01 GT After changing spark plugs and coil packs, car started ticking/knocking, now it wont run.

jakov

New Member
Apr 20, 2012
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Hey, I'm new to this forum, and forums in general. So i'll start off by listing my mods. hi-tech stage 2 cams, trick flow 75mm TB and plenum, u/d pulleys, magnaflow magnapack exhaust, long tube headers and x pipe, and that's all I can think of.

Now, the issue at hand. I've had a miss for a while, so I finally broke down and bought a new set of Accel coil packs and autolite manufacturer replacement spark plugs. After I changed them, the car ran smooth and had a noticeable increase in power; however, it had a very loud ticking or knocking sound that would go away and come back.

I thought it could be a valve spike so I was driving to the gas station to see if some 93 octane would make any change. On the way the car started the tick/knock again (it would increase and decrease with RPMs), but this time shortly after it started stumbling like it were out of fuel and abruptly died.

After I towed it home, I scoured forums and noticed that 4.6 mod family is notorious about blowing out spark plugs and that the symptoms were a ticking noise followed by complete loss of power. So, I checked the plugs and one was really loose, so I checked the rest and the rest were normal and the threads seemed fine. I tightened it up and tried to start it to no avail. So, I tried the old coil packs, no change. I installed all of the old plugs, no change.

One thing I did notice, fuel pressure seems low. I don't have a gauge, but it doesn't squirt out with very much pressure. It has a new fuel pump and new fuel filter, and it does prime.

One more thing to note, it does crank over normally, and after a while it will start for about 2-5 seconds and then die and wont start again for a while.

I'm pretty dumbfounded at this point, and I would be grateful for any help.

Thanks
 
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I was under the impression that 96-98 Mustangs had the coil packs while the 99-04 Mustang GTs had COP style ignition. Why does the engine have coil packs? Still tho, from your symptoms it sounds like a fuel pump issue. Which pump did you put in?

And BTW, welcome to the forum!!
 
I was under the impression that 96-98 Mustangs had the coil packs while the 99-04 Mustang GTs had COP style ignition. Why does the engine have coil packs? Still tho, from your symptoms it sounds like a fuel pump issue. Which pump did you put in?

And BTW, welcome to the forum!!

^this.

And aftermarket COPs and coil packs are inferior to factory parts. Accel coil packs and COPs are garbage compared to Ford replacements. Put the stockers back on and have a dealer test them to see if one is causeing an issue. If so, replace it with a Ford part, not crappy aftermarket.

Companies like Accel make money convincing peole their car will be faster with their cheaper part, but it's a lie. An attractive lie, but a lie nonetheless.
 
^this.

And aftermarket COPs and coil packs are inferior to factory parts. Accel coil packs and COPs are garbage compared to Ford replacements. Put the stockers back on and have a dealer test them to see if one is causeing an issue. If so, replace it with a Ford part, not crappy aftermarket.

Companies like Accel make money convincing peole their car will be faster with their cheaper part, but it's a lie. An attractive lie, but a lie nonetheless.
I agree...and I was one of the people who fell for the marketing years back. Like 40oz said, just put the stock stuff back on. Years after buying Accel COPs guess where they are now...they ended up in my garbage can. I might as well have just set $300 on fire...because then at least I would've saved myself the install time...
 
One thing I did notice, fuel pressure seems low. I don't have a gauge, but it doesn't squirt out with very much pressure. It has a new fuel pump and new fuel filter, and it does prime.
Why guess? Measure the fuel pressure. Most autoparts stores will rent/loan tools for the job.

While at the autoparts store, rent a mechanical fuel pressure gauge as well as an ODB2 scanner. Use the ODB2 scanner to find out what the PCM "thinks" the fuel pressure is. Use the mechanically gauge to measure the actual fuel pressure.

This could save a lot of effort chasing wild geese.

Also make sure the battery is fully charged and the battery cables are clean and tight. Cover the basics. Check for vacuum leaks.
 
wmburns is right. you need to check the vacuum at the fuel pressure regulator. with your mods it seems like you improved the breathing and intake side of your car but what about the fuel. you need to compensate for the extra air you are throwing in. if you are running lean with a really good fire(new plugs and wires) you might be experiencing a lil case of preignition. if you have a hot lean mix with not enough fuel to compensate for the extra air the heat will ignite the A/F mixture before your plugs will and you will have 2 fires at one time. with a lil leaner mix you will have felt the 'extra power'. and lastly, check your injectors if they are dirty, old, or just arent putting out the fuel they should be, this would explain a lean mixture. got a ?, since you had this problem did the ecu through you any new codes?
 
actually, she was running lean. i had a misfire on cylinder four, and a while back, replaced the coil pack on that cylinder, and a week or two ago i replaced the injector. After i changed the injector, it didn't really run any better, but the code went away. The check engine light was on but didn't have any codes, which I didn't quite understand. Furthermore, I still don't have any codes. But that is only using the diagnostic mode on the cluster, my friend is bringing his scanner to work tomorrow for me to use.

