87 k5 blazer wont start

[leyva]

just bought the blazer about 2 weeks ago. the blazer wont start it only cranks. i bought the fuel pump and fuel pump relay but before that it would just crank and not with those changes it still does. it also has an after market alarm. one thing that i noticed was that the wiring that goes to the fuel pump is not getting any power to it. if anyone can help i will appreciate it.

 

[crazy4offroad]

Most alarms have a starter interrupt box, but I'm not sure about feul pump power interrupt. Need to check if you're getting fire to the plugs. Dump a small drink into the throttlebody and crank it and see if it hits. If it does it's definately fuel delivery, or the alarm. A truck I once had with an aftermarket alarm, the PO didn't secure the control box very well under the dash and it slipped down and some of the wires got tangled up in the steering column. You may want to check for something obvious like that.

 

[leyva]

First of all thank you for replying. i have dumped drink in the throttle body and it does start then it dies out. and about the wire it has a lot of wires under the dash. also another thing that i noticed was that it was 3 alarm horn under the hood not sure why it has so many.

 

[crazy4offroad]

OK glad to hear it hit with the drink of fuel, that eliminates the ignition system. I think that may also eliminate the alarm as well. I'm not much help on TBI/fuel injection but I'm sure others will be chiming in soon. You may have to trace your power wire for your fuel pump and see if it has a break somewhere along the way. If the wiring for the alarm looks bad under the dash if I were you I would take some time and some zip ties and tidy it up, and make sure they are away from the steering shaft, park brake pedal/lever/etc, brake pedal, linkages, anything that could cause problems. Hearing electrical arcs and smelling electrical smoke while you're driving isn't fun lol.

 

[leyva]

the one thing that does not make sense to me is that where the fuel pump wiring connects to the wires that give it the power is not getting enough electric flow to the fuel pump. i checked that with a tester the light does not light up how is suppose to. it has to be something electrical i suppose.

 

[smurph20]

Check you oil pressure sending unit. On my 92 s10 if it looses oil pressure to the computer it kills the power to the fuel pump to save the motor. I had some trouble a few years back with it the wiring got burnt on the manifold and i had a short from the sending unit to the computer. And just for good measure check all of your fuses which im sure you have already.

 

[dhamp]

Also, see if your alarm brain has the index for the harness labeled on it. If not, search online to get the listing of what wires go to what. Trace the one that's for the starter disable and see if it's hooked up. Reason being, if you disable the starter control ckt at the column, someone could still jump across the starter terminals to get it going once they pop the ignition switch. I've installed alarms on my cars before that disables the fuel pump (live and learn, I wouldn't do it anymore). That could be the way yours is wired.

 

[Jims86]

check for corroded terminals on your fuel pump relay while your at it, its on the firewall above the passenger side valve cover, it has the orange and gray large gauge wires, and a smaller green/wht and a red/wht wire.
Welcome to the forums!

 

[leyva]

Thank you im sure the forums are going to help me.
well alarm is off already. No Alarm. so it cant be the alarm at all. But still cranks no start. Or am i missing something?
Bought new Fuel pump relay.
New Fuel pump.
Cant hear the pump turn on for 2 seconds. No sound of the fuel pump.

 

[Jims86]

Thank you im sure the forums are going to help me.
well alarm is off already. No Alarm. so it cant be the alarm at all. But still cranks no start. Or am i missing something?
Bought new Fuel pump relay.
New Fuel pump.
Cant hear the pump turn on for 2 seconds. No sound of the fuel pump.

are you getting a check engine light before you try to start it? if not, check all of your grounds, and the ecm fuse. do you have a fuse marked "ecm b"?

 

[leyva]

No check engine light. can you give me more a list of all the grounds i need to check im not that familiar with this blazer just got it 2 weeks ago. And where is the ecm fuse located? Sorry if im asking so many questions.

 

[crazy4offroad]

There is a large ground from the battery to the alternator bracket usually. Also one from the battery to the frame, or engine to frame. Also one from the passenger rear cylinder head to the firewall of the cab, a braided ground strap. Sometimes there will be one from the battery to the radiator support as well. Doesn't hurt to have plenty to the body since it is mostly insulated from the frame by the rubber body mounts.

 

[89Suburban]

I didn't know 87's had electronic fuel pumps.

You have a TBI truck?

 

[leyva]

Thank you i will check all the grounds. hoping to find the problem.

 

[leyva]

yes i do and yes it has an electrical fuel pump.