1G Rough idle/no power under load

[91STROKER]

1990 Talon TSi. Car sat in the garage over winter about 2 months. Start it and it has a rough idle and and no power under load. You can hold the gas to the floor and it goes nowhere. It will build boost though just doesn’t move. Plugs, wires, ignition coil, air filter, fuel filter were all replaced before winter.

It almost feels like when piping blows off the turbo or intercooler and the car loses power. I’m going to test fuel pressure tomorrow I have someone bring me a kit to do that, just trying to get any thoughts that may point me in somewhat of a direction. I have read and there is just so many different scenarios trying to maybe narrow it down if anyone has had this type of experience.

Also intermittent CEL

 

[91STROKER]

Just going through stuff. I just got under the car and can see black stuff dripping from the Knock sensor, possible problem? How TF are you supposed to get that out

While I was looking at the knock sensor I noticed two connection where it looks like vacuum lines should be connect but there isn’t anything there on the bottom side of the intake manifold.

Picture attached is this correct? Should these be capped off?

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[BLACK'98DSM]

Just going through stuff. I just got under the car and can see black stuff dripping from the Knock sensor….possible problem? How TF are you supposed to get that out

https://www.dsmtuners.com/threads/knock-sensor-ooze.531657/

 

[dwb]

Pull the CEL code. Even if it is intermittent, as long as you haven't pulled battery power, it will store the code. That should give you something to start looking at.

Two of the four hard lines under the intake manifold are open/nothing attached to them from the factory, but make sure the other two have vacuum lines hooked up to both ends.

Do a boost leak test. It's possible over the winter a vacuum line got brittle and broke. May not be visible, but a BLT will tell you.

My knock sensor had that goo dripping for a long time before it started to act up. Probably best to leave it alone unless your CEL points you in that direction. 1g knock sensors are practically unobtainable new unless you're lucky.

 

[91STROKER]

Knock sensor just for reference. Actually looks fine to me. Working on getting the codes pulled

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[steve]

Sorry, that one is done. You shouldn't be able to see the screw.

 

[dwb]

Sorry, that one is done. You shouldn't be able to see the screw.

Has there been a consensus 1g replacement?

 

[91STROKER]

Sorry, that one is done. You shouldn't be able to see the screw.

F*ck…anyone have one? So this could possibly be causing the issue?

 

[steve]

While a bad knock sensor is going to cause problems trying to get any performance it shouldn't have much or any impact at idle. While you look for a new sensor I'd focus on on that.

Compression test, inspect all the stuff you changed last year. Boost leak test, make sure you have good spark on all cylinders.

Fill out a profile for this car, I know you had a bad ECU that ECMTuning fixed, assuming you don't have DSMLink but you could read the diagnostic code with a meter, 12v LED, or 12v Piezo buzzer and see if that provides any clues.

 

[dwb]

Also verify mechanical timing - it's possible that you slipped a tooth without damage and runs like you described.

 

[1cleangsx]

Check your throttle cable, MAF, tps

 

[We're on Boost]

Has there been a consensus 1g replacement?

No real consensus that I know of. You've probably seen the last couple of show and tells that we've had - I'll put some links here.

gpd 1811840 from CARiD.
and
Chenho MD141510 from the Chenho store in AliExpress.

The discussions and show and tell were in these threads:

gpd and a few others, starting in post #1: https://www.dsmtuners.com/threads/where-to-buy-1g-knock-sensors-in-2024.546134/

Chenho, starting in post #153: https://www.dsmtuners.com/threads/help-with-tuning-sd-what-next.545837/page-7#post-153912119

 

[91STROKER]

While a bad knock sensor is going to cause problems trying to get any performance it shouldn't have much or any impact at idle. While you look for a new sensor I'd focus on on that.

Compression test, inspect all the stuff you changed last year. Boost leak test, make sure you have good spark on all cylinders.

Fill out a profile for this car, I know you had a bad ECU that ECMTuning fixed, assuming you don't have DSMLink but you could read the diagnostic code with a meter, 12v LED, or 12v Piezo buzzer and see if that provides any clues.

Compression test was good 150 across the board
Spark on all 4 cylinders
I was able to pull the code and If I am correct it’s code 41 which comes back as injector circuit error. I attached a video to confirm I am reading the code correctly

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I verified that all 4 injectors have power so maybe one is clogged?

Pulled injectors and there was nasty residue built up where the injectors go into the rail so fingers crossed clogged injector is the problem.

 

[steve]

That is a 41, does it just repeat?

It's an electrical issue that triggers that code when the ECU doesn't see the normal current draw and inductive spike that follows firing the injector based on what I saw in the ECU Code.

Are all the spring clips in place on the injector connectors? How are the wires and resistor pack. My car would drop the misbehaving cylinder until the fault cleared. Have you narrowed down which cylinder it acting up?

This happened to me back when I have the original injectors, one would have it's coil go open when it got hot and connect back up when cold. I had a datalogger so I could quickly turn off the other injectors one my one to see which had no additional effect to identify the cause.

 

[91STROKER]

That is a 41, does it just repeat?

It's an electrical issue that triggers that code when the ECU doesn't see the normal current draw and inductive spike that follows firing the injector based on what I saw in the ECU Code.

Are all the spring clips in place on the injector connectors? How are the wires and resistor pack. My car would drop the misbehaving cylinder until the fault cleared. Have you narrowed down which cylinder it acting up?

This happened to me back when I have the original injectors, one would have it's coil go open when it got hot and connect back up when cold. I had a datalogger so I could quickly turn off the other injectors one my one to see which had no additional effect to identify the cause.

Actually yes there was a clip missing on 1 of them and yes it would just repeat. 41 was the only code. I have a local Injector shop local to me so I’m going to drop them off Monday to be tested and cleaned since I have them out. Maybe the missing clip was the issue causing it to lose continuity.

Also the resistor pack connector could definitely be cleaned slight corrosion on the metal connection points as well as the injector connectors as well . Cylinder #2 had the missing clip

 

[91STROKER]

UPDATE: car seems to be back to normal. Took it out for a cruise last night after getting the injectors back in and it’s running great!

 

[steve]

Cleaning fixed it or replugging the connector?