Just won't start

[Cad]

83 frame and cab with a 98 t100 3RZ. Ok, I am gonna give you every detail I can. I will even post a video if you need it, But I am at my wit's end with this shit. The truck has run fine for the year I have had it. I hooked up a heater core went riding a few times no issue other than the heater core wasn't as hot as I wanted it to be. I pull it into the shop unhook the hose going to the heater core to make sure I am getting good flow. (The core lines run through the firewall on the passenger side.) I also pulled the thermostat so I could get flow without waiting on it to warm up. I went to start it to check my flow and it would turn over but not start. It would hit every once and a while. The longer you tried to start it the more it would hit and try to actually start until eventually it would idle a few seconds and die. After doing that for about 5 minutes it would start to idle but like a sack of ass. If you even gave it gas it would die immediately. After letting it run at shitty idle for 5 minutes you could lightly touch the throttle and slowly bring it up to higher RPMs and it would run fine after you revved it a few times and it cleared up. I have replaced the Coil packs. the wires, the plugs, fuel filter, fuel pump, crank position sensor, checked the fuse boxes, and no blown fuses. Again after you get it running it runs like a champ. But getting it started blows ass. if it has been running for a while you can shut it off and it will start right up again. But if it sits for like 15 or so minutes you have to go through it all over again. So I am at a loss, Anyone ran into this before?

 

[DMG]

Do you have a scanner that will read data? it could be a coolant temp sensor, for example. Or you could have soaked the pcm in coolant.

 

[Cad]

Yeah no way to check codes on this shit box. The ECU/PCM is tucked way up under the dash. Coolant cant get to it.

 

[DMG]

Unplug the coolant temp sensor and try to start it. Then get a basic code reader from the parts store or Amazon.

 

[Cad]

OK, again I have a code scanner that isnt the issue. I cant read any codes because the port doesnt work. How would the CTS stop it from running?

 

[TrikeKid]

OK, again I have a code scanner that isnt the issue. I cant read any codes because the port doesnt work. How would the CTS stop it from running?

It would make it hard to start if it's open circuit and the computer thinks it's -40 out. Figure out why your data link connector doesn't work and fix that instead of just throwing parts at it.

Any little ground wires on the thermostat housing that might've been left off? If it ran fine till you started messing with the heater hoses/thermostat that's where you ought to look first.

 

[DMG]

OK, again I have a code scanner that isnt the issue. I cant read any codes because the port doesnt work. How would the CTS stop it from running?

If it thinks the coolant is 195 degrees it will try to start it fueling way too lean for a cold start. I would fix the obd port ASAP.

 

[Boomtacoma01]

Agree ^

Id pull and check your your O2 sensor while you are at it for peace of mind. Mine (22re) seemed to foul overnight and ran shittliy until I cleaned it.

 

[Alex123456]

There isn't that much that can keep it from running right, fix the diagnostic port and lets start there. Grounds, vacuum, the basics first.