prob NO one can fix

[mapoff]

First of all the people here and the forums are the best i've ever seen. Please bookmark this to return because i'll definitely need follow ups. Please read, sorry so long, very complicated

My story, car ran great when i got it, stock 5.0 lx aod trans, mass air, and the car started running very week from what i remember. I took to a friend that had fixed, on the side, lots of peoples prob and all i heard was praise. So when i got the car back, he wanted to show me something. He drove and gassed it and I, heard spark knock, he said "ya hear that, your gonna need a new transmission soon", I knew it was spark knock so i said whatever. He said he had to change the maf which still has "ford" on it, and replaced spark plugs. The car really did run very very strong just knocked. I was a mustang novice at the time. Learning more rmvd the spout conn, no timing advance but didn't knock, moved timing to 10*tdc, spout back in, same prob, so i drove with no spout, heard poss the tfmodule, replaced it, spout back in, still knocking but now with fluttering rpms. The codes on ecu said o2 sensors lean, replaced both, ran better, but same problem. When the spout is conn is when the problem begins and i don't know what is involved once that is conn. No one can give me an answer and have been to about 3 shops.

Everyone hear sounds like real gearheads and not people just assuming things. Not sure if i'm allowed but i'm getting desperate to the point of offering some money to someone that offers something that actually fixes it. I don't want to swap the ecu yet because theres no way to tell if it will work and its pretty expensive. Thanks for the help your awesome----Mike

 

[jd351]

Sounds like it's not getting enough fuel. I would change the filter first, then if that deosn't work, get a cheap fuel pressure gage, the type that goes on the fuel rail fitting. Check to see if you have good fuel pressure, if not it is your pump. I say this becuase your ignition SHOULD be OK given the things you have said and a lean O2 reading is usualy a fuel system problem. Other posibility could be bad O2 sensors, or wiring to them, but start with the filter than check fuel pressure.

 

[86/92stang]

Did the guy replace the Maf? Maybe its just a dirty maf. You are setting timing with the spout out correct?

 

[mapoff]

reply

I have tested the feul pressure for another problem i had and it was running 35-40lbs i remember, and problem woudln't be fuel if started happening when i conn the spout conn. if it doesn't get enough gas with it out the spout woudln't change anything.

for the other reply i was checking the timing with the spout out. and he said he had to replace the maf but it is still the ford one, he works at advance auto and only using advance parts when he works on a car. I tested the voltage on the maf and was perfect so rules that one out.

The key seems to be what ever detects and adjusts the timing. I would think a knock sensor has failed so when i gas it, it doesn't realize it needs to retard the timing, i've also heard of the hall effect sensor detects the timing from the 8 spokes that are under the distributor cap. so to recap i have spark knock and irratic rpms. while idling the tach just jumps like crazy. I'll even use my digital camera if some a/v would help

 

[TrickStang37]

5.0's dont have knock sensors.

 

[jd351]

The spout only allows or locks out the EEC from advancing the timing. As the spout in/out is changing the timing, then it is working and so if the TFI and hall sensor in the distributor, so rule these out. Also should be able to rule out the EEC too. What i see is that with less timing it runs better (spout out), and your EEC is throwing lean o2 codes, these are symptons of a fuel problem. If the ignition was week you would get rich o2 codes, not lean ones, unless the engine was not firing at all. there is the far out posibility that the FPR is stuck open or that the diaphram in it has a leak, But these are really rare occurance items on any vehicle and nearly unheard of on 5.0's.

That leaves me back at filter and pump. these things can change quickly, so unless you have checked them since this problem appears, they could be bad.

If the problem is not in the supply system, then it could be in the injection wiring, bad ground possibly. You could check the orange wire at the back of the intake to see if it is connected good and also check the wire condition.

Also, I would suggest you run the EEC through a complete cylinder ballance check, just to make sure you don't have a bad cylinder or injector. If you do not know how to perform this, read your manual. Basicaly you do a KOER test and at the end of the test you hit WOT momentaraly, the EEC will cycle through shutting down one cylinder at a time. Then give you fail codes for the cyliders that do not pass. (are not contributing at 85%) then if you WOT again it will retest at a 75% threshold, you can repeat this test a total of three times, if a cylinder fails on the third test, it is not contributing at all and has either zero compression or injector has failed.

