350 tbi problem???

[Snoots]

When the Service Engine Soon (Check Engine) light comes on, the ECM has detected a problem with one of the sensor circuits in the car, and it sets a trouble code. The ECM holds stored trouble codes in memory as long as it has power from the battery. To retrieve the stored trouble codes, do the following:

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1. Locate your OBD1 block.
2. Take a paperclip or wire, and short the 'A' and 'M' terminals.
3. Turn your ignition to 'ON'. DO NOT START THE ENGINE!
4. Watch the Service Engine Soon (Check Engine) light.

It will flash a series of codes at you. First, it should flash:
FLASH-PAUSE-FLASH-FLASH. That is 1-2, (Code 12).

This signifies that the ECM is not receiving reference pulses from the distributor, and therefore that the car is not running.

It will flash this code three times, with a long pause between each code. If there are any stored trouble codes, it will flash them after this, starting with the lowest numbered codes, up to the highest numbered, each one repeated three times. It does NOT flash the codes back in the order in which they were set.

One more example. If you see the following:

FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-FLASH-long pause
FLASH-FLASH-FLASH-FLASH-pause-FLASH-FLASH-FLASH-FLASH-long pause
FLASH-FLASH-FLASH-FLASH-pause-FLASH-FLASH-FLASH-FLASH-long pause
FLASH-FLASH-FLASH-FLASH-pause-FLASH-FLASH-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause

Then your ECM is giving you code 13 (oxygen sensor) and code 44 (lean exhaust).
Ignore the Code 12 at the start and end.

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Code 13 - Oxygen sensor circuit

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Code 14 - Coolant sensor circuit

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Code 15 - Coolant sensor circuit

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Code 21 - Throttle Position Sensor

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Code 22 - Throttle Position Sensor

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Code 23 - Manifold Air Temperature (V6 only)

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Code 24 - Vehicle Speed Sensor

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Code 25 - Manifold Air Temperature (V6 only)

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Code 32 - Exhaust Gas Recirculation system (V6 only)

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Code 33 - Manifold Air Pressure sensor

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Code 34 - Manifold Air Pressure sensor

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Code 35 - Idle Air Control

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Code 42 - Electronic Spark Timing

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Code 44 - Lean exhaust

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Code 45 - Rich exhaust

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Code 51 - PROM

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Code 52 - Fuel CALPAK (V6 only)

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Code 53 - System over-voltage (V6 only)

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Code 55 - ECM
Note that component replacement may NOT solve the problem in all cases.

 

[Snoots]

ALSO,
If you have ANY plastic vacuum lines that lead to any rubber connector or elbow, I can 99% guarantee you that one or more of them have cracked.
Find some small aluminum tubing at a hobby/hardware store and replace them ALL, INCLUDING the rubber elbows. You can use rubber hose available at auto parts stores for this.

 

[1987 GMC Jimmy]

OK, not to step on anyone's toes, OBD-1 is not a dumb system, it is just the first. Just like we have MS windows now, back in the eighties we used DOS. I have two trucks a 1990 Silverado 1500 and a 1988 K5 Blazer. Both have OBD-1. So, when you start the truck does the "Service Engine Soon" light even come on ? When you start the engine, the ECM or computer ( Which is on the right side just in back of the glove box.) It's silver square and it's about 3" X 15". But lets not go near it just yet. When you start the engine, the ECM takes reading from the coolant sensor, 2 wire sensor right behind the thermostat housing. That is the sensor that goes to the ECM and there is another, it is on the drivers side head right behind #1 spark plug, that goes to your gauge. With that and the signal from the O2 sensor, which if your truck is stock is in the 'Y' pipes just aft the exhaust manifolds. It needs to be hook up and working for the ECM to get a signal and the exhaust flow, and finally there is the IAC or Idle control Motor. To set the IAC, take it out and push the ' Pintal ' of the sensor back into the sensor till there is just about 1 " from the base of the motor and the very tip of the Pintal, Put a dab of silicon one the bottom treads so once tighten, it seals OK. It doesn't need any heavy tightening, it's aluminum and will strip easily. So now you have the 1.coolant sensor, 2 the oxygen sensor and the IAC idle control motor out, adjusted and your ready to go.

