'89 Suburban doesn't like humidity

**rdnkdrummer** · 07-30-2009, 11:08 AM

This will be my "work in progress" page for my '89 Suburban. It's been very "weird" lately. won't start on humid days. Before this started happening, I remember on a few humid days that it would "hesitate" while driving when cold, once warmed up it was fine.

I had an '01 4.3V6 pickup before, and there was a problem with condensation in the distributor cab which caused a similar problem. I know I need to get new cap, rotor, plugs, and wires on this truck, just because it's "time".

I'm starting this thread to see if any of you have had an issue like this, and it WASN'T the cap/rotor causing the problem. Over the next month I will be replacing: cap, rotor, plugs (what kind should I get? +4 or Delco platinum?), and wires. Also I will be doing a good sea-foam cleaning, in oil, gas, and brake booster line. I'll update you as things progress.

If you have any ideas on probable causes of my anti-humidity suburban, please post.

Muchas Gracias!

**2COR517** · 07-30-2009, 11:25 AM

Do the SeaFoam before you put your plugs in. As for plugs, and cap&rotor, Only use AC Delco. My truck did not run well with the +4. Napa Premium wires are fine. Don't forget air and fuel filter, and PCV Valve. An O2 sensor is a good idea too. And, on the 89, you need to check/set the timing.

**rdnkdrummer** · 07-30-2009, 11:38 AM

Thanks for that...i will seafoam before plugs, made that mistake once before! That's what happens when you mix Coors Light with a tuneup. Air filter and pcv are new already. question about fuel filter, as I'm new to TBI, I've only messed with carbs...where is it, and how hard is it to change?

**2COR517** · 07-30-2009, 01:21 PM

Fuel filter should be on the inside of the left frame rail. Usually under the drivers door area. Might want to spray some penetrant on the fittings for a few days. Sytem is under pressure, but once you crack a fitting open it will bleed right off.

**bill190** · 07-30-2009, 02:42 PM

Check the spark plug wires for cracks in the insulation.

Also test your Coolant Temperature Sensor which provides engine coolant temperature data to the engine computer.

**rdnkdrummer** · 08-04-2009, 02:11 PM

Thanks for the fuel filter info...are there two different coolant temp sensors: one for gauge and one for computer?

**bill190** · 08-04-2009, 07:09 PM

Originally Posted by rdnkdrummer

Thanks for the fuel filter info...are there two different coolant temp sensors: one for gauge and one for computer?

There could be. Older vehicles have two.

The one for the computer is called the Engine Coolant Temperature Sensor, would have two wires, and would be located near the top radiator connection on the engine.

If you have a Coolant Temperature SENDER (separate for gauge), this would have one wire and would be located on the side of the engine near cylinder #1.

With the newer vehicles, they use one sensor and get a computer to calculate the appropriate readings for the instrument cluster gauge.

**rdnkdrummer** · 02-12-2011, 10:45 PM

WAY late back to this post...as the truck is now totalled....that's beside the point. New Distributor fixed the problem. Plugs, wires & sea foam helped mileage. Got up to 16-ish. At some point before I owned the truck...there must have been a loose distributer cap that collected some condensation that caused permanent damage that worsened over time. Good to know for future.