Not as fast as it should be.

Low 12's will happen with a bit of suspension and tire traction...otherwise worry about your mph trap speed.

Any track times at all?

So what are your plugs gapped too? What is your timing set too? What is your fuel pressure set at?

3.73's will help a lot over stock gears.

It's diagnostic time...
Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

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. You watch the flashing test lamp or Check Engine Light and count the flashes.

See http://www.troublecodes.net/Ford/





IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.



89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.



Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

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 AutoZone or Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

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 9 for everything OK, or the number of the failing cylinder
such as 2 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/

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.



89 through 95 cars have a working Check Engine light. Watch it instead of a test lamp.




Do a compression test on all the cylinders.
Take special note of any cylinder that shows up as weak in the cylinder
balance test. Low compression on one of these cylinders rules out the
injectors as being the most likely cause of the problem. Look at cylinders
that fail the cylinder balance test but have good compression. These
cylinders either have a bad injector, bad spark plug or spark plug wire.
Move the wire and then the spark plug to another cylinder and run the
cylinder balance test again. If it follows the moved wire or spark plug,
you have found the problem. If the same cylinder fails the test again,
the injector is bad. If different cylinders fail the cylinder balance test,
you have ignition problems or wiring problems in the 10 pin black &
white electrical connectors located by the EGR.

How to do a compression test:
Only use a compression tester with a screw in adapter for the spark
plug hole. The other type leaks too much to get an accurate reading.
Your local auto parts store may have a compression tester to rent.
If you do mechanic work on your own car on a regular basis, it would
be a good tool to add to your collection.

With the engine warmed up, remove all spark plugs and prop the
throttle wide open, crank the engine until it the gage reading stops
increasing. On a cold engine, it will be hard to tell what's good &
what's not. Some of the recent posts have numbers ranging from
140-170 psi. If the compression is low, squirt some oil in the cylinder
and do it again – if it comes up, the rings are worn. There should be
no more than 10% difference between cylinders. Use a blow down
leak test (puts compressed air inside cylinders) on cylinders that
have more than 10% difference.

See the link to my site for details on how to build your own blow
down type compression tester.

1Fine89stang said:

I recently bought a 91 lx that has a trick flow heads cam and intake kit, full msd ignition , 5 speed , 4.10 gears , as well as long tubes and all the other bells and whistles such as MAF CAI , and 24lb injectors. Everything looks great on the car , and it seems as though everything is perfect. The problem is that the car just doesnt seem like it goes as fast as it should. My friends subaru beat it and it only runs low 13's. My other friends 92 doesnt have as much work as mine ( he has a cobra intake , edlebrock heads , and some other stuff) , and it just seems like it has so much more power than mine. He can roast the tires in almost every gear. I'm thinking that maybe everything needs to be fine tuned , meaning rockers adjusted , and maybe some computer tuning? I also have some 3.73's for it , will this help? I'm really frustrated because i know that the car has run low 12's before , and it really doesnt feel like that is where it is at right now. Please help.

Click to expand...

First off with 4:10's the car is gonna have traction issues,unless it has drag radials.
Second does it have any codes in the eec?What are the total mods?Some times peaple just slap stuff on and hope that it works like its suppose to..But the truth is almost every car can use a good tune to get everything working together.

you said the car has 4.10s in it now? putting 3.73s in it will make it feel slower.

You said in your original post that the car has 4.10's. are those 4.10's installed in the car or are those the gears that are waiting to be installed? If you are still running stock gears...thats most of your problem. You also have to remember that while it may seem like your car has a ton of mods...its still just a basic trickflow HCI. 315rwhp at best. I'm in the same boat...i feel like i've been modding my car for years now and it just doesnt feel fast?!?

sounds like a tuning issue! What is your total timing set at

1Fine89stang said:

Took the car to a tuning shop today. They said there is a bad vacuum leak and i need to get everything tuned. It is completely out of wack. Is 500 for a dyno tune and chip too much? I can get it to another shop , but not for a couple of weeks ,a nd i need the car asap because it is my daily driver. Thanks in advance. I also decided not to go with 3.73's because i was just givin an 8.8 rear with 4.10's , disc brakes , a spool ,and slicks.

