Well I pushed a paperclip in ports 5 and 6 and then ports 6 and 12. Turned the key over, and The Check Engine Light just stays lit up. Am I doing somethin wrong? I tried a few different ways to lodge the paper clip into the ports but nothing is happening! BTW, The car is an 89 Formula 350 with TPI. Ny help would be greatly appreciated!

 

Rik,
Did you turn the key to the "ON" position or the "RUN" position? The car must not be allowed to start at all while the jumpers are connected to the terminals. Turn the key to the "OFF" position. You want to connect terminals "A" and "B" with the jumper wire; the top right terminal and the one just to its left. Turn the key to the "ON" position. Make sure only the ignition is on, not the engine. That's all the procedure calls for. If the engine light is not blinking while the jumper is connected and the key is in the "ON" position, there is most likely a fault in your system. And be carful where you stick that jumper wire. If you connect certain terminals together, you could burn some sh** up.

 

The jumper should only be placed in contacts 'A' and 'B' to scan for stored error codes. Jumpering any other contancts may have less-than-desireable results. If you're REALLY lucky, you may not have smoked anything in the ECM.

 

If the A and B connectors are jumped and the engine is started you should get a steady flash either fast or slow depending on closed or open loop. If code 12 is flashing with engine running, then code 12 chart needs to be used to diagnose no reference pulse from distributor. That's why you get a code 12 with KOEO, because the computer doesn't see the distributor pulse.

 

DO NOT EVER START THE ENGINE WITH THE TERMINALS JUMPED. REGARDLESS OF WHAT ANYONE ELSE SAYS. DO NOT START THE CAR WITH THE TERMINALS JUMPED SHOULD I SAY IT AGAIN? OK.DO NOT START THE CAR WITH THE TERMINALS JUMPED.

 

On 2.5L engines and on Cadillacs that is the only way to check/adjust timing. There is no problem with grouding the diagnostic connector with the engine running.

 

But there is a huge problem with doing so in a TPI controlled vehicle, which he has. At least that's what I think he has. That's the only thing I was referring to. I didn't want to see the guy burn anything up.
----------
I just noticed your username, don't you have an L98?

 

If you ground the diagnostic terminal with the engine already runnin you enter field service mode, and the steady flashing of the ses light will tell you whether you are in open/closed loop and if you are rich/lean.

 

I didn't realize that. I have always been under the impression that if the terminals are grounded on a TPI, the engine should never be running. I have come across this warning in a few articles as well, citing the possability of damaging the ECM. If what you're saying is true I'm going to do some research on it because that would be a useful tool. I'm definately hesitant though because of all that I have read, and what I believed to be at stake.
----------
Toe, you are referring to a 5.7 TPI, right?

 

As far as I know, its a GM ecm thing, and should work with most. I interpret the warning as "never ground while starting, but afterwards is ok." I'll try some searches and see what I can dig up.
Edit- Found some posts which reference the field service mode, and may be useful.
https://www.thirdgen.org/forums/tech...d+service+mode

 

Thanks Toe, I'll do the same.

 

That link had a lot of info about this, Vader pretty much locked it down. I'm going to keep looking for other info though. I can't believe that I've been dealing with these cars for this long without knowing about that. Live and learn.

 

So what your saying is, if it's right for a 2.8 and a caddie, it's right for a 305 and a 350? RRrrriiiggggghhhhtttt?

 

Sqz, that's what I was saying. But it seems that there might actually be somthing to this. Check out the link that Toe laid down and read Vader's post.