95 5.0ho Wot Problem

[disgruntled]

Hi. Have a problem with a friends 95 5.0 that has me scratching my head.

They have had this problem for a long time and have changed alot of stuff trying to throw parts at it. Ie. Plugs, wires, dizzy cap and Innards. Fuel pump and filter cleaned maf and throttle body. All kinds of stuff.

I went over checked the TPS and MAF both check out to be good.

When the car is in park it opens up to WOT no problems. Engine comes uncorked. Runs smooth no roughness or anything. But when you put it in drive, and go WOT. The motor doesn't load up runs smooth and pulls consistently. But it is only giving it like 1/3 throttle or 1/4 throttle. The engine sounds fine. But it just isnt opening up. It's like it's in a limp mode or something. And with no exaggeration as the 5.0 is pulling now. A smart for two would literally out run it.

I haven't check the stall on the converter or anything yet. Cause I'm kinda at a loss of what it could be. I was figuring from the way it's acting it was going to be the TPS wasn't going to 4.5v but everything checks out.

Any ideas or help would be greatly appreciated.

 

[mikestang63]

run the codes

 

[disgruntled]

No check engine light And from what they said no codes when they had it scanned. Next time I'm that way I'll hook it up to a scanner to verify.

 

[jrichker]

Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way 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.

Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

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.

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

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

The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

Some 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.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

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

Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
See AutoZone Part Number: 25886 , $10

Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® 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 www.midwayautosupply.com/Equus-Digital-Ford-Code-Reader/dp/B000EW0KHW Equus - Digital Ford Code Reader (3145It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $22-$36.

 

[Mustang5L5]

Run the codes, both engine running and engine off. Then perform the cylinder balance test.

This is pre OBD2 as we know it, so you actually run three sets of codes (engine off, continuous memory and engine running) and then at the end you can run a cylinder balance test to determine if all 8 cylinder are contributing the same.

5.0's usually have codes. VERY rarely do i ever encounter a 5.0 that produces three "11" (all pass) codes for each test. Even my own fox won't give three 11's.

We can go from there. Otherwise we are just guessing and throwing money at something that is not the problem

 

[disgruntled]

Will do. Thanks for the info. I'll post back with some updates soon. They work days and I work nights so, kinda have to wait for weekends to do much.

 

[Shawn conard]

Does anyone no what cam I csn use on stock 5.0 with speed density?

 

[mikestang63]

crower, crane, and comp cams all make SD cams. So do custom guys like Ed Curtis I ran both a crower and crane cam. I think the crower # was 5115? Cant remember the crane one.---2031? They need to be easy ramp up and a stock LSA

 

[Shawn conard]

crower, crane, and comp cams all make SD cams. So do custom guys like Ed Curtis I ran both a crower and crane cam. I think the crower # was 5115? Cant remember the crane one.---2031? They need to be easy ramp up and a stock LSA

Bc I have gt40 heads with headers 65 mm throttle body pulleys with speed density. So u think I should be safe with a crower 1511 cam with no idle problem or drivable

 

[Decipha]

have you checked fuel pressure?

the tps has no effect on WOT performance, either the inlet is blocked (air filter clogged), or the exhaust is blocked (failed cat) or the fuel pump isn't doing its job

did you verify the base timing is 10 degrees btdc with the spout out and the spout plug actually works?