Idead of poor running new engine???

Fuel pressure is with or w/o vac?

What injectors? If still 19#ers I would bump the FP to at least 45 psi, 24"ers should be 38~40. Check your TPS. Did you reset the CPU? Larger cams will want quite a bit more fuel down low, you can play with the TPS to get around this, but a part throttle tune would be the best.

My cam is ~.580/~.615 222/232@.50. A Tweecer was needed to get it to idle correctly. Part throttle performance under 2k improved dramatically as well.

87'GTstang said:

The list:
304 with 165cc AFR heads, SRP dish pistons with 8.9 CR, Eagle SIR rods, balanced assembly, MLS head gaskets, 1.6 roller rockers (stud), Comp cams XE270HR-14

I have been trying all I can with the running condition of this thing. The foundation is for a future blower but I need to get this fixed before it goes on. The idle is complete crap (if I can get it to do so at least). It feels just like two cylinders are trying to fire at once, so basically not as strong as a miss. The timing is pretty much dead on. Coming up on TDC, the exhaust valve was just closing, and going past TDC the intake valve was just opening (so being far off is not a thought). I get roughly 10" of vacuum at idle (as much as 20 with higher rpms), which should not be with a cam that specs out as .512/.512 218/224 @ .050" and it is the 114 LSA version. I have the firing order right 13726548. Fuel pressure is around 36-38 and rises a little with rpm.

Now with the RPM around 2000 it starts smoothing out, around 3000 it will get fairly smooth and will practically rip with engine speed. I have been told that the windsor is a fairly rough idle but this is not natural. Be it as it is, even though this is an aftermarket cam, it is VERY computer friendly and the engine should not be behaving like it is, so I am out of ideas.

Anyone with any thoughts here?

Click to expand...

sounds like you are checking the fuel pressure with the vacuum line on the regulator if its moving with RPM ....disconnect and plug the vacuum and set it to 36-38 and then hook it back up and see how it acts ......

Do the basics first:

Cylinder balance test:
Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. The engine RPM should exceed 2500 RPM's for a brief second. The engine RPM's will increase to about 1450-1600 RPM and hold steady. The engine will shut off power to each injector, one at a time. When it has sequenced through all 8 injectors, it will flash 99 for everything OK, or the number of the failing cylinder such as 22 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures. Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at Walmart.

Or for a nicer scanner see http://www.midwayautosupply.com/detailedproductdescription.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $33.

Post the codes and results of the cylinder balance test.

Is your ignition timing set with a timing light or by guess and by gosh?

HJave you checked for vacuum leaks? Use a squirt oil can and motor oil to squirt around the flanges and joints. When you hit a leak, the oil gets sucked in and the engine speed changes. It is much safer than flammable liquids like throttle body or carb cleaner.