I think this is a stuiped question but hopefully someone can help

[raykeo]

Ok so my car has been in limp mode for the last couple of weeks. now i took it down to master tech cause i have already changed the plugs and wires boost leak test(ill come back to that), fluid change, hollowed out the cat(it was cooked). so it runs semi decent, but i took it to master tech and they said my ignition control module was buzzing in and out, and o2 sensor is fryed. So heres the million dollar question. Would a ICM reading in and out make my car go into limp mode??? I get no CELs. and the boost leak test i preformed. me and my step dad could hear any leaks other than a faint intake manifold. it held pressure, but was a steady leaking sound. is that normal??? we don't have a gauge to hook up to tell how long it took for the pressure to release. anyway thanks for listening lil long winded
1992 eagle talon awd tsi TURBO BABY hahahaha

 

[anteversion]

the leaking sound from your intake manifold might come from some slightly open valves. you must set the engine to TDC before putting some pressure into the tubing. Running without ( or with a fried o2 sensor ) will cause the car to go into limp mode

 

[96ETT]

Definitely the O2 sensors needs replacing and the cat being hollowed out is going to mess with the engine performance.

 

[habitatguy187]

the cat being hollowed out is going to mess with the engine performance.

Not on a 1g. MUHAHAHAHAHA!!

 

[95CarbonEclipse]

Definitely the O2 sensors needs replacing and the cat being hollowed out is going to mess with the engine performance.

I agree with the O2 sensor... but, the cat being hollowed out isn't going to effect performance negatively.

 

[raykeo]

yeah trust me that 1G spools far quicker than it used to. i noticed that right off the bat when i first yanked that cat off. so really the 02 sensor can make it go into limp mode with a cel. and i guess it just reads that its lean the whole time

with out a cel sorry

 

[anteversion]

thats a bit more complex than this. Engine runs in closed loop and open loop dependly on how much throttle your are giving. The fact that your o2 sensor is toast does not necessarly mean that the ecm is reading your a/f as too lean. And yes 1g are under OBD1 emmission system wich means that there's no o2 sensor after the cat... so ecm is not even detecting if a cat is present or not. Obviously, no cat is much better for performance wich mean less restriction.

 

[96ETT]

thats a bit more complex than this. Engine runs in closed loop and open loop dependly on how much throttle your are giving. The fact that your o2 sensor is toast does not necessarly mean that the ecm is reading your a/f as too lean. And yes 1g are under OBD1 emmission system wich means that there's no o2 sensor after the cat... so ecm is not even detecting if a cat is present or not. Obviously, no cat is much better for performance wich mean less restriction.

You are right to a point. OBD1 does not imply no O2 sensor monitoring the cat, maybe just on DSMs. Many other OBD1 vehicles had O2 sensors after the can even in 90 models. And yes no cat is better for performance only if your vehicle doesnt use an O2 sensor to monitor the cat such as 1g dsms. My mistake for not seeing it was a 1g in my other post. But a toasted O2 sensor can cause all sorts of problems regarding ECM, fuel mileage ect... Basically get a new one and see what happens.

 

[raykeo]

mk well im getting it back 2 morrow. hopefully it will shift i want the power again .

 

[brownfinger]

How is it in limp mode without a CEL?

 

[raykeo]

well i have heard that you dont have to get a cel when it goes into limp mode. sssooooo update i got it back no luck. heres a question if the TCU goes bad or the capaciters will that not bring up a cel, and also wheres it at how do i inspect??? i gotta rip the turbo apart and check it out. its pulling in way to much air and wont stop running ugh.

 

[steve]

I don't remember the TCU being connecting to the CEL and I don't see it in the FSM diagrams.

There is one 47uf cap in the TCU that is the same part as the one in the ECU and both leak.

Pin 6 on the DLC is the diag output of the TCU and it can be read the say way as the ECU with a analog voltmeter, 12v LED or piezo buzzer. The error codes are listed in the FSM.

 

[knochgoon24]

DSM Lingo 101:

FSM: Factory service manual
(for your help and/or anyone who comes along later)

 

[raykeo]

I understood that magical car lingo. getting ready to pop out the tcu and see what it looks like. fingers crossed thats the problem

So F me in the A. Took the tcu out took it apart and it burnt a capaciter. not a huge burn out but should be my problem. so if you ever take out a tcu and smell it through the connecters, and it smells like electric crap, could be time for a new one .

 

[steve]

Sorry to hear that but not surprised. Like the ECUs these caps will all fail and need to be replaced before they fail.
The TCU is a crapshoot for fixing them after their have failed. The ECUs usually work but it's 50/50 on the TCU.

 

[raykeo]

yeah well im hoping the problem is where it burnt out i dont feel like pulling the tranny , auto can be a biatch to rebuild, and i want my powa back