Deciphering Live Data.

[PlayingWithTBI]

I never had much faith in testing a coil with an Ohm meter. It'll tell you if it's bad but, it won't tell you if it's good unless you have a Megger. Got a spark plug tester for HEI?

 

[Nick88]

I never had much faith in testing a coil with an Ohm meter. It'll tell you if it's bad but, it won't tell you if it's good unless you have a Megger. Got a spark plug tester for HEI?

No. I have a warranty though so since it had high resistance i can just get it for free new

 

[Orpedcrow]

So I have a question. Can anyone think of a reason after its been sitting (even on a HOT day) when I start the truck it misfires for about 30 secs to a minute in varying amounts. Also if I put it in drive for up to a few minutes after starting it misfires pretty bad and the truck reaks like gas( probably from mis). The CTS and wire for it are new. Any ideas I think that might be part of my issue.

The injectors could be leaking. They’ll dribble fuel into the intake giving you a really rich start.

Take the TBI unit off, put a piece of cardboard or paper underneath it, turn the key on to pressurize the system, turn it off and let it set for a while. Check for signs of fuel on the paper/cardboard. There shouldn’t be any at all.

The smallest piece of trash on the end of the pintle will keep it from sealing 100%.

 

[Nick88]

The injectors could be leaking. They’ll dribble fuel into the intake giving you a really rich start.

Take the TBI unit off, put a piece of cardboard or paper underneath it, turn the key on to pressurize the system, turn it off and let it set for a while. Check for signs of fuel on the paper/cardboard. There shouldn’t be any at all.

The smallest piece of trash on the end of the pintle will keep it from sealing 100%.

Interesting, Ill test that. Is there any way to text that without taking the tbi off? I have a couple spare gaskets but they are a different type. Maybe cupping an index card under each injector to test?

 

[Orpedcrow]

Interesting, Ill test that. Is there any way to text that without taking the tbi off? I have a couple spare gaskets but they are a different type. Maybe cupping an index card under each injector to test?

Yea that could probably work. Just something clean that will show the fuel. Brown paper from packaging, toilet paper. It’ll evaporate so just keep an eye on it for a while.

I use cardboard because it has a better contrast when it’s wet.

 

[Schurkey]

I just tested my coil according to the picture online

Link to this picture?

The test 2- the resistance of the front two connectors on round side of coil connectors is reading 2.5 ohms.

White wires?

Online its supposed to be .1-.4.

Is this is a test of the primary windings? I'd have expected between .5--.7. What brand and part number of coil is this?

... I tested an old accel and it was also around 2.3ish ohms. Are both coils shot or is it a typo and its supposed to be 1-4 ohms???

First Guess: inaccurate ohmmeter. What does it show when the test leads are touched together?

 

[Nick88]

Link to this picture?


White wires?


Is this is a test of the primary windings? I'd have expected between .5--.7. What brand and part number of coil is this?


First Guess: inaccurate ohmmeter. What does it show when the test leads are touched together?

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Yes White wires. Its a brand new Delphi unit. Ironically the warrantied new unit had over 5 ohms of resistance I think the part number is #GN10048, could be wrong thats off the top of my head.

Ill check in a bit what test leads touched show.

 

[Nick88]

Today ironically the truck drove pretty good, but the start up was horrific, lots of misfiring. Might swap in a spare brand new Dynamod ICM see if that helps the starts. Last two AcDelco ICM's i bought have been bad.

 

[scott2093]

Today ironically the truck drove pretty good, but the start up was horrific, lots of misfiring.

You mentioned getting a new ECM... Everything good there? Was it a remanufactured one? Correct box and prom? Guessing yes...

 

[Nick88]

You mentioned getting a new ECM... Everything good there? Was it a remanufactured one? Correct box and prom? Guessing yes...

Yes its just a regular old standard motors one. The old one was getting tired