1996 Collector Edition Corvette

Update your progress on your various car projects.

Moderators: MostMint, wxo, Fred32v, Basement Paul, ttamrettus

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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

BP, I don't believe my AFR meter will work with the stock narrow band O2 sensors. It requires a wide band O2 sensor. BUT, Silvia has two upstream O2 sensors, so I think I can replace one of them with my wide band and let the sensor on the other side talk with the PCM. I'm sure the PCM will complain about the wide band sensor being there (with a service code), but I think the engine should keep running on the sensor information coming from the one on the other side. It would be the same as if one of the O2 sensors went bad. I doubt that would stop the motor from running. Anyway I'm going to give it a try.
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Basement Paul
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Re: 1996 Collector Edition Corvette

Post by Basement Paul »

I have a code scanner that reads live data on OBD2 cars and I thought it had A/F as one of the readings. I just checked and I was wrong. It will read what each O2 sensor is doing, and give live data on all temps, throttle position, timing, etc, but you have to determine from those readings what is happening.
Is there an LT4 blog anywhere, and if so are there any complaints of the same bogging/hesitation issue?

-BP
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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

I've been going over the basics of engine management and there is one obvious thing that could cause this. The mass airflow sensor. The LT4 runs great at high speed, but what if the MAF is not correctly metering the low speed incoming air. If I dial down the fuel pressure to stock specs, the engine will run very poorly. The MAF on this car looks to be original, so before I do anything else, I think it would be prudent to replace the MAF. The engine needs to have an accurate measurement of incoming air to calculate the fuel required. There's an ACDelco reman unit on Amazon with one day shipping. I believe I'll go for it.
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MostMint
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Re: 1996 Collector Edition Corvette

Post by MostMint »

I trust you cleaned the current one already
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]
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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

Yep.
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Basement Paul
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Re: 1996 Collector Edition Corvette

Post by Basement Paul »

I had a Regal GS that had an intermittent miss, buck, whatever you call it, under light throttle, but never under WOT or just cruising. It went for several months and I searched for an answer with NO check engine light. I finally found a guy that complained about the same thing an cured it with a new MAF. So I ordered one, and while it was on it's way to me, the check engine light finally came on and told me that was the problem. The new one cured it. Godspeed.

-BP
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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

I decided it makes sense to eliminate the obvious possibilities before doing any detailed diagnostic work.
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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

The new Mass Airflow Sensor arrived Thursday evening.
MAF.JPG
I discovered a problem right away. The MAF is affixed to the throttle body ducting with semi-permanent Oetiker bands.
MAF clamps.JPG
These are 1/4" wide and about 3.75 inches in diameter. It took a lot of searching but I finally found the correct dimensions in the CV boot category. They will be here Monday.
Amazon boot clamps.JPG
I have adjusted the fuel pressure down to 43 psi and I'm waiting patiently to find out if this is going to remove this burr from under my saddle.
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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

I decided to explore the Oetiker bands securing the MAF sensor. I was able to use a screwdriver to open up the ears enough to undo the oem bands. They came off easily and without much damage so I believe they can be reused. When I get the tool on Monday I'm hoping I can reform the ears to tighten the bands just like stock. While I had everything apart, I took the time to clean up the ducting before installing the new MAF.
New MAF.JPG
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wxo
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Now that's what I'm talkin' about!!!

Post by wxo »

WOW!! The new MAF did the trick. On the first test run, I had the fuel pressure set at 43psi and I could feel that the drivability had improved substantially. Just for the fun of it, I bumped it up to 45psi and went out again. Another Wow! It finally feels just like it should. What fun!! I gave that gearbox quite a workout. No hesitation at all.
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Basement Paul
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Re: 1996 Collector Edition Corvette

Post by Basement Paul »

If you live in Ohio, it would snow tomorrow so you couldn't drive it for five months. Congrats! That was quite the journey!

-BP
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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

I've discovered another interesting problem. The fall leaves are being scooped up and sucked against the the AC condenser. Each time I went out today, I had to pull the leaves out of the front of the condenser. I'm glad I noticed it so at least I can clean them out every time I go out. I'll have to keep an eye on the engine temperature.
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MostMint
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Re: 1996 Collector Edition Corvette

Post by MostMint »

I have heard that the C4 is prone to picking up trash due to the cooling air inlet design. I'll have to put some wire mesh on mine to keep that stuff out.
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]
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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

Put away the party hats, boys. Silvia is back to her evil ways again. Don't ask. I don't understand what's going on (yet). This morning it took several tries to get her started. Then she stumbled around for a little while before settling down to a normal idle. Then I blipped the throttle a few times to see if the hesitation/bog is back, and it is. So as before, I jacked up the fuel pressure to eliminate most of it. Looks like I have a lot more figuring and testing to do to get to the bottom of this. Gotta take it out for a ride now to see what she feels like.
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wxo
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Re: 1996 Collector Edition Corvette

Post by wxo »

Follow up from today's test drive: With the fp set at 50psi she runs without bogging or hesitation. She likes the higher fuel pressure. She also starts reliably when warmed up. I'm going to drive it more to see how it acts over time.
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