Who is up for a good SC challenge!

edspringer

Registered User
This is a little long so, please, bear with me. I have a 94 SC auto with a new engine installed 10,000 miles ago by the previous owner. I have had the car for a month and my funmeter is peg. After replacing almost every engine sensor, the EEC and the MAFS I still have no power on acceleration with tons of boost. When I finally get to 60 MPH and push the throttle to get 5 to 10 pounds of boost, the engine stumbles and will not take it. When I let off the throttle it resumes it normal cruise state. Also, I get 11 miles per gallon using 93 octane gas. Now I'm a pretty good mechanic having installed several mods on my highly modified 90 Super Cougar 5- speed, but today I got desparate and took the 94 SC to my local Ford dealer. Well they got the same two codes (both O2 sensors are indicating they are both running rich and then running lean) that I got with my Wally World code reader. The Ford tech just about scratched what little bit of hair he had left off his head over those codes. He had never seen that before and this guy has worked on some Fords. That is when he called Ford and got them to start scratching. They came back with three suggestions all of which I or the technician had done. He also check all of the Ford Tech Bulletins for this problem with no joy. As of now the technician is still talking to Ford and is going to get back to me with any new "FORD IDEAS", no pun intended. He has taking this on as a personal challenge.

Have I changed the exhaust, you say! Oh yes, I have completely replaced the exhaust with SCCOA high flow cats and a Maganaflow muffler. I checked the fuel pressure. Got 35 lbs at idle and almost 40 LBS when I opened the throttle. I have checked high and low for vacuum leaks and have replaced any hose that looked suspicious. I even took the supercharger off so I could do a through check behind the inlet plenum and the EGR stuff. No fix de problamo.

So, here we are. I'm throughly frustrated and am looking for any help. I can assure you I will put out to y'all what the fix is when I find out what it is.

Ed Springer

edspringer1@aol.com

90 Black Super Cougar 5 - Speed - highly modified
94 Red SC Auto - ready to run it into the creek
 
Might sound silly but...

Check your plugs..All of em..Also check your wires..Also try pulling the octane plug and see what happens....Ill tell you my car would buck under full acceleration..It was the plugs..Now I have an overall lack of top end power because of my knock sensor kicking in due too to much boost..There is a chance you are suffering flame blow out..And when your motor was rebuilt..An overbore and a mill of teh heads might have raised your compression to teh point that it is activating the knock sensor to retard timing....Just a few easy things to check out here :O)..Good luck
 
Change the O2 sesnors. If you have 4 (2 in fron and 2 behind the cats) change just the front 2 as these are the ones the EEC looks to adjust air to fuel mixture when in closed loop operation.

Bad O2 sensors always (usually) throw both lean and rich codes when they are bad. Let's assume the O2s are bad. Now when the car is cold do you have a problem? When the car is cold (before engine warms to 160-180 degrees) the EEC doesn't look at the O2 sensors. I agree with Damon Slowpoke Baumann about the spark plugs and wires. Get some new Motorcraft double Platimum plugs and Motorcraft 8mm wires and change them out. The stock parts here are very good and really there isn't any aftermarket stuff out there that will help performance. Some guys run Ford Motorsport 9mm wires with success, but Jacobs and some others have casued nightmares.

I know you said you have new cats, but you sort of describe clogged cat or cats. If you ran too rich too long with those cats (bad O2 sensors will cause you to run rich) they can clog up. Clogged cats usually alow the car to run when the car is cold and as they heat they really kill performance.
 
You said you changed every sensor, so I assume that includes all o2 sensors.
You said you changed the exhaust, so I assume this problem occured before and immediatley after the change, and it was changed to eliminate it as one of the potential causes.
You said you checked the fuel pressure, I can not verify what levels you should get, but I assume you have therefore checked the fuel pressure regulator.
Now I will assume you have considered things like plugs/wires, injectors, bad dis module, ect do to the missing.
So, with codes for running rich then lean, and these other things eliminated as possibilities.. Perhaps it is a problem with the ECU...
 
An update on my info

Damon, Shackwave & Digitalchaos..........thanks for the info and the timely replies.

