OT tech help, GM 5.7L V8 - PeachParts Mercedes-Benz Forum

davestlouis · #1 08-05-2006, 06:14 PM

Here's the deal, I'm looking at a 92 Buick Roadmaster sedan, plain old 5.7L V8, not the later 260HP version. It won't pass emissions testing, the guy at the test station says it won't rev up high enough to complete the test...supposedly the oil pressure is too low,, and there is some sort of fail-safe in the ignition system to keep the engine from hurting itself.
1. does this failsafe really exist?
2. the thing has 150xxx miles on it and says 5w30 on the filler cap...
3. I have to imagine 15w40 would increase the oil pressure, which reads 30 LB at idle and climbs under load. Not sure what weight of oil is in it now.

The car drives out just fine and behaves normally. Any GM fans here?

OMEGAMAN · #2 08-05-2006, 06:26 PM

I have never heard of a car with engine protection devices for oil pressure or water temp.
People that work in emissions stations are usually bone heads (at least the ones in Colorado and Vancouver B.C. dont listen to a word they have to say.
Does the car run well? What happens when you mash the gas pedal in low gear and stay in it for about 20 seconds? Do this and report back it sounds like you have a plugged fuel filter. Or maybe really late timing.

davestlouis · #3 08-05-2006, 06:29 PM

It accelerates like a freight train...strong runner, no miss or other hesitation, no indication that anything is amiss. Just failed the test when a buyer took it to get plates, then returned it when it failed. The dealer is my x-father-in-law, who is very upfront with me, so he was telling me the truth as far as he knows.

OMEGAMAN · #4 08-05-2006, 06:33 PM

What did it fail on. What were the readings?

davestlouis · #5 08-05-2006, 06:40 PM

My understanding is that they never got as far as running readings because the car wouldn't physically run the test...but I'm hearing that 3rd hand.

davestlouis · #6 08-05-2006, 06:42 PM

Keep in mind this is a $800 beater, clean interior, amazing hail damage on the outside, but otherwise OK. I don't mind doing some repair to get it to pass, I just don't want to spend a fortune on it. My gut, the more I think about it, is that the buyer got second thoughts and made up a story to bail on the sale...

t walgamuth · #7 08-05-2006, 08:32 PM

that dog might hunt.

the plugged filter might have legs too.

tom w

OMEGAMAN · #8 08-05-2006, 11:22 PM

Its easy to get those things through emissions even sometimes without a cat convertor. Would be a fun car to beat on for $800. The fact that it accelerates good means it should pass with little problem.

davestlouis · #9 08-05-2006, 11:44 PM

I'm willing to take a chance for $800...what the heck.

davestlouis · #10 08-05-2006, 11:46 PM

I need something to tow a 17 ft fish and ski boat with, and this looked like a cheap way to tow a cheap boat. That, and the boat is silver and blue, and the car is silver, so they kinda match. Nothing bugs me more than mismatched tow rig and boat...

t walgamuth · #11 08-05-2006, 11:49 PM

well that clinches it.

now you are committed to get it to pass!

matched rigs do look cool. i bought some blue paint to paint the center hubs on my dodge truck (silver) so it would match the stripe on my airstream. unfortunately i havent painted them yet!

tom w

davestlouis · #12 08-05-2006, 11:56 PM

More power to ya Tom...how big's the Airstream? New or classic?

t walgamuth · #13 08-06-2006, 07:46 AM

it is a 97 excella. 35 x 8.66'

i had an avion 29' before this one. i figured how hard can it be to maneuver another 6'?

WRONG dog breath!

this thing is a real handful to get in and out of places. the worst is the gas stations.

i am getting better though. i seem to actually be able now to take it out without putting any ding s in it after 2 years. i dont think i ever dinged the avion even once.

once out on the road it is a piece of cake.

and if i can see i am fine. but the mirrors on the right side of the truck are totally inadequate to see the trailer when i am turning right. i am working on that.

tom w

davestlouis · #14 08-06-2006, 08:01 PM

I have done very little towing and I'm not entirely comfortable doing it, but I have to pull the boat about 20 miles each way from the place where it's going to be stored, and it'll live in the water all summer. My wife told me today I come up with the dumbest reasons for buying additional cars...why not just put a hitch on the Jeep? She just doesn't understand.

Wodnek · #15 08-06-2006, 09:41 PM

I have had several Buick Roadmasters, including a 92. Good solid cars. The 91-93 had an electric controlled EGR that caused them to fail emmissions. Replace the EGR with a factory one from the dealer, not an aftermarket one. The 92 will get you about 14-15 around town and 18-20 hwy milage. Check the tie rods. They are cheap but not long lasting on these cars. If you carefully count the turns, you can typically change them without getting a front end allignment. Its an easy car to work on other than changing the cap and rotor, thats a real B. I sold my 91 (wagon) at 212,000 miles and the 92 sedan at 227,000 miles, both with the original drive train. Any other questions PM me, I'd be happy to help.