car shutters at cruising speeds

[VtheGNMan]

I don't see any monitoring devises in the interior picture but its really dark so they may be there and I just can't see them. Do you have a scanmaster or power logger?

If so, when driving set it to watch the TPS voltage. (Throttle Position Sensor). When at a steady cruising speed watch the voltage. It really shouldn't change. Observe the voltage when it acts funny. If the voltage drops way off then comes back up as it smooths back out you may have a bad spot in the sensor. This has happened to me. Tricked me into think the Torque Converter was coupling and uncoupling.

Depending on the scanmaster too, the refresh rates won't always catch the drop if it comes back really quickly. It took me a good 6+ times of watching it go thru a stumble to finally catch it. Replaced sensor and no problems since.

You can also watch voltage with engine off but ignition on and work the accelerator very slowly and smoothly thru the whole range to WOT to see if you can find a dead spot. I never could find one using this method but others have.

But without a monitoring devise, you can throw parts at the car for a long time and maybe eventually get it right.

Possible you are getting a little cruising speed turbo flutter that is common with the 44's and especially the 49 series turbos.

 

[Mr T type]

Any chance that car came from Illinois? Did it once have a police strobe light package?

Yup, was scotts car and it still has the strobes

 

[Mr T type]

At this time the car has no devices or gauges other than factory digital dash which is worthless when it come to info. So I pulled the chip and took some pictures of the added parts and the description of the chip specs. It's the pit bull chip description to the left of the page

 

[Mr T type]

Also found this vacuum line off and can't find where it goes

 

[1986 Buick GX1]

View attachment 296717 View attachment 296716 View attachment 296715
Far as I can tell from receipts it has new cat back exhaust, 3" down pipe and 3" cat, big mouth cold air injection system and adjustable fuel regulator and gauge set @ 41#

I like the black car wheels on the non- black car.

 

[Mr T type]

Based on my research the pit bull chip is old tech and I need a new chip.
I need to upgrade my fuel pump and pump power delivery.

So questions
What and why a scanmaster tool?
Do I need different injectors?
What's a good chip?
I was planning on getting a Moats chip programmer for my chevy tbi 454 and it has an adapter for doing Buick chips as well, i s this better than just ordering a chip. I'm pretty handy but completely new to these concepts.

 

[GNRick]

Yup, was scotts car and it still has the strobes

Scott spent hours detailing that car. He sold it to the local Buick dealer who I think sold it at an auction. At one point it turned up on eBay but it didn't sell.

 

[Mr T type]

[QunUOTE="GNRick, post: 3728279, member: 12687"]Scott spent hours detailing that car. He sold it to the local Buick dealer who I think sold it at an auction. At one point it turned up on eBay but it didn't sell.[/QUOTE]

I actually talked -to Scott today letting him know ho much i appreciate the effrt he put into the car.

 

[VtheGNMan]

Based on my research the pit bull chip is old tech and I need a new chip.
I need to upgrade my fuel pump and pump power delivery.

So questions
What and why a scanmaster tool?
Do I need different injectors?
What's a good chip?
I was planning on getting a Moats chip programmer for my chevy tbi 454 and it has an adapter for doing Buick chips as well, i s this better than just ordering a chip. I'm pretty handy but completely new to these concepts.

The Scanmaster is an easy to install monitor of all the basic functions and voltages on our cars. It allows you to toggle between a bunch of different setting and readings. These were designed specifically for our cars. You can find the older style good used ones on here in the parts for sale section or last year they came out with a new one that is a 2 1/8" gauge design. You'll have to decide which is for you.

Injectors. Maybe you do, maybe you don't. What are your goals for the car? The chip info page doesn't mention what injectors it is designed for so you may choose to upgrade them. Just going by the looks in the pic, I'd guess them to be stock injectors which are 28#. If you choose to upgrade, here is where you need a goal as you want to get the right injectors. You can go up to 80#ers before you have to have the ECM itself modified.

Turbo Tweak is the go to source for all your chip needs. They have matching injector and chip sets.

That I am aware of the modern day programmers do not work on our era of cars.

 

[earlbrown]

I would get a new set of 60's with a matching TT chip. Your stock injectors are 30 years old. At that age mileage really doesn't matter.


Since you're in touch with Scott find out if the timing set has been changed (and the age on the valve springs).


You have a loose line on the intake manifold around all the EGR crud. Is that a vacuum leak? Where does it run to?



For your shutter at cruise, unplugging the transmission plug will eliminate the TCC from unlocking and locking right back up. Many years ago my car would 'cut out' on the interstate while driving to work. It took me FOREVER to figure it out. The problem felt EXACTLY like it was electrical. It would cut out EXACTLY like a car with a bad spark.

Turns out I had flaky pressure switches in my trans. I verified that because I had a manual lockup switch in my ashtray. If I got on the interstate and locked the converter, it would never 'cut out' as long as I forced the lockup to stay locked up at speed. That's easy to do for testing. If you want to force a lock up, you can jump out two ports in the ALDL port. If you want to force it to never lock, do like Rick mentioned and unplug the transmissions electrical plug.


Honestly, those switches are cheap enough to go ahead and replace while doing a trans service. You need 2 of them, one for 3rd gear and one for 4th. It doesn't take any disassembly to swap them other than dropping the pan for a filter change and to install a drain plug. I had both of mine go bad on my new low mileage trans from from sitting. Which was very odd considering the switches are NC.

 

[87geeinn]

Check your coolant level and entire cooling system. Your overflow tank is completely empty. A severely overheating car can cause similar issues to what you're describing.

 

[87geeinn]

Also, an alternative method to checking the lockup solenoid is to get up to cruising speed, 4th gear, torque converter locked, and press on the brake pedal just slightly while maintaining throttle with the right foot. This will automatically unlock the torque converter.

 

[Mr T type]

thanks for all your advise guys, just bought a used car lift for my house that transmission investigation will be my first order of business.

 

[mikestertwo]

I doubt it is a TCC issue. If it was you would get early and hard 2-3 and 3-4 shifts unless that's something you failed to mention in your post. I would suspect a lean condition or too much timing in the chip.

 

[GNRick]

Was this ever figured out? My car sputtered at about 40 mph but cleared up if I gave it some gas. Problem was a bad crank sensor.

 

[FullThrottle87]

I had this exact problem when I purchased my factory original 87. One of the first things I did after fixing vacuum leaks and changing transmission fluid I realized it was the lock up at low RPM in 4th gear doing it. I got a turbo tweak chip and all my problems went away with the chip! Cruising at 50 miles per hour it no longer felt missing or lugging around smooth as glass. I started leaving it in overdrive again because it felt great after changing the factory chip. Yours isn't Factory, but do yourself a favor and start with a modern turbo tweak PCM chip!

 

[Mr T type]

i changed the lockup speed in the ecm and that seemed to take care of it.