Dyno run Blahs

Donfordman30 · Dec 12, 2010

Ok i need some help here guys please. Got 94 GT. Took it to the dyno yesterday. Lost 65 horses from my last dyno run. Got AFR'S 165, COMP Cam , all bolt on's and Edelbrock intake. But guess heres my real question.

My EGR Valve was leaking. It wasnt caught until we got the car off the dyno. The dyno guy said my car was running out of power at 5100. But the last dyno run was fine. All i done was changed my push rods and roller rockers. Now 65 horese less. Can the leaking EGR valve make this loss HP?

Donfordman30 · Dec 12, 2010

anyone know the answer?

Dino Dino Bambino · Dec 12, 2010

I guess it's possible. A leaking EGR valve could make the engine run too lean. Can you post the "before and after" dyno printouts?

seijirou · Dec 16, 2010

It will absolutely affect power. It may not necessarily make you run rich, that depends on if it was leaking because the pintle couldn't seat due to carbon buildup or other causes, and the position sensor indicated to the computer the position of the valve.

Anyway, recirculated exhaust gasses effectively reduces the displacement of your engine. The exhaust gas is a useless gas, it's already spent and it's no good for combusion. If you have a 302 cubic inch engine, but 50% of the gasses sucked in are exhaust gasses (major exaggeration just to make the math easy on me), you have the rough equivalent of a 151ci engine. Great for cruising fuel economy

If your computer knows about the exhaust gasses being recirculated, it will squirt in less fuel because there's less oxygen. Your AFR will be dead on, but you will be down on power.

If your computer doesn't know about the exhaust gasses being recirculated, it will add too much fuel and you'll go rich, making the problem that much worse.

You only go lean when the computer thinks the EGR is open and it really isn't.

Donfordman30 · Dec 20, 2010

Ok So i fixed the leaking gasket that was on my EGR valve and the power is back once more. But now the car was dynoed with a leaking EGR valve and is running very lean. And now im having more issues. Please correct me if i'm wrong here, but i carriede the car to the trans shoip today and was informed that my car doesnt have a kickdown cable and my car is now going into a neautral state when i'm driving. It will only do it once in a while. The car revs up like it's in neautral then after a few secounds in seems the rpm's drop and the car goes back in gear, or I can just shift to neautral then back in gear and it will catch after a secound. I think it has something to do with the tune to my transmission, but not sure at this point. Was working fine?????????? Also once in a while the car dies at stop light and not sure why. Cleaned my AIC and MAF sensor. Hate to ramble here but have thought and thought and need some advice from my fellow stangers here?

Help Help Help before i have a break down other then my car LOL.

Don

seijirou · Dec 20, 2010

Donfordman30 said:
Ok So i fixed the leaking gasket that was on my EGR valve and the power is back once more. But now the car was dynoed with a leaking EGR valve and is running very lean. And now im having more issues. Please correct me if i'm wrong here, but i carriede the car to the trans shoip today and was informed that my car doesnt have a kickdown cable and my car is now going into a neautral state when i'm driving. It will only do it once in a while. The car revs up like it's in neautral then after a few secounds in seems the rpm's drop and the car goes back in gear, or I can just shift to neautral then back in gear and it will catch after a secound. I think it has something to do with the tune to my transmission, but not sure at this point. Was working fine?????????? Also once in a while the car dies at stop light and not sure why. Cleaned my AIC and MAF sensor. Hate to ramble here but have thought and thought and need some advice from my fellow stangers here?

Help Help Help before i have a break down other then my car LOL.

Don

That's only half true about the cable. It doesn't have a "kick-down" cable in the literal sense, but it does have a TV cable.

If someone messed with that cable, it's likely that it's not right. Here is a cheesy, but accurate video on how to adjust it.

YouTube - Ford AOD TV cable adjustment

Beyond that, symptoms of automatic transmissions and their causes is not my strong point at all, but, have you checked the fluid level?

It should be done with the motor warmed up and while it's running. I had a bronco that would seem to be in neutral sometimes, but if you rev'd it would catch up after a second. It had a slow leak and this would happen when the fluid was low.

Chythar · Dec 21, 2010

Um, I don't remember a TV cable on my 94 AODE. The only manual cable is from the shifter to the tranny, to indicate F, R, Neutral, etc. There's a sensor called the MLPS that tells the computer if you're in F, R or neutral. If that sensor isn't indexed properly, or it's failing, the computer might think you've popped into neutral when you haven't. There are two lines on the sensor; one on the outer part, and one on the inner ring. When the car is in neutral, they have to be lined up almost perfectly. You can adjust the sensor by loosening the two bolts holding in the sensor and rotating it. If the car is not in neutral, you'll never be able to line up the marks - there isn't enough play in the bolts.

The early MLPS sensor was not properly waterproofed and will corrode eventually. If you don't see an orange gasket between the two parts, you may need a new MLPS.

Another possibility is if you have 3.73 gears and have the white 23-tooth gear on the VSS. You need this gear to get your speedometer accurate when you put in 3.73's or higher gears in the rear axle. The teeth on the gear are thin and tend to strip, thus making the computer think you're not driving as fast as you actually are.

Considering you can "fix" the issue bu shifting to neutral and back again, it's likely an MLPS problem.

seijirou · Dec 21, 2010

Chythar said:
Um, I don't remember a TV cable on my 94 AODE.

Good catch, you're absolutely right. I didn't realize I was in the 94/95 forums when I posted.

Sorry about that Don!

Donfordman30 · Dec 26, 2010

I will check the MLPS sensor as soon as the snow is gone. One thing I have noticed with the car is the problem seems to happen more in the cold weather. I drove the car the other day when it was 50 plus out side and it did not die or slip in to neautral status. Actually ran really good. Couldnt keep the tires from spinning. So the power is definatly back, just have to find out why it wants to die when it cold out side. Talked to a guy at Speedsouth the other day and going to take the car to him after the first of the year. He talked a good game and acted like he knows alot about the 94-95 issues when it comes to tuning. My previos tuner may have messed with to many settings in the tranny and could have caused these issues?????

Dan95-5.0 · Jan 3, 2011

i have the same symptoms with my tranny. by the time i found out i needed to replace the MLPS, the car was in storage. i would be driving then the car would free rev then shift back into gear.

first think i do when the car gets home is change it out.

pretty crazy to loose all that power from the stupid EGR.

Zero_chance · Jan 9, 2011

The MLPS is a VERY common concern in the AODEs, for exactly the symptoms you're describing. A lot of people can bypass the symptoms by going down into second and then back up into drive when you decide to take off, as opposed to just pulling it down from park until it locks into drive. Also, keep in mind most parts stores will not know what an MLPS is, they're typically listed under neutral safety switch.

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