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1991 Suburban acts like out of gas or fuel pump

If the ECM isn't "seeing" the spark, it won't fire the injectors. Everything fuel pump related seems to check out.

Check for injector spray with the air cleaner off while cranking. I'm guessing none. Should be a nice cone of fuel spraying.

Check engine light works properly, and no error codes?
 
Your guess is right. I did not see any gas spraying. The check engine light is not on, which, if I am correct, means no error codes. I am not sure I trust it. But what does this indicate. I have a basic repair manual, but it refers to another specialized manual for TBI info, which I don't have. Thanks again.
 
So 1st lets make sure the MIL (malfunction indicator light) works. with key on the warning lamps in the instrument panel should light, including the MIL aka check engine lamp.
Does the light light ?
If it does short the aldl terminals A to B, watch the MIL it should start blinking. Count the blinks. It will be a pattern of blinks repleted 3 times. You will see 1 blink and then 2 blinks for code 12, you will see this code. Code 12 is an EST ( electronic Spark Timing), this code will shows when engine is not running, and is normal.
After code 12 blinks 3x if there are other codes they will blink out, lowest to highest. The codes will blink as long as the aldl a and b are shorted, and the battery is good.
If you have a battery charger I would charge up the battery. All these tests and diagnostics will put a good drain on the battery. Sometimes leading to bad diagnoses.

If I get ambitious this evening I will go look for my tbi diagnoses book.
 
Awsome list of manuals! Thanks, I downloaded mine. As for the trouble codes. I jumper-ed the top right terminals on the obd1 connector and learned that my engine trouble light does not work, so I can't read any stored codes my that method. It looks like everything in this truck has been worked on previously. I think someone had this dis-assembled for a resto then had to sell. My high beam indicator does not work either. I will attempt to absorb the manuals. In the mean time this led to TBI stuff which I never dealt with before. Already been walking way too long. Any suggestions appreciated. Thanks again.
Update: The proper manual assumes a working service engine light and doesn't have a no start condition listed in the driveability condition troubleshooting chapter. I'm sure it's all in there but larger bite to swallow than hoped for. For me it looks like the engine trouble light is now first on the list. I'm almost at panic mode which means send to shop for first time in a long while.
 
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It may just be a burned out bulb. Or bad cluster connection. Both would be common and pretty easy fixes. But to get the cluster out takes some work. Not hard, just a lot of screws and being gentle with the plastic cluster housing.

Never know what you are going to get with these older trucks, people start trying to fix stuff and make it worse usually.

Correct assumption, need to figure out why the CEL doesn't work first. Swapping the bulb with known good from another position in the cluster is a cheap test. The printed flexible circuit on these clusters does not tolerate idiots, if a previous owner was in there, you may find the contacts are torn up. Which is often an easy fix.
 
@dyeager535 I was thinking that the ECM has to see a signal from the ignition control module before it turns the injectors on. Correct? So if there is spark but no injector pulses, could there be no signal to the injectors from a bad connection or a failed ground for the injectors?
I am just thinking that even with a functioning MIL, it may not have a code if it doesn't know that the injectors aren't firing. I am going off of my memory though.
 
You are correct...ECM must see the distributor is turning before it commands the injectors to fire.

If the CEL doesnt work, we don't know if the ECM thinks it is working properly.
 
Removing the dash pad before the instrument cluster bezel. Is the best way.
The ipc bezels are so brittle, and the dash pad kinda holds one corner to close.

Edit sound like a big deal to remove the dash pad but it is actually very easy
 
Hi everyone. I pulled the dash cluster to check for codes at gauge cluster connector using a test light so I wouldn't have to worry about bulbs or the circuit, Brn/Wt to ECM A5 & Pnk/Blk to 12V IGN. In diagnostic mode it showed no output from A5 to activated SES light. I checked fuses and found 10A ECM B fuse blown. I first tried to replace the fuse without disconnecting the power. It sparked when inserted and meter confirmed it as blown again. Replaced it a second time with power disconnected. Meter confirmed it was good before battery re-connected. Same fuse blew again when the battery was connected. Manual on preceding page says to find the short to ground in the circuit. Any suggestions? Thanks again.
 
Did you look in the wiring manual?

Off the top of my head I want to say one fuse is for the injectors and one is actually for the ECM?

The wiring diagram will tell you what that fuse feeds. If it's the injectors, I'd be inspecting the injector wiring where they pass through the throttle body. Those are commonly in very bad shape.

Just doing quick google searches, it unfortunately looks like ECM B can be a bunch of different things.
 
Yes inspect the wiring at the tbi. Those wires are always in iffy condition. Even when they are no where near 31 years old
 
The ECM B fuse kept blowing on me when I would try to start my '89 TBI. It ended up being the wires coming off of the fuel injectors. They had gotten smashed by the air cleaner housing to the point where some raw wire was exposed. It's worth checking on yours because it is apparently a pretty common occurrence on our trucks.
 
I had the same issue and it was the wires going to my oil pressure sender. They were rubbing on the cab and would arc and blow the fuse.
 
Yes. I was renting and missing work, so I caved in and sent it to a shop. As an amateur I totally depend on the manual to get me through a repair. The manual is not clear how a blown ECM B fuse indicates a bad distributor. I hope to benefit in some way from a repair exercise which didn't happen this time. This is the first time in 30 years I had to resort to a shop, so I'm ahead of the game. But this will bother me.
 
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