Asking for some return help..

[006]

Car has a stumble/hesitation and it's driving me nuts.

Two weeks ago while on the frwy, car was running pretty bad with a bad stumble/hesitation.

Pulled coil cover and found the plugs and coils saturated in oil. Some coils were damaged/cracked (I posted pics too) and at about this time, I got a CE light P0304 (cylinder 4 misfire). Turns out that #4 plug was rusty and in bad shape.

Replaced the plugs
Replaced the COPs (coils)
Cleaned IAT sensor
Cleaned MAF sensor

Stumble/hesitation persisted and I began to notice a rattle sound that seems to be related to RPM, so I called a tech buddy to come over and plug in his diagnostic equipment. He found bank 2 was lean and the O2 readings were all over the place. Pulled plug #6, checked out the piston (cylinder #6), and it was wet/oily. He suggested replacing the plug grommets/seals for the valve (cam) covers, all the gaskets and suggested replacing that injector as it could be bad.

Sourced a brand new set of 24lb FRPP injectors M-9593-LU24 (yes they're discontinued, but found a whse with a set in stock).

Over the weekend, I did this:

Replaced Fuel filter
Replaced Injectors
Replaced Valve (cam) cover grommets/seals
Replaced Valve cover gaskets (yes the hydroboost was a bitch)
Checked the Cam position sensor, seems good, chains guides and everything in the head seems fine.

Car still stumbles/hesitates and occasionally I hear a low RPM rattle which *might* be coming from underneath.

Next on the usual suspects list is:

Clogged or broken up cat/s (OEM 99-01 catted H pipe)
Bad O2 sensor/s (OEM O2 sensors that came with the brand new H pipe & crate motor) Motor now has 96,000 miles.

What's your take on this or what would you do?

 

[Jamie R.]

I had a low speed intermitten miss like under very light load but never a rattle and my miss turned out to be a bad dpfe sensor. I could audibaly hear the car missing crusing through town under light load. CEL never came on till a while after having the miss and that's when we knew what was wrong.

Jamie R.
'01 Silver Cobra

 

[01yellercobra]

I'd pull the mid pipe and see how much debris falls out. I had a rattle under my car and shortly after the rattle went away my car got noticably louder. The aftermarkets cats had come apart. Thankfully the Stingers don't have anything to stop the pieces.

Right before all that I noticed the car didn't seem to have the oomph it used to have. Once the cats blew out all the power came back.

 

[006]

I'd pull the mid pipe and see how much debris falls out. I had a rattle under my car and shortly after the rattle went away my car got noticably louder. The aftermarkets cats had come apart. Thankfully the Stingers don't have anything to stop the pieces.

Right before all that I noticed the car didn't seem to have the oomph it used to have. Once the cats blew out all the power came back.

Yeah, I'm gonna look at that next. Perhaps this evening.

I had a low speed intermitten miss like under very light load but never a rattle and my miss turned out to be a bad dpfe sensor. I could audibaly hear the car missing crusing through town under light load. CEL never came on till a while after having the miss and that's when we knew what was wrong.

Jamie R.
'01 Silver Cobra

I have an extra DPFE sensor from a different year (94-95 I think), that I swapped in, and there was no change. Dunno if the voltages are the same, but they look identical. Want to stop tossing parts at this damn thing. I found a vid on youtube to test the DPFE, but I don't have a diagnostic computer. Think the predator has the ability?

 

[01yellercobra]

You also might want to replace the O2's while you have the mid pipe out. I had one that would stay right around 200mV. I replaced both sensors an the readings went back to normal.

 

[006]

You also might want to replace the O2's while you have the mid pipe out. I had one that would stay right around 200mV. I replaced both sensors an the readings went back to normal.

Ok

 

[olgreydog7]

I had a rattle that was the dust cover for the clutch cable on the transmission.

 

[jacker1991]

I had a rattle that was the dust cover for the clutch cable on the transmission.

Same here.

Mike out!:coolman:

 

[006]

I had a rattle that was the dust cover for the clutch cable on the transmission.

Thanks, I'll check that out as well.

 

[01yellercobra]

I had a rattle that was the dust cover for the clutch cable on the transmission.

Had that rattle too. But mine only happened at idle. The cover is now sitting on a shelf.

 

[006]

Had that rattle too. But mine only happened at idle. The cover is now sitting on a shelf.

Update:

The intermittent rattle was the clutch lever cover as diagnosed correctly above. I normally have a spring set inbetween the lever and the bellhoiusing stop where the cable sheath slips into. The purpose of the spring is to keep the TOB from making constant contact with the presure plate. The spring has a slight bend when compressing and it was making contact with that tin-like cover. I'm still trying to figure out how to handle that.

The injectors I had on the vehicle were fine. Nothing wrong with them since the new ones perform just like old ones did

I did have a "lazy/slow" O2 sensor on bank 2 that was switching slowly in waves (as seen on the graphs below). Replaced it as well. New one switches fast as bank 1.

So far, here is a list of the new parts and work done:

1. New spark plugs 8
2. New COP coils 8
3. New fuel filter 1
4. New injectors 8
5. New O2 sensor 1
6. New valve cover grommets 8
7. New valve cover gaskets 2
8. New Throttle body gasket 1
9. Clean MAF
10. Clean IAT
11. Clean all EV6 Injector connectors (took the entire piece apart and cleaned the receptacles and everything inside the housing)
12. Clean all COP connectors (took the entire piece apart and cleaned the receptacles and everything inside the housing)

Here are the datalogs and graphs:
http://www.svtperformance.com/forums/tuning-la-carte-375/937117-help-datalog-reading.html

If anyone has any suggestions or advice, please chime in. This issue has me stumped :shrug:

Lazy O2 in pink

Replacement/new O2 in pink:

Here is the log showing most PIDs after the O2 sensor swap and resetting the PCM/ECU memory:

Can I haz some halp

 

[DSG2003Mach1]

the injectors check out, have you all logged/monitored what the fuel pump is doing when the problem occurs?

