New to me notchback issues.

[Black4VPower]

I seem to be having 2 problems with my new to me 91 Notchback. I am A little inexperienced with fox bodies I am coming from a modular Cobra that I still own. The foxbody has a Vortech blower running low boost, I believe it has a small cam, longtubes, and gears. The first problem is a popping that started coming from the AC compressor, I was letting it warm up and all of a sudden it started to pop and I could see air pop out at the same time real fast. I noticed that the electric fan wasn't coming on at around 190 degrees like it does, I shut it off when the temperature rose to 205 but once I shut the car off the fan came on. To my understanding this has to do with too much pressure from the temperature because the fan wasn't coming on in time? The other problem is I noticed when I shift at 5,000 RPMs it seems to nose over real bad, seems like its almost hitting a wall, once it hits 5,000 RPMS it doesn't want to rev. The car makes great power below that, from 40 MPH in second gear it will smoke the 275/50 tires into 3rd. The car doesn't smoke at all or smell like its burning any oil. The engine doesn't make any strange noises or shake either. Thanks in advance for any help.

 

[crazycarlo]

does the electric fan have an adjustable thermostat? Can you post a picture of the setup. May just need to have the on off temps set diff.

Do you have an idea of the cam in the car? Stock displacement? What heads and intake? Tuned with a chip?

 

[Black4VPower]

I think it may have been a fluke with the fan not coming on because I have been driving it the last 2 days for 4 hours at a time and it always comes on around 190 degrees. Stock displacement, stock heads and intake but I am not sure what cam it has but it has a ton of low end grunt, on regular 275/50/15 street tires from a 40 mph roll in 2nd gear it will roast the tires into third. When the popping started from the ac compressor I was warming the car up and the heat was on. I was told if I warmed it up with the heat on it would do that, I am not to sure but it has been running flawlessly the last 2 days. I have been shifting quick around 4800-5000 rpm because that's where it feels like it wants to spit all its power out, anything higher I can feel it lay over. I am not sure if its been tuned or has a chip but if not it may be the problem unless its just how these engines are as I am used use to shifting at 6400 RPM in my modular Cobra.

 

[crazycarlo]

Well the overheating thing may have been a fluke i dont know. The 5000 rpm thing could be a few issues. Without knowing the cam or if they changed the srpings its anyones guess. To check for a tune/chip just look on the computer in the passenger side fender well. If it doesnt have one im guessing it has an adjustable FPR and a FMU.

 

[parksr5]

I think it may have been a fluke with the fan not coming on because I have been driving it the last 2 days for 4 hours at a time and it always comes on around 190 degrees. Stock displacement, stock heads and intake but I am not sure what cam it has but it has a ton of low end grunt, on regular 275/50/15 street tires from a 40 mph roll in 2nd gear it will roast the tires into third. When the popping started from the ac compressor I was warming the car up and the heat was on. I was told if I warmed it up with the heat on it would do that, I am not to sure but it has been running flawlessly the last 2 days. I have been shifting quick around 4800-5000 rpm because that's where it feels like it wants to spit all its power out, anything higher I can feel it lay over. I am not sure if its been tuned or has a chip but if not it may be the problem unless its just how these engines are as I am used use to shifting at 6400 RPM in my modular Cobra.

Also, the pushrod and modular motors are two different animals. All of my fox bodies started to lay over a little after 5k but my modulars keep pulling. Once I hit third in my foxbodies, the fun started to subside. FWIW, I just had normal bolt on's and exhaust on my fox body cars.

 

[Black4VPower]

I am just used my cobra which made all the power in the upper RPM range. This foxbody has a boat load of torque right off idle so its a whole different animal, I am just getting used to it and shifting sooner rather than winding it out like on my cobra. I do love this car though, it feels like it would be a good tree stump puller with all the torque down low hahaha. Also the whole cluster has been changed out to Autometer gauges so the tach is more than likely more accurate than the factor tach.

 

[crazycarlo]

Yes the 4V makes power higher in the RPM's. they are two different animals. A SBF can be made to rev higher just takes different parts. Good springs, heads, cam. There are plenty of guys shifting around 6K.

I saw you said your car noses over at 4800 rpm. Even my stock 93Gt didn't do that. Have you checked the timing to see what it's set at?

 

[Black4VPower]

Someone was able to tell by looking under my hood, I cant remember what they were looking at but they said it was bumped really high.

 

[crazycarlo]

What they were looking at was the harmonic balancer it has timing marks etched on it. You hook a timing light up to the number 1 plug wire (pass side front wire) then you squeeze the trigger pointing it at the balancer and it lights the timing marks up.

I would deff check it. Before I could see the marks on my balancer a guy tried to adjust the timing. It was was high and the car would ping. There is a spout connector you have to take out before you adjust the timing and plug back in when your done.

It you have the original balancer on the car it could be bad. It's a common problems with the foxes. What happens is the outer ring slips so it will show a diff timing then what the car is actually set at. Just a thought.

 

[Black4VPower]

The car doesn't ping at all, it pulls really strong. The engine will free rev beyond 4800 RPM with no issues. Could weak valve springs be the culprit also?

 

[crazycarlo]

I honestly couldn't tell you that and I don't want to give you the wrong info. If your not already a mber join corral.net thy deal mostly with the older pushrod stuff.

 

[Jimboslice751]

Weak valve springs could be the issue, might be fine depending on the cam. If it's a stock cam I wouldn't think it'd be the valve springs. Only way to know if that is the issue is to take them out and check the spring pressure, also need to know the cam too.

 

[Black4VPower]

It sure sounds and feels like it has a small cam. I don't know what the odds of it being a RV/towing cam because it has a huge amount of grunt right off idle, I would think with that type of cam it shifted the torque curve down low. It feels as if all the power is from idle to 4500-4800 RPM.

 

[Jimboslice751]

That sounds like a stock cam

 

[Black4VPower]

It has a lope at idle and I can feel the car shake a little when stopped in traffic or anywhere, that's why I think it may have a small cam. I think I am going to bring it to my dyno tuner just to make sure the tune is ok if it even has one or to see if he can diagnose anything else, if anything is wrong. I would rather know than drive around wondering if the car is ok.

 

[Black4VPower]

Car is going on the dyno next week but before I take it I am replacing the fuel filter and the plugs with the ones the dyno tuner recommended to me along with the proper gap. I am hoping it just needs a better tune or worse case scenario a better fuel pump......For what its worth it has 42 pound injectors and does not have A FMU or boost timing retard if it makes a difference.

 

[ashleyroachclip]

42 's in them selves , without supporting mods , are a bit big.

Stock red line is 5260 rpm. Controlled by the computer.
Factory tach , not real accurate.
Car shaking at an idle, not indicative of a cam, may be sign of a problem.

Not only would I replace the plugs, but also the rest of the soft parts that can be old and a problem.
Plug wires, I use Taylor's , you can cut to your desired length, and make sure the wires are not routed near hot surfaces, and sharp edges.
Distributor Cap and rotor,
Vacuum lines, to eliminate leaks, and air filter.

Just some things that will need to be checked and addressed , that is you do before going to the tuner, will save you money and head aches.

 

[Black4VPower]

Once the idle settles down you can hear the lope, when I first start the car it idles high and you don't notice it but once the idle settles down I can hear the lope and feel the slight shaking. The whole factory cluster has been changed out to all Autometer gauges so I would think the tach or at least hope the tach is more accurate.