Did connect the negative terminal from the battery for 30 seconds and reconnect. Now start the engine see if the idle is stable and the 'Service Engine Soon' light should come on fro a 10 seconds and the go out. If it stays on the ECM has had a code set. Shut off the engine and use the paper clip and short out terminal A & B on ALDL connect under the dash and the get comfortable and turn the key to the on position. The service engine soon light will light up. It will flash 1 long flash and 2 fest times, thus you have a code 12. That is just the ECM saying hello. it will flash each code 3 times, and don't worry if you miss one it will go back to the first code 12 and start over. Write down what each code is and if you get them all, and the ECM is back to 12, shut off the ignition.

Now with the codes before you see what each code is coming from. If you don't have a code chart, just go online and you will find a OBD-1 listing. see what is in the code and that is you culprit. Between the blazer in my avatar and my pickup It took me a long, long time to find my problem. On my 1990 305 V8 we went to just about every sensor and nothing worked till we realized the only thing we hadn't changed was the ECM itself. got a Cardon rebuilt unit and installed it and that took care of the problem. Problem was a crack in it's motherboard.

On my 1988 Blazer this one was almost the one the broke the donkeys back. SES light kept coming on and coming and coming. If I had any hair I'd of pulled it all out. A technician from a Detroit GM dealership came to my aid, he said take off the distributor cap and the rotor and look at the ignition module. He said if it is white, take it out and throw it away. If it's red like a high performance module, take it out and throw it out. Go to a old time parts store or Chevrolet Dealership and get a AC Delco ignition module. Take some Acetone and wipe off the plate inside the distributor and open the packet of white heat insulator paste and apply it to the back of the ignition module. DON'T go overboard, The paste should be about the thickness of a loose-leaf page of paper, put 3 connectors on the module and put it back on, and only tighten it finger tight, then just a tad more so it snug. The 2 screws just hold it in place and have no other purpose. Did connect the battery for 30 seconds and reconnect it. I did and that was the last time I had a "Service Engine Soon" come on. The most important thing is to get AC Delco Parts. all the other crap is made in Mexico or Thailand Indonesia or. . . China. ALL the other stuff is such poor quality it a waste of your time to even try using them.

If you have any questions my name is Jim Ward.

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I couldn't resist. Sorry. On a more serious note, I agree with the ECM and ICM stuff. My first module that I replaced, it didn't come with a packet of heat sink paste so I thought I could rely on what was caked on the inside of the distributor. Wrong. It lasted 13 months before leaving me stranded in a difficult place. After having learned my lesson, I cleaned up the old stuff and applied two of the little paste packets (one to the module and one to the distributor). I also keep a spare module and paste packet now. With the ECM, I've learned the extremely hard way that they're pretty sensitive. The integrated circuits can burn in them, and I've actually seen one smoke. They are also sensitive to static, and it's a bad idea to solder wires that are in the engine management circuit with the ECM in the loop. I've also had them get wet from a firewall leak and die (duh), and a rat severed plug wire grounding to the frame blew another one. I think I replaced the ECM in my car eight times before I got all the stupid kinks worked out.

 

[4WDKC]

When the Service Engine Soon (Check Engine) light comes on, the ECM has detected a problem with one of the sensor circuits in the car, and it sets a trouble code. The ECM holds stored trouble codes in memory as long as it has power from the battery. To retrieve the stored trouble codes, do the following:

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1. 
   
   
   • Locate your OBD1 block.
   • Take a paperclip or wire, and short the 'A' and 'M' terminals.
   • Turn your ignition to 'ON'. DO NOT START THE ENGINE!
   • Watch the Service Engine Soon (Check Engine) light.

It will flash a series of codes at you. First, it should flash:
FLASH-PAUSE-FLASH-FLASH. That is 1-2, (Code 12).

This signifies that the ECM is not receiving reference pulses from the distributor, and therefore that the car is not running.

It will flash this code three times, with a long pause between each code. If there are any stored trouble codes, it will flash them after this, starting with the lowest numbered codes, up to the highest numbered, each one repeated three times. It does NOT flash the codes back in the order in which they were set.

