[Chief2Horses]

What all makes the exhaust suck backwards.

I have no exhaust leaks. Im figuring a stuck valve, but which side intake/exhaust?

Compression test was bad, but could it be anything else. All cylinders pumped up about the same.

 

[fast9050]

Maybe remove your valve covers and hand rotate your engine with a ratchet on the crank bolt. You'd see pretty quickly which valve(s) are problematic.

 

[Chief2Horses]

Compression ring wouldn't do that would it?

Im not worried about which valve really, just got a valve job on spare heads and all new top end valve train is gettin put on.

 

[specializedbndt]

ive been told about the dollar bill "trick", albeit im not sure if theres any validity to it. tried it on my mustang and the dollar did infact suck back to the exhaust which, in theory, would suggest a partially open valve...compression test revealed nothing....hmmmmm

 

[Chief2Horses]

Im do a compression test again. With a different gauge.

 

[bwery3]

If you still have the stock H pipe, a misfire will cause the same symptoms as a valve not seating. I just checked my 96 gt and that's what it was doing. I searched last night for other causes and quite a few people had a misfire and when that was fixed it was back to normal.

 

[ratio411]

If you still have the stock H pipe, a misfire will cause the same symptoms as a valve not seating. I just checked my 96 gt and that's what it was doing. I searched last night for other causes and quite a few people had a misfire and when that was fixed it was back to normal.

Yeah, but he failed a compression test.

I don't know how a valve would "stick". The cam will push it open and the spring will push it shut. It mostly likely a burnt valve.

A collapsed lifter or broken spring would be fairly catastrophic and have more symptoms in the way of unmistakeable engine noises/damage.

Bad ring(s) can fail a dry compression test, but I don't think they cause exhaust reversion. Did you do a wet compression test? If you get more compression wet, it is generally rings.

Do you have adjustable rocker arms?
A rocker arm adjusted too tight can cause issues.

 

[Chief2Horses]

Well, I ripped the heads off and replaced the entire valve train with all new parts. Rebuilt/surfaced heads, new springs, lifters and everything. It doesn't pull the dollar bill backwards anymore but still runs rich. Still same gas mileage.

I replaced MAF(runs 5% better) with junkyard one 2 days ago. Seems not as rich now. New CAI also, EBAY $40!!! My exhaust is "tinging" now from where its getting hotter(leaner) and the smell doesn't run you out of the garage as quick. Also warms up faster.

I think the MAF was makin it run rich tho. I thought it was a bent/burnt valve or spring or something as well, with it suckin a dollar backwards it would have had to been, but it --is-- possible for this to happen and it run ok, im pretty sure, idk. I bet a lot of cars a dollar bill will pull backwards and be fine. I wanted to make sure a valve train component wasnt the culprit tho. I watched while the mechanic drove it while the Scan tool was plugged in and the MAF was movin around so I skipped it. He said it looked good too.

Im gettin a new MAF just to see what it will do. Im gonna fill up gas tank and see what the junkyard MAF -MPG- gets me compared to the new, out of the box one.

 

[ratio411]

How are your o2 sensors?
They go bad, you run rich.

 

[Chief2Horses]

Brand new. Bosch. They read fine(scan tool) before I replaced them as well.

It just runs like it takes too much effort. Trans shifts way too soon and won't downshift like its supposed to. Idk anymore. Its for sale, lol!!! Low miles, swapped heads with no wrist pins knockin!! Sounds mean, runs real good with your foot half way in the pedal. The car is very quick don't get me wrong, 110mph in second gear. Just auto trans and those air plane gears are killin me!!

I'll see what this next full tank gets me. Mite be solved-MAF. Ill post with results soon!!:bigthumbsup

 

[Smurf stang]

I would suggest running your codes as it might be something as simple as a temp sensor or a vacuum leak.

What have you done to the car or replaced?

 

[Chief2Horses]

Lol, Ive done everything!! Just about every sensor already replaced. I replaced all vacuum lines with rubber hose. I even did a smoke test(push smoke thru engine to check for leaks.)

No MIL either. Once it came up with a fuel pump somethin but it only showed up once. Open circuit/ground or somethin like that. Prob a false code I was told by the mechanic since it doesn't show up in every scan.

All new igntion components, new press regulator. Timing at 14* base. It runs good, just won't putt around.

 

[ratio411]

Well, you mention it is an auto and shifting poorly...

Make sure the TV cable is adjusted properly so you don't burn up the tranny. A misadjusted cable will do it quick. Just a heads up.

Another thing that can affect tranny shifts is the speed sensor.

Is the tranny acting up new, or are you saying it just shifts poorly for your personal taste?

 

[Chief2Horses]

New VSS lol. Shifts premature. There is no adjustment on AODE trans right? Just a throttle cable and cruise control is only cables up there. 95' GT conv.

 

[ratio411]

Sorry, I was thinking Fox, not SN95.

I had a 94 AODE GT that my son has now, and doing some research, it seems Ford programmed the computer on SN95 cars to shift REALLY lazy to protect the tranny.

My son got a Bama chip and the shifting is day and night from stock. Really agressive, so the tranny does have potential.

 

[Chief2Horses]

Im thinkin chip too. I want one written for it tho

 

[Chief2Horses]

Mass Air Flow MAF got it runnin right. Not the junkyard one that I wasted money on. I swaped with a used one and still ran wrong for me. So I got a new NAPA one. Sounds and runs totally different. Getting in and out of gas pedal, recovering momentum, letting off pedal. Much better now. Sounds good too. I probed MAF and it was within ranges. Maybe just lazy or not so far out.. Idk?? Ford Junk!!!!!!!!!!!:shigrin Ill report back with MPG increases to see if this car has fooled me once more.