90 350 service engine soon flashing while running

[PlayingWithTBI]

I will check all the grounds at the thermostat and double check my work and am looking for a scan tool that has obd1 ability all of mine that I have are not able to do obd1

Do you have a laptop? You can scan and data log OBDI ECMs for ~$60 and a little research.
Free download with suggested contribution;
http://www.tunerpro.net/downloadApp.htm

You'll need the 12 pin ALDL to USB one
http://aldlcable.com/aldl.asp

I didn't see where you have a ground from the back of the block to the firewall, do you?

 

[munrom77]

Do you have a laptop? You can scan and data log OBDI ECMs for ~$60 and a little research.
Free download with suggested contribution;
http://www.tunerpro.net/downloadApp.htm

You'll need the 12 pin ALDL to USB one
http://aldlcable.com/aldl.asp

I didn't see where you have a ground from the back of the block to the firewall, do you?

I don’t have one from the back of the head to the fire wall, I do have one front block to the battery, I’ll add another ground to the back of the head to the fire wall see if that changes anything also


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[Schurkey]

Catalyst? I assume you mean cat converter? This truck doesn’t have it and is not required to have it, it has stock manifolds (new) new y pipe, 3 in to the muffler and dual 2.5 out to the tail pipes

You're in Canada, and I'm not familiar with Canadian emissions legislation. In the USA, a catalyst (Catalytic Converter) is ABSOLUTELY "required"--nationwide--if the vehicle was originally equipped with one or more to begin with; but in many states nobody does an inspection to find if the vehicle complies with FEDERAL law.

 

[Gramps]

You're in Canada, and I'm not familiar with Canadian emissions legislation. In the USA, a catalyst (Catalytic Converter) is ABSOLUTELY "required"--nationwide--if the vehicle was originally equipped with one or more to begin with; but in many states nobody does an inspection to find if the vehicle complies with FEDERAL law.

This is absolutely true in Canada too.

 

[unruhjonny]

all of the obd1 code readers regaurdless of if it's a laptop, or hand held device, are cash-grabs;
All they do is give you the exact same information as the blinking codes.

I believe that the codes blink three times, and move to the next, but it's been a while since I have monkey'ed with this stuff;
IIRC the first code should be a flash, pause, flash-flash, with is "1"-"2" or 12;
This is a self check, verifying that the ECM/wiring is ok, then after code 12, it sequences through the codes, till it comes back to 12.

If you are able to get a Tech1 with appropriate modules, or another tool which gives live data, those can be worth your time and money, but if you're thinking of getting just ha code scanner of some sort I'd suggest you save your money;
Think of it this way:
When these were new vehicles, not all dealerships were setup with a Tech1, or if they had one (or two), a technician might have had to wait in line to get access to it - so the blinking codes were used by the technicians to service your car - and if they could do it, why can't you (or I)?

I am surprise that initial mechanical timing is set to zero degrees.
But having never previously worked on one of these trucks, that could very well be the case.

 

[Schurkey]

all of the obd1 code readers regaurdless of if it's a laptop, or hand held device, are cash-grabs;
All they do is give you the exact same information as the blinking codes.

Yes. A >>>CODE READER<<< is a piece of shiit.

If you are able to get a Tech1 with appropriate modules, or another tool which gives live data, those can be worth your time and money, but if you're thinking of getting just ha code scanner of some sort I'd suggest you save your money;

A >>>SCAN TOOL<<< is not a "code reader". Calling it a "code scanner" is just confusing the point. That is, a scan tool is not just a code reader, although it'll read codes in addition to accessing the data stream, and provide bi-directional control of select systems.

Think of it this way:
When these were new vehicles, not all dealerships were setup with a Tech1, or if they had one (or two), a technician might have had to wait in line to get access to it - so the blinking codes were used by the technicians to service your car - and if they could do it, why can't you (or I)?

Tech 1 was a required tool for dealerships. EVERY GM dealership had at least one. Ford had...Star (?) scan tools, no doubt Mopar had their own kind. Independent shops had the OTC "Monitor" series or the Snap-On MT2500 "Red Bricks". Eventually more-sophisticated aftermarket scan tools came along; along with additional brand names.

Yes, there is limited information provided by the "Check Engine" light on most GM OBD-1 vehicles. Codes, open-loop vs. closed loop, rich/lean. Codes are ALMOST as helpful as the data stream. With access to the data stream, stuff that takes "all damn day" to diagnose freestyle, and three hours with a "breakout box" can be done in half-an-hour. Well worth the expense for anyone who plans to dick with a computer-controlled vehicle. (Especially so, since nobody knows what a "breakout box" is any more.)

 

[PlayingWithTBI]

all of the obd1 code readers regaurdless of if it's a laptop, or hand held device, are cash-grabs;
All they do is give you the exact same information as the blinking codes.

Well, this is a code reader and data logging AP (TunerPro RT on an 88 C1500 with 1227747 ECM) on a laptop that gives me a lot more than just codes. Cost me $60 for the ALDL to USB cable, the software is free with a suggested contribution.

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Here's an EBL Flash2 ECM What's Up Display with a WBO2 on the same 88

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Either one can help troubleshoot these issues, plus I can tune with them too.

 

[PlayingWithTBI]

Here's where I can see error codes on TP as an example

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[munrom77]

Here's where I can see error codes on TP as an example

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I believe I may have found the possible issue, with the flashing.

It was doing so very faintly. I figured I would try putting a battery charger on it.
With the charger it now stays on solid so I’ll let it charge for a while and see what happens,
I do believe I will be getting that adapter


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