89 k1500 5.0 no start

[Mathies]

Hello im pretty new here so first im mathies a belgium car mechanik student and in love with the american muscle and pickups.

A few months ago i bought a beautiful non running gmc sierra k1500 5.0 305 from 1989. I knew it would be a challenge to get her fired back up but a great learning school also. First i did was change the oil and filter. No start bcs of no spark. I changed the icm, coil, pickup coil,fuel pump relay, rotor and distributor cap. Stil wouldnt start but now it has spark. I eventually changed the fuel pump bcs i thought maybe it isnt strong enough anymore. Stil wont start. Also when turning over the key it wont prime the fuel pump. The major problem is that when jumping the fuel relay and then cranking the injector arent spraying fuel. I checked all the wires and they came out good with no shorts or high resistance. Al the fuses are good an recieving 12 volts. Now im a bit stuck bcs i dont know if i schould risk buying a ecm and hoping that could fix my problem or do you guys think i should chek some other things out first. I also repaced the ground wire from batt to cab and from engine block to chassis the one behind the engine is still in good shape and zero resistance.

Any help would be greatly apreciated.

 

[evilunclegrimace]

Does the fuel pump run at all ?Does the truck have fuel pressure? (9-13) PSI. Did you change the fuel filter. Is the ground from the sending unit to the frame rail attached and does it have continuity? Do you have access to a scan tool?

 

[Mathies]

Yes if i jump the fuel pump relay or oil pressure sending unit the fuel pump works. I have no tools to meausure fuel pressure. I changed the filter and fuel pump. I cleaned that ground up and it has continuity. I dont have acces to a scan tool however i tried jumping A and B on the obd plug to see if i have any fault codes and normally the check engine light should come on but it doesnt come on.

 

[evilunclegrimace]

Yes if i jump the fuel pump relay or oil pressure sending unit the fuel pump works. I have no tools to meausure fuel pressure. I changed the filter and fuel pump. I cleaned that ground up and it has continuity. I dont have acces to a scan tool however i tried jumping A and B on the obd plug to see if i have any fault codes and normally the check engine light should come on but it doesnt come on.

Check to make sure that the bulb is good and then down load the fuel and emission/Driveability for your truck. You will need to follow Chart A-1.

 

[Mathies]

Check to make sure that the bulb is good and then down load the fuel and emission/Driveability for your truck. You will need to follow Chart A-1.

sorry i dont know where i can downloas the fuel and emissio/driveability is it on the forum or?

 

[evilunclegrimace]

sorry i dont know where i can downloas the fuel and emissio/driveability is it on the forum or?

yes there is a link some where on the forum.

 

[evilunclegrimace]

/www.gmt400.com/threads/88-98-service-manuals.43575/

 

[Mathies]

tankyouvery much

 

[SlowZ71]

Check the ground for the ecm on the thermostat housing stud. If you cycle your key on and the check engine light doesn’t illuminate, you may not be getting a ground to/from the ecm. I had the same issue after having most of my harness disassembled in my truck for the last 10 years.

 

[Mathies]

thx for the reply but i already cleaned that one up the one on the thermostathousing and the ground on the right side of that one