93 civic backfire

[bowlofturtle]

A coworker of mines is having trouble with his civic. Its a 93 vtec, automatic model with 150k. It starts and moves pretty decent.

His problem is when it isn't warmed up, it would backfire at RPM above 2.5k randomly. Really nasty poping noises and somewhat chunging. Its a lot better once warmed up.

Common sense was to start with a simple tuneup. He told me he did the cap and rotor a while back ago but he moved the distributor, so i think he screwed up the timing hence why the backfire on colder engine.

He has done air filter, cap, rotor and now plugs and wires. Will be doing a fuel filter shortly and i'll help me check out the ign-timing.

I never found those honda connectors to disable ECU from adjusting timing. Everyone says its easy and in the pass side floor. All i ever found was the blower motor.

 

[The_Eric]

I think you already know the problem. And even if it's not the issue, it needs to get fixed so everybody isn't chasing their proverbial tails...

FYI, the connector (blue?) can be on the floor area, or I have also seen them tucked under the dash, close to the kick panel.

 

[Dakota1820]

actually im not sure but i dont think those distributors are adjustable. are they ? i know the late 90 ones are not.

 

[bowlofturtle]

All distributors can be used to adjust ign timing AFAIK. From 350 chebby to this civic. Of my personal cars i've only have one car using it. I set the timing once and the grounding port was in the engine bay.

I was still never able to find that connector, on the 2 civics i worked on. THis being the 3rd but i haven't looked for it yet. All yotube videos show them to be so easily pulled.

I'll bust out the timing gun and try this out.

 

[SOHCman]

my 94 accord's distributor can be adjusted like your coworkers, but I was never able to get it to backfire or anything. The idea was to advance it and run premium fuel, but the difference was so negligible I put it back to stock timing. Slightly bigger engine, but no backfiring or anything.

Parhaps his timing belt has slipped a tooth???

 

[mechtech2]

Interim distributors [between old school to modern coil on plug or waste spark ignitions] are not used to set the ignition timing.
They only direct the spark to the proper wire and spark plug.

Sounds like retarded timing. Maybe a lean condition.

 

[SOHCman]

Originally Posted By: mechtech2
Interim distributors [between old school to modern coil on plug or waste spark ignitions] are not used to set the ignition timing.
They only direct the spark to the proper wire and spark plug.

Sounds like retarded timing. Maybe a lean condition.


Are you saying the distributor on this vehicle does not set the timing? I don't believe that to be correct.

 

[Tegger]

Originally Posted By: SOHCman
Are you saying the distributor on this vehicle does not set the timing? I don't believe that to be correct.

Ignition timing on the '93 Civic is done through rotation of the entire distributor.

If the timing is suspected to be incorrect, and no timing light is available, a very rough correction can be done by centering the distributor housing's upper bolt in its slot. This will set the timing closely enough that there should be no backfiring.

If backfiring persists, then there is some other sort of problem, such as a timing belt that is off by a tooth or two.

 

[mechtech2]

Originally Posted By: SOHCman
Originally Posted By: mechtech2
Interim distributors [between old school to modern coil on plug or waste spark ignitions] are not used to set the ignition timing.
They only direct the spark to the proper wire and spark plug.

Sounds like retarded timing. Maybe a lean condition.


Are you saying the distributor on this vehicle does not set the timing? I don't believe that to be correct.


No. I was referencing bowturtle who said all distributors can set timing. I have no idea about exactly what is in all cars, all years, all models.