Head gasket compressed thickness affects this too .Question: Compression Ratio.
1) 308 cid block
2) stock design pistons
3) X307 heads w/58cc
4) stock camshaft w/1.72 rocker arms.
What's my compression ratio? Go!
Yes. The typical compressed gasket is about .040. I'm going with that.Head gasket compressed thickness affects this too .
Sent from my iPhone using my fingers while my auto correct makes me seem illiterate
Hoopty5.0 has been pretty helpful throughout this whole thread. One other factor is that we had to use 90 thousandths of Ford shims on the rocker arms in order to obtain compression. Without the shims the valves wouldn't close all the way. Everything works fine, but I'm scratching my head on that one. The pushrods are stock length, hardened from LMR.com.I believe @hoopty5.0 has a good formula for compression ratio. Maybe he'll chime in.
Hoopty5.0 has been pretty helpful throughout this whole thread. One other factor is that we had to use 90 thousandths of Ford shims on the rocker arms in order to obtain compression. Without the shims the valves wouldn't close all the way. Everything works fine, but I'm scratching my head on that one. The pushrods are stock length, hardened from LMR.com.
This was the case with either the stock heads we tried or the X307 heads which are on it now. I figured maybe the block had been zero decked so I called the builder. The builder said that he only decked the block 5 or 8 thousandths and put the reason on the X307 heads. I didn't tell him about the stock heads doing the same thing so I think he may be mistaken.
Anyhow, that's another variable.
This is what I'm thinking, but I can't get the builder to help, so here I am.Sounds like that block got decked before you got your hands on it. That's going to raise compression quite a bit.
That's understandable. Thanks for the input. Have a relaxing time!Sorry I've been unresponsive lately. I'm on vacation with very little service, but it sounds like your IAC may be bad. I'd start there before messing with vacuum lines
Thank you for the info. I'll have to work through it and digest it. It seems odd that:44/94 codes deal with the Thermactor air System, which to the best of my knowledge does not effect idle. You may have a leak in one of the vacuum lines that operates the control valves.
For reference, here is the code 44/94 test path;
Codes 44 & 94 - AIR system inoperative - Air Injection. Check vacuum lines for leaks, & cracks. Check for a clogged air crossover tube, where one or both sides of the tube clog with carbon.
Revised 21 Sep 2012 to correct the description of the process that sets the code and include Thermactor Air System diagram.
If you have a catalytic converter H pipe, you need to fix these codes. If you don't, then don't worry about them.
Code 44 passenger side air not functioning.
Code 94 driver side air not functioning.
The TAD solenoid/TAD diverter valve directs smog pump output to either the crossover tube attached to the cylinder heads or to the catalytic converters.
The O2 sensors are placed before the catalytic converters, so they do not see the extra O2 when the smog pump's output is directed to the converters or the input just before the converter.
The 44/94 code uses the O2 sensors to detect a shift in the O2 level in the exhaust. The smog pump provides extra air to the exhaust which raises the O2 level in the exhaust when the smog pump output is directed through the crossover tube.
When there is an absence of increase in the O2 levels when the TAD solenoid/TAD diverter valve directs air through the crossover tube, it detects the lower O2 level and sets the code.
Failure mode is usually due to a clogged air crossover tube, where one or both sides of the tube clog with carbon. The air crossover tube mounts on the back of the cylinder heads and supplies air to each of the Thermactor air passages cast into the cylinder heads. When the heads do not get the proper air delivery, they set codes 44 & 94, depending on which passage is clogged. It is possible to get both 44 & 94, which would suggest that the air pump or control valves are not working correctly, or the crossover tube is full of carbon or missing.
Testing the system:
Note that the engine must be running to do the tests unless stated otherwise. For safety’s sake, do test preparation like loosening clamps, disconnecting hoses and connecting things to a vacuum source with the engine off.
Disconnect the big hose from smog pump: with the engine running you should feel air output. Reconnect the smog pump hose & apply vacuum to the first vacuum controlled valve: Its purpose is to either dump the pump's output to the atmosphere or pass it to the next valve.