One more example. If you see the following:

FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-FLASH-long pause
FLASH-FLASH-FLASH-FLASH-pause-FLASH-FLASH-FLASH-FLASH-long pause
FLASH-FLASH-FLASH-FLASH-pause-FLASH-FLASH-FLASH-FLASH-long pause
FLASH-FLASH-FLASH-FLASH-pause-FLASH-FLASH-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause
FLASH-pause-FLASH-FLASH-long pause

Then your ECM is giving you code 13 (oxygen sensor) and code 44 (lean exhaust).
Ignore the Code 12 at the start and end.

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Code 13 - Oxygen sensor circuit

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Code 14 - Coolant sensor circuit

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Code 15 - Coolant sensor circuit

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Code 21 - Throttle Position Sensor

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Code 22 - Throttle Position Sensor

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Code 23 - Manifold Air Temperature (V6 only)

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Code 24 - Vehicle Speed Sensor

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Code 25 - Manifold Air Temperature (V6 only)

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Code 32 - Exhaust Gas Recirculation system (V6 only)

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Code 33 - Manifold Air Pressure sensor

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Code 34 - Manifold Air Pressure sensor

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Code 35 - Idle Air Control

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Code 42 - Electronic Spark Timing

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Code 44 - Lean exhaust

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Code 45 - Rich exhaust

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Code 51 - PROM

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Code 52 - Fuel CALPAK (V6 only)

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Code 53 - System over-voltage (V6 only)

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Code 55 - ECM
Note that component replacement may NOT solve the problem in all cases.

um never connected A&M its always been A & B, the ecm in my truck is a 7747 and only connects at 160 baud rate so I know using the M pin wont work. I am pretty sure the M pin is empty on my truck.

Holy **** that is ridicolous for what they used to give away.
https://www.amazon.com/OTC-7739-Code-Retrieval-Key/dp/B000K1DYS4

 

[1987 GMC Jimmy]

um never connected A&M its always been A & B, the ecm in my truck is a 7747 and only connects at 160 baud rate so I know using the M pin wont work. I am pretty sure the M pin is empty on my truck.

Holy **** that is ridicolous for what they used to give away.
https://www.amazon.com/OTC-7739-Code-Retrieval-Key/dp/B000K1DYS4

Lower tier of the ALDL is completely empty on mine so I second. I think that's a 92-95(?) thing.

 

[Snoots]

Holy **** that is ridicolous for what they used to give away.
https://www.amazon.com/OTC-7739-Code-Retrieval-Key/dp/B000K1DYS4

Holy Highway Robbery Batman!

um never connected A&M its always been A & B, the ecm in my truck is a 7747 and only connects at 160 baud rate so I know using the M pin wont work. I am pretty sure the M pin is empty on my truck.

Just tryin' to help.

I cleaned up the old stuff and applied two of the little paste packets (one to the module and one to the distributor). I also keep a spare module and paste packet now.

Smart move.
This is some damn good stuff! Surprisingly tiny syringe (you don't get a lot) but well worth it.
https://www.amazon.com/Silver-Thermal-Heatsink-Compound-Syringe/dp/B00M5G6AHY

 

[JOHN MEADOWS]

Today I got in truck on first cold start of the day. This thing dies on me a few times before it will idle on its own. For about 5 mins it's wants to surge and finally idle good .....just high. So I take her down the road get her warm and mat the throttle then my check engine light comes on. The truck has all kinds of power and running decent. So i get back and check my codes and it's shows 22 and 43. I then clear the codes and takes her for another ride and mat the throttle again and the check engine light comes on again. I then check my codes again and it's only showing 43 for code.

 

[1987 GMC Jimmy]

