Code 16 on a '91 Civic

This problem has been driving my nuts for awhile. I've changed the
injectors. What happens is that the check enigine light comes on (the
code 16) and if the car is idleing for 5 minutes it starts smoking,
floods out and dies. Sometimes it'll die at a stop sign too. No amount
of cranking will clear it and allow it to start. If I pull the wires to
the injectors it'll clear the flooded condition and start right up. I
hate to replace the ECU and find that the condition is caused by some
sensor. So, I guess my question is; is there some sensor that can cause
this problem and what's the test proceedure for the sensor. BTW, it's a
1.5l DPI engine.

Thanks for any help.

 

Try a google search. Lots of answers and checks. Search "Honda Civic code
16"

 

Code 16 often indicates a failed main relay. The main relay is located
under the the dash at the far left side by the coin tray and it controls the
fuel injectors. A relay failure is quite common with a car of this age. A
common problem with the relay is cracked solder joints and some people have
success resoldering them. I chose to replace mine with a new one from Honda
as the contacts inside the relay were pitted like an old set of distributor
points. Note that a new relay will run you about $40 or so.

Eric

 

Code 16 often indicates a failed main relay. The main relay is located

A bad main relay will not set any trouble codes, the main relay
controls the fuel pump and when it fails the car will not start,
usualy when it gets hot outside. This is not the problem Chuck
describes. Sounds more like a fuel pressure problem.

 

Actually, if just the right solder location cracks, the Main Relay CAN
set a code 16.
http://www.tegger.com/hondafaq/mainrelayoperation/badmainrelay.html

However, this will be accompanied by a no-start, not a flooded
condition.

OP has not stated the trim level of his Civic. I suspect it is below an
Si, in which case it has dual-point throttle body injection.

I agree with Grahame here; check the fuel pressure. That is a good place
to start. Certainly a better one than replacing injectors; Keihin
injector failure is extremely rare.

Also, the OP has failed to indicate whether the problem occurs on a cold
start or when hot. This is important. Is the cold-start injector (the
upper one) still spraying fuel after five minutes of idling? Has the OP
tried pulling ONLY the connector for the UPPER injector?

 

i don't think code 16 is your problem* - here's what i think is the clue:

"I've changed the injectors."

with the throttle body injection, the injectors are deep set and have 2
or 3 o-ring seals on them. on reinsertion, if you didn't grease
properly, i think you snagged one of the o-rings and now you're leaking
fuel into the t.b. you'll have to re-pull the injectors and check.

but this begs the question of why you pulled them in the first place -
is this a california vehicle and do you have a hesitation problem?


* - code 16 is usually a main relay problem. it happens on hondas this
age. either re-solder or replace as a matter of course. it won't
affect your injectors with the symptoms you describe.

 

in my experience, it does set a #16 on this vehicle. i've had no less
than 5 [yes five] 88-91 dpfi hondas with this problem. new/resoldered
relays fix it every time.

 

I checked this. 40psi at the fuel filter with the vacuum hose
disconnected.

 

I have a 91 Accord. Would you suggest replacing the relay on a
preventive basis? I have no symptoms and want none.

 

Yes, it's a DPI.

The fuel pressure checked ok.

I beleive this to be the problem. I don't think it's a leaky injector. I
guess my question should be; What will cause the ECU to power the upper
injector when it shouldn't be powered? A temperature sensor? Will this
cause a Code 16? BTW, I did check the wire harness and cleaned the
ground wire at the thermostat too.

 

Pull the connector from the upper injector. See what happens.

How old is your thermostat? Have you tested the ECT sensor for correct
resistance?

If the ECU is powering the upper injector inappropriately, it may have been
fooled into thinking the engine is too cold. Is there any overfueling
problem with the engine stone-cold? Or only when hot?

 

The O-ring that generally gets torn/folded is the one that goes into the
fuel rail. This results in fuel leakage into the engine compartment;
dangerous and smelly.

The seal that goes between throttle body and injector is an air seal only.
They are much larger and are harder to damage.

 

but there is no fuel rail on the dpfi - all the workings are housed
within the throttle body.

see above. i'll email you the diagram offline.

 

I see the diagram, thanks. The DPFI injectors are somewhat different
from the port-injected ones.
I also see I had it backwards which injector was the main one. It's the
UPPER injector that is the main one, not the lower.

However, it is not obvious how the O-rings shown could cause fuel
leakage if torn. The ones that are indicated on the diagram appear to be
air/vibration seals, performing much the same role as the big rubber
rings that are used in port injected cars.

Two questions:

1) Where is the fuel inlet? There should be a third (much smaller) O-
ring where the top of the injector goes into the fuel connection, should
there not?

2) Does the auxiliary injector supply fuel through a pintle on its end,
or does it instead somehow supply fuel through the drilling that angles
up from its body?

 

the fuel circulates in passages in the throttle body and enters the
injector through ports between seals 1 & 2 [iirc], if you're counting
from the narrow end. if seal 1 is munged or missing, you're getting
substantial leakage into the throttle air passage.

there is a 3rd ring iirc, at the thick end. mainly a dust seal i think.
can't recall for sure - the injector i have is at the bottom of the
parts bin.

through the injector end. technically, that's not the "pintle" - that
term refers to the trumpet shaped protrusion on the end of the injector
pin that forms the spray pattern when the pin moves to open. a lot of
diesel injectors don't have pintles.

 

Why not locate the Main Relay, then purchase a spare to keep available
for if/when it does go? Once you know where it is, replacing it is a
pretty quick task...


--
Joe - Registered Linux User #449481

"Hate is baggage, life is too short to go around pissed off all the
time..."
- Danny, American History X

 

I went to the wreckers today to get some trim parts. Wandering around, I
had a peek at a few Civics with DPFI. It was an education, that's for
sure.

On one vehicle, I removed the lower injector to have a look at it
(couldn't break the screws loose on the upper one due to poor leverage
and bad hammering angle; I didn't bring enough tools).

I see now what you mean. The fuel line goes into the throttle body, not
the injectors. On the injector I pulled, there is a series of narrow
rectangular screened "windows" arrayed around the injector between the
two O-rings. These admit fuel through the screens. The outer O-ring is
quite thick and robust, and, I would think, hard to tear.

The injector I pulled had a shallow green plastic "trumpet" surrounding
the nozzle and pin. Would this not be the "pintle"?

 

I hate to bring this up again, but this is my winter beater and I'd hate
to have it fail in the winter. I've been driving it about 1-1/2 months
now with no problems, but I haven't done anything to fix it either.

Maybe I have a clue to the problem. This car is used mainly to transport
the family snowboarding throughout the winter. It gets lots of moisture
on/in the carpets from the snow. Usually, the thing starts acting up 2
months into the season. I wonder if the moisture combined with the ECU
location could be giving me problems. I did pull the ECU cover and
didn't see any signs of water. If this scenario is feasible, I wonder if
I could install some sort of vapor barrier around the ECU that would
still allow it to ventilate.

BTW, the moisture problem is extreme. Every fall when I pull this car
out of the field, I have to scrub the whole interior with bleach to
remove the mold.

Thanks for any advice.