The "Test Only" smog station failed my 90 Accord and said that my timing was at 11 BTDC (should be set at 15 BTDC).

So I found info on how to set the timing on 4th Gen Accords and went and bought a timing light.

Every thing worked well except for one thing. I installed a jumper cable on the service connector located under the passenger front dashboard as per the instructions that I downloaded and set the timing to 15 BTDC.

I then removed the jumper cable from the service connector and rechecked the timing. Upon removal of the jumper, the timing went back to 11 BTDC.

The instructions that I have says that I need the jumper their to perform the timing adjustment, but it did not work.

So I reset the timing with out the jumper and everything was fine.

I took my car back to the smog test station and they checked it again and said it was good (checked at 16 BTDC).

Is it wrong to use a jumper to set timing on 4th Gen Accords? Did I get bad info?

The service connector that I used was blue and it had 2 pins down inside of it.
Did I use the correct service connector?

TIA

Car passed smog test by the way.

 

umm, im assuming the test only station did not even use a jumper cable. how was the test before and after the timing change?

when is et mine, i never put the jumper in and for shits and giggles, i did it and it still came out to the same.

 

Correct.
The "Test Only" station is just that. TEST ONLY.
They are not allowed to make any adjustments, it is either PASS or FAIL.
And they do not use a jumper to check the timing.


I took my Accord in for a smog check (every 2 yrs in California)
and it failed because the ignition timing was off.
I then bought a timing light and adjusted the timing myself,
then I went back to the "Test Only" station for a retest and passed.

I'm the one who used a jumper in the service connector and set the timing to 15 BTDC.
When I pulled the jumper out the timing went back to the original bad timing of 11 BTDC.
So using the jumper was useless and a waste of time.

I got the info from this forum to use a jumper prior to adjusting the timing, but I believe it is bad information.

 

The procedure to use a jumper in the SCS connector comes from the Helm manual (factory shop manual). But I don't have a Helm book for 1990...

The idea is to tell the ECU to QUIT making it's constant little timing adjustments based on idle control and knock sensor. However...
1) I don't think a '90 Accord has a knock sensor.
2) Maybe the procedure is different for '90?
3) Maybe your base idle is set too high & the ECU is trying to pull it back?

 

did you notice anything improved (gas/acceleration) after correcting the timing?