Click to expand...

If they are burning a chip plus dyno time to tune it.Thats sounds about right.SOme are a tad cheaper some a little more.

Time to step up to the plate and be a man. Get out your shop manual, voltmeter, test light, vacuum gauge, compression gauge and test jumper to dump the codes. Go through the diagnostic steps and eliminate what does work and what doesn't.

Haven't got a clue and don't know where to start? Time to check out the library and find some books to help.The shop manual for your car is the first step. Engine Computer is a mystery? Here's a book that will get you started with how the Ford electronic engine control or "computer" works.

Ford Fuel Injection & Electronic Engine Control 1988-1993 by Charles Probst :ISBN 0-8376-0301-3.

It's about $25 from Borders.com see http://www.amazon.com/ . Select boo...ing engine that has potential for more power.

The number one problem I've had in quarter mile racing is that the clock doesn't lie no matter what.

The main reason my normally consistent cars would run "slow" is poor quality (or contaminated) fuel. Get the octane back up and away you go. Crappy gas and lose a whole second or two even tho' the 60ft times were good. No legs.

white99gt said:

I disagree on a few comments.

Paying someone to fix something doesnt mean they "own" your wallet.

For the time and money spend trying to fix something that you have no clue about a true mechanic can fix is a 1/3 the time..I see it everyday,ive even seen peaple have me tell them whats wrong but stillput on the wrong part or damage the new part putting it in..

I agree on a dyno tune is not a fix all,but not all cars will run correctly without a tune..Try a lmaf ,24's and a cam in a fox and see how good it runs without a tune..It will try to idle and run like crap till its tuned..

To many 5.0 guys expect a matched maf/injectors to run perfect,when there is always something left with a good tune(by a knowledgeable tuner of coarse)..

Click to expand...

The point is that these cars are old and need lots of TLC. It requires a certain dedication to keep them running good. That dedication can be expensive if you pay someone else to do it. Mechanic shop rates run from $60 to $100 a hour or more. This totals up very quicky when they spend an hour or two troubleshooting things and then fixing them. A bill for $300-$400 to find vacuum leaks and cure the common Mustang idle problems would not be unusual.

The cost of one hour of professional mechanic shop time buys the books and some of the diagnostic tools I mentioned. Two hours would pay for all of it, and a timing light too.

Most of the don't run good problems are simple stuff that some educated troubleshooting would find and fix easily. Just dumping the codes will spot many simple problems like bad O2 sensors, bad MAF, or MAP/BARO sensor. Any one of those will hurt performance, and is easy to replace. A cyinder balance test will spot weak cylinders and with some extra thought and effort can even find bad injectors, bad spark plugs or plug wires. All it takes is a jumper wire or a paper clip and the shop manual. Don't want to dig out the shop manual? Look at my first answer to this post: all you need to do both procedures is in it.

Stangnet is a great resource for the guys who are willing to roll up their sleeves and do some work. Post your codes and someone will post the fixes. Got some common problem? See the Technical Thread Index sticky at the top of the forum. Everything from 3G alternator conversion to transmission troubleshooting is in there.

Don’t even think of having a custom tune done until you know that there are no codes, vacuum leaks or weak cylinders. All the basics need to be covered and working the best they can before you plunk down your money to get a custom tune. The custom tune is to get the last bit of Hp out of an engine that is in peak mechanical condition. It is not a band aid to cover over mismatched or defective parts.

If it feels slow, just throw a 125 shot of NOS on it and BAM!!!! instant HP baby!!! J/K. Good luck with your prob. and i agree with jrichker about the tlc. You gotta bay these cars to keep them goin and looking right. Take a lil time and try and figur it out yourself, it will help you in the long run. It's all just nuts and bolts bro. good luck.

what was your oil pressure at? foxs like to have lifter ticks and exhaust ticks, but knocking? Make sure your mechanic justifies to you the time and cost spent to diagnose it. see a bearing when he tears it down. its your money, so feel free to second guess what they say

good luck selling a car with a shot bottom end. if you bought that car with all thos mods already on it I am sure that it was beaten on fairly heavily. may as well park it till you can fix it, or fix then sell it. you will be biting a big bullet if you let go of it now.