EMI???? How would you know????
Thread Starter
Le Mans Master
Joined: Sep 2002
Posts: 6,569
Likes: 2,404
From: Redacted
EMI???? How would you know????
Ive been working on a project for a while now to relocate the coil packs to an out of the way place so that i could run normal valve covers. I recently completed the project and have been driving the car to work daily for the past week and have noticed that every so often, when cruising at a constant RPM, the car has an ever so slight, yet noticeable hesitation. Outside of that, the car runs fine, hasn't thrown any codes, and all appears to be good. Im wondering if the significantly longer spark plug wires, or the relocation of the coils is resulting in some sort of EMI that intermitently effects the strength of the spark produced by the coil and therefore causes the hesitation.
Any thoughts on how to trouble shoot?? I've got a local dyno shop that can probably hook the car up and read the timing/air-fuel/spark info....if I did that, what should I be looking for?
Any thoughts on how to trouble shoot?? I've got a local dyno shop that can probably hook the car up and read the timing/air-fuel/spark info....if I did that, what should I be looking for?
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
Tune your radio to an AM setting that is not a station. If you can hear the spark plugs firing in time with the engine's RPM, then you have some EMI going on. If you can't hear anything, then all the shielding is working good.
Thread Starter
Le Mans Master
Joined: Sep 2002
Posts: 6,569
Likes: 2,404
From: Redacted
hmmmmm, interesting, Ill give it a shot after I replace my water pump that decided to take a dump on the way home from work. Any thoughts as to what else might be causing a slight hesitation??
Tech Contributor
Joined: Jan 2007
Posts: 19,450
Likes: 1,155
From: Dyer, IN
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Greg
Please give some HISTORY on your car,, Mods, Tuning, mileage etc...
There are a whole host of low voltage critical wiring in the passengers fender well outboard the battery. If the spark-plug wires are working properly,, they shouldn't effect the wires and the signals and voltages going thru them but,,, ya never know. Trying to think out of the box
SO,, If you temporarily cover them in foil and ground that foil to the chassis,, that would tell you if the wires are effecting them.
What kind of wires are they?
What DTCs are you seeing? Do some data logging (find someone with EFI LIVE or HP Tuners or get a scanned that shows live sensor data) and see what your LTFTs are doing.
What is the voltage reading on the IPC Volt meter?
Fuel Pressure value??
When was the last time you Cleaned your MAF and Throttle blade
Are the coil metal parts grounded?
Lots of questions but,, that helps eliminate stuff..
BC
Please give some HISTORY on your car,, Mods, Tuning, mileage etc...
There are a whole host of low voltage critical wiring in the passengers fender well outboard the battery. If the spark-plug wires are working properly,, they shouldn't effect the wires and the signals and voltages going thru them but,,, ya never know. Trying to think out of the box
SO,, If you temporarily cover them in foil and ground that foil to the chassis,, that would tell you if the wires are effecting them.
What kind of wires are they?
What DTCs are you seeing? Do some data logging (find someone with EFI LIVE or HP Tuners or get a scanned that shows live sensor data) and see what your LTFTs are doing.
What is the voltage reading on the IPC Volt meter?
Fuel Pressure value??
When was the last time you Cleaned your MAF and Throttle blade
Are the coil metal parts grounded?
Lots of questions but,, that helps eliminate stuff..
BC
Thread Starter
Le Mans Master
Joined: Sep 2002
Posts: 6,569
Likes: 2,404
From: Redacted
Bill,
The car is a 2003 Z06 with 40K miles on it. The only real engine mods are a FAST intake and TB, cam, and long tube headers. Tuning was done when I put the cam in about 3 years ago by the now out of business MTI in Houston Tx.
The wires Im using are the 8mm MSD cut to fit wires.
Voltage is reading normal.
Ive got an appointment this week at the local dyno shop, what specifically should I have them log/look it?
I cleaned the MAF and TB a month or so ago and yes the new coil pack mounting brackets are grounded to the frame.
Any other thoughts are greatly appreciated.
The car is a 2003 Z06 with 40K miles on it. The only real engine mods are a FAST intake and TB, cam, and long tube headers. Tuning was done when I put the cam in about 3 years ago by the now out of business MTI in Houston Tx.
The wires Im using are the 8mm MSD cut to fit wires.
Voltage is reading normal.
Ive got an appointment this week at the local dyno shop, what specifically should I have them log/look it?
I cleaned the MAF and TB a month or so ago and yes the new coil pack mounting brackets are grounded to the frame.
Any other thoughts are greatly appreciated.
Greg
Please give some HISTORY on your car,, Mods, Tuning, mileage etc...
There are a whole host of low voltage critical wiring in the passengers fender well outboard the battery. If the spark-plug wires are working properly,, they shouldn't effect the wires and the signals and voltages going thru them but,,, ya never know. Trying to think out of the box
SO,, If you temporarily cover them in foil and ground that foil to the chassis,, that would tell you if the wires are effecting them.
What kind of wires are they?
What DTCs are you seeing? Do some data logging (find someone with EFI LIVE or HP Tuners or get a scanned that shows live sensor data) and see what your LTFTs are doing.
What is the voltage reading on the IPC Volt meter?
Fuel Pressure value??
When was the last time you Cleaned your MAF and Throttle blade
Are the coil metal parts grounded?
Lots of questions but,, that helps eliminate stuff..
BC
Please give some HISTORY on your car,, Mods, Tuning, mileage etc...
There are a whole host of low voltage critical wiring in the passengers fender well outboard the battery. If the spark-plug wires are working properly,, they shouldn't effect the wires and the signals and voltages going thru them but,,, ya never know. Trying to think out of the box
SO,, If you temporarily cover them in foil and ground that foil to the chassis,, that would tell you if the wires are effecting them.
What kind of wires are they?
What DTCs are you seeing? Do some data logging (find someone with EFI LIVE or HP Tuners or get a scanned that shows live sensor data) and see what your LTFTs are doing.
What is the voltage reading on the IPC Volt meter?
Fuel Pressure value??
When was the last time you Cleaned your MAF and Throttle blade
Are the coil metal parts grounded?
Lots of questions but,, that helps eliminate stuff..
BC
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Bill,
The car is a 2003 Z06 with 40K miles on it. The only real engine mods are a FAST intake and TB, cam, and long tube headers. Tuning was done when I put the cam in about 3 years ago by the now out of business MTI in Houston Tx.
The wires Im using are the 8mm MSD cut to fit wires.
Voltage is reading normal.
Ive got an appointment this week at the local dyno shop, what specifically should I have them log/look it?
I cleaned the MAF and TB a month or so ago and yes the new coil pack mounting brackets are grounded to the frame.
Any other thoughts are greatly appreciated.
The car is a 2003 Z06 with 40K miles on it. The only real engine mods are a FAST intake and TB, cam, and long tube headers. Tuning was done when I put the cam in about 3 years ago by the now out of business MTI in Houston Tx.
The wires Im using are the 8mm MSD cut to fit wires.
Voltage is reading normal.
Ive got an appointment this week at the local dyno shop, what specifically should I have them log/look it?
I cleaned the MAF and TB a month or so ago and yes the new coil pack mounting brackets are grounded to the frame.
Any other thoughts are greatly appreciated.
-Actual AFR in part throttle cruise
-WOT Power enrichment AFR
-Knock Retard value
-Long Term Fuel Trims. "Should not be significantly positive"
-MAP sensor reading when the issue happen
Hope you find it and its something simple. Maybe it just needs a more refined tune.
BC
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