Honda Car Forum

My son's 91 civic with a regular 1.5 liter engine had some problems with oil
leaks and leaking head gasket. A used engine dealer talked us into replacing
the engine ( long and short block)with a used VTEC model as it has more
torque and power. He claimed everything else could be retained from the old
engine. Here is what's happening after the transplant.

1.\ Idle especially with a cold engine goes drrrttt-drrrttt-drrrttt-drrrttt,
idle improves when the engine warms up, roughness sometimes even disappears
..

2.\ If I let go of the accelerator when going at any speed, engine RPM drops
abruptly and feels like the engine is going to stall but it won't.

3.\ I noticed a green connector beside the distributor assembly but nothing
is hooked to it. I asked the used engine dealer's mechanic what is it. He
told me that the connector is supposed to be be hooked up to the computer,
that without that being connected, the engine runs as a regular non-VTEC
engine. Mechanic also told me that I will have to replace the engine
management computer in order for the VTEC feature to function.

We don't want to spend much and we can live without the VTEC feature but is
there a way to make the engine run smoother? Comments please and thank you.

"nntp" <renora@rogers.com> wrote in
news:Mfmvc.542$8tr1.455@news01.bloor.is.net.cable. rogers.com:

> My son's 91 civic with a regular 1.5 liter engine had some problems
> with oil leaks and leaking head gasket. A used engine dealer talked us
> into replacing the engine ( long and short block)with a used VTEC
> model as it has more torque and power. He claimed everything else
> could be retained from the old engine. Here is what's happening after
> the transplant.
>
> 1.\ Idle especially with a cold engine goes
> drrrttt-drrrttt-drrrttt-drrrttt, idle improves when the engine warms
> up, roughness sometimes even disappears .
>
> 2.\ If I let go of the accelerator when going at any speed, engine RPM
> drops abruptly and feels like the engine is going to stall but it
> won't.
>
> 3.\ I noticed a green connector beside the distributor assembly but
> nothing is hooked to it. I asked the used engine dealer's mechanic
> what is it. He told me that the connector is supposed to be be hooked
> up to the computer, that without that being connected, the engine runs
> as a regular non-VTEC engine. Mechanic also told me that I will have
> to replace the engine management computer in order for the VTEC
> feature to function.
>
> We don't want to spend much and we can live without the VTEC feature
> but is there a way to make the engine run smoother? Comments please
> and thank you.
>
>
>

You need the ECU (engine control unit,or 'computer') from a VTEC car
because thats what controls the VTEC function.The VTEC function is integral
to that engine.
The ECU also has the proper "map" for that engine.(proper fuel and ignition
management at any particular RPM)

--
Jim Yanik
jyanik-at-kua.net

nntp wrote:

> 1.\ Idle especially with a cold engine goes drrrttt-drrrttt-drrrttt-drrrttt,
> idle improves when the engine warms up, roughness sometimes even disappears

If by that you mean that the idle speed keeps fluctuating, then it could
be a problem with the coolant. There is a fairly elaborate procedure for
filling and bleeding the system on some Hondas. If you have air pockets
trapped in the system, you can get fluctuating idle.


> 2.\ If I let go of the accelerator when going at any speed, engine RPM drops
> abruptly and feels like the engine is going to stall but it won't.

Does the RPMs drop below normal idle speed and then bounce back up to
normal, or are you just concerned about how quickly it drops down to
idle?

In article <Mfmvc.542$8tr1.455@news01.bloor.is.net.cable.roge rs.com>,
"nntp" <renora@rogers.com> wrote:

> My son's 91 civic with a regular 1.5 liter engine had some problems with oil
> leaks and leaking head gasket. A used engine dealer talked us into replacing
> the engine ( long and short block)with a used VTEC model as it has more
> torque and power. He claimed everything else could be retained from the old
> engine. Here is what's happening after the transplant.
>
> 1.\ Idle especially with a cold engine goes drrrttt-drrrttt-drrrttt-drrrttt,
> idle improves when the engine warms up, roughness sometimes even disappears
> .
>
> 2.\ If I let go of the accelerator when going at any speed, engine RPM drops
> abruptly and feels like the engine is going to stall but it won't.
>
> 3.\ I noticed a green connector beside the distributor assembly but nothing
> is hooked to it. I asked the used engine dealer's mechanic what is it. He
> told me that the connector is supposed to be be hooked up to the computer,
> that without that being connected, the engine runs as a regular non-VTEC
> engine. Mechanic also told me that I will have to replace the engine
> management computer in order for the VTEC feature to function.
>
> We don't want to spend much and we can live without the VTEC feature but is
> there a way to make the engine run smoother? Comments please and thank you.

I advise you to find out what type (example 1996 Honda Civic) of car the
engine was removed from. Once you find out the information, visit a junk
yard and buy a computer and hook it to the connector.

--
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