help me fix my knocking problem

stang_gt_1994 · Sep 9, 2004

stangman1 said:
I did that to my car and it stiil pinged

And do you really think the spout would be the problem? NO

final5-0 · Sep 9, 2004

JimTMich said:
did you use the cobra files as your base when you tweecer ed your car? or can't you do that. been thinking about getting a tweecer, heads, cam... but wanted to get this knocking thing figured out first.

Jim

I'll answer your Q's and add bit of info that might help.

I started with and learned my way around the Cabza EEC strategy by using the original T4M0 cal file in my GT. Combo then was ported E7's, intake, shorty's and some other little stuff. Picked up a good bit of power by tweecing the fuel & spark tables, killing shift retard, etc.

I put on heads, cam, 30# inj's, and lt's all at the same time. The car would not hardly idle, stall at stop signs, surge when trying to cruise and just generally had many drivability issues. At wot the car would just rip however.

I tweeced on the T4M0 cal file for about a week or two and made some progress but not much. At that time a few folks on the Tweecer site had loaded the J4J1 cal file in their T4M0 pcm that had similar combos like mine and said the J4J1 was a better platform to start from if you had cam, inj's, lt's, bla bla bla.

I switched to the J4J1 cal file with only two changes at first, my inj values & maf transfer. The difference was like night & day on the first drive around the block. About 85% of my drivability probs were gone with that one file change.

I've been using the J4J1 file ever since and have never looked back.

Now it seems that everybody who has a GT with larger cam, inj's, etc is using the Cobra file. All of those people can't be wrong.

Later
Grady

stangman1 · Sep 9, 2004

PINGING

DUDE, I HAD THAT FIXED AND IT DID CAUSE THE PINGING AND IT WAS NOT JUST THE SPOUT IT WAS THE HARNESS TO, AND THE CAR WILL PING AND RUN LIKE **** WITH THAT THING ALL SCREWED UP. AND EVEN WORSE IF
YOU DRIVE IT IN 110 DEG WEATHER WITH THE AC ON.

stang_gt_1994 · Sep 9, 2004

You said the harness(EST wire was open) correct. This would cause the car to run in base timing all the time. No wonder you took it to the shop, you dident know the system. But for you to come in and say the problem is with the spout is just ignotant.

mo_dingo · Sep 9, 2004

stangman1 said:
DUDE, I HAD THAT FIXED AND IT DID CAUSE THE PINGING AND IT WAS NOT JUST THE SPOUT IT WAS THE HARNESS TO, AND THE CAR WILL PING AND RUN LIKE **** WITH THAT THING ALL SCREWED UP. AND EVEN WORSE IF
YOU DRIVE IT IN 110 DEG WEATHER WITH THE AC ON.

Simply put, if your spout connector was bad, then the timing would be a static 10*, with no advance. This completely remove detonation!!!

But whatever they did, it fixed it. Who knows what else they actually did. They are mechanics, so who knows.

Back on topic, like I said. You have tried everything else besides replacing the maf sensor, or an extreme cleaning of the heads/cc's. Assuming your timing is in order, you are down to those.

I still haven't heard anything concrete about upping the fuel pressure and it's effect at WOT. I know for 100% sure that in closed loop, the O2's will simply read rich, and the computer will cut the fuel injector pulse widths. At WOT, I have no idea.

Scott

JimTMich · Sep 9, 2004

stang_gt_1994 said:
Try this out man. First off do you run a K&N filter, or any aftermarket filter that has oil on it to coat the hot wire on the MAF? If yes then the hot wire will become coated, thus causing the meter to send a signal to the PCM at idle that more air is flowing then it really is (causing a rich condition). But at cruising or load the meter will tell the PCM a false reading that less air is coming in but really it is more air, thus causing a lean condition. Lean means pinging. So you say you cleaned the MAF many times? So? Cleaning it is just a temp fix that doesent always work. To test the MAF you will need to do a snap voltage test. Get a DMM (digital multi-meter) and put it on the min. max volt scale(DC). Back probe the MAF at the output and ground pins and have the engine running and snap the throttle wide open and release. If the Max volts do not go past 3 volts then the MAF is bad. Simple as that.