I dunno what all parameters to log but Im sure someone can help out with that

good luck!

 

[CJK440]

Did the #4 misfire code come back after plugs, COPs and rocker cover grommets?

 

[006]

the injectors check out, have you all logged/monitored what the fuel pump is doing when the problem occurs?

I dunno what all parameters to log but Im sure someone can help out with that

good luck!

I don't know how to read the fuel pump and some of the other data, hence this thread

Did the #4 misfire code come back after plugs, COPs and rocker cover grommets?

No, it did not. The coils had cracks in them during that period and that particular spark plug was in pretty bad shape as well. Since I replaced the coils and the plugs there has been no misfire. Just the constant hesitation this entire time.

 

[99cobra09]

Really sounds like a tune issue. I would go to a dyno so they could check your A/F and maybe the tune.

 

[2000 gt]

Make sure when clearing the codes you also clear the keep alive memory or kam. Sounds crazy but I've seen that been left alone and caused issues. Also after all this work is done and the hesitation continues the only way to check if you still have a misfire is to check mode 6 in a scan tool. A local shop can do this it takes a while for a ce light to set on a ford

 

[006]

Really sounds like a tune issue. I would go to a dyno so they could check your A/F and maybe the tune.

The tune on it is the factory 01 cobra. Nothing has been changed or messed with :shrug: I think the lambda info in the datalogs above should be able to tell how my A/F is looking.

From yesterday's datalog, it shows the max lambda recorded being at:

1.082 on bank 2
1.070 on bank 1

Are both of these lean?

Also shows the min lambda recorded was:

0.89 on bank 2
0.87 on bank 1

Make sure when clearing the codes you also clear the keep alive memory or kam. Sounds crazy but I've seen that been left alone and caused issues. Also after all this work is done and the hesitation continues the only way to check if you still have a misfire is to check mode 6 in a scan tool. A local shop can do this it takes a while for a ce light to set on a ford

That makes sense.

I've unplugged the battery after all these installs and changes. Doesn't the KAM get cleared when you unplug the battery terminal and the PCM/ECU reboots? ..or is there a specific procedure on clearing the KAM? :shrug:

 

[mwolson]

This is a strange one.

You normally have to leave the battery unplugged for several minutes to clear the KAM due to the large capacitor they have on the KAM power line inside of the PCM. But if you press the brakes while the battery is unhooked, the brake lights discharge that capacitor right away so you don't have to wait.

My first suspicion after reading this thread is some kind of EGR related problem since it is happening at part throttle. Can you datalog your EGR system to see if there are any glitches when the problem occurs?

Your fuel trims indicate that the MAF transfer function in the stock tune is off a little bit, but at idle and part throttle, your O2 sensors are keeping it under control, so no worries there. With a perfect MAF transfer function, the trims would be centered on 1.0.

 

[01yellercobra]

The tune on it is the factory 01 cobra. Nothing has been changed or messed with :shrug: I think the lambda info in the datalogs above should be able to tell how my A/F is looking.

From yesterday's datalog, it shows the max lambda recorded being at:

1.082 on bank 2
1.070 on bank 1

Are both of these lean?

Also shows the min lambda recorded was:

0.89 on bank 2
0.87 on bank 1





That makes sense.

I've unplugged the battery after all these installs and changes. Doesn't the KAM get cleared when you unplug the battery terminal and the PCM/ECU reboots? ..or is there a specific procedure on clearing the KAM? :shrug:

You're really not that far off with the STFT's. Generally tuners aim for +/-5% from 1.00. But I have some spots that read the same as your's and the car runs fine.

I don't know how to read the fuel pump and some of the other data, hence this thread

If you have a return style system there's nothing to datalog. All you can do is watch the fuel pressure if you have a gauge.


I'm thinking the guys talking about EGR are onto something. When I had my EGR the car would buck and surge and hesitate. I finally got rid of mine so I tend to forget about it. Can you turn the EGR off with the Diablo? If it runs better then something in the EGR system is acting up.

 

[006]

This is a strange one.

You normally have to leave the battery unplugged for several minutes to clear the KAM due to the large capacitor they have on the KAM power line inside of the PCM. But if you press the brakes while the battery is unhooked, the brake lights discharge that capacitor right away so you don't have to wait.

My first suspicion after reading this thread is some kind of EGR related problem since it is happening at part throttle. Can you datalog your EGR system to see if there are any glitches when the problem occurs?

Your fuel trims indicate that the MAF transfer function in the stock tune is off a little bit, but at idle and part throttle, your O2 sensors are keeping it under control, so no worries there. With a perfect MAF transfer function, the trims would be centered on 1.0.

Hmm.. I asked a local friend about this, and he said to look into my EGR. Said he suspects it to be my culprit. :dw:

I will see if I can datalog it and test it.

You're really not that far off with the STFT's. Generally tuners aim for +/-5% from 1.00. But I have some spots that read the same as your's and the car runs fine.



If you have a return style system there's nothing to datalog. All you can do is watch the fuel pressure if you have a gauge.


I'm thinking the guys talking about EGR are onto something. When I had my EGR the car would buck and surge and hesitate. I finally got rid of mine so I tend to forget about it. Can you turn the EGR off with the Diablo? If it runs better then something in the EGR system is acting up.

I do have a returnless system. All the fuel lines, fuel system, wiring, emissions etc is 100% 99-01 'bra.

I'll now focus on the EGR and see what I can find.

Cheers guys! :beer: