ALDL connector not powering scan tool

[Jwernatl]

Hey All - thanks for any replies!

My 87 v10 350 ALDL connector is not powering up my scan tool -

I'm using a INNOVA 3170rs tscan tool to help diagnose my 'issues' - truck is running rich - idle is up and down ect. (I found a vacuum leak - got that taken care of, but the truck is still is not up to performance.

I know the ecm is reading the MAP, O2, TPS, COOLANT, VSS and MAT sensors. -


- I want to read my codes - but---

The scan tool is supposed to power up when you turn ignition to 'on' - it doesn't - is there a fuse? could it be my ecm?

I've got 5 terminals in my connector - all on the top row. looking at the service manual - it's right -

where should I start looking? ground?? ecm faulty? fuse??

thanks all.

 

[Vbb199]

Probably should be looking at thr CTS for that rich, funky idle condition lol

 

[HotRodPC]

And you're 100% sure you tool doesn't require a battery? I have known some tools that depend on it's own battery. What tool do you use?

 

[Matt69olds]

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Hopefully this helps. Check all the fuses, pretty sure these trucks will run with the ecm not powered. The mixture control solenoid won’t work (engine will run pig rich, sound familiar?) the timing will be stuck at base timing. Maybe your inop scan tool, and drivability problem are related

 

[Jwernatl]

Probably should be looking at thr CTS for that rich, funky idle condition lol

Im with you on this - because - my temp gauge never gets over 150- (I've got a 195 thermostat - just changed) I think the old one was in good shape - putting a new thermostat in, made not difference.

So it's the sensor or the gauge.


I do have a question - we have on an '87 350 and Engine TEMP Sensor and the Coolant temp sensor - which reports to ecm?

if you read the 1987 FUEL and EMISSION manual (from GM) - it mentions nothing about the engine temp sensor

here's what it reads - copied from manual...

In addition to the ECM, the Computer Command Control System has the following information sensors:

• Oxygen sensor
• Coolant sensor
• Throttle position sensor
• Manifold absolute pressure sensor
• Vehicle speed sensor
• Manifold temperature sensor
• Knock sensor

and the following input signals:

• Park/neutral switch signal
• Crank signal
• Distributor reference signal
• Power steering pressure switch signal
• A/C control signal
• Transmission gear position signal
• EGR vacuum signal

 

[Jwernatl]

And you're 100% sure you tool doesn't require a battery? I have known some tools that depend on it's own battery. What tool do you use?

I put the battery in the scan tool for sure….

- I can turn the scan tool on with the power button. It's not recognizing the ecm - the scan tool is supposed to turn on by itself once it's plugged in with ignition key on.

 

[Jwernatl]

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Hopefully this helps. Check all the fuses, pretty sure these trucks will run with the ecm not powered. The mixture control solenoid won’t work (engine will run pig rich, sound familiar?) the timing will be stuck at base timing. Maybe your inop scan tool, and drivability problem are related

I'll pull every fuse tonight. - (from your diagram above) my ALDL only has pins in 'F' 'E' 'D' 'B' & 'A

 

[Itali83]

Ok, the coolant temp sensor in the intake by thermostat is the coolant temp sensor for the ecm. It’s got two wires. The single wire temp sensor in the drivers side head is for the gauge. You need a scan tool to see what the ecm is seeing for coolant temp. But since you can’t connect, I’d just put a temp sensor in the intake for the ecm just because. It’s like the number one most important sensor for drive ability on these things.

now on to your connecting issue. I had the same issue with my 87 Jimmy. I couldn’t connect with my scan tool. Mine would at least power up but wouldn’t read the ecm. I tried everything and thankfully have several tbi parts trucks so I just swapped ecm’s to try and that took care of my issue. So, maybe you have a bad ecm if everything else checks out.

Ben

 

[Itali83]

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Hopefully this helps. Check all the fuses, pretty sure these trucks will run with the ecm not powered. The mixture control solenoid won’t work (engine will run pig rich, sound familiar?) the timing will be stuck at base timing. Maybe your inop scan tool, and drivability problem are related

tbi trucks won’t run without ecm. The earlier ones with the feedback carb will but very poorly.

Ben

 

[Jwernatl]

Ok,
the coolant temp sensor in the intake by thermostat is the coolant temp sensor for the ecm. It’s got two wires.
The single wire temp sensor in the drivers side head is for the gauge.

now on to your connecting issue. I had the same issue with my 87 Jimmy.
I couldn’t connect with my scan tool. Mine would at least power up but wouldn’t read the ecm. I tried everything and thankfully have several tbi parts trucks so I just swapped ecm’s to try and that took care of my issue.
So, maybe you have a bad ecm if everything else checks out.

