[99v6stang]

okey i am having a serious issue with my car that i just cannot seem to solve. The car was just rebuilt and now it will start up but i can hear loud tapping noises and when i give it gas it revs up but barely accelerates. I checked the timing and posted pictures online everyone said that was fine. I got a new tune from vmp. I replaced cps, and injectors. The cps i didnt use the alignment tool but i set it up following rpm-mustangs instructions

[itschristorres8]

where is the tapping coming from?
did you lube and soak your lifters in oil?

[99v6stang]

yes i lubed them and covered them in oil, I cannot tell where the noise is coming from it sounds like around the intakes but is very hard to pinpoint

[itschristorres8]

might just be your injectors. mine make a clicking noise at a quick paste

[Onemanzu]

bad exhaust header gasket

[99v6stang]

no i just replaced the injectors thinking that could be the problem, and yes i do have an exhaust leak but that is DEFINTATLY not the problem here, this is much more severe. IT is much louder and the car hardly moves when i floor it, just revs up

[97fordsixer]

could this be some kind of drivetrain issue/ converter something like that or clutch? just thinking out loud

[99v6stang]

The car is automatic, and there were no problems at all before the rebuilt so im pretty possitive the issue is all engine related

[stephen]

You checked valve timing and engine compression and that seemed normal. With good compression and correct valve timing it is unlikely the poor acceleration is from an internal engine problem.

The tapping noise could be a bad lifter. If the lifter leaks down it will make a loud tapping noise till it refills with oil. You should measure the oil pressure with a gauge. Low oil pressure can cause lifter noise. Most likely you just have a clogged lifter. If you get the engine running you can probably free the lifter by adding Sea Foam to the oil for a few hundred miles.

The acceleration problem is probably fuel related. Check the fuel pressure with a gauge or you can get some idea by bleeding the fuel system at the place where you attach the gauge. When you open the valve (like a tire valve) fuel should spray out. Another possibility is the mass air flow sensor (MAF) or throttle position sensor (TPS).

I would go for the fuel pressure issue first. After rebuilding my engine the fuel pump failed within a few days. I believe it was from sitting so long (several months).

[99v6stang]

Well i just replaced the fuel injectors and fuel pressure regulator as well and before that i couldnt even get the car started. Fuel leaked out a whole tun but didnt seem to spray. I do have svt fuel pump that i will install this weekend to see if that fixes anything. But this tapping sounds terrbile and has me worried. I will recheck the rocker arm torque tonight and pour more oil above the lifters. Could the cps affect this? I didnt use the tool as i followed rpm's instructions but ive read about many other people not using the tool and it worked fine for them.

[99v6stang]

wouldnt the tps or maf throw a code if they were having problems?

[stephen]

Originally Posted by 99v6stang Well i just replaced the fuel injectors and fuel pressure regulator as well and before that i couldnt even get the car started. Fuel leaked out a whole tun but didnt seem to spray. I do have svt fuel pump that i will install this weekend to see if that fixes anything. But this tapping sounds terrbile and has me worried. I will recheck the rocker arm torque tonight and pour more oil above the lifters. Could the cps affect this? I didnt use the tool as i followed rpm's instructions but ive read about many other people not using the tool and it worked fine for them.

The CPS is supposed to control the timing of the fuel injection. If it is way off it could cause all kinds of problems. I would think if you set it about right it would be OK, but it would be good to get the tool just to be sure.

I think the noise is a separate problem, probably a lifter, but it's hard to tell.

When you replace the fuel pump it would be a good idea to drain all the old fuel out of the gas tank and replace it with new.

Hopefully the new fuel pump will fix it. Before my fuel pump went out it was apparently delivering some fuel but was weak and the engine ran but lacked power. Maybe you have the same problem.

[99v6stang]

well i ran the car for about a minute today and then immeadiatly rechecked compression on cylinder 4 and it was now at 120. I believe it was 135 or 140 last time i checked. Blown head gasket maybe? i will be checking the oil and coolant later

[stephen]

Originally Posted by 99v6stang well i ran the car for about a minute today and then immeadiatly rechecked compression on cylinder 4 and it was now at 120. I believe it was 135 or 140 last time i checked. Blown head gasket maybe? i will be checking the oil and coolant later

Did you take out all the spark plugs or just #4? You're supposed to remove them all. I still doubt compression is the main problem.