Troubleshooting Your TBI Fuel Injection System

[Jims86]

Trouble Code

SYSTEM

Indicating
12 Diagnostic Checking for operation of CEL bulb
13 Oxygen Sensor Circuit No signal to computer
14 Coolant Sensor Circuit Excessive HIGH temperature indicated
15 Coolant Sensor Circuit Excessive Low temperature indicated
16 VSS - Vehicle Speed Sensor Signal Loss
21 TPS - Throttle Position Switch High Signal Voltage
22 TPS Low Signal Voltage
24 VSS Set when in motion only - disregard if set in park
32 EGR EGR system failure
33 MAP - manifold absolute pressure sensor MAP sensor voltage high
34 MAP MAP sensor voltage low
35 IAC - Idle Air Control Motor Idle speed above/below desired idle speed
36 Idle Speed Control Actuator Open or Short Circuit
42 Ignition Control open/short/component failure
43 ESC - electronic spark control ESC module not receiving knock sensor signal
44 Lean Exhaust Low oxygen sensor voltage
45 Rich Exhaust High oxygen sensor voltage
51 PROM (Memcal) Faulty computer chip
53 System voltage high Carging System is over 17.1 volts
54 Fuel pump relay Low voltage / short
55 ECM Computer (ECM) failure

 

[89Suburban]

Troubleshooting Your TBI Fuel Injection System

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[89Suburban]

The first diagnostic that I do in a non-start situation is squirt a shot of ether (starting fluid) down the throttle body.

If it momentarily fires up - assume a fuel delivery problem.

If it just cranks over and doesn't even attempt to fire - assume an ignition issue.


Here are the non-start diagnostic charts for your vehicle:

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Thanks for the additional info Chengy/Jerry!

 

[chengny]

1987 GMC Light Duty Truck Fuel & Emissions Including Driveability Manual

Download the complete manual here:


http://depositfiles.com/files/qpeifotjh

11 MB, 262 pages

 

[smoothandlow84]

Fantastic info. Definately gonna save this for reference...Thanks!

 

[Galane]

Download the complete manual here:


http://depositfiles.com/files/qpeifotjh

11 MB, 262 pages

Dead link.

Is the check engine light required to get the blankety-blank thing to trigger the injectors? If so, then I'll need to get that hooked up on my truck.

 

[chengny]

Dead link.

Is the check engine light required to get the blankety-blank thing to trigger the injectors? If so, then I'll need to get that hooked up on my truck.

Download the complete manual.

1987 GMC Light Duty Truck Fuel & Emissions Including Driveability Manual
11 MB, 262 pages


Re-upped. Try it now:

http://depositfiles.com/files/xhf2z5s3d

 

[JACK34]

I have a 1994 and have replaced everything but the Engine. TBI trucks are junk. Good luck.

 

[tadslc]

I'm not sure why this is still a sticky.

Pictures aren't showing up and links are dead.