The air/fuel mixture hasn't been right since the cams were installed. i assumed once i got it tuned it would be better. What I don't understand is why it started the tick or knock immediately after changing the plugs and coils. Like i said, i installed all of the old coils with no change and then installed all of the old plugs with the new coils with no change. None of the plugs were damaged and none of the threads in the heads seemed to be damaged.

Another thing that i just can't understand is why it will fire up for a second or two then quit and just crank. A while later it will fire up again and rinse and repeat.

When i first heard the knocking sound the first thing i thought of was something could have fell in the plug hole, but like i said, the noise would go away then come back and go away and come back periodically. I do have a compression tester, but i haven't had the chance to run a test.

The next thing i planned on doing before it quit was buying 8 new injectors.
 
well with your mods, before you buy your injectors, you need to tune your cams and see if your stock injectors will pump out the extra fuel it needs to have that right A/F mixture. the thing is you have a nice amount of extra air: cams, intake, tb, exhaust... you need to compensate for all that air. if the stock injectors cant make up for that after a tune, you will prob need at least 24lb/hr to 30lb/hr injectors. the stock fuel pump and lines will be more than capable with keeping up with bigger injectors. lastly, running 91 or 93 octane def wouldn't hurt. you will see full potential of the upgrades you already have.
 
ok, so here are my codes:


P0135 O2 Sensor Heater Circuit
P0141 O2 Sensor Heater Circuit
P0155 O2 Sensor Heater Circuit
P0161 O2 Sensor Heater Circuit
P0174 System Too Lean

P0443 Evaporative Emission System Purge Control Valve Circuit
P1000
P1409
P1451

Fuel pressure rail = 28.65
 
fuse #8 under the dash was blown, I replaced it, cleared the codes and tried to start it. All it does is backfire occasionally and crank. Fuel pressure rose to around 55 during crank. I'm giving up for tonight, tomorrow im going to change the plugs again and see if that changes anything.
 
ok, so here are my codes:


P0135 O2 Sensor Heater Circuit
P0141 O2 Sensor Heater Circuit
P0155 O2 Sensor Heater Circuit
P0161 O2 Sensor Heater Circuit
P0174 System Too Lean

P0443 Evaporative Emission System Purge Control Valve Circuit
P1000
P1409
P1451

Fuel pressure rail = 28.65
ok, that is some good info. now i have a question for you. is that x pipe an off-road pipe or catted? what exactly kind of cold air intake do you have, is it a fenderwell or under hood? is it paper or cotton? and does it require to be re-oiled? after those ?s are answered i can tell you whats going it on and narrow it down a lot for you. From experience had similar issues. i can look at the last 4 codes for you on Alldata or shopkey on thursday when i go back to work. keep it posted
 
those codes are a result of the blown fuse. its an off road x pipe and I have a new k&n CAI. the MAF was reading .02 volts CT, and .02 volts WOT.
Just wondering if you see a problem because I do. Does it make sense for the MAF volts to be the same at idle and WOT? The MAF should change with the slightest change in throttle. If not, then:
  • The MAF is bad
  • The electrical connector to the MAF is loose/disconnected.
  • The fuse that supplies power is blown.
  • There is a wiring harness problem.
  • There is a huge vacuum leak between the MAF and TB.
  • Bad PCM.
Disconnect theMAF electrical connection. Does it run better now?

OBTW, if the MAF volts is correct, then likely what is happening is the motor dies when the PCM switches from open loop to closed loop. Since the reported air flow is grossly too low, this results in the PCM leaning out the fuel injectors under closed loop operation. Disconnecting the MAF works because the PCM will use default values instead (limp in mode).
 
i do see a problem, thats why i posted those MAF values. the only question i have, does the car need to be running for the MAF to report normal voltage? These values were with the engine off. i unplugged the MAF last night and tried it, it wouldn't start normally, and wouldn't run any different with throttle assistance. The smell of fuel is very heavy and fuel vapor is visible coming out of the exhaust. TPS reports normal values
 
the only question i have, does the car need to be running for the MAF to report normal voltage? These values were with the engine off.
The value of MAF volts relates to how much air that the MAF is seeing. One would expect when the motor is off to have zero air flow. Therefore the near zero MAF volts.

I'm sorry but it was not clear to me that the motor was off. MAF volts with the motor off is not very helpful.
 
i'm thinking about picking up an IAC from autozone along with some MAF cleaner.. i dont expect this to fix my problem; however, before i had this problem, i did have a problem with the ilde. IAC is only $50, so it wont hurt to go ahead and get it out of the way. Thoughts?