What am I doing wrong? A few questions

[sweet88gt]

I cannot get this car to have any driveability whatsoever. I have narrowed it down to a few possible issues.
#1 how much does the computer (A9L) try to compensate for difference in clyinder pressures?? I have a high mileage 302 stock bottom end with whats in my sig below. Nothing too major. I did a compression test awhile back and had 2 cylinders that were within the % of spec but were lower than the rest. If I recall all were about say 120-130 and the other two were 108 ish. I am right on the within spec? Would the computer try to do different things to compensate for the differences and cause issues?
#2 How accurate is the intake temp sensor?? I just finished up install of a 2 core Procharger intercooler and took it for a spin. I have a LM-1 installed with rpm converter and with 1 of the channels I am recording intake temp. Now I live in FL. and it is hot and humid toady, but didnt see any difference in intake temp before and after? The sensor ohms out within its working range.I do see a difference when the methanol is injected. Intake temps around town with the intercooler were 220*. I just dont know if that is too hot causing the computer any issues? By the way on the smallest setting with methanol the intake temp reads about 180* after a full throttle long pull, say on the dyno. This was without the air to air intercooler installed. Thanks

 

[LEE93COBRA]

According to my EEC (via Tweecer) my intake air charge temps are around 150 most of the time with my 3 core procharger setup. If you are seeing that high of IA temps then your EEC is probably pulling timing.

What is your LM-1 showing on a/f and what are your timing settings.

Oh and your compression is low. You should average at least 140 on all cylinders on a stock motor

 

[sweet88gt]

A/F ratio is all over the place. It will even jump a little at idle from say 14.3-15.5. I beilive this is normal becuse of the constant changes the computer makes. At different times the A/F will range between 14.0-16.0. At the 16.0 range the car sputters and this is when the driveability sucks the most.
As far as the intercooler I dont know what to do?? I have had readings of 230+ * before. I am assuming this increase of intke temp is due to the car running lean during cruise. Like I said before is will range the A/F and doesnt run lean at WOT.
Low compression is what I thought, but was grasping at straws. It leaks some oil and seems to be having some blow by more than it used to. I know what I have to do, but hate doing so at this time.
Timing is set at base 10* but the tuner made cahnges in the chip of unknown timing adjustments.

 

[Dayzed50]

It seems from your a/f readings that you are running extremely lean. Cruise a/f should be between 13:1 to 15.5:1 at the most. Under full throttle it is considered unsafe to run any higher than 12.5:1. If you are higher than 14:1 under throttle you may be experiencing insufficient combustion and/or lean detonation. Sometimes high a/f readings can be caused by vacuum leaks.

 

[sweet88gt]

When under part throttle I see the numbers as stated 14.0-16.0. This is trying to keep a steady pace. WOT I see 11.8-12.5. I havent realy studied the WOT A/F mainly because I havent gone to the track recently.
I also havent checked for vac leaks in awhile. Maybe Ill give that another shot. I have checked before but never could find anything.

 

[jrichker]

Pin 25 ACT signal in. At 50 degrees F it should be 3.5 volts. You can measure at the computer if you use pin 46 for a ground.


It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.

Pin 7 ECT signal in. at 176 degrees F it should be .80 volts. You can measure at the computer if you use pin 46 for a ground.


The ACT & ECT have the same thermistor, so the table values are the same.

Here's the table: The values are +/- 15%, so don't get worried if your readings vary a little bit.

Voltages are measured across the two connector pins of the sensor with the sensor connected. You can measure at the computer if you use pin 46 for a ground.
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms

 

[sweet88gt]

I have ohmed the sensor recently and is in working order. Is the voltage test a more accurate way to confirm the sensor? The sensor is in the lower intake instead of the air inlet. I have a newer style mass air meter with 6 pins from Pro flow ( old Pro M). There is an additional sensor mounted in the meter itself. Would this be a intake temp sensor I could use for more accurate inlet temp readings? How would I hook up such a senor -- delete wiring from original sensor in lower intake and transfer wiring to meter mounted sensor??

 

[sweet88gt]

So I thought I would check ohms again to see what they read.

Inlet temp sensor= 27.9k ohms

Coolant temp sesnor= 26.1k ohms

In my garage car sitting overnight approx 80* air temp. I thought the orginal intake temp ohm was incorrect so I ohmed the coolant temp and have a different reading. Is this of any concern, or are the values within range??

 

[LEE93COBRA]

One thing you need to remember is the IAT and ECT are different sensors and measure 2 different things, so they are not going read the same. Also engine temp should NOT have that much effect on the air temps coming into your engine. It almost sounds like you intercooler is not doing its job OR you have a leak in the piping and it drawing engine bay air into they system.

By the way, where is your air filter located? In the driver's side inner fender?

16:1 is way to lean for your car to run effectively.

 

[sweet88gt]

The ACT & ECT have the same thermistor, so the table values are the same.

Here's the table: The values are +/- 15%, so don't get worried if your readings vary a little bit.

I have always thought these two sensors have the same values, even though they measure different items.

The air filter is in the drivers side fender. As far as the a/f I dont know where to start anymore. I had the chip burnt and it took forever to get it to were its at now. It must have been at least 20 dyno pulls. I changed the items I was told were the problem but still no luck. This driveability problem has been here since I bought the blower and hasnt gotten any better. The funny thing is when the tuner does what he needs to and I take it for a drive- around the area of the tuner- it does fine. I take it home which is about 30 mins away and it starts to run like crap again. Followed by me getting bent out of shape. The tuner has reburnt the chip 3 times at no cost but he is about done with this car. He has put into tuning this car about 30 labor hours.

 

[sweet88gt]

One thing to add, what about spark blow out?? How can you tell if this is an issue?? It doesnt break up at WOT. The plugs Im using are 2 stages colder than stock.

 

[LEE93COBRA]

The car basically cuts off when you have spark blow out at WOT. Temp ranges of the plugs have nothing to do with this. Its the spark plug gap that you change when having spark blowout.

What exactly are your drivability issues other than high IAT's

 

[sweet88gt]

Driveability is the everpresent surge and sputter only at cruise or part throttle. Now I have gone through the checklist of items very carefully. I have checked the items 3 or 4 times and have had a friend go through the steps with me. WOT no hesitation or problems there. Any help would be great. I have even thought about taking it to someone that deals with mustangs. I would even drive long distances if I thought someone could for sure fix it.

 

[sweet88gt]

Does anyone have any thoughts about the difference in ohm readings on the air charge sensor? I have checked the sensor before and no problems. In my other post I found a small change in the sensor readings. Air charge temp sensor was reading of 27.9k ohms which is about 85*. Air temp in my garage was close to 80*. This reading was after the car sat all night. I have not checked it when it was at operating temp. I assume this is the reading the computer is recieving and is contributing to my problem. Is this an acceptable reading +/- % wise. I know all sensors vary, or is this one crapped out?

 

[LEE93COBRA]

+/- 5 degrees on your ACT sensor is not going to cause driveability problems.

Have you verified there are no air leaks in the incoming air piping after the MAF