 

[mapoff]

Good replies, i have replaced the pump and filter because the pump quit working, well after replacing i found out when i closed the hatch it was the safety switch that tripped so all that was a waste and i am getting the near 40lbs of pressure. Also wondering if since the motor runs incredibly strong without the spout and i get 150lbs of compress for every cyclinder what would change when the spout is conn? Does all this lead back to the ecm? What is the orange ground wire for? is that the ground for the ecm? Thanks for the help, keep the suggestions coming

 

[strtracer442]

What grade of fuel are u using?
When the spout is connected, the computer adjusts timing according to throttle position,air intake(maf), coolant temp,and barometric pressure. If youre running 87 octane, thats not enough, especially if the motor has carbon buildup on the pistons. Set the timing to 8* and put the sprout in, and check again.

 

[mapoff]

I run 93 all the time, and i can tell the difference, i've cut the timing all the way down to 5* and i belive 0 and it still did it

 

[jd351]

The SPOUT is the EEC's way of modiying the timing. When it is out the EC can not change timing and as the distridutor has no means of this (no vac. or mech. advance) then the timing will be whatever the base timing is set at ALL the time. With it in the EEC can advance the ignition, and will advance the ignition the minute you install the spout. From your symptoms your having it appears you engine does not like to run with any advance at all, this is not normal. So the engine does not 'like' advance and the O2 indicates lean, both of those symptoms corespond to not enough fuel.

The orange wire on the back of the motor is the injector ground.

The EEC ground is near the EEC, easy to find when you remove the kick pannel, but not a problem here as the EEC has shown no indications of malfunction. Thowing codes, manipulating ignition timing, and running engine, even if poorly, would all indicate the EEC is functioning fine.


Now, if you engine is runing "really, really good" with the spout out, there could be a completely differnt explenation for this all. It could be that your timing is way-way out of whack... This can occcure when the harmonic damper goes bad. The outer ring of the damper will spin and the timing marks will be incorrect, even though you time it to the correct mark it will not be anywhere near where you are setting it.

OR the timing chain could be bad (streched) and jumped a tooth, not likely though... I have seen an engine run off a tooth, but not for long before the chain gave out all together.

 

[mapoff]

thoughts are pounding out. not questioning you guys but curious. i have replaced the o2 sensors, and they were reading lean because they were old, really old and had carbon caked on it. Also about the timing i cut the timing so far back that is was barely running, put spout on same thing, spout in rpms kick up and same prob. Also was wondering if timing chain was loose wouldn't it skip with spout out, because the chain still has to turn the cam to match everything else. i feel like i'm running into alot of dead ends. would it be best to just go to a ford dealership and pay out my rear. I feel they are ripoffs personally.

 

[HISSIN50]

ive gotten bits and pieces of this thread, so forgive anything i missed.

the MAF wire is clean, right? its being dirty can cause lots of detonation.

do you have a FP gauge mounted so you can see FP when you get detonation?

is the EGR still hooked up (removing it w/o burning a chip, Tweecer'ing it, etc, can cause detonation)?

remember, at WOT there is no lambda input (for helping with diagnosis perhaps).

you are getting a good spark at higher rpms (or where ever the detonation occurs)?

if you suspect a lot of build up in the chambers (artificially raising the compression ratio), a lot of guys have had good luck with products like Seafoam (i cant attest to them, as i have not used them).

those were the couple random thoughts i had. i suspect they have been thought of already, but i wanted to hit them again in case not all had been hit.

good luck.

 

[Daggar]

I've got two suggestions:

Replace the TFI. They're cheap. There's a slight possibilty it could be sending garbage to the rest of the ignition system.

Install a fuel pressure guage that can be read from inside of the car while you are driving. Your fuel pressure is fine when running at idle but it may help to see what's going on with the fuel system and particularly the fuel regulator as throttle settings and vac pressure changes over the range of the power band.

 

[sillyg]

make sure your timing is not a couple of teeth off

 

[HISSIN50]

make sure your timing is not a couple of teeth off

Silly, if you mean that the dizzy gear/rotor position could be off by a tooth or more, this is a bit of a misnomer.

as long as the dizzy has physical clearance to move (for adjustment), one cannot be a tooth off. now if you got to where you could not physically move the dizzy because of interferance (the TFI hitting something, etc), a restab is in order. short of that, the dizzy can be adjusted to correct having stabbed it in 'a tooth off'.

i think this is where you were going and you knew this, but i wanted to expand and clarify a little.

 

[Daggar]

Silly, if you mean that the dizzy gear/rotor position could be off by a tooth or more, this is a bit of a misnomer.

as long as the dizzy has physical clearance to move (for adjustment), one cannot be a tooth off. now if you got to where you could not physically move the dizzy because of interferance (the TFI hitting something, etc), a restab is in order. short of that, the dizzy can be adjusted to correct having stabbed it in 'a tooth off'.

i think this is where you were going and you knew this, but i wanted to expand and clarify a little.

