Fresh engine..... spark problems

[neilb]

Hey everyone, I was just wondering, I just recently finished my first engine build ever, and have been having issues with the spark plugs fouling up really badly very quickly! The car has gone maybe 10 miles on the rebuild and I've gone through 2 sets of plugs!! I realize that the rings aren't seated in yet, but is it normal for the plugs to foul up so badly during break-in? The car runs pretty smoothly with fresh plugs, but as they foul, it misfires and eventually won't idle.

thanks

 

[mikestertwo]

You have a problem Are the plugs oil fouled or gas fouled?

 

[neilb]

At first I was just thinking it was oil fouling, but after a quick check of the tail pipes, I realized its gas. I did a fuel pressure check, and verified it to be set at 43PSI with the vacuum line off as per what the TurboTweak chip requires. When the vacuum line is put back on, the pressure drops to approx 36-38 PSI. I did a few more checks and found (can't believe I missed this before) that my TPS sensor was reading opposite of what it should! at idle it read 4.63v, and at WOT it read .44v! apparently the parts store sold me the completely wrong sensor! I imagine that this is the source of my problem. I'll order a new TPS and we'll see how it goes.

New question... What exactly is the difference between a 2 bar MAP and a 3 bar? How do I know which one I need? I'm assuming it has something to do with the target boost levels the car will run.

 

[mikestertwo]

New question... What exactly is the difference between a 2 bar MAP and a 3 bar? How do I know which one I need? I'm assuming it has something to do with the target boost levels the car will run.

The TPS is definitely the source of the over rich problem. The MAP sensor is only used to run the boost gauge. It has nothing to do with the amount of boost the car runs at. A 2 bar Map sensor can read pressures up to 14.7 lbs. A 3 bar can read up to approximately 29 lbs.

 

[neilb]

I replaced the TPS with the proper one, and reset the ECM. She's running much better now! I took it for it's first real drive on the new engine, went only about 20 miles, got some fresh gas, and headed home. ran well. I pulled a spark plug when I got back, and it looked a nice even tan/brown colour. I'm pleased with it so far, as soon as I get my Scanmaster I'll start really fine tuning it.

Just have to fix my Powersteering issue and maybe look into a vacuum pump for my vacuum brake setup (It was kinda a firm pedal).

Thanks for your help mikestertwo!

 

[vacuum 6]

Put some boost to the motor and seat the rings.