surging idle question. (1 Viewer)

[HawkGunner]

I just picked up this truck last week, and bought it with a hard start condition and surging idle once started. I jumped the diagnostic port and got a Code 52... knock sensor.

I changed the knock sensor. Didn't fix it.

I noticed the coolant was low, so I topped it off. Once i did that, the surging idle got worse. The hard start didnt improve. I've pulled the throttle body off and I'm going to change the TPS out.

If after changing and adjusting the TPS the issue isnt fixed, where should I look next? IAC?

 

[morganism]

Repair / replace temp sending unit before doing anything else. Known prob for many ECU probs.

Hard start is usually a bad ground from the coil, unbolt the cage holdowns, clean bolts n holes, replace. Now add a wire from the ignitor case to a solid ground, and see if start probs go away. If you get chattering or hard clunks, you will need start solenoid contact replace kit, usually 25 bucks.

 

[HawkGunner]

It's too dark to work, but I'll get back to it tomorrow with those tips and report back.

Thanks for the help!

 

[HawkGunner]

@morganism , you are referring to the coolant temp sensor, right? The one with the green plug near the throttle body?

 

[Mudder]

22re or 3.0?

 

[HawkGunner]

22re

 

[Mudder]

it could be the knock sensor wire needing to be to be replaced the only problem is that it goes all the way to the ECU and isn't replaceable like the 3.0. What year of truck is it?

 

[HawkGunner]

it could be the knock sensor wire needing to be to be replaced the only problem is that it goes all the way to the ECU and isn't replaceable like the 3.0. What year of truck is it?

It's a 92.

What do you mean by "not replaceable"?

I can solder and repin wires, if that's what it means. How do I test it?

If it's not replaceable like that, will I need a new wiring harness?

 

[morganism]

Yeah, I hear the connector rot on temp sensor is consistently bad.

 

[HawkGunner]

@Mudder , I've been doing some reading on the KS wire. Maybe you can tell me if I'm on the right track. I'm fairly certain the wire is my issue. It looks like the PO just soldered some regular wire onto the end after the original wire broke.

As I understand it, the KS wire is a shielded coaxial cable... essentially, an old cable-TV cable.

I think I can take a TV coax cable and splice it onto the original wire at the unbroken portion on the CPU end, then peel back the outer coating of to expose the inner mesh and ground that to something at the sensor end... probably the engine block.

Am I way off base here?

 

[gnob]

Just get the signal wire out and extend it. The shield goes to ground.
I however doubt the KS is causing the idle issues. These are where I would look.
Tps,
Timing,
Iac.

 

[HawkGunner]

Just get the signal wire out and extend it. The shield goes to ground.
I however doubt the KS is causing the idle issues. These are where I would look.
Tps,
Timing,
Iac.

I just tested and replaced the old TPS with a new unit. The old one had a dead spot in it when I tried to calibrate it.

I've also replaced the temp sending unit with a new unit, it's easy and I figured why not.

I'm about to clean up the ignition coil and add a new ground. I'll post when I'm finished.

Thanks everyone for your help.

 

[Mudder]

The wire does need to be shielded. If there is a section that isn't try putting some tin foil around to see if it takes the code away. As for what type of cable to use I used Coaxial cable when I had to deal with mine.