One of the first things I did was replace the plugs. When I got the car the Ford dealer who installed the motor put in regular 3.8L plugs, not the Ford double platinum. I thought I had found my problem when I put in the PP plugs. No joy! Also, I got Magacore wires and still no joy. So it is not plugs or wires.

I had the car 4 days when I removed the Ford cats and put on straight pipe to the Ford muffler. No change. I put on a Magnaflow with no change except I got the V-6 exhaust buzz. That is when I put on the cats to get rid of the buzz and they did.

I did not know the 94 SC had four O2 sensors. I found only two. One in the driver side manifold and the passenger side O2 sensor is in the pipe between the manifiold and the converter. If there are more please tell me where they are. My 94 Ford T-Bird & my 90 Super Cougar maintenance mannuals shows ony two O2 sensors. Did they put 4 in in 94?


Damon.......you raise an interesting point concerning the KNOCK sensor. I pulled the KNOCK sensor and put an OHM meter across it. The sensor was open. After I put in the new KNOCK sensor, the car ran the best it has since I've had it. But it only lasted for a short time. So could I assume the KNOCK sensor is bad again and the possibly higher compression may be killing the KNOCK sesnor? . The replacement motor is a Ford SC replacement long block. I would asume when Ford rebuilt the motor they rebuilt to SC specifications. So if it is another bad KNOCK sensor can I plug the hole and trick the computer? If I get another KNOCK sensor, can I just read the resistance with an OHM meter and replace the sensor with a resistor? Sounds like you have had a lot more experience with KNOCK sensors then I have. Any help would be greatly appreciated.

Ed Springer
SCCOA # 1496

edspringer1@aol.com

90 Black Super Cougar 5-speed: 3:27 gears, 70MM TB, Kook Headers, Magnacore wires, IC fan, S-90 blower & inlet plenum, 5% pulley, Magnaflow (with no cats), underdrive pullyes, SCP fresh air inlet (built this one myself)

94 Red SC Auto: 70MM TB, Magnaflow, Hi-flow cats, Manacore, 3:73 gears, SCP fresh air inlet.
 
Ed...Even if rebuilt to spec..An overbore and a milling of the heads will both increase compresion...When you pulled the plugs how did they look?..Regular plugs will not cause your car to run bad...What kind of boost are you getting?..Does the car run rough at all??...Im still having a feeling your knock sensor may be kicking in..Try running some high octane gas and see how the car runs..Ill keep up with your post and see what you find
 
I reread original post......2 things.....I had a similiar problem with an old SC of mine that involved a bad air charge temp sensor...A freind had the same problem and it involved the water coolant temperature sensor..Ive never had they come up as being bad on a scan so di dyou check em out?....Also what injectors and MAF are you running??
 
Damon..........after I wrote the last update I went out and pulled the # 6 and #1 plugs. The porcelin was white with a very slight black tint. I'm getting 10-15 lbs of boost depending on how hard I hit the throttle but it does not go anywhere compared to the Cougar. It idles a little rougher then my 90 Cougar but it does not stall. I run 93 octane in both SCs all of the time. Also, it seems to perform better when it is cold

As I have said before I have changed every sensor except the crank trigger and the cam position sensor. I had a used cam sensor from my 90 Cougar and replaced the one on the 94 with it. That made no difference. The injectors are stock and the new MAF is the stock 94 SC sensor. The only sensor that I had come up bad with codes is the KNOCK sensor and the O2 sensors with the rich and lean codes.

Friday, my day of despaeration, the Ford tech and I had a discussion about the position of #1 cylinder when setting the Cam Position sensor timing. I bought the special tool required to set it properly. The 94 & 90 Ford maintenace manual says 26° ATDC. He said that was wrong and I needed to have it set at TDC. I set my 90 Cougar at TDC and noticed some pinging and knocking with 93 octane that was not there before. I set it back to 26°ATDC and it performs and runs great. Do you know what the correct setting is?

