Odd issue. Engine stalls from a cold start at exactly 60 seconds. Like clock work. Then you have to feather the gas to get it to idle for maybe another 60 seconds, then it's all ok.

I've gone through the prom looking for things that would run for 60 seconds, but no luck.

It's an iron duke 2.5L TBI (in an S10 actually). My tunerpro won't connect up and read the data stream. Not sure why. The ECM number looks to be a 1 or 2 year only number. So I am running without data here.

Looking for ideas on what runs for the first minute of operation.

- ECM is 16156647
- Out side temp is about +3C.
- Cool temp sensor was swapped.
- IAC cleaned and swapped with another one.
- Same results with EGR disconnected as well as O2.

I'm wondering if the Spark timing runs some sort of startup advance and then after 60 seconds goes into a different mode.

I'll have to try some more data stream configs and see if I can get some data. It's like having a chisel, but not hammer. Tough to sculpt!

Cheers!
Mark.

 

Well the 16156647 is certainly an odd duck of the PCM family. Not much out there. Found a few things. Going to try a $D5 setup for a 4.3 and the ADX file to see if that will at least get me some data.

Also reading the A178.ads file.

And the novel continues ...

 

Well using a ADS file for the wrong engine ... I do get a data stream, but obviously wrong map. So good news ... ECM works and data works. Bad .. .nothing in the right place.

IAC is showing up TPS voltage. Funny to watch.

I don't think there is a definition for this BIN/ECM combo.

Mark.

 

Can you read the PROM? Goes a long way to getting the maskid. Without that we are flying blind.

RBob.

 

LOL ... um yes. Wasn't thinking clearly obviously. Jumped in the I'm smarter than I think I am approach!

 

Turns out the BIN is from a 1993 L38 which uses the 16156647. The ECM in the truck is the 1227165.

I can read the BIN. All good. Comes up as a $94.

I compared a 1991 L38 bin with the 1993 one ... very similar. $94 mask works on both.

I had a 1987 2.5L PROM around ... so I tried it ... no go. It just sputters and won't start. So the wiring or sensors must be different from a 1987 to a 1991-1993.

Next step ... burn a 1991 version and see if it comes to life.


Soooo if the 16156647 the "same" as the 1227165? Same plugs.

Mark.

 

This may help narrow down some possibilities for you.

http://www.exatorq.com/ludis_obd1/p4xref.html

 

1987-91 truck 2.5 L4 TBI “E” LN8
1991 truck 2.5 L4 TBI “A” L38

used the 165 ECM

“E”: = ADHF ($53), AMJW ($53) , ASWY ($83), AXAA ($83),
“A”: = AUXH ($94)

These are some possible bins and (Mask ID for comm definitions) to try.

 

After some reading ...

This engine is the A code engine. It will run with the $94 Bin's and won't run with the earlier ones (best I can determine something with the Dist signal).

1991 was an odd year - transition from A to E. So some weird one year stuff.

I found a 1991 2.5L auto bin AUXM ... I switched the BIN to man. It ran quite well ... even through a new engine code about the MAT sensor. It was dead. The Shift light was on steady ... so not sure where that flag/code is in the bin.

Today I found the AUXH bin ... which is the stock one I need. I've burn it ... now to test it out.

Strange ... I put back in the 1993 prom and the engine does run "ok". Still not sure what else was different in 1993. It takes a while to fire up ... cranks a while and then fires up. So something still not right.

From my reading the $94 is not great. Getting the data logging to work has been problematic. Can't get a proper data stream. I've been reading through the ADX files to see what I can learn. The packet size seems off. I have another version to try (which more closely resembles the $6E for send/receive requests).

And to boot ... when I got it running after the MAT swap .. the ALT died. Now I am wondering if that wasn't a problem all along. I swapped in a spare.

Thus far ... this engine has been interesting.

- No SES light in the dash (no socket either).
- Wrong PROM
- Coolant temp and MAT sensors dead.
- Alt just died or was on the edge of failing.
- AND the CAT was plugged something aweful.

It's taken a while to get it to the point of normal troubleshooting.

With the correct BIN and the best $94 datastream ... I'm hoping to solve this.

Mark.

 

Success! (well one step forward).

After replacing some vacuum tubes (a.k.a. degrading my APU1 moates scanner to passthrough mode using a com port!), I was able to get the datastream! It may have also been due to using the AUXH BIN that matches the engine! With the stars aligned, I fired it up. Only to have Murphy kick me in the butt with a low battery! A boost ... and away it went!

Now armed with data ... I watched the engine run. Right around the mystery 60 seconds ... the O2 sensor started to operate (O2 status went to "Ready") and the engine started to stumble and then stall.

Upon restart I had to feather the throttle to keep it running. The engine entered closed loop. And then it started to settle out. Overall the INT went up. BLM's after time ended up at 136.


Soooo ... is the O2 sensor faulty? Once it comes to life, the data is flawed?

I have to see if I have a spare to use. Somewhere in a box I recall having one.

Mark.

 

Set the closed loop enable CTS high to disable closed loop. Then see if it still occurs. It may be something else that is activating at about the same time.

RBob.