cleaned the maf again by spraying carb cleaner down the hole of the maf. Then let it idle for a while while I found the shop manual then did the snap test. .75v idle little blip of the throttle 2.0 volts, big snap 3.1volts so it looks like my maf is functioning, it may still be off, but at least it's in the ballpark, is that what I am to assume? I put the timing back to 10* and at 55f out it pinged like crazy, so back to 7*....... sure felt good at 10* in first though, and second before the pinging hit.

stangman1 · Sep 9, 2004

ping

Hey I can say what I want so don,t come in and say what I can and
cant say ,I was just trying to help out so dont be an ******* and talk ****.

JimTMich · Sep 9, 2004

vacuum

my vacuum is 18.5" at idle (600-700 whatever for set it at). is that good? I don't find any vacuum leaks.

So how about that fuel pressure trick?

looks like my options are:
1. try a new maf $80
2. bump fuel pressure? $100 + gauge $50
3. clean the heads (get new ones) how much do I want to spend
4. get a tweecer and richen up the top end/check the cal on the maf. $380... oooooo how about the RT version and hook up a wide band o2......$$$$$$$ I wish there was a dyno shop around here, nearest one is 2 hours away.

stang_gt_1994 · Sep 10, 2004

stangman1 said:
Hey I can say what I want so don,t come in and say what I can and
cant say ,I was just trying to help out so dont be an ******* and talk ****.

Im sorry if I came off as a a** but I am going to school to become a diagnostic tech right know and it just sounded fishy.

stang_gt_1994 · Sep 10, 2004

JimTMich said:
cleaned the maf again by spraying carb cleaner down the hole of the maf. Then let it idle for a while while I found the shop manual then did the snap test. .75v idle little blip of the throttle 2.0 volts, big snap 3.1volts so it looks like my maf is functioning, it may still be off, but at least it's in the ballpark, is that what I am to assume? I put the timing back to 10* and at 55f out it pinged like crazy, so back to 7*....... sure felt good at 10* in first though, and second before the pinging hit.

Good for atleast checking the MAF. So you only ping at WOT correct? If so you can get a AFPR for a temp fix to add some fuel at open loop. The increased FP will not have any affect when the car is at closed loop though. BTW do you still have your EGR? Also why are you running a 160* temp stat, just wondering? BTW you vacuum is good.

JimTMich · Sep 10, 2004

stang_gt_1994 said:
Good for atleast checking the MAF. So you only ping at WOT correct? If so you can get a AFPR for a temp fix to add some fuel at open loop. The increased FP will not have any affect when the car is at closed loop though. BTW do you still have your EGR? Also why are you running a 160* temp stat, just wondering? BTW you vacuum is good.

Yes, I still have EGR

160* tstat was one of my first attempts to get rid of the pinging. I should probably put a 180 in there.

pinging is only at wot at 10* with premium gas. If I put in 87 then I get pinging at part throttle past 3500 as well as wot past 3500ish.

thanks

sn95grnstang · Sep 10, 2004

Let me answer a couple of questions asked.

The AFPR as stated above is only going to be a bandage for the problem if it fixes it at all. All an AFPR does is regulates the min pressure that is seen at the fuel rail. You can adjust this to a rich condition by increasing the pressure. This “basically makes you injector “bigger” and added more fuel then what the ECU expects. More fuel will be seen by the O2 sensors during closed loop and after time the ECU will fix the “problem” for a CL operation which is most of the time. I’m not at all stating not to get an AFPR, they are good mods to set the min static pressure so that you know that you’ll have enough fuel for you combo, with an appropriate fuel pump of course.

The only way that this will help your problem is if your stock regulator is bad and running less then around 38 PSI. So check the pressure your at with the stock regulator.

The MAF of course will cause the opposite effect, which is well stated above.

The Temperature of the block IE the thermostat is another place to look which is also stated above.

To ask a stupid question, you are changing your timing with the spout connector off correct?

It seems that most have been focused on fuel/air what about spark. Even if you changed you wires plugs cap and rotor, you distro is still questionable. I have had the distro burn me a couple times with the same thing you facing.

Also not mentioned is the balancer, what does it look like, has it spun?

