Plug Wires?

[NYSteve]

Just aquired a '95 Aurora that runs rough. I figured something electrical. Maintenance records show that the plugs were replaced 6 months ago, as were the coils. When I unplug the spark plug wires on cylinders 1 and 4 while the engine is running, nothing happens. If any other wires are unplugged, the engine slows down and runs worse. If the wires are switched (cylinders are fired in pairs, so you can switch them with the paired cylinder), the new cylinder with the old wire does not have spark. I’m 99% sure it’s the wires, but I just wanted to verify before I spent $120 on new wires. Anyone have a similar problem, or a suggestion?

[zimaad]

These cars are fairly picky when it comes to plugs and wires. What kinds was put on the car 6 mos ago? I think you'll find that most people recommend putting on the AC Delco OEM plug wires and plugs. Yeah...they are a bit expensive at $100+ for the wires and $6/plug, but they just seem to work better. Also, wires 1 and 4 come from the same coil pack. Maybe you have a bad coil pack. That's a cheap fix...maybe $30 for a coil pack I'd guess. Other things that tends to lead to rough running car is fuel pressure regulator(FPR), fuel pump, intake leak(common...will hear a whistling esp when cold and rough/hesitation when under slight acceleration). The mass air flow sensor can lead to a bunch of idle/fuel mix problems too...thats a whole other bag of worms though. I'd rule out the simple fuel/electrical things first. Also...you getting any codes?

best of luck

[androsvalentino]

i currently have borg warner select ch7855 wires. denso iridium IT-16 (5325). check out vitek wires. vitekperformance.com good design. look sharp. i had ngk iridium, denso is better design, smoother, better economy, more power. i'm gona switch to vitek next.

[NYSteve]

Originally Posted by zimaad

These cars are fairly picky when it comes to plugs and wires. What kinds was put on the car 6 mos ago? I think you'll find that most people recommend putting on the AC Delco OEM plug wires and plugs. Yeah...they are a bit expensive at $100+ for the wires and $6/plug, but they just seem to work better. Also, wires 1 and 4 come from the same coil pack. Maybe you have a bad coil pack. That's a cheap fix...maybe $30 for a coil pack I'd guess. Other things that tends to lead to rough running car is fuel pressure regulator(FPR), fuel pump, intake leak(common...will hear a whistling esp when cold and rough/hesitation when under slight acceleration). The mass air flow sensor can lead to a bunch of idle/fuel mix problems too...thats a whole other bag of worms though. I'd rule out the simple fuel/electrical things first. Also...you getting any codes?

best of luck

1 & 4 come from the same coil? I traced all the wires back to each coil and 1 & 4 dont come from the same one. I assume that could be the problem, however, theres still no spark on the other end of the wire no matter where its plugged in. And no, no codes. The check engine light isn't even on. Coils are around $30, yes. Everything else you list I dont believe has to do anything with the car running poorly. Theres no spark to 2 cylinders, and the plugs w/o spark are wet (with gas). And it runs, so the fuel pump isnt bad.

[androsvalentino]

fpr fuel pressure regulator. possible. vacuum leak. clean egr valve, throttle body, new fuel filter.

[androsvalentino]

idle sensor.

[androsvalentino]

i just changed fuel pressure regulator. new fuel filter, cleaned throttle body, new goodyear gator belts. smooth, picked up mileage, power. sounds like bad wires if the coils were changed recently. vitek wires. go with the good plugs. denso iridium.

[blindman858]

I had a number of OBDII sensor code errors relating to fuel system,0701 and 0703. Replacing fuel ralated components had no effect. Took it into dealer and he said car had bad plug wires and two plugs with carbon traces. Dealer replaced plug wires and cleaned carbon off plugs and it now runs like a champ

[Smoothe LJ]

Originally Posted by androsvalentino

i just changed fuel pressure regulator. new fuel filter, cleaned throttle body, new goodyear gator belts. smooth, picked up mileage, power. sounds like bad wires if the coils were changed recently. vitek wires. go with the good plugs. denso iridium.

http://www.volvospeed.com/Reviews/iridium.htm check out this site it might change ur mind!

[androsvalentino]

i will post if i have any probs. anything can happen when changin plugs. not putting anti seize lube, over tightening, bad threads, doesn't mean this plugs suk just cause of some guy with a volvo.

[NYSteve]

Just bought a new coil, and put it in. Now i have another problem. The wire from the coil to cylinder 1 sparks all over the place from the terminal. what could be causing this?

[androsvalentino]

change the wires.

[NYSteve]

Change the wires eh? Ugh, thats what i was afraid of. $140 aint cheap but i guess i dont have too many options.

[androsvalentino]

get the viteks. vitekperformance.com if u put the cheeps you'll wana change them in bout 2 months after you begin to appreciate the car more. not everyone wants to do this car up, i know. some wana keep the blend in sleeper, mini van look.

[NYSteve]

Well, i think ive ruled out the wires. switching wires completely with another cylinder still gives very little spark at the other end, even with a new coil installed. and the wire that i thought was bad, gives great spark when put on another terminal. Now im thinking that either the ignition module is bad, or the ECU is junk. both big $$$$. i cant really think of anythig else that could be making one coil give weak spark, and the other three fine spark. i'd like to not have to spend $500 and find out there still something wrong.

also, where is the connector to plug the car in to get codes? maybe that'll narrow it down for me