Ed Springer
SCCOA # 1496

edspringer1@aol.com

90 Black Super Cougar 5-speed: 3:27 gears, 70MM TB, Kook Headers, Magnacore wires, IC fan, S-90 blower & inlet plenum, 5% pulley, Magnaflow (with no cats), underdrive pullyes, SCP fresh air inlet (built this one myself)

94 Red SC Auto: 70MM TB, Magnaflow, Hi-flow cats, Magnacore, 3:73 gears, SCP fresh air inlet.
 
I'v'e had rich and lean....

Rich and lean means that the O2 sensors are shot. These cars are EEC-IV or "OBD-I" that means it only has 1 O2 sensor per exhaust manifold pipe

What happened to the previous motor? Did it blow Head gaskets? If so, the O2 sensors could have been contaminated by the anti-freeze.

Also back to the plugs and wires, I run Jacob's wires and I have had a Pi$$ and Sh!t time with them. In the end, I do run Motorcraft Double plats, but I had to undergap them to .035" in order to get the engine to pull smoothly and NOT misfire under boost, since I was running into a flame out prob.


This is also a dumb Idea, but even though you are pulling the proper fuel pressure , did you change your fuel filter? It could be pressurized but not flowing enough fuel and then the fuel pressure regulator overcompensates, hence the Rich/ lean thing...

You said it idles a little bit rougher, that could indicate fuel probs. But on your reading the of the plugs, it doesn't seem that way....

Think that all of your injectors are clogged?
 
The correct setting for the cam sensor is with the engine at 26 ATDC. I don't know why the mechanic said TDC. Maybe he was thinking it was set up the same as a distributor.
 
Re: no power

Had a problem once, got full boost but no power. It was a peice of converter stuck in 'Y' pipe.
 
EEC IV only has two O2 sensors I was in error. I have been spending too much time on TCCOA and 4.6 V8 models.


The problem is either Fuel or Spark. Either you have a weak spark that can't ignite under boost or you are running lean or way too rich.

I don't have any experience with Magnecor wires, but I see this hasn't thrown any flags from others so far so they must be ok. You have new plugs so that is good.

Let's look at Fuel.

11 miles per gallon is very BAD. You have to be running too rich.

What kind of MAF are you running?

Try swapping a known good MAF from a fellow SCer.

EEC never going to closed loop (ECT sensor bad) or ACT sensor BAD)

I still think always rich and always lean codes mean bad O2 sensors.

Hey if you want to write to me the complete history of the car my e-mail is below. Tell me everything you did from the time you got the car and everything you have changed trying to fix the problem.

I love these kind of hard to find problems.
 
From the experience that one of our club members in SCCoO has had with running Magnecor wires for many years, the plug gap should be tightened up a bit, to around .045" to work best.


cheers
Ed N.
 
1. make sure its in closed loop
2. hook up vacuum guage
3. hookup F/P guage (disconnect vacuum line to FPR, it should raise roughly 10 psi. then hookup vacuum pump and with the engine off, it should hold a sustained 18 psi of vacuum, if not, replace it.)
4. disconnect maf sensor (if runs better, replace with known good part)
5. if all of the above don`t turn up anything, disconnect the exhaust downpipes and recheck ( if problem goes away, find restriction in exhaust system.


aaron
 
I didn't see it listed, but do you have a K&N filter and was it re-oiled recently? If it was, remove the MAF sensor from the MAF and check the wires. They may be covered with the oil. You can clean them with alcohol and a q-tip, "Very gently".
 
Here is my plan to fix the problem!

First, thanks to all who have responded. I'm really impressed with the wealth of knowledge and how many of my fellow SCers want to help.

Here is what I'm going to try and if y'all think I'm getting ready to do something stupid please let me know ASAP.

