a 90 Dodge Spirit, 4 cyl 2.5 L carb engine. It
occasionally has been hard to start when real cold (Wisconsin winter
cold, 10 degrees and lower), the gas mileage is not what I think it
should be (low 20's on mostly highway driving); and it has twice
stopped on her when driving (when she stopped at a light) and would not
start up. Seems like a classic case of flooding when it wouldn't start
- both times it started right up a couple of hours later when I tried
it. The engine computer has not stored any trouble codes when it
stopped or at any time. It just passed the annual emissions test (they
plugged into the computer, didn't sniff the exhaust).

I have replaced the inductive pick-up in the distributor, the spark
plugs, wires, distributor cap and rotor. I tried replacing the TBI fuel
injector, but the engine wouldn't catch with the new one in - didn't
smell any gas coming through (put the old one back in and it started
fine).

Any suggestions?

 

Also, regarding your low-mileage complaint: How long since the Oxygen
sensor was replaced? They tend to get lazy/slow with age and use. They
won't set a code until they actually stop switching, but a slow O2S will
put a dent in mileage.

Use a Mopar, NTK, Echlin or Standard-BlueStreak, NOT a Bosch.

DS

 

How many miles have you got on it? Mid-to-high 20s is more normal highway
mileage in that car with that engine and that trans, but if you're in
Milwaukee-metro or another area where oxygenated gasoline is mandated in
winter, that can drop the MPGs by several. The refusal to start and the
stalling is not normal.

That doesn't necessarily indicate flooding (did we try holding the
accelerator on the floor and cranking to see if it would fire immediately
after it stalled?).

OK, good, so you checked.

That's unfortunate -- sniff test results often give valuable information.

The injector was a good idea. Your '90 still has the original
ball-and-seat type injector, and those are somewhat problem-prone
(sticking open, sticking closed). You got a *new* injector, did you, or
was it a used/reconditioned one? Sometimes the recon ones don't work right
out of the box; carefully but firmly rapping their top surfaces (NOT the
electrical pins!) on a tabletop often frees them up. That said, new ones
are available and not very expensive through any Bosch jobber, and the new
ones are a more reliable pintle type.

Also, check your EGR system carefully; it could be stuck partially open or
failing to close properly.

Do a complete go-through of the PCV system (not just the valve!) and
careful inspection of ALL the vacuum hoses in the area of the throttle
body and camshaft cover. They cook/crack/break with age. Also, install a
different PCV valve from the one the parts store wants to hand you. Info
here: http://tinyurl.com/6hkvt

You'll want to remove the 60-pin disconnect from the engine control
computer (located outboard of the battery; remove battery to access single
10mm bolt holding connector to computer) and carefully inspect for
corrosion in pins or sockets. Clean if you find, liberally apply Ox-Gard
to connector sockets (work in with your thumb) and reinstall connector.

Another tough-to-trace fault that can happen on these cars is that
moisture can condense and/or freeze in the vacuum line to the MAP sensor.
The next time the car won't start, or stalls, unplug the MAP's electrical
connector. If it starts up, suspect the sensor, but first carefully
inspect the vacuum line to be sure it's not "wetted up".

If none of this reveals the problem, then the fix will have to be
preceeded by the use of a datalogging scanner.

Also, regarding your low-mileage complaint: How long since the Oxygen
sensor was replaced? They tend to get lazy/slow with age and use. They
won't set a code until they actually stop switching, but a slow O2S will
put a dent in mileage.

Use a Mopar, NTK, Echlin or Standard-BlueStreak, NOT a Bosch.

DS