bad injector? bad connection? bad wiring?

[fastforded]

wonderted if anyone was famililar with checking cylinder balance?

i think after you run key on, engine on test, and it sends results, if you floor car it will tell ecm to run cylinder balance check????

im trying to chase down bad injector or injector wiring isssue.

changed plugs, and had one come out looking brand new inside. mint shape.
all white porcelin, clean as heck.

first thought about bad wire/cap/rotor...but the plu doesnt have any stains/discolorations. thinking its not getting fuel pulse to turn on?

bad injector?
bad wiring?
bad connection?

any suggestions where to start?

either number 6 or number 7 injector under intake.

didnt want to split upper and lower...

any thoughts/advice /suggestions appreciated...

http://www.mustangmods.com/ims/u/4459/13395/265804.jpg

http://www.mustangmods.com/ims/u/4459/13395/265805.jpg

 

[HISSIN50]

You got it with the CBT. It's a quick, clean way to find a cylinder that isnt contributing. Once it pinpoints a cylinder, confirm spark, check the plug, check compression and use a noid light to check the injector's electrical path.

For testing spark, tossing an inductive timing light on the wire works decent most of the time (unless the issue in at the plug boot, Put the plug back in the wire and ground the plug's threads to check actual gap firing).

A dry plug while others are wet is a tell of no inj pulse. The noid light helps you see that the injector receives accessory 12 volts and pulsed (modulated) grounding.

If you think you got a bad plug, swap it out with an old one or swap the suspect plug with another one from another cylinder. If the miss follows the plug, you found the issue. Doing the same thing (but separately, to keep variables to one) with a suspect bad injector can work too.

Doing a CBT and all this testing might take but 15 mins, so it's no biggie. Dont burn yourself though.

Good luck.

 

[fastforded]

You got it with the CBT. It's a quick, clean way to find a cylinder that isnt contributing. Once it pinpoints a cylinder, confirm spark, check the plug, check compression and use a noid light to check the injector's electrical path.

For testing spark, tossing an inductive timing light on the wire works decent most of the time (unless the issue in at the plug boot, Put the plug back in the wire and ground the plug's threads to check actual gap firing).

A dry plug while others are wet is a tell of no inj pulse. The noid light helps you see that the injector receives accessory 12 volts and pulsed (modulated) grounding.

If you think you got a bad plug, swap it out with an old one or swap the suspect plug with another one from another cylinder. If the miss follows the plug, you found the issue. Doing the same thing (but separately, to keep variables to one) with a suspect bad injector can work too.

Doing a CBT and all this testing might take but 15 mins, so it's no biggie. Dont burn yourself though.

Good luck.

compression blow by test?

rhat kinda noid light? Detail Page for 27800 Universal Noid Light - Lisle Corporation

 

[NIKwoaC]

If a cylinder isn't firing, doesn't the plug come out saturated in oil (that would usually have been burned off)? That was my experience when my 250K mile Crown Vic had a miss, but that could have also been due to poor ring sealing/valve seal leak. That and the cylinder had been dead for a long time, haha.

 

[HISSIN50]

compression blow by test?

I'm not sure what this was in regard to. CBT is Cylinder Balance Test.
Doing a Compression test would be useful while doing diagnostics. A leak-down test is more useful but not necessary.




You can get a Ford TFI noid light at most parts stores for about 5 bucks. If that noid you found has wire leads, it would work with about any injector connector however.

 

[drpgtcoupe]

had a problem like this once it would idle ok and sound right. but when u reved it it would miss and backfire. since u said it was 6 or 7 im beting on 7 thats where ur brake booster pulls vacume from. it was completly killing that cylinder had spark and fuel just no fire. it was a vacume leak causeing my problem. and that can take awhile to find cause ur air vents run off the brake booster and ur cruise control i believe. good luck

 

[fastforded]

I'm not sure what this was in regard to. CBT is Cylinder Balance Test.
Doing a Compression test would be useful while doing diagnostics. A leak-down test is more useful but not necessary.




You can get a Ford TFI noid light at most parts stores for about 5 bucks. If that noid you found has wire leads, it would work with about any injector connector however.

best way to do CBT? thru eec after u pull codes?

and i havent had any luck finding ford tfi noid light....could i use.....

Detail Page for 27800 Universal Noid Light - Lisle Corporation

 

[fastforded]

had a problem like this once it would idle ok and sound right. but when u reved it it would miss and backfire. since u said it was 6 or 7 im beting on 7 thats where ur brake booster pulls vacume from. it was completly killing that cylinder had spark and fuel just no fire. it was a vacume leak causeing my problem. and that can take awhile to find cause ur air vents run off the brake booster and ur cruise control i believe. good luck

???? im getting 7-8" hg.

not sure what you mean since u said

" it was 6 or 7 im beting on 7 thats where ur brake booster pulls vacume from."

cylinder 6????? im confused? what do u mean 6 or 7? thats inches/hg i was refering too.

1 vacuum line goes to brake booster only.
1 vacuum line goes to cruise control.
1 vacuum line to fuel pressure reg
1 vacuum line to egr valve
1 vacuum line goes to thermactor/smog system
1 vacuum line goes to pcv valve
1 vacuum line(?) goes to throttlebody from oil filler tube....


heater has seperate vacuum line from vacuum tree....

i just dont understand why vacuuum all over place...unless something in smog system?

 

[Bligaderski]

I had a similar issue last week, I found the noid lights at Advanced Auto Parts for 12 or 13 dollars (its was a set of lights). I found the issue in my main harness plug. The black and white engine connectors (I have heard of them referred to as the salt and pepper shakers) the black harness has the injectors in it and I had a broken wire in the plug (not visible), the only way I could tell was to pull the cap off of the back of the connector and wiggle the wires I had traced. I used a digital voltage meter on tone to see if there was a connection but you don’t have to go that far. The number eight was my issue the wire color was light blue. Also the injectors have a common wire on each it will be the same color on all the injectors. The other wire is the ground that pulses the injector. If you plug the noid light in and it doesn’t blink then try shaking the connectors and harness if it comes on and off then it’s in the harness.

 

[fastforded]

I had a similar issue last week, I found the noid lights at Advanced Auto Parts for 12 or 13 dollars (its was a set of lights). I found the issue in my main harness plug. The black and white engine connectors (I have heard of them referred to as the salt and pepper shakers) the black harness has the injectors in it and I had a broken wire in the plug (not visible), the only way I could tell was to pull the cap off of the back of the connector and wiggle the wires I had traced. I used a digital voltage meter on tone to see if there was a connection but you don’t have to go that far. The number eight was my issue the wire color was light blue. Also the injectors have a common wire on each it will be the same color on all the injectors. The other wire is the ground that pulses the injector. If you plug the noid light in and it doesn’t blink then try shaking the connectors and harness if it comes on and off then it’s in the harness.

noid light replaces the injector?

 

[HISSIN50]

noid light replaces the injector?

The noid light is a test light. It simply lets you know if power and ground reach the injector connector.