Just swapped a 350 Vortec into my 2000 Blazer and am having trouble getting it to run

When I did my 350 vortec with a lt4 hotcam engine swap I went ahead and swapped to a 411 PCM. On initial startup it wil idle down to 200rpms and almost die (sometimes it does die) and then go up to 700rpms and idle somewhat like it should. It's a straight shift and doesn't have anywhere near the power it should. When I shift into third and give it gas the Rpms go up high, but it doesn't actually seem to have power until the Rpms drop. I've checked pretty much every sensor on the engine, the wiring, replaced spider injectors, and have had a crank relearn and camshaft retard set. The guy that did the relearn said the PCM's temp was reading around -40*. The gauges read correct and when I hook my iPhone up to the port it reads correct. Also I have one two wire temp sensor. Most of the sensors on the 350 are off my 4.3, I've cross referenced them and they're the same part #'s. I have a 5.7 MAF ordered since theyre slightly larger, i know a guy that ran his 4.3 and it caused it to run somewhat worse but he didnt experience anywhere near the problems i am. My phone says im getting around 21mpg and is throwing a p0172 and p0175(rich in both banks) and sometimes a p0300(random misfire)

what could it be?

IAT and/or ECT showing large negative temperature indicates a broken wire;

when PCM see either temperature go that low it adds a huge amount of fuel during startup.

So you're saying I need to check IAT or ECT sensor wiring? I've confirmed that the ECT is working and the PCM is sending 5v to the yellow wire and ground to the black.

Also when I unplug the knock sensor nothing changes and when I remove it from the engine, plug it in, and wrap a towel around it nothing changes. I've read the 411's have a different knock sensor than the black box, I'm using a 5.7 black box knock sensor. Does this matter at all?

Post a log, using the efilive scan tool and also a tune file showing the ect and iat sensors. Alot easier to help see whats going on. Also log 24 total channels.

Unfortunately I don't have efilive. I joined because I seen that you guys are knowledgeable about the problems I'm experiencing.

The iPhone app I have can do data logging. I've never done it before though so I'll need to know what all PID's I need to tell the app to log. Sorry I'm a noob to this so I don't even know if this is what you're looking for.

Quote:

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Originally Posted by zq8blazer

... Unfortunately I don't have efilive ...

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What tuning software are you using ?


Regards,
Taz

I had wait4me do the tuning. I sent them everything done to my engine and had them tune a 411 for me.

Well, you are at a bit of crossroads in your project. Either purchase tuning software, and learn how to tune the PCM yourself, or take the vehicle to a professional tuner.

Guessing very few Forum members are familiar with the I-Phone app you are using as a scanner - and frankly, this is not the Forum where you should be seeking support for this scanner.

This website in not a DIY project site - it is dedicated to EFILive users assisting EFILive users with tuning related issues.


Regards,
Taz

I wasn't asking for help with the app, I was just asking for was PID's needed to be logged. I thought since people here know more about the PCM's than me and I've seen other questions not restricted to PCM tuning resolved I could get some help with my possible wiring issue. Guess not.

Purchase the EFILive tuning package (V2 interface) and ask all the tuning questions you want on this Forum. Otherwise, consult one of the many of the DIY Forums on the internet.

Many of us who answer questions, and generally help out, run businesses that would otherwise sell much of the tuning information shared here with EFILive users. That's the price of admission here - being an EFILive software user, such that information sharing is bi-directional.


Regards,
Taz