Engine runs uneven on all rpms

[MoeJr]

I think getting rid of the car is a bit rash myself.

You can also use 8 oz of Marvel Mystery in the gas. That will provide a lubricant. I used this in my 87 Grand National when I first got it in order to get the injectors working smoothly.

I would efinitely try and find the BG 44k. That stuff flat works.

Moe

 

[Doktor-t]

Redline

Update

I poured in a bottle of Redline S1 injectioncleaner today and drove the car for about 10-15 miles after that. I didn´t notice any improvment so I drove of to GM Corvette sale and repair dealer.

I told the girl behind the desk that I need a damn good mechanic. After a while she came back with a mechanic and after a couple of minutes he told me that he though that the injectors were done. According to him these Bosch injectors tend to fail even if they´re almost new!

I guess it´s as good as certain that the injectors are gone or what do you guys think?

Best regards: Tobias

 

[John Robinson]

Drive it

10 to 15 min. won't even warm the oil to full operating temperature. Injector cleaner does not work that fast. You need to drive the car continually for 3 or 4 hours so that the whole tank of gas goes past the injectors with the cleaner in it. GM did not put anything in the car that was not tested to run at least 125K for a normal life span. That is their test criteria. Yes things will fail earlier because of unforeseen manufacturing errors etc. Try the drive and see what happens. If a soccer player does not work out in the off season and comes out for practice after a long time he will be stiff and hurt from a lack of staying in shape. That is what has happened to your car take it out and work the stiffness out of it.

 

[Doktor-t]

valves

Yes I think you´re right John. The only thing is that I´m a bit scared that it can burn the exhaustvalves if the injector doesn´t provide the right amount of fuel. The fuel does cool the valves and if it´s to little...

What´s your opinion? Is it safe to drive it cautiously?

Perhaps time for good old Holley 650/750 and Weiand intake instead? :crazy

 

[John Robinson]

Yes I think you´re right John. The only thing is that I´m a bit scared that it can burn the exhaustvalves if the injector doesn´t provide the right amount of fuel. The fuel does cool the valves and if it´s to little...

What´s your opinion? Is it safe to drive it cautiously?

Perhaps time for good old Holley 650/750 and Weiand intake instead? :crazy

What you are concerned about is running a lean mixture in the cylinders that the injectors are fouled in. That could be a concern but I would still try driving the car.

Maybe someone who is a mechanic could comment on the probability of damage to the valves. LT4 man for example. As for me I would try running the car 300 miles and see if it improves. I say that because my 93 when I got it was sluggish from not being run. I put a fresh tank of gas in it and an injector cleaner. Then I drove it over 500 miles in one day. By the time I had put a hundred miles on the car it was running better and kept improving the more I drove it that day and the rough idle went away.

 

[Doktor-t]

Drive it

I´d better try to put some miles on it and if I´m lucky it will clear the problems.

 

[WhalePirot]

There was, years ago, a post that referred to a study from a Pontiac fuels engineer. They took a ratty, injector-clogged TPI and found that TWO tanks of good, detergent gasoline cleaned them up as well as the injector cleaning products/services.

Doc, your theory was that the injectors were not fully closing, which would make the engine run richer, not leaner. That is inconsistant with your valve burning statement. If there is unmetered fuel (leaking injector) getting in, the ECM will 'hunt' in all RPM ranges, trying to adjust the mixture. That is why my engine did it and probably why VetteBoy's did; both cases due to unexpected (not in the fuel tables) sensor inputs. Both of our engines were intentionally modified; yours is modified, but not intentionally.

What's the worst case here? You enjoy and relax with your gal, enjoying two tanks of quality Vette time, while cleaning your injectors; possibly saving the cost of replacing them. There could even be fringe benefits!

I'd submit that ANY car that gets so little drive time, will suffer some consequences and you'd be hard pressed to find a forum for whatever car, as helpful as this one.

I have mixed feelings on the fuel filter, but they are cheap and rather easy to change. A fuel pressure gauge would tell you if there is restricted flow. I would ensure that your experiment with fuel pressure has you setting it back to factory specifications for your stock engine.

Go drive, buddy.

 

[LT4man]

c4c5specialist recommends Techron fuel cleaner.

I concure wholehearedly.

A container of Techron added to a tank of gasoline will do wonders for your injectors.

I would follow up the first tank with a second tank.

I am betting the Techron will unplug your injectors!

SAVE THE WAVE!

 

[marthaco]

Can this be the thing that cause the uneven running

Thankfull for all help; Tobias

I concur get a can of 44K and see what happens. Excellent products.
Go to their website for more information BG products are commercially sold at NAPA stores nationwide.

GOOD LUCK!





BG Findashop
... bgfindashop.com BG's Locator for Authorized BG Service Center ... Find an authorized BG service center near you!
http://www.bgfindashop.com/

 

[Doktor-t]

Goner

Hi again guys, I have to thank you all for you help trying to point out the problem with the engine.

I believe it was a bad valve and therefore I got rid of the car.

I might buy a C5 instead but only time can tell what´s next in my garage.


Best regards/ Tobias, Sweden

 

[John Robinson]

Premature

You never did say if you took the car for a long drive as suggested by others. I believe your fear of a bad valve was nothing more then a gummy hydralic lifter which would have freed up if the car was driven. I hope you have better luck with your next car. I feel the party who just bought your car has gotten a car that should provide years of fun and enjoyment. I am sure we all have had cars that just did not measure up to our expectations and we found ways to convince our better half it was time to trade.

 

[G Winter]

I think getting rid of the car was a bit rash. VERY seldom do you have a bad valve in a low milage Chevy V8. I agree that it may have been a sticky lifter. If very bad fuel was used there could have been carbin deposits on a valve stem holding it open. Which is not that hard to take care of.

Glenn

 

[MoeJr]

Sad to hear you gave up on the car. I agree with G that it was a bit rash. I see this all too often being in the auto business. People buy a car and when it doesn't fix itself they get rid of it. Someone probably got one heck of a deal.

 

[Doktor-t]

new car

I felt that it was no fun to start digging into the engine because I´ve been there before so I´m pretty fed up with problemcars.

Anyway, the guy who bought it said that he was a car mechanic and he was real cocky about it so I let him listen to the car and he didn´t even notice that the engine ran badly! If you ask any mechanic he is the best damn mechanic in the world, isn´t that strange? *Laughing*

They did like the car and they payed me more than I gave for it so with all my expenses related to the car I only lost about 200 buck and that´s kinda fair I think

Now the only thing is to find another cool car, donno what kind, yet but Chevy has allways been close to my heart so.. In the mean time can entertain myself with my boat insted