1984 Buick Regal GN over my head

[Bergjo91]

Looking for help

Bought my 1984 Buick Regal GN last year at a car auction of one of my growers I sell to. Didn't think it was in to bad of shape knew it needed some engine work as told by owner definitely over paid let it get to me that I wanted a Grand National and it being this certain persons car made it being a rash buying decision.

At the beginning car would over heat instantly so changed out thermostat, and replaced the radiator as original was was plugged and corroded solid. Solved the over heating issue. Also replaced spark plugs and plug wires. Also replaced belts and water pump. Along with find a stock air cleaner putting that in with a new MAF sensor. And a new 02 sensor. Lastly a EGR valve.

Car would run and could drive around likes to stumble and back fire on the low end when getting going and usually would smooth out.

Recently drove it home from where I store it, wanted to replace the MAP sensor, Idle air control valve ( Read on other posts hoping these might fix the hard starting and rough throttle and trouble getting going from a stop. Got it home and have had trouble ever since with the new parts installed and even trying putting all the old parts back on. Pulled plugs and they were fouled lots of carbon and suit on them. So put a new set of plugs in and no improvement, pulled 02 sensor out and cleaned that as that was suited up somewhat.

My dad a GM mechanic for 20+ years tells me I couldnt have bought a worse car that could have so many things go wrong and why I didnt buy a car with a 350 in it.

I appreciate any tips or information anyone can provide me or probably for a guy like me that doesn't have a ton of mechanical experience to find a tech that could pull the engine and completely go through it top to bottom.

Located in far north, North Dakota

 

[NorCalTurbos]

First thing you need to know is if it runs without serious problems it’s okay relax. These cars are great but they can be a PITA. You don’t have to be Richard Clark although it would be nice to dial things in. These cars are old and so are most of the existing parts. I’ve literally built my car with help from the great guys and information on this forum/club. Check your wiring harness and search like hell for vacuum leaks check fuel pressure and get a new fuel pump in it asap stay out of boost until you figure things out. What chip and injectors are in the car. Vortexbuicks.com has probably enough info to get you headed in the right direction do the spring cleaning and do research here. VACUUM LEAKS, Proper fueling coil pack ignition module, cam sensor not set properly, bad or incorrect maf, trippy ecu these are a few things to consider before you pull the motor.

 

[mblum]

Being these cars are fuel injected, as they age it's death by a thousand paper cuts. Meaning a long list of little issues add up to a poor running car. These are definitely not as simple as a small block chevy and a carburetor. From what you describe I highly doubt the engine needs to be pulled. One way to check is to do a compression test and look for even pressures and then a leak-down test. This will confirms that mechanically you have a healthy engine, which is the foundation you need to fix the list of small issues and will help you avoid throwing parts and labor at a car that has issues.

If you plan to keep this car and really want to resolve these issues you really need a device like a Scanmaster, there are used ones listed for sale on this forum often. This will allow you to collect data from the ECU (the computer) and will make accurately diagnosing issues much easier.

The first place I would start is the fuel system, from front to back. Injectors, if they are stock there is a good chance that they are not flowing correctly nor evenly if this car has sat for period of time with crap fuel in the tank. You could have some not flowing at all and others leaking internally causing rich fuel in some cylinder and lean in others. Yes, the stock injectors can be cleaned, but I would just start fresh with a set of 60lb injectors and matching ECU chip from Turbo Tweak.

The fuel tank needs to be dropped, inspected and cleaned, and the fuel pump needs to be replaced. A fuel pump hotwire kit is also wise, this ensures your new fuel pump will have the proper voltage. Without proper fuel pressure there is no amount of parts or time spent on the car that will fix anything. Bottom line is the fuel system needs to be gone through and properly functioning. Put a new fuel filter on the car. An adjustable fuel pressure regulator and a way to measure fuel pressure will be required for the new ECU chip as there is a recommended target fuel pressure as well as confirm your fuel system is functioning.

All vacuum leaks and exhaust leaks before the turbo will need to be addressed, these can really cause a car to run poorly.

If you put a stock replacement MAF sensor on the car, it could still be causing issues as they are known for not being reliable. A MAF Translator and a modern MAF is the best route.

Post up questions as you tackle each of these areas. There are more items to check than I listed above, but if all of these things are up to snuff you will see a big difference in how the car runs.

Yes, it can be daunting, but as you chip away at these items you will learn more about the car and become more comfortable with working on it.

 

[Bergjo91]

Talking about Fuel I forgot to add in there. Previous owner had put a new tank in, and I thought a new fuel pump. But I am thinking it sat for a period even after that was done. I did get a fuel pressure gauge from my neighbor. When I would turn the key on it would get up to 34lbs turn key off and it quickly bleed down to 10lbs.

I also got from my dad the tool to check for codes little metal key to put into ports AB, I tried and no luck with the car doing anything service engine light just stayed on steady.

Thank you for posting and giving me some direction on where to head next! I have enjoyed tinkering on this car kind of my escape from my full time job of farming and sales, and I do plan on keeping it.

 

[NorCalTurbos]

You are definitely going at least need a scanmaster it’s been a while since I’ve switched over to Lc2 86-87 from the hot air set up but I think you need the 86/87 ecu and a chip. Make a list a long list of little things like previously mentioned make a post in the parts wanted section and get familiar with the vendors. Good luck