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  #1  
Old 04-06-2020, 09:46 AM
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elskeptico elskeptico is offline
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GM TBI swap - I'm stumped

Looking for a little help.

- AMC 360 (healthy pre-swap)
- GM TBI junk yard parts and some new/rebuilt
- 1227747 ECU and TB from a 1991 Chevrolet Sport Van G20
- Used the 8-pin ignition control module and existing ESC with knock sensor
- Distributor is welded and disconnected from vacuum
- Fuel pump is brand new MSD mounted outside tank
- Coil is new Delco HEI
- Separate relays for fuel pump and other stuff

I spent much of the weekend reading through posts and double checking my wiring and assumptions, but I still can't get it started normally. I don't have a way of datalogging yet, sorry.

I have spark and fuel. No error codes.

MAIN ISSUE: the only way I can get it started is if I set the distributor WAY advanced (like about 50 degrees), and give it throttle while cranking. I got it started (real rough) and kept it running to warm it up enough that I could check the timing at idle, which showed about 10 deg. BTDC. I drove it around the block, actually drove okay (not great), got it back in the driveway and turned the key off but...it kept running I was out of time, so I just pulled the fuse on the TBI stuff and it shut off.

I'm assuming the fact that I couldn't shut it off means my ignition switch is bad. Anything else that could cause that? I suppose a stuck relay could do it.

My hunch is a bad ignition module, but it's getting spark, so...

Things I've already checked/calibrated:
- All typical voltage checks (coil, injectors, ALDL)
- TPS sensor adjusted to about .58V at idle
- Coil (resistance checks found online, checks out fine)
- System is well-grounded to engine block

[I have not "reset" the IAC because that requires a running engine and I just barely got it running]

There
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  #2  
Old 04-06-2020, 10:24 AM
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You may need a diode on the alternator wire to resolve the run-on with key off issue...had to do that on my 90GW.

Try reversing the distributor pickup wires. They will cause big issues if reversed.
Specifically, timing that is WAY outta whack.
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Old 04-06-2020, 10:27 AM
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elskeptico elskeptico is offline
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Quote:
Originally Posted by babywag
You may need a diode on the alternator wire to resolve the run-on with key off issue...had to do that on my 90GW.

Try reversing the distributor pickup wires. They will cause big issues if reversed.
Specifically, timing that is WAY outta whack.

Thanks, I'll look into the diode.

I've already swapped the pickup wires, actually, didn't help. Previously had purple going to P and orange to N, and switched them after seeing one of your prior posts about doing it the other way.
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Old 04-06-2020, 10:31 AM
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Distributor a tooth off? Or plug wires 1 position off?
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Old 04-06-2020, 10:33 AM
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Also if this is a "new" made in China module YES it could be bad...
many many instances of new aftermarket junk right out of the box.
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Old 04-06-2020, 10:47 AM
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elskeptico elskeptico is offline
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Quote:
Originally Posted by babywag
Distributor a tooth off? Or plug wires 1 position off?

Plug wires, no. Tooth off is possible. One thing I couldn't find was what's the "optimal" place to set the distributor in relation to TDC for this swap? Like I said, I had to rotate it very advanced to get it to start/run at all.


Quote:
Originally Posted by babywag
Also if this is a "new" made in China module YES it could be bad...
many many instances of new aftermarket junk right out of the box.

The module I'm using was from the junk yard.
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Old 04-06-2020, 10:55 AM
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I run them @ 0 degrees and let the computer do timing.

Some folks for whatever reason cannot do 0 degrees.
If not 0 degrees the .bin needs to match the initial timing and the timing table needs to be correct to account for the difference.

What is the .bin BCC#?
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Old 04-06-2020, 11:25 AM
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elskeptico elskeptico is offline
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Quote:
Originally Posted by babywag
What is the .bin BCC#?

I had set it at or close to 0 initially, but couldn't get it to do anything until advancing it significantly.

BCC is ARJV (or maybe ARJU). The Bin finder on gearhead-efi.com doesn't give any results for this BCC.
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  #9  
Old 04-06-2020, 02:03 PM
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ARJU sounds familiar CA-only .bin iirc

Have you checked for codes?

Do you have ability to read/burn or swap a diff chip?
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Old 04-06-2020, 02:20 PM
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elskeptico elskeptico is offline
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Quote:
Originally Posted by babywag
ARJU sounds familiar CA-only .bin iirc

Have you checked for codes?

Do you have ability to read/burn or swap a diff chip?

I don't have any codes, even after getting it started rough and driving around for a bit.

I don't have any chip burning capabilities yet, and no other chips to try. I might try to get to picknpull tomorrow and see if I can find another ignition module to try. Thanks for the help.
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Old 04-06-2020, 03:05 PM
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For clarity, I followed this wiring diagram almost exactly:



And here's how I did the coil wiring:



Even though the coil gets 12V+ from the black connector, I assumed it also needed a source through the bigger wire in the gray connector.
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  #12  
Old 04-07-2020, 11:06 AM
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Okay, I'm an idiot. The engine run-on issue was due to the way I wired the coil (wrong).

Does the coil only require the pink and white wires that come from the ignition module (pink gets 12+ from relay)?
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  #13  
Old 04-07-2020, 12:33 PM
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Small wires from coil pink/white go only to module.
Should NOT get power from elsewhere.
Only large gauge coil wire should get power in crank/run positions.

Here is a GM wiring diagram I simplified many years ago.
http://www.ifsja.org/forums/vb/showthread.php?t=169223
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Old 04-07-2020, 12:57 PM
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Quote:
Originally Posted by babywag
Small wires from coil pink/white go only to module.
Should NOT get power from elsewhere.
Only large gauge coil wire should get power in crank/run positions.

Here is a GM wiring diagram I simplified many years ago.
http://www.ifsja.org/forums/vb/showthread.php?t=169223

Wow, thanks. I followed that diagram I found elsewhere (maybe binderplanet), guess it's wrong or I misunderstood it.

I have a relay for injectors, ECU, O2 sensor and ignition. Separate relay for fuel pump.

Should I have a third relay for ignition alone?
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Old 04-07-2020, 01:20 PM
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Your choice...both mine only have/use 2 relays
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  #16  
Old 04-07-2020, 05:42 PM
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Well I changed the wiring per your diagram, and it solved my run-on problem (obviously), but otherwise nothing changed.

Started it up, ran pretty rough, drove it around the block (felt pretty good), back in the driveway and it died.

At this point I’m spittin in the wind but thinking maybe the ignition module is bad. Tested resistance on the pickup coil and it’s about 650, so no obvious trouble there.
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  #17  
Old 04-08-2020, 02:56 PM
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Does look like weak spark? It's the only thing I can think of that could cause this.

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  #18  
Old 04-08-2020, 05:45 PM
wiley-moeracing wiley-moeracing is offline
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Looks good, blue would be weak, but then again my vision is not what it used to be!
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  #19  
Old 04-08-2020, 06:02 PM
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elskeptico elskeptico is offline
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Quote:
Originally Posted by wiley-moeracing
Looks good, blue would be weak, but then again my vision is not what it used to be!

Hmm...I thought blue or white is strong, red or yellow is weak.

Anyway, I swapped to a different coil (older TFI) and things are just as wacky.

I've set the dizzy to ZERO. I tried putting a timing light on it while it's cranking and the mark doesn't even show up, I can't see it anywhere on the scale (which only shows advanced), so my thinking is the ECU/ICM is retarding the timing so much that the mark on the crank is showing up behind all that stuff.
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  #20  
Old 04-08-2020, 07:10 PM
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Did you unplug the timing set wire connector?
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