Ben

Thanks Ben - I've been researching and going over the manuals to figure this out…

This is great stuff to know. That helps a lot. - I would think it's probably a very common mistake.

I've replaced the MAP and TPS when I installed the new TBI so...

this afternoon I'll replace ALL of rest...

1. Manifold temperature sensor
2. Coolant sensor
3. Oxygen sensor
4. engine temp sensor

lets see what all this does - and then evaluate the ecm….

 

[Matt69olds]

tbi trucks won’t run without ecm. The earlier ones with the feedback carb will but very poorly.

Ben

I guess I should have clarified things. A truck with a CCC style carb will run with the ecm inop, but won’t run well. Any truck with fuel injection won’t run at all without the ecm powered up.

 

[Itali83]

I guess I should have clarified things. A truck with a CCC style carb will run with the ecm i op, but won’t run well. Any truck with fuel injection won’t run at all without the ecm powered up.

i just wanted to clarify for the original poster. I figured you knew but since he stated he has an ‘87 truck, that means tbi and not ccc.

carry on

Ben

 

[Vbb199]

Im with you on this - because - my temp gauge never gets over 150- (I've got a 195 thermostat - just changed) I think the old one was in good shape - putting a new thermostat in, made not difference.

So it's the sensor or the gauge.


I do have a question - we have on an '87 350 and Engine TEMP Sensor and the Coolant temp sensor - which reports to ecm?

if you read the 1987 FUEL and EMISSION manual (from GM) - it mentions nothing about the engine temp sensor

here's what it reads - copied from manual...

In addition to the ECM, the Computer Command Control System has the following information sensors:

• Oxygen sensor
• Coolant sensor
• Throttle position sensor
• Manifold absolute pressure sensor
• Vehicle speed sensor
• Manifold temperature sensor
• Knock sensor

and the following input signals:

• Park/neutral switch signal
• Crank signal
• Distributor reference signal
• Power steering pressure switch signal
• A/C control signal
• Transmission gear position signal
• EGR vacuum signal

The CTS has alot of say based on fueling.... im referring to the one thats a 2 prong plug, on top of the intake.


The one in the side of the block (1 wire) is just for the gauge.

 

[Jwernatl]

The CTS has alot of say based on fueling.... im referring to the one thats a 2 prong plug, on top of the intake.


.

It worked. Swapped a new coolant temp sensor - cleared ecm - and mam o man. That exhaust smelled so much better!

Thank you to all you smart sombeaches. You guys make me a better man!

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[Vbb199]

It worked. Swapped a new coolant temp sensor - cleared ecm - and mam o man. That exhaust smelled so much better!

Thank you to all you smart sombeaches. You guys make me a better man!

You must be registered for see images attach

You must be registered for see images attach

I would like to recommend a little hardware, and a little software to you for ECM monitoring of your truck.... the baud (communication) rate is slow (as in, frames per second), BUT, its soooo much cooler than a standard plug in thingy.

You can perform data logs, dump them, open them in microsoft office to see where you're losing power, or in general get an idea of your engine health, sensor readings, or status.

Its much cheaper than paying 300$ for an older OBD1 tool.

For me, i used it on my 89 to tune out the spark knock, diagnose i had a vacuum leak (map kpa), etc etc.

Iirc, it even shows spark advance on the data sheet.

The app (for android) is called ALDLDroid. It costs 10$ in the app.
WELL worth it.
Link: https://play.google.com/store/apps/details?id=com.sgiroux.aldldroid


It allows bluetooth interface to the device that im about to tell you about, which obviously, in turn, your phones display is the "ecm output" of your truck.

The hardware:

http://www.1320electronics.com/12pin_ALDL_BT_USB_MK2.html
They have an ebay store.

This hardware and software package will also double as an obd2 tool. It can also tune a obd 1 ECM's, but it will require a aftermarket ECM that can be tuned.
(The current way to tune a stock ecm is to burn a prom chip everytime you make a change, like an old CD-R)


The upgraded, tuneable ECM is on my list of things i want, but for now, being able to see actual ECM data makes all the differencr in the world.

These old tbi units are just old enough to be "junk" by all the internet experts, but "too new" for the carb guys so they usually get ripped off and replaced with a carb, or get canned completely, and replaced with a LS.

Both are stupid. Im sorry, but its stupid to throw away something you dont understand.

With 100$ in equipment, diagnosing is so much easier.
The data is Live obviously.


If you wanted to pursue that route let me know when you get it . I have the ECM file you need for your motor, and i can show you how to setup the switch pins of the module so it'll communicate with your phone.