9C1 cam with stock TBI?

[Schurkey]

An ECM has several quad drivers. They are an integrated circuit that essentially acts as four small relays to control the solenoids and stepper-motors that the computer turns on and off--EGR solenoid, IAC motor, AIR solenoid, fuel injectors, etc. If the wire harness or the solenoid/motor shorts to ground, it'll pull too much current through one or more sections of the quad driver; damaging it.

In the TBI era, sometimes the quad drivers were "protected" and sometimes they weren't--depending on the application the computer was used on. I have no idea why GM wouldn't protect the quad drivers other than saving a few cents per car. Seems to me the V8 computers were not protected, but the Iron Duke four-poppers were. Go figure.

 

[PlayingWithTBI]

The warm start is sometimes just like it was before I replaced the IAC

What's your fuel pressure?

if I'm at a steady speed on the highway, the check engine light comes on and stays on as long as I'm holding steady speed.

Sounds like your EGR or ICM depending on what code(s) come up.

 

[Supercharged111]

Yes. I bought it from O'Reilly, came in a Standard box. It's the second one I've had to warranty out this year already

Most everything you buy from there is made in Chy-nah guaranteed to fail garbage. Have you shotgunned any other Blow Reilly's bits onto it? If so I'd start there before racking your brain over engine internals.

 

[Supercharged111]

An ECM has several quad drivers. They are an integrated circuit that essentially acts as four small relays to control the solenoids and stepper-motors that the computer turns on and off--EGR solenoid, IAC motor, AIR solenoid, fuel injectors, etc.

Kinda sounds like 4 transistors mashed together. I had a standalone engine management system that used transistors to drive relay coils. A common failure mode was people trying to run actual things through the transistors which would smoke them.

 

[blackdeathmessenger]

You posted the picture about the TCC solenoid. If it goes bad what part of the ECM fails? Does it totally die, does some of the outputs die, etc? That picture alone doesn't do us much good.

Unfortunately, nothing mentions any particular part of the ecu that gets damaged. The only thing was that bulletin

 

[blackdeathmessenger]

What's your fuel pressure?


Sounds like your EGR or ICM depending on what code(s) come up.

I'll have to recheck the fuel pressure when I get a chance. The codes that just came up were 31, 32, 33, 34, 43, 51, 52, 54, 55

 

[blackdeathmessenger]

Most everything you buy from there is made in Chy-nah guaranteed to fail garbage. Have you shotgunned any other Blow Reilly's bits onto it? If so I'd start there before racking your brain over engine internals.

Well, finding AC Delco or other more quality sensors has been a bit difficult lately, so I've had to just go with what I could find

 

[Supercharged111]

Well, finding AC Delco or other more quality sensors has been a bit difficult lately, so I've had to just go with what I could find

What was wrong with the original?

 

[PlayingWithTBI]

The codes that just came up were 31, 32, 33, 34, 43, 51, 52, 54, 55

You may have a bad ECM after all, or your chip isn't seated properly. Code 51 (and 55 may) tells us that. Click on the error code in this link and it'll give you hints on what to do.
www.repairpal.com/gm-obd-I-code-chart

GM OBD I Trouble Code Chart

Code Description Code 12 No distributor reference pulse (diagnostic test active) Code 13 Oxygen sensor circuit open or no

repairpal.com

 

[blackdeathmessenger]

Well, turns out it was a couple of sensors going bad at the same time. The sad part is, they tested just fine. I finally said screw it and replaced them and it ran better after that. The sensors I replaced, aside from the obvious of the broken idle air control valve were the coolant temperature sensor, map sensor, tps, and o2 sensor.

I now have a new problem, which from what everyone has told me, sounds like collapsed lifters. What's wild is I was just sitting at a light and then there was a bang and now a mechanical tapping sound from inside the engine