You beat me to it.

...and he already said his timing was at 10*. Makes no difference how it's stabbed.

 

[mapoff]

this is reply for hissin50:

The maf is tested and read good voltage and is clean

I have not ckd pressure while driving but have replaced the fp reg and measured while revving

The egr is something i haven't fully explored, some explaination?

How would you suggest i check for good spark at higher rpms.

Nothing is making any sense if when the spout is out runs fine, since it runs weak with spout out i run timing at 20* instead of 10* so i don't loose my gas milage. If something was wrong with fuel and spark it would run bad all the time.

Any response about just paying out for a dealer. I want to rebuild my motor but not until i solve this problem.

 

[jd351]

I am really starting to suspect you Harmonc damper is bad. You say you have run spout out at 20deg. base timing and it ran good. That would rule out timing chain and should rule out fuel system too. How far up can you run the timing befor you have a problem? Sounds like the damper has spun, or there is a problem with the EEC and SPOUT circuit. Either I would not rule out.

Sorry for questioning things so much, but without all the info it looked like a fuel problem. It's realy is difficult to diagnose anything your not working on yourself with the proper tools, and imposible without a lot of information. Keep it coming, someone will figure this one out I'm sure.

Reminds me of this old story, about a little old lady who takes her car to the mechanic and says, "whenever I drive to the store and get Strawberry ice cream my car won't start, but when I get Vanilla ice cream it starts just fine"

So the mechanic drove with the little old lady to the store for Strawberry ice cream.

Come to find out whenever the lady got Strawberry ice cream the stockboy had to go back to the store room to get it and it was hand packed ice cream, and it took longer then just getting the Vanilla that was in the cas ready to go. That was just enough time for her car to get a vapor lock!

Moral of the story: Don't dismis the symptoms/conditions no matter how far fetched they may sound, and you can get to the root of the problem untill you get some strawberry ice cream...

 

[HISSIN50]

the EGR: at cruise/part throttle, it allows spent (inert) gasses into the chambers to cool things down and improve fuel economy. the puter knows when the EGR is active (gasses being passed into the chambers) and dials in a ton of timing (the diluted mixture is not as volatile as when these gasses are not being introduced).

some guys remove the EGR function, but dont 'let the computer know'. so now there is no dilution in the mixture, but there is a ton of timing being added (the puter still thinks EGR gasses are being introduced) - result is detonation for some.
the reason i brought this up is to address the timing issues. you seem to run alright with locked out timing, but not so when the puter can modify it.

if the EGR is leaking, that can diminish the idle. a common test is to apply vac to the EGR - if the idle diminishes or dies, the EGR was likely alright. if no change is noted, there is a problem which should be addressed.

i will add that quite a few guys run locked out timing. it is very common with forced induction on foxes and on stockish SN cars (they are very prone to detonation). it is a bandaid, but if it works........... (some guys like to run 20-25* -sometimes more, locked out timing).


as Jd has brought up, i would give the balancer a real good once over. you dont want a compromised one on there. the outer ring does slip (timing marks dont seem correct for the performance of the vehicle). also, the outer ring can shift on the inner hub (appears that the balancer wobbles). the elastomer between the two rings being deteriorated is often a sign of a bad unit.

i agree that if the motor runs alright one way (Locked out timing) but not with puter advance, you have narrowed down a lot of systems. again, why i suggested the EGR as it is one major thing that has timing advancement built into the puter mapping.

i would not go to a dealer. they are good for newer stuff. i would hit a local stang shop if i HAD to go to a shop at all. it sounds like you have a good working knowledge and it is just gonna take some more time and tweaking to get it figured out.

my two cents. good luck.

 

[jd351]

Hissn50 may be on to something there. And the EGR system is prone to problems too. You should be getting codes for this though. If it was not operating at all (stuck open/closed or EVP sensor not connected) it would throw a code. But that does not say it could not be some kind of anomily with the sensor and such, as the EGR does have a big effect on the timing.

For that matter so does the TPS and the BAP. Do you have a source for a spare TPS and BAP sensor.. like a friends car. Swap them out just to eliminate them from the issue and while your at it you may want to do the same with the EGR and vaccum solenoid that operates it. I would not buy anything for parts untill you know what you need or you must, otherwise this could leave you broke, and thats the surest way I know to discurage you from fixing and/or owning a 5.0.

Again, the right tools could likely diagnose this much easier. May want to take it to a truely compitent shop, not Ford unless you must, but a local tuner shop, hopefully someone with late model Ford/Mustang experience.