Honda Car Forum

I have a 1987 Honda Prelude 2.0 SI. It's the fuel-injected model. If
the car is cold, it will start up immediately and runs great - i can
lay a patch of rubber. It will run perfectly immediately following a
cold start. Once the car has traveled a few miles, however it starts
to lose power quite dramatically as I attempt to rev it up past about
2000 RPM as though it were starving for fuel or air or something. The
problem will happen in any gear but seems a teeny bit more pronounced
in the higher gears. Around this time, the PGM-FI light comes on on
the dash.

I've been looking at this problem for some time now and I have had
some repairs done:
* rebuilt/replaced fuel injectors
* new fuel pump
* new air/fuel/oil filters
* replaced EGR valve
* checked main relay for broken solder - it seems fine

After posting here previously someone told me to check the ECU codes.
The ECU code that is blinking is code #12 which for my car means a
problem with the EGR system. When I took the car in for repairs last
January to a small shop, the mechanic claims he replaced the EGR valve
so I'm inclined to rule that out.

Any hints on what it could be? Would a clogged oxygen sensor result
in the ECU sending code 12? Any advice would be much appreciated! I
MUST fix this problem and simply cannot afford expensive repairs.

zardozrocks wrote:

> I have a 1987 Honda Prelude 2.0 SI. It's the fuel-injected model. If
> the car is cold, it will start up immediately and runs great - i can
> lay a patch of rubber. It will run perfectly immediately following a
> cold start. Once the car has traveled a few miles, however it starts
> to lose power quite dramatically as I attempt to rev it up past about
> 2000 RPM as though it were starving for fuel or air or something. The
> problem will happen in any gear but seems a teeny bit more pronounced
> in the higher gears. Around this time, the PGM-FI light comes on on
> the dash.
>
> I've been looking at this problem for some time now and I have had
> some repairs done:
> * rebuilt/replaced fuel injectors
> * new fuel pump
> * new air/fuel/oil filters
> * replaced EGR valve
> * checked main relay for broken solder - it seems fine
>
> After posting here previously someone told me to check the ECU codes.
> The ECU code that is blinking is code #12 which for my car means a
> problem with the EGR system. When I took the car in for repairs last
> January to a small shop, the mechanic claims he replaced the EGR valve
> so I'm inclined to rule that out.
>
> Any hints on what it could be? Would a clogged oxygen sensor result
> in the ECU sending code 12? Any advice would be much appreciated! I
> MUST fix this problem and simply cannot afford expensive repairs.
>
Hi,
Manifold vaqcuum leak?

zardozrocks wrote:
> I have a 1987 Honda Prelude 2.0 SI. It's the fuel-injected model. If
> the car is cold, it will start up immediately and runs great - i can
> lay a patch of rubber. It will run perfectly immediately following a
> cold start. Once the car has traveled a few miles, however it starts
> to lose power quite dramatically as I attempt to rev it up past about
> 2000 RPM as though it were starving for fuel or air or something. The
> problem will happen in any gear but seems a teeny bit more pronounced
> in the higher gears. Around this time, the PGM-FI light comes on on
> the dash.
>
> I've been looking at this problem for some time now and I have had
> some repairs done:
> * rebuilt/replaced fuel injectors
> * new fuel pump
> * new air/fuel/oil filters
> * replaced EGR valve
> * checked main relay for broken solder - it seems fine
>
> After posting here previously someone told me to check the ECU codes.
> The ECU code that is blinking is code #12 which for my car means a
> problem with the EGR system. When I took the car in for repairs last
> January to a small shop, the mechanic claims he replaced the EGR valve
> so I'm inclined to rule that out.
>
> Any hints on what it could be? Would a clogged oxygen sensor result
> in the ECU sending code 12? Any advice would be much appreciated! I
> MUST fix this problem and simply cannot afford expensive repairs.

--------------------------

If it's a problem when it warms up, what's your TEMP gauge showing,
and how full is your rad and reservoir? Your engine can run like crap
if the computer is getting wrong info from the coolant sensor(s) because
they aren't immersed.

'Curly'

> Hi,
> Manifold vaqcuum leak?

Which manifold? How does one test it? Also, sounds expensive.

> If it's a problem when it warms up, what's your TEMP gauge showing,
> and how full is your rad and reservoir? Your engine can run like crap
> if the computer is getting wrong info from the coolant sensor(s) because
> they aren't immersed.
>
> 'Curly'

When I say 'warms up' I didn't mean to imply anything at all about the
temperature. I was only trying to imply that the problem happens once
the car has been running awhile...like after 20 minutes/5 miles or
so. The temp gauge appears to be fine...it definitely doesn't appear
to be running hot or anything. I'll check the radiator but I'm fairly
certain radiator levels are fine. The car doesn't leave any leak
spots at all on the driveway.

Thanks for the response.

zardozrocks wrote:
>>Hi,
>>Manifold vaqcuum leak?
>
>
> Which manifold? How does one test it? Also, sounds expensive.
Hi,
Intake. You can hook up vacuum gauge.

> Hi,
> Intake. You can hook up vacuum gauge.

Thanks for the response!

Wouldn't that problem be evident even when the car is cold? Any links
or advice on how to test or where to buy a vacuum gauge?

zardozrocks wrote:
>>Hi,
>>Intake. You can hook up vacuum gauge.
>
>
> Thanks for the response!
>
> Wouldn't that problem be evident even when the car is cold? Any links
> or advice on how to test or where to buy a vacuum gauge?
Hi,
Heat/cold expand/shrink things. You already done quite a few rmedial
tries. Checking vacuum for proper level won't hurt.
Also checking all the ground point like fuel pump ground joint is good idea.

> Hi,
> Heat/cold expand/shrink things. You already done quite a few rmedial
> tries. Checking vacuum for proper level won't hurt.
> Also checking all the ground point like fuel pump ground joint is good idea.

OK I'll buy the heat expansion/contraction, but I'm also wondering if
that will solve the car complaining about the EGR problem (code 12 on
the ECU).

Most importantly, HOW do I check for a vacuum level on the intake
manifold? Got any links or suggestions?

zardozrocks wrote:
>>Hi,
>>Heat/cold expand/shrink things. You already done quite a few rmedial
>>tries. Checking vacuum for proper level won't hurt.
>>Also checking all the ground point like fuel pump ground joint is good idea.
>
>
> OK I'll buy the heat expansion/contraction, but I'm also wondering if
> that will solve the car complaining about the EGR problem (code 12 on
> the ECU).
>
> Most importantly, HOW do I check for a vacuum level on the intake
> manifold? Got any links or suggestions?
Hi,
Take a minute and think about how EGR valve operates. Manifold vacuum
does many things. One example is helping brake master cylinder. Usually
there is a test port for vacuum connection with little rubber nipple cap
on it, or you have to find where you can tap into vacuum line using a T
fitting. Vacuum level is highest when idling. If it fluctuates wild or
unsteady moving up and down, etc. Bad sign.
I am not pretending an expert but this is very basic stuff.
DTC code is a starting point for trouble-shooting a problem. It does not
mean pointed part is bad. Old cars often have cracked vacuum hose
causing leak as well.