Damom Slowpoke Baumann I think has the answer to my problem considering my engine is a Ford remanufactured long block SC engine. The compression ratio has been raised higher then a new SC original engine due to the remanufacturing process. In talking with some good mechanics, they all agree that KNOCK sensors are very sensative. When I replaced the KNOCK sensor last week, the car ran really good for a short period of time. Also, when I really crowded it with boost it would misfire. I believe the KNOCK sensor is either bad again or is constantly sensing the higher compression ratio which is not allowing the engine timing to advance. Here is what I'm going to do. I'm going to have a machinist friend make me a KNOCK sensor blank off plate to put between the KNOCK sensor and the engine. Basically, it will be a peice of 1.125" aluminum hex stock threaded to fit into the engine and then tapped for the production KNOCK sensor to screw into. Therefore, the engine should never see the higher compression ever again. That should make the EEC happy. Next I'm going to regap all of my plugs, as a few of you who responded recommended, to .040. If I still experience misfires, I'll gap them to .035 and keep going until the misfire goes away.

Is that a good plan?

The MAF sensor installed is a stock 94 SC MAF sensor.

Shockwave........if this does not fix it, I'll send you a complete history of what I have done to the car during the five weeks I have owned it.

Ed Springer
SCCOA # 1496

edspringer1@aol.com

90 Black Super Cougar 5-speed: 3:27 gears, B&M Ripper Shifter, 70MM TB, Kook Headers, Magnacore wires, IC fan, S-90 blower & inlet plenum, 5% pulley, Magnaflow (with no cats), underdrive pullyes, SCP fresh air inlet (built this one myself), Rear Suspension Air Bags

94 Red SC Auto: 70MM TB, Magnaflow, Hi-flow cats, Magnacore wires, 3:73 gears, SCP fresh air inlet, Haydon 10,000 lbs. Capacity Auxiliary Transmission Cooler.
 
Try disconnecting...

....Your knock sensor first. KNock sensors can be very sensitive and can detect knock before the human ear can which by that time, could already be too late for the engine.

I don't think that a re-milling of the engine would increae CR to some sort of exorbinant amount. But if you did get a twitchy knock sensor, it could have burned out.

Try disconnecting it first or replacing it again (ford parts/aftermarket parts have a warranty right?)

Then run it. If you run it diconnected be care ful, you've now just removed your "saftey net" and the only thing protecting your engine from detonation is your right foot.

ALso there is supposed to be a test for KNock sensors, I think you can measure the voltage from them and then tap the engine block with a hammer, if there is voltage, then it is working.

Are you actually "running out of juice" when you push it or are you getting a violent cutting out/misfire???
 
DEEP6.........thanks for the response!

I removed the Knock sensor. The original bad sensor I pulled apart to see what was inside. I have now put the metalic base of that sensor into the hole in the block where the knock sensor with a connector normally goes. Effectively, I have made a Knock sensor blank off plate. I took the car for a spin with the blank off plate installed and the Knock sensor plugged in and tied off. No joy! I think the Knock sesnor is bad........again. I tried to read a resistance with a VOM and the circuit was open like the original sensor. I'm getting a new sensor tomorrow and do the same thing with a new sensor. In the five weeks I have owned the car and after replacing all of the stuff I have the only time the car ran like it was suppose to is right after I replaced the Knock sensor the last time.

When the car ran really well for that short period of time after I replaced the Knock sensor, I did get some misfires when I jumped on it. I believe that I need to reduce the plug gap to cure that.

I have pratically no acceleration. I step on the throttle, get plenty of boost and it tries to go and it eventually does, sort of. It cruises decent but when I try to give it 5-10 lbs of boost it sort of tries to die. I have to real careful when I pull out in traffic.
Reminds me of a carburatered V-8 that is cold. When I give it gas it stumbles and then when I let off the gas it runs OK.

Ed Springer
SCCOA # 1496

edspringer1@aol.com

90 Black Super Cougar 5-speed: 3:27 gears, B&M Ripper Shifter, 70MM TB, Kook Headers, Magnacore wires, IC fan, M-90 blower & inlet plenum, 5% pulley, Magnaflow (with no cats), underdrive pullyes, SCP fresh air inlet (built this one myself), Rear Suspension Air Bags

94 Red SC Auto: 70MM TB, Magnaflow, Hi-flow cats, Magnacore wires, 3:73 gears, SCP fresh air inlet, Haydon 10,000 lbs. Capacity Auxiliary Transmission Cooler.
 
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