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View Full Version : Ok need a little help from a SC Guru...



SLP007
10-10-2005, 11:58 AM
Heres the deal...
I have a 1995 SC that for the most part has been a wonderful car. That is to say until a gremlin popped up. Went from running perfectly to a miss or stumble even during boost. I've exhausted the search function and took care of all the stuff that everyone seems to think it might be. DIS, New plugs (autolite 103's gapped at .045), Wires, Sealed IC Tubes, Checked all vaccuum hoses, Balancer, Cam Sensor, IAC etc etc.. The only other thing that I've seen mentioned that I havent looked at yet was a clogged cat. Anyone have an opinion or know of someone I can take the car to in the DFW area??? :o

Thanks

James

Joisey Jim
10-10-2005, 05:20 PM
I'm not familiar with Autolite 103's and such a small gap; but if you are not getting any CEL's then I would re-check the plugs & wires.

southwestman sc
10-10-2005, 05:46 PM
I've had the same problem! I tried a couple different types of after market platnum plugs and the car ran like $h!T. The local Ford dealership told me that I should use the factory double platnum plugs. I did this and it ran great. I would also test the resistance in your wires.

S_Mazza
10-10-2005, 07:11 PM
I would say it's probably electrical. I've never even seen a plugged cat. When you say DIS, do you mean just the coil pack, or did you swap out the ignition module too? The modules are notorious for intermittent faults. Also, try checking your ECT, ACT, and oxygen sensors.

Shockwave
10-12-2005, 05:21 AM
What brand wires you running? What size pulley?

XxSlowpokexX
10-12-2005, 09:28 AM
potential Fuel pressure problem....Hows your MAF?

CMac89
10-12-2005, 09:41 AM
THe only autolite that should EVER be used in our cars are the double platinums. I highly suggest you get those before you get too farfetched ideas from yourself or others.

Jason Wild
10-12-2005, 10:51 AM
Auto light 103 are fine to use they have been used in 3 of the top 10 Sc forsure. As well I have been useing them for 2 years.

xThunderbirdSCx
10-12-2005, 10:55 AM
IMPOSTERS!!!!!!
NONE OF YOU ARE XR7DAVE!!!!
When he said "SC GURU" he obviously meant Dave Dalke.

...get it right; he is THE guru :p :p

SLP007
10-12-2005, 11:27 AM
I used the AL 103's after searching around here and seeing that quite a few people run the plug with no problems. This is the 3rd time I've changed the plugs since I started having problems. After trying motorcraft,bosch and now autolite I think I've safely ruled them out. :o

I put in a new ignition module.
I have motorcraft Wires.
I have a stock Pulley.

Damon: I was also starting to think fuel/pressure problem and went and picked up a new regulator. Haven't had time to put it in seeings how its buried behind a bunch of stuff. Will be trying that this weekend. Are MAF's notorius for going out on these cars? I had a 300z a while back that the MAF went out on and it wouldn't rev over 2k.
Something else to tho, The CEL light has never came on? :confused:

<----Pulling my hair out

lube70
10-12-2005, 12:15 PM
I used the AL 103's after searching around here and seeing that quite a few people run the plug with no problems. This is the 3rd time I've changed the plugs since I started having problems. After trying motorcraft,bosch and now autolite I think I've safely ruled them out. :o

I put in a new ignition module.
I have motorcraft Wires.
I have a stock Pulley.

Damon: I was also starting to think fuel/pressure problem and went and picked up a new regulator. Haven't had time to put it in seeings how its buried behind a bunch of stuff. Will be trying that this weekend. Are MAF's notorius for going out on these cars? I had a 300z a while back that the MAF went out on and it wouldn't rev over 2k.
Something else to tho, The CEL light has never came on? :confused:

<----Pulling my hair out

I have seen the alternator on later model cars switch from DC to AC charging due to bad diodes.

A mechanic in NJ had the same problem with the car and after a month of playing with parts, figured out the alternator theory after talking to Ford.

Get it checked. It usually do it around 2000 rpm.

If any questions, call me at (973) 277-4294

Don

S_Mazza
10-12-2005, 05:24 PM
These cars don't seem to have many cases where the MAF fails outright. Sometimes it gets dirty, but you can (very gently) clean it. This seems to happen more often in cars with K&N or other oil-style air filters.

Upon rereading your post, I think that what DamonSlowpokeBaumann said may be right. It would be really good to check your fuel pressure. If it's not right, it could be a bad regulator, or a bad pump. The pumps seem to last about 15 years, then konk out.

Mike8675309
10-12-2005, 06:31 PM
Went from running perfectly to a miss or stumble even during boost.