So, if you check your fuel pressure and it turns out around 38-40 PSI (vac off) spend the money that you were going to buy a AFPR with and by a distro, you may be surprised.

As for a Tweecer, this is the single best most I have done to my car, but you can easily bandage your problem with this. Get one after you fix your problem.

JimTMich · Sep 10, 2004

sn95grnstang said:
Let me answer a couple of questions asked.

The AFPR as stated above is only going to be a bandage for the problem if it fixes it at all. All an AFPR does is regulates the min pressure that is seen at the fuel rail. You can adjust this to a rich condition by increasing the pressure. This “basically makes you injector “bigger” and added more fuel then what the ECU expects. More fuel will be seen by the O2 sensors during closed loop and after time the ECU will fix the “problem” for a CL operation which is most of the time. I’m not at all stating not to get an AFPR, they are good mods to set the min static pressure so that you know that you’ll have enough fuel for you combo, with an appropriate fuel pump of course.

The only way that this will help your problem is if your stock regulator is bad and running less then around 38 PSI. So check the pressure your at with the stock regulator.

The MAF of course will cause the opposite effect, which is well stated above.

The Temperature of the block IE the thermostat is another place to look which is also stated above.

To ask a stupid question, you are changing your timing with the spout connector off correct?

It seems that most have been focused on fuel/air what about spark. Even if you changed you wires plugs cap and rotor, you distro is still questionable. I have had the distro burn me a couple times with the same thing you facing.

Also not mentioned is the balancer, what does it look like, has it spun?

So, if you check your fuel pressure and it turns out around 38-40 PSI (vac off) spend the money that you were going to buy a AFPR with and by a distro, you may be surprised.

As for a Tweecer, this is the single best most I have done to my car, but you can easily bandage your problem with this. Get one after you fix your problem.

fuel pressure 38psi with hose off

distributor.. just changed the pickup and the module under the air cleaner as well. bearing seemed fine.

Thanks for the answer on the AFPR

timing has been set with the spout pulled out.

what do I look for in the ballancer? That's about al that is left, except we haven't don't know if my maf is a little off. (got 3.1volts on a big snap test)

mo_dingo · Sep 11, 2004

JimTMich said:
fuel pressure 38psi with hose off

distributor.. just changed the pickup and the module under the air cleaner as well. bearing seemed fine.

Thanks for the answer on the AFPR

timing has been set with the spout pulled out.

what do I look for in the ballancer? That's about al that is left, except we haven't don't know if my maf is a little off. (got 3.1volts on a big snap test)

JMO - His spark system is not the problem. The maximum compression of the air/fuel mixture is at TDC, which is 10* before the spark plug even fires. Thus, if "pinging" is occuring, the spark plug doesn't even fire until well after the mixture has exploded. If it's pinging, logically it has to occur during or slightly before maximum compression is reached. Otherwise, the spark plug will fire, and there will be no pinging present. [/JMO]

Like said before, it doesn't take much for the 94-95 5.0's to ping. Any small decrease in injector pulse width will do it. So you basically confirmed that the MAF is working, but maybe off slightly. You need to know the actual CFM of air flowing into the motor, then check the voltage to make sure the MAF is reading it correctly. This isn't easy, and probably not feasible.

The easiest way is to get the sensor at autozone, and see if it fixes the problem. You can always return it, because you aren't running fluid (traceable fluid that is) through it, so they would never know if you even installed it.

But if that isn't the problem, then like I said earlier, you need to clean your piston tops and cc's. You don't need to "replace" the heads, but if it's an excuse to replace them with some aluminium heads, then by all means go ahead.
Scott

rapidsft · Sep 12, 2004

Bloody to hell 94-95 ping problems

I got this 95GT 118k miles, only way I could get the bastard to stop pinging was to reduce the timing down to 6degrees. Now it'll hardly ping even at blazing temps. California coded 95-95 ECC IV's are P.O.S's, thats the problem.
Turn your timing down to 5or6 degrees and you will no longer ping. Only problem is that, you lose a noticeable amount on the lowend.

stang_gt_1994 · Sep 12, 2004

And top end. And higher EGT readings.

