1990 TBI 350 refuses to start and idle nicely, I have log files.

[GearGrinder]

Need a bit more info from your truck. How many miles? Is it a bone stock truck and no modifications? Has the distributor been pulled and reinstalled? Has the truck been sitting for a long time and was it running well when it was parked?Start by checking all connectors on the coil and distributor as the plastic over time gets brittle. I’ve seen a truck be hard to start and run like crap and die just like you describe only to find that the connector from the main wire harness to the coil pack. Just a guess but I would say you issue is with the distributor or coil or the connectors.

[brian617]

One of the most common TBI running issues is coolant temp sensor reading that is erratic. Log the temp sensor and make sure it looks normal. The fueling is heavily dependant on CTS. Examine pins in connector for corrosion.

[The_Joe]

Need a bit more info from your truck. How many miles? Is it a bone stock truck and no modifications? Has the distributor been pulled and reinstalled? Has the truck been sitting for a long time and was it running well when it was parked?Start by checking all connectors on the coil and distributor as the plastic over time gets brittle. I’ve seen a truck be hard to start and run like crap and die just like you describe only to find that the connector from the main wire harness to the coil pack. Just a guess but I would say you issue is with the distributor or coil or the connectors.

Truck has 250,000 miles and is completely stock. Sis purchased it in the fall and it had a high idle and dying in gear issue that had led to it being parked for a while. I worked on it for a month and the issue was getting worse instead of better, then I gave up during the holidays and I'm just now getting back to it.

Distributor was out when I did the intake manifold gasket, I checked the timing after and set it back to 0 degrees. It's possible that is having a connection issue, but I haven't been able to see any evidence with the timing light.

One of the most common TBI running issues is coolant temp sensor reading that is erratic. Log the temp sensor and make sure it looks normal. The fueling is heavily dependant on CTS. Examine pins in connector for corrosion.

That was the first thing we did on the truck, and in the logs it looks fine to my eyes.

[GearGrinder]

Hmm. 250k on the mileage. Pull that distributor and junk it. Normally I would say go back with a good one but an engine with 250k on it I would go back in with a cheapo from your local auto parts dummies. I couldn’t get my 89 truck to pass emissions until I put a cheapo distributor in it. That same year I blew a head gasket in it ��
Did you change the coolant temp sensor on top of the intake or the one in between number 1 and 3 spark plug. I’m sure Brian617 was referring to the one on top of the intake as the one by 1 and 3 spark plug only shows the temp on the cluster.

[The_Joe]

Hmm. 250k on the mileage. Pull that distributor and junk it. Normally I would say go back with a good one but an engine with 250k on it I would go back in with a cheapo from your local auto parts dummies. I couldn’t get my 89 truck to pass emissions until I put a cheapo distributor in it. That same year I blew a head gasket in it 😞
Did you change the coolant temp sensor on top of the intake or the one in between number 1 and 3 spark plug. I’m sure Brian617 was referring to the one on top of the intake as the one by 1 and 3 spark plug only shows the temp on the cluster.

I have another 350 tbi parts truck that is running well and I could barrow the distributor for testing.

I'm not at the truck until this weekend but I'll give it a shot.

And as for the sensor, yeah I got the one near the Tstat.

[GearGrinder]

Double check all grounds!!! One from the fender to the negative battery cable and of course the negative battery cable itself. One by the charcoal canister on the core support. One on the backside of the passenger side head to the firewall under the AC drier. Another one that runs from the frame to the firewall under the AC drier. Those last 2 on the firewall attach on the same stud sticking out from the firewall. Some models have one that runs from the frame to the block off plate under the ac compressor beside the water pump inlet. Another beside the ALDL connector under the dash screws to a price of sheet metal. Another bolted to the frame on the drivers side by the rear bumper brackets. One more by the gas tank door that bolts to the bed and the last one is under the bed coming off your fuel pump bolting to the frame. I wouldn’t worry about the fuel pump one though if your fuel pump is working and running at the correct psi then that ground is good. I think that covers all the grounds.