No Power....?

ACstang5.0

New Member
Apr 2, 2005
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The car starts and idles OK, but when i hit give it full throttle it seems like it totally bogs out....its not NO power. I have a bunch of mods and my car used to put my in the back of my seat but not anymore. It had a recent tune up but the wires were not changed and i still have stock wires.
 
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Check the wires using an ohmmeter or DVM, measure the resistance of each spark plug wire. They should be about 2000 ohms per foot of length. A 2 foot wire would be 4000 ohms, a 3 foot wire would be 6000 ohms.

Do the light show thing too. Wait until dark and then open the hood and start the engine. Look closely at the spark plug wires to see if there is any glow or flashover.

Do a cylinder balance test to spot weak cylinders. Dump the codes while you are at it.

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.
 
thanks for the great info as usual jrichker. i think i better specify a little more to help out...my car seems to pull OK from 2-3 rpm but thats it. from 3 on up it has NO torque or power, it took me forever to get from 40-80 mph. seems like the engine is suffocating or something. the mechs i work with are saying it could be clogged injectors, bad wires/plugs, or possibly that i f'ed up while installing my CAI.
 
The cylinder balance test will find bad injectors.

The light show trick finds bad spark plug wires.

Try replacing the fuel filter & checking the fuel lines for damage & dings. If you have access to a fuel pressure gauge, connect it up where you can see it, and make a run while observing the fuel pressure.
 
I would also chk for codes, and the cylinder balance test would be a good idea if you think the inj are bad. Aside from that, all of the basics, already mentioned were the timing chk, and checking the wires, maybe clean the maf(or if you can, chk the voltage of the maf), chk to see if you have any vacuum leaks, (broken vacuum lines, hoses, ect..) Just my opinion.
 
a guy i work with took a look at my car and said he thought it was the MAF. I just got home, unplugged the MAF and took my car for a spin and DAMN!!!! It felt like my car gained 100 horse power! Is this a sure sign that it is indeed the MAF, because im about to go to the store and get one.