Interesting. 22 is TPS low sustained voltage and 43 is ESC circuit fault. Something that can analyze serial data would tell you what the TPS is or isn't doing, or you could go straight to the TPS with a multimeter. I'll attach an instruction sheet for that - ignore the OBDII codes on it. The 43 is gonna be the knock sensor. It's either disconnected, faulty, or not there. That 43 comes up instantly because the knock sensor is supposed to start reporting the instant the engine starts. The TPS code will pop off only if the issue is sustained for x period of time. I'd do the TPS test, which should also give you a clue about grounding issues (especially the ones on the manifold and the strap that attaches to the passenger side cylinder head) and either a faulty sensor or a faulty signal. I'd also see what's going on with the knock sensor. It could be the ESC module or an ECM issue, but the knock sensor is the easiest starting point. I zipped through the thread, but I have a question. With regard to the high idle, have you gotten a manifold vacuum reading yet? A low reading and a big leak there could explain the high idle and the dying at the same time. If you're going to be looking at live data, your MAP sensor extrapolates engine vac and will tell you what it is. The 43 isn't responsible for the issues, and the 22 might be a part of it, but I'd be hard pressed to believe it's the sole culprit. I'd hit the brakes on any replacement parts until you go through the whole diagnostic gauntlet that's been suggested up to this point. Plenty of people throw parts at these TBIs and get nowhere, and I think a big reason is because the OBD I diagnostics are kind of a niche thing where OBD II or pre-OBD I methods have a lot more ubiquity. It sounds like yours is not hell and gone from being right, which I think is a good sign it can be resolved without purging your wallet of the green stuff too badly.

 

[JOHN MEADOWS]

Interesting. 22 is TPS low sustained voltage and 43 is ESC circuit fault. Something that can analyze serial data would tell you what the TPS is or isn't doing, or you could go straight to the TPS with a multimeter. I'll attach an instruction sheet for that - ignore the OBDII codes on it. The 43 is gonna be the knock sensor. It's either disconnected, faulty, or not there. That 43 comes up instantly because the knock sensor is supposed to start reporting the instant the engine starts. The TPS code will pop off only if the issue is sustained for x period of time. I'd do the TPS test, which should also give you a clue about grounding issues (especially the ones on the manifold and the strap that attaches to the passenger side cylinder head) and either a faulty sensor or a faulty signal. I'd also see what's going on with the knock sensor. It could be the ESC module or an ECM issue, but the knock sensor is the easiest starting point. I zipped through the thread, but I have a question. With regard to the high idle, have you gotten a manifold vacuum reading yet? A low reading and a big leak there could explain the high idle and the dying at the same time. If you're going to be looking at live data, your MAP sensor extrapolates engine vac and will tell you what it is. The 43 isn't responsible for the issues, and the 22 might be a part of it, but I'd be hard pressed to believe it's the sole culprit. I'd hit the brakes on any replacement parts until you go through the whole diagnostic gauntlet that's been suggested up to this point. Plenty of people throw parts at these TBIs and get nowhere, and I think a big reason is because the OBD I diagnostics are kind of a niche thing where OBD II or pre-OBD I methods have a lot more ubiquity. It sounds like yours is not hell and gone from being right, which I think is a good sign it can be resolved without purging your wallet of the green stuff too badly.

What do you mean by manifold reading report?

 

[1987 GMC Jimmy]

I mean the inches of Hg manifold vacuum reading. You should be looking for a stable reading of around 17-20" of Hg. Anything less indicates a likely presence of vacuum leaks which could be contributing to your high idle and conking out when you give it gas.

 

[4WDKC]

It dies after the IAC calibration and with the tps connected?

 

[JOHN MEADOWS]

It dies after the IAC calibration and with the tps connected?

YES , ON A COLD START YOU HAVE TO BABY IT UNTIL IT WARMS UP A BIT. THATS WHEN THE SURGING IS UNTIL IT WARM. WHEN ITS WARM , IT IDLES BETTER BUT IDLE IS HIGH. WHEN DO THE IAC RESET I TRIED TO ADJUST THE IDLE SCREW BUT IT WONT IDLE DOWN BUT IT WILL UP

 

[4WDKC]

YES , ON A COLD START YOU HAVE TO BABY IT UNTIL IT WARMS UP A BIT. THATS WHEN THE SURGING IS UNTIL IT WARM. WHEN ITS WARM , IT IDLES BETTER BUT IDLE IS HIGH. WHEN DO THE IAC RESET I TRIED TO ADJUST THE IDLE SCREW BUT IT WONT IDLE DOWN BUT IT WILL UP

That shouldnt happen, when you hit the key it should start like a new car. Did you check the passages for the IAC to make sure they were clear of carbon? Does it do that with the TPS disconnected?

 

[JOHN MEADOWS]

I did a complete rebuild on the Tbi and nothing was stopped up on passages. I will try to put a link to you tube on my truck on a cold start and what it is doing. I will post a link shortly

 

[JOHN MEADOWS]

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Here should be video link. If it doesn't work let me know