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Wierd TBI problem: Runs, but doesn't start.

DavidB

1/2 ton status
Joined
Oct 8, 2001
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Location
El Centro, CA
I think the fuel pump isn't running the few-second prime cycle when I turn the key on. Won't start if I get in and crank it unless it's just been running. If I give it some starting fluid, it fires up and runs fine. Fuse, computer, wire? It's been flipped and beat. Wheeling trip tomorrow, repairing the frame and gonna try to fix TBI tonight if I have time after the frame. Ideas anyone?

Thanks
 
Replace the fuel pump relay first, cheap and easy. Located on the firewall just to the left of center (passenger side).
 
I've seen a tps do that. If it went bad, and is showing the computer that you are at wot, it won't pulse the injectors during crank, but will when running.
 
Thanks guys. Didn't get to it last night, but noticed the exhaust burns the eyes and nose bad. Hope it doesn't poop out on me today.
 
Bought a TPS and Relay this AM wheeled all day no time to wrench on it. Later...whole Blazer needs torn apart and the drivetrain put in something else. It's done.
 
Wished I had seen this before I worked on mine.Would have saved me alot of time and money
 
Still haven't fixed mine. Something is unplugged up by the TBI but I don't see what it's supposed to be plugged into.

PLUG.jpg
 
That's for a relay of some type. Don't think any of the GM fuel pump relays were that style (oval relay body) but other things did.
 
That was the relay. It was missing entirely. Surprised it ran. Stupid me. Guess flipping/beating it made it fall off. Here's a link to my phone album. I hooked up the relay, but there's a red wire hanging out of the pigtail and an empty mounting tab next to the relay. Anyone know what goes there? Also there is a pic of my coil. One wire isn't hooked up, there's a wire coming off the loom on the firewall that looks like it might go there, dunno.

link
 
Last edited:
K10A'sBROinSLO said:
That was the relay. It was missing entirely. Surprised it ran. Stupid me. Guess flipping/beating it made it fall off. Here's a link to my phone album. I hooked up the relay, but there's a red wire hanging out of the pigtail and an empty mounting tab next to the relay. Anyone know what goes there? Also there is a pic of my coil. One wire isn't hooked up, there's a wire coming off the loom on the firewall that looks like it might go there, dunno.

link

The connector on the fuel pump relay is a test connection for the relay. You can actually put 12 Volts to that tab and the pump should turn on. I also want to say the if you put a volt meter on it it should read 12V for about 3 sec when the key is turned from off to Run.

The connector on the coil is the Tach connection. It looks similar to the connector on the fuel pump relay. The only wires that get hooked to the distributor have weather pack connectors on them.

Ira
 
4X4HIGH said:
My 89 blazer has the oval fuel pump relay.

Sweet. For some reason the '80's TPI stuff used a different one. At some point I'll be converting to the oval, so all my relays (fan1, fan2, MAF, MAF burnoff, fuel) are interchangeable. :)
 
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