Can you further qualify what the miss is that you're experiencing. You say miss, or stumble even during boost. Does that mean it only happens under boost, or it's a constant miss even at idle?

Fuel pressure issues are typically seen as engine load and rpm increase. A idle miss isn't likely caused by fuel pressure if the engine runs fine except for the miss when going down the road. Thus the need for clarification.

It never hurts to check fuel pressure though.

Have you done the cylinder balance tests? See if you have a bad cylinder.

SLP007
10-13-2005, 10:19 AM
Can you further qualify what the miss is that you're experiencing. You say miss, or stumble even during boost. Does that mean it only happens under boost, or it's a constant miss even at idle?
Fuel pressure issues are typically seen as engine load and rpm increase. A idle miss isn't likely caused by fuel pressure if the engine runs fine except for the miss when going down the road. Thus the need for clarification.

At idle the car runs perfectly. I can even go and drive it around, but as soon as you get into any sort of boost the car kinda falls on its face. Just has no power and feels heavy. Sounds like it has a miss. Once back at idle or in vaccuum the car runs great! :confused:




Have you done the cylinder balance tests? See if you have a bad cylinder.


No, haven't gotten that far yet.

Thanks for all the ideas ya'll. I'll be putting them to the test this weekend. :o

lube70
10-13-2005, 10:50 AM
If it's happening ONLY UNDER BOOST......then you have a fuel problem. Although it could be a spark issue (mainly wires), the pressure regulator increases fuel pressure upon boost (approx. 1psi/psi of boost). Therefore, check the regulator. You need a vacuum tester (available at Sear's, Autozone, etc) and make sure that the regulator does not have a leak. Common problem on these cars.


Good luck,


Don

SLP007
10-13-2005, 11:47 AM
If it's happening ONLY UNDER BOOST......then you have a fuel problem. Although it could be a spark issue (mainly wires), the pressure regulator increases fuel pressure upon boost (approx. 1psi/psi of boost). Therefore, check the regulator. You need a vacuum tester (available at Sear's, Autozone, etc) and make sure that the regulator does not have a leak. Common problem on these cars.


Good luck,


Don

Thanks a lot Don! This will be the first thing I check when I jump back into it this weekend. I'll post up and let ya'll know what I find out. :)

SLP007
10-24-2005, 12:11 PM
Well I ran a fuel test yesterday and found that there appears to be no press present until the car actually starts. I turned to Key On and it sat at zero. I left KOEOff for about a minute and still nothing. After that, car fired right up. Went wot a few times and got it to about 10lbs of boost, fuel pressure was reading correctly (judging from searching here). I took the car up and had it scanned at vato-zone and came up with code 111 with a KOEOff test. The guy didn't do a KOERunning test.... Said he didn't have to..... Didn't sound right. Anyway long story short, fuel pressure checks out while running AND in boost. Came up with a passing code after being scanned. Car still has that boggy feeling but if you stay outta boost it's perfectly fine. I drove it around all day yesterday. Even ran some decent injector cleaner thru it. I checked every possible vaccuum hose double checked that all my plugs and wires were set...still nothing.

This car has me stumped like no other! :confused: :confused: :confused: :confused: :confused: :confused:

Mike8675309
10-24-2005, 01:44 PM
Any chance of a plugged exhaust? Maybe a cat comming apart?

Does it still fall on it's face at Wide Open Throttle? Or does it seem to behave then as well?

Have you verified the condition of the plug wires? The plugs are good? Poor quality ignition could do this.

Do you smell the fuel at all? Just wondering if maybe you're too rich. Maybe that fuel pressure regulator is leaking by it's diaphram.

SLP007
10-24-2005, 02:25 PM
Nope. No fuel smell. The problem happens mostly at WOT. It's not a on/off thing it always there. I got on it yesterday as much as it would let me and there was a little puff of blackish smoke...not a lot tho...

I've only changed the plug wires once, maybe I'll just change em again and see what that does....

This cars a money pit.

Who wants it. Seriously.

SLP007
10-25-2005, 10:39 AM
Anyone ???

ThunderCoupe
10-25-2005, 11:57 AM
How many miles do you have? You could have bad tension on your supercharger belt? worn tensioner/jackshaft? Right now mines toast and most of the time when i get on it, i can feel the belt slip... the car wants to go then only goes like halfway and then starts going again as i let of the gas. If i ease into it, it holds, but still... I know i can hear my bearings sounding like marbles and it causes close to the same problem your explaining... you've checked the fuel and spark, that leaves air flow to be the culprit...

S_Mazza
10-25-2005, 02:00 PM
The idea about the SC belt is a good one. That's a pretty cheap part, so it's not a bad idea to swap it out. Also, could you have a boost leak? Have you ever taken the IC tubes apart?