Nosfurato · Sep 12, 2004

My 95 GT was pinging alot when I ran a base timing of more than 10*, and even then.. if it was hot outside... I would get some engine rattle. (at WOT anyway)

It was just a few days ago. that a Friend and I where tinkering with my stang.. standard tunup things.

Check and clean points.. rotar... blablabla.

Anyway. we also rerouted the plug wires. to keep them as far away from each other as possible. (hepls prevent cross jumping.) or, simply put. electrical FUBAR in the plug wires lol

Anyway, while moving the wires around. I had removed the intake tract (before the T-body. And I was looking at the Mass Air Meter.

Now, I also have a 1990 LX 5.0 and ive raced that car in the past. and I know that there isnt a plate behind the sample tube of the meter.
But, the 95's. (at least mine) as a plate directly behind the sample meter.

Just for chits and jiggles. I was curious what would happen if I removed that plate. (requires a pin head torx bit).

Keep in mind the battery was disconnected for about 25 mins while we where foolin around.
Anyway, fired her up. let her idle for a while. I wanted to get some heat-soak into the engine on purpose.
Simulate stop and go.. blablabla. anyway.

Got it up to temp. took her out. and beat on it. not one single ping out of it.

Came back, we advanced the timing from 10* base.. to 14 deg's. pounded on it. ran like a champ.

I have only heard one single teeeeeeny tiny ping from the motor since. and that was a WOT when the engine was HOT.

side note. I dumped 4.7 gallons of prem in it today. got 94 miles out of that. IN TOWN. thats exactly 20 MPH!!!

Anyway. Im not saying that this WILL fix the pinging. but, it seemed to have helped me out.

JJ95GTID · Sep 12, 2004

Modified stock MAF

I sorta did the same thing with my MAF. I cut out that support thing between the sample tube and inner wall of the MAF and removed that back plate. In theory it should see more air flow which would tell the ECM to richen the A/F mixture. I run @ 14* with 91 octane fuel. I get pinging under load (4k rpm) only when the outside temp gets above 90*F. I also have new ECT, IAT, 180* t-stat, and run 2 bottles of Water Wetter in the stock radiator.

I would check that stock harmonic balancer (dampner) to see if it slipped. A few people here said that at around 80K miles theirs went bad as did mine.

final5-0 · Sep 12, 2004

rapidsft said:
I got this 95GT 118k miles, only way I could get the bastard to stop pinging was to reduce the timing down to 6degrees. Now it'll hardly ping even at blazing temps. California coded 95-95 ECC IV's are P.O.S's, thats the problem.

I am curious!

How do you know that your pcm is any different than mine

Later
Grady

Nosfurato · Sep 12, 2004

JJ95GTID said:
I sorta did the same thing with my MAF. I cut out that support thing between the sample tube and inner wall of the MAF and removed that back plate. In theory it should see more air flow which would tell the ECM to richen the A/F mixture. I run @ 14* with 91 octane fuel. I get pinging under load (4k rpm) only when the outside temp gets above 90*F. I also have new ECT, IAT, 180* t-stat, and run 2 bottles of Water Wetter in the stock radiator.

I would check that stock harmonic balancer (dampner) to see if it slipped. A few people here said that at around 80K miles theirs went bad as did mine.

Actually, that would cause a lean condition as far as the computer is concerned. The EEC is programed to accept a certain voltage from the MAF.
I was having a PAIN with my car pinging.

Granted, I did a few different things (at the sime time) that seems's to have cured the problem. so I cant narrow it down.

Anyway. My thinking on the MAF, was simply this. I have a 1990 LX 5.0 as well. the samle tube is a strait shot through the MAF.

In my 95, I couldnt understand why they would put a plate right behind the sample tube. So, we removed the plate ONLY.

The piller in the MAF remains.

Anyway, keep in mind. The EEC expects a certain amount of air flow/MAF input.
That is with a stock MAF mind you.

So, if you modify it. the computer has no way of knowing this. removing the "piller" for example.

All it knows it what is flowing through its sample tube.

I am not stating that what I have done in my previous post will solve everyones problem, but it seems to have worked for me.

help me fix my knocking problem

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