1998 L29 454 Torque pro app findings

[RichardSwinger]

I didn't want to keep cluttering the official 454 thread so I wanted to start this one for anyone looking for or having information on the various readings for sensors and what "correct" might look like.

First question: Is anyone able to see oil pressure or oil temperature with their OBDII scanner apps? I found out there is a way to open up "GM" PIDs on the torque pro app and was able to see some more useful information. I was able to start seeing trans temp (awesome!) But the oil pressure and oil temperature still won't show anything. I'm wondering if something is unplugged (like the random wire by the steering shaft maybe?) or if there just isn't an input to the ECU. I do have an oil pressure gauge on the cluster and it does seem to respond appropriately (about 80psi/maxed out when cold, about 40psi when hot/cruising, about 20psi when hot and idling) but I'm learning that the gauge cluster indications can read a good bit higher than actual when compared to the OBDII scanner (like my RPM which seems to be consistently 300 RPM higher than what the scanner says).

Next question: what would cause me to be stuck in "closed loop" and how do I fix it? I made sure to get everything up to temperature (about 30 minute drive to work) and it never came out of closed loop, scanner says "feedback fault" and my O2 sensor voltages are all over the place. At first it looked like bank 1 sensor 2 was the only one reading low, but after watching them for a bit they all seemed to jump all over the place. I've read about people fabricating "three wire" O2 sensors, is that something I could/would/should do for all 4 sensors?

I appreciate you guys for taking the time to read!

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[someotherguy]

No PCM input for oil pressure # (or temperature)

Closed loop is normal warmed-up operation.

Richard

 

[RichardSwinger]

No PCM input for oil pressure # (or temperature)

Closed loop is normal warmed-up operation.

Richard

Thank you! Glad I can stop worrying about trying to find out about oil temp and pressure.

Ok, so closed loop is normal for a warmed up truck. Weird, it said closed loop as soon as I turned it on. And fuel system status is saying "Closed loop using 1 O2 sensor (feedback fault)" so I guess only one bank of the O2 sensors is actually feeding information to the ECU? I'm contemplating replacing all of the O2 sensors but if there's an easy to do "three wire/heated" upgrade I'd rather start chasing that rabbit down.

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[someotherguy]

Yep, go read up on open loop/closed loop operation and it'll make more sense. Open loop means warm-up mode for lack of a big technical explanation. Why Torque is telling you it's in closed loop right off the bat, don't know. I'm not sure I would rely 100% on what Torque says. It's a useful tool but it's also only $6 vs. ridiculously-expensive dedicated scan tools.

Your truck already uses heated O2 sensors, by the way.

Richard

 

[RichardSwinger]

Hey now, don't you go talking down about my $10 china scanner and $3 app! Very good points all around, and thank you for the confirmation on having heated O2 sensors. Huge help as usual Richard, thank you!

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[0xDEADBEEF]

I think full throttle goes to open loop. Or at least I've seen that in other vehicles.

 

[someotherguy]

Hey now, don't you go talking down about my $10 china scanner and $3 app! Very good points all around, and thank you for the confirmation on having heated O2 sensors. Huge help as usual Richard, thank you!

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LOL.. I use Torque Pro plenty as well, though I found I had to spend a little extra for a better reader as the cheapo one wouldn't work on my later GM stuff. So in other words my $10 clear blue reader wouldn't connect on the SS, so I had to spend $20ish to get the BAFX Pro. Works like a champ.

Richard

 

[df2x4]

LOL.. I use Torque Pro plenty as well, though I found I had to spend a little extra for a better reader as the cheapo one wouldn't work on my later GM stuff. So in other words my $10 clear blue reader wouldn't connect on the SS, so I had to spend $20ish to get the BAFX Pro. Works like a champ.

Richard

I bought a BAFX Pro and it didn't work on either of my '97s. I have two $10 blue ones that will work with one truck respectively, but not the other.

The point stands though, cheaper Bluetooth OBD2 dongles are hit and miss, and you do tend to get what you pay for. The only Bluetooth OBD2 dongle I have that has reliably worked on every vehicle I've used it with is my PLX Kiwi, which was around $100 IIRC.

 

[someotherguy]

Yeah, the first time the blue one didn't work for me was on my '97 Suburban with the LS swap. Didn't want to connect to that PCM. It wouldn't connect on my '06 SS either, so at that point I got the BAFX. It works great on the SS. Also works on my 300. The cheapo blue one worked on the 300, which I didn't expect.. so when a buddy needed a reader for his car, it got donated.

Richard

 

[454cid]

LOL.. I use Torque Pro plenty as well, though I found I had to spend a little extra for a better reader as the cheapo one wouldn't work on my later GM stuff. So in other words my $10 clear blue reader wouldn't connect on the SS, so I had to spend $20ish to get the BAFX Pro. Works like a champ.

Richard

I should really get into this.