Hello, I just posted a question like this in the TPI forum and was told to ask the same here b/c its more known or more expertise is on this side concering the ECM and wiring harness.

Anyway I have the wiring harness and ECM on a bench test hooked up to the intake and sensors and problem is, when I turn the igniton on, meaning I give the ECM juice. The injector output lights up the test lighter, they both have positive current flowing through them. I ground one side of the light tester, touch one side, it lights, touch the other side and it lights as well.

Could I have a tripped wire that can cause this? I'm going to hook up the ALDL and see if the engine light gives me any codes.

 

The injectors are ground side controlled by the computer. Meaning your always going to have 12 volts on both sides of the injector until the computer grounds it. So that's normal

 

OK great, I see how that is not a problem anymore, but The wire that feeds into the ground side of the SES ( service engine soon) does not carry any energy. I tried to test it with a lighter from the wire to the positive terminal but still nothing. I would like to be able to check if the ECM gives any codes but if the SES light doesnt work then it just wont happen.

 

Ripper,

I read your sig, Swap in a ZF-6 instead.

 

Too expensive, and costly to rebuil them. T56 are cheaper than a Zf initially but to install them into a Corvette would require a little fabrication. Thats okay with me I enjoy it.

Just can figure out the SES light out. On the TPI board they told me to check the memcal, I'll get the ECM opened up and see if thats inthere or not.

 

Actually, having just gone through the same process, I found the ZF's to be less expensive than the T56's. Bought mine for $1600 and have seen them in the $1200 range recently. From what I have read of the T56, the ZF is the stronger trans especially the "black label" ones with the square cut teeth. Either one is a quantum leap over the 4+3.

 

The Muncie 4 speed infront is undestructable, but the overdrive is a winnie, they say leave it in od off when going full throttle, just cruising put it in overdrive.

Other then that off topic discussion. I got a distributor from the junkyard, hooked it up, hooked up the maf sensor, and still no go. Injectors still showed positive juice in both lines, I can get it to pulse. Also that goddamn SES wire does not feed any juice with the ignition on, so I cant check any codes. I checked to see if the memcal is in the ECM and its there, blue chip. Please guys I need some help on this thing, is thier a way to test out the ecm and make sure its good to go and how exactly do I test the distributor to make sure it works to, junkyard quality you never know.

 

The injectors could be pulsing and you don't know it depending on what type of indicator light you are using. The pulse width at crank is not very long, usually 10mS or less. Unless you are using a noid light or an L.E.D. you might miss it. Just about any other kind of light would have too much persistance to display that low of a pulse width. Also, the SES wire is not a current source but rather a current sink, just like the injector wire. It does not provide a voltage source to power anything and will only sink enough current to power a low current lamp or relay. HTH

 

You gave a very good point indeed my friend. I have thought about this but then I looked over it due to other things. Thank you for pointing that out. I will tomorrow run fuel in the lines, and check if it sprays any out.

BTW I tested the Junkyard distributor, and the output lines show constant ohms I think 18.7 on a 20Kohm setting I think it was. Anyway the distributor didnt pulse either, I hooked it up to an electric drill with a screw attachment, and it runs at about 800rpm. Plus I tried slower speeds, hand turning the distributor, same deal, no change in ohms at all which leads me to believe the dist is bad. Then again I bought it for 50, and Im starting to think maybe I should return it, spend another 50-60 and get a reman from pepboys or kregan.

 

TTT