blazer quit while driving

[viggy58]

2001 blazer, 2wd, manual trans

while driving today, ran over some RR tracks, and the blazer shut off. temp gauge and tach are not registering now, however voltage, all lights, and odometer are. fuel pump is also not powering up.

i'm gonna start by checking fuses, and connections to the ecm (or whatever it is for this truck). just wondered if anyone had any ideas on what to troubleshoot.

i should add, the engine will crank normally, however wont start (because of no fuel i assume)

thanks in advance.

[MT-2500]

Originally Posted by viggy58

2001 blazer, 2wd, manual trans

while driving today, ran over some RR tracks, and the blazer shut off. temp gauge and tach are not registering now, however voltage, all lights, and odometer are. fuel pump is also not powering up.

i'm gonna start by checking fuses, and connections to the ecm (or whatever it is for this truck). just wondered if anyone had any ideas on what to troubleshoot.

i should add, the engine will crank normally, however wont start (because of no fuel i assume)

thanks in advance.

Fuses and connections and grounds and battery cables first.

Is it also losing spark to all plugs?
On fuel pump not running check for power on gray fuel pump feed wire engine cranking or key on 2 second prime up.

Let us know what you find.

[viggy58]

well something is def draining power when the key is on.
also, key on, i'm not getting power to the large fuses and some of the small fuses in the fuse/relay panel under the hood.

no prime from the fuel pump with key on. seems to be getting spark.

i've checked all connections on the the ecm and fuse/relay panel. everything is snug. all battery, alternator, and ground connections are good. showing correct voltage. i'm losing about about 2 volts right away when i re-attach the neg terminal. turn the key on, and it has a constant (and fairly rapid - about a volt every 2 minutes) drain. that's with all lights, including the under hood lamp OFF.

i'm gonna check the pump next... can you guide me to where the wires for it are?

[GT55]

Viggy58
This might help. I have a 97 Blazer. While driving it would completly shut down and then come back on. Scare the hell out of me at night. No lights, nothing. Everthing off then on again. You never knew when it was going to happen. After many hours of searching I run down a large electrical connector running above the brake booster in the engine well. This connector connected the wires running from the inside of the vehicle to the needed areas in the engine well. It was hard to find because it was under a piece of black plastic to protect it. Anyway, thru years of vibration and such this connector started to work lose. Not all the way, just enough to cause the problems I was having. Took it apart, cleaned it well and put it back together. To make sure it did not come apart I used zip ties to keep it together. 20,000 miles later it's still running without any problems.

Hope this can help...

GT

[viggy58]

thanks indeed!!! i'm pretty sure i'm dealing with some electrical issues here. gonna check grounds and stuff tomorrow. thanks for the info on that connector. good to know!

[MT-2500]

Originally Posted by viggy58

well something is def draining power when the key is on.
also, key on, i'm not getting power to the large fuses and some of the small fuses in the fuse/relay panel under the hood.

no prime from the fuel pump with key on. seems to be getting spark.

i've checked all connections on the the ecm and fuse/relay panel. everything is snug. all battery, alternator, and ground connections are good. showing correct voltage. i'm losing about about 2 volts right away when i re-attach the neg terminal. turn the key on, and it has a constant (and fairly rapid - about a volt every 2 minutes) drain. that's with all lights, including the under hood lamp OFF.

i'm gonna check the pump next... can you guide me to where the wires for it are?

First thing.
You have to have good voltage for the pump to work good.
If you are losing power/voltage at fuses trace it back to the battery cables and battery voltage.
Make sure battery will carry a load and check battery charge/voltage.
Let us know what you find there.
Lose connection and dirty bad battery cables are common problems on losing voltage.

[viggy58]

yea the battery is good. positive leads are good. neg leads are nice and snug. battery is fully charged right now. i've had to charge it twice, because with the key on, it just drains.

fuel pump primes and pressure is good, when the test lead is jumped to B+.

[MT-2500]

Originally Posted by viggy58

yea the battery is good. positive leads are good. neg leads are nice and snug. battery is fully charged right now. i've had to charge it twice, because with the key on, it just drains.

fuel pump primes and pressure is good, when the test lead is jumped to B+.

If still losing power to fuse box trace the wiring from battery to fuse box and see where it is losing voltage.

Let us know what you find there.

[viggy58]

found a bad ground (loose) at the front drivers side, next to the radio. that got power back to the fuse/relay panel.

still no fuel pump, NO SPARK, and still a large drain of power with the key "on"

starting to get stumped. fuel pump still spins with the test lead hooked up.

i just saw an OOOLD post where someone mentioned the security system was locking out the fuel pump. faulty ignition switch was to blame. i do remember the security light coming on when the truck died, and staying on with the key "on".

do you think a bad ignition switch could be attributed the my power drain with the key on? or is it more likely there is something else draing power?

[viggy58]

FOUND IT!!!

I guess, when i hit the RR tracks, it put just enough pressure on the fuse/relay box that it punched some wires.

I got pissed, had a few beers, and went back at it at 11pm. Yanked that fuse/relay box again and started tugging on some wires and suddenly *POP* and a little spark. the ECM 1 fuse popped. grabbed my wiring diagram, found the wire, and sure enough, the positive was stripped back enough to ground out. fixed the wire, replaced the fuse.

jumped in the truck, turned the key, and the most beautiful sound ever...MY FUEL PUMP!!! loud and clear! Started right up!

ABS light stayed on, on my brake pedal is at the floor. the fuse isnt blown, but im guessing those got pinched too. i'll get to them in the AM though.

Just glad it finally started, after 2 days of hair pulling and cussing.

[GT55]

Way to go. Drink a brew for me while your at it..


GT

[MT-2500]

Originally Posted by viggy58

FOUND IT!!!

I guess, when i hit the RR tracks, it put just enough pressure on the fuse/relay box that it punched some wires.

I got pissed, had a few beers, and went back at it at 11pm. Yanked that fuse/relay box again and started tugging on some wires and suddenly *POP* and a little spark. the ECM 1 fuse popped. grabbed my wiring diagram, found the wire, and sure enough, the positive was stripped back enough to ground out. fixed the wire, replaced the fuse.

jumped in the truck, turned the key, and the most beautiful sound ever...MY FUEL PUMP!!! loud and clear! Started right up!

ABS light stayed on, on my brake pedal is at the floor. the fuse isnt blown, but im guessing those got pinched too. i'll get to them in the AM though.

Just glad it finally started, after 2 days of hair pulling and cussing.

Good find.
Thanks for posting back how it went and what you found.
Good Luck