The next vacuum controlled valve directs the air to either the cylinder heads when the engine is cold or to the catalytic converter when the engine is warm. Disconnect the big hoses from the back side of the vacuum controlled valve and start the engine. Apply vacuum to the valve and see if the airflow changes from one hose to the next.
The two electrical controlled vacuum valves mounted on the rear of the passenger side wheel well turn the vacuum on & off under computer control. Check to see that both valves have +12 volts on the red wire. Then ground the white/red wire and the first solenoid should open and pass vacuum. Do the same thing to the light green/black wire on the second solenoid and it should open and pass vacuum.
Remember that the computer does not source power for any actuator or relay, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.
The following computer tests are done with the engine not running.
The computer provides the ground to complete the circuit to power the solenoid valve that turns the
vacuum on or off. The computer is located under the passenger side kick panel. Remove the kick panel & the cover over the computer wiring connector pins. Check Pin 38 Solenoid valve #1 that provides vacuum to the first Thermactor control valve for a switch from 12-14 volts to 1 volt or less. Do the same with pin 32 solenoid valve #2 that provides vacuum to the second Thermactor control valve. Turning the ignition to Run with the computer jumpered to self-test mode will cause all the actuators to toggle on and off. If after doing this and you see no switching of the voltage on and off, you can start testing the wiring for shorts to ground and broken wiring. An Ohm check to ground with the computer connector disconnected & the solenoid valves disconnected should show open circuit between the pin 32 and ground and again on pin 38 and ground. In like manner, there should be less than 1 ohm between pin 32 and solenoid valve #2 and pin 38 & Solenoid valve #1.
The following computer tests are done with the engine running.
If after checking the resistance of the wiring & you are sure that there are no wiring faults, start looking at the solenoid valves. If you disconnect them, you can jumper power & ground to them to verify operation with the engine running. Power & ground supplied should turn on the vacuum flow, remove either one and the vacuum should stop flowing.
Typical resistance of the solenoid valves is in the range of 20-70 Ohms.
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif
http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif
If you have a catalytic converter H pipe, you need to fix these codes. If you don't, then don't worry about them
Standard procedure to find and fix idles problems...
You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.
It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 200,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
The high idle with a delayed start after resetting the computer is caused by the computer relearning the sensor settings. When you disconnect either the battery or computer wiring connector, it clears the adaptive learning settings stored in the computer. Once it "learns" the sensor reading, it goes into closed loop operation where to computer uses sensor settings to control idle speed and air/fuel mixture ratiosThank you for the info. I'll have to work through it and digest it. It seems odd that:
Observation 1) It takes a few minutes for the high idle to manifest once the computer has been reset.
Observation 2) That unplugging the IAC brings the high idle down.
To be clear, I'm not arguing any points w/you. I'm just trying to think through the issue(s) and communicate it. I'm thinking about a vac leak too. However, if there is a vac leak:
Question 1) Wouldn't it always have an idle problem from "go?" Why would it take several minutes to manifest after an ECM reset?
Question 2) How would unplugging the IAC help with a vac leak (i.e., bring the idle back down)? I'm thinking there could be more than one issue, or there is one root cause which affects more than one component.
Again, my smog pump is by-passed and my crossover tube is only bolted up for visuals. The heads don't accept the tube. I do have the 2 front cats on my car. Any further thoughts?
Okay. Is that telling me that the IAC is bad (and maybe other things, too)? Hoopty suspects the IAC and so did I at first. However, the code 44 is throwing me a bit. I don't think that code is related to an IAC, but I can see where it could cause a high idle if the TAD is not functioning properly (i.e., improper or no vac). I'm just struggling to see where/how disconnecting the IAC could bring a vac loss/high idle down.The high idle with a delayed start after resetting the computer is caused by the computer relearning the sensor settings. When you disconnect either the battery or computer wiring connector, it clears the adaptive learning settings stored in the computer. Once it "learns" the sensor reading, it goes into closed loop operation where to computer uses sensor settings to control idle speed and air/fuel mixture ratios
The high idle is caused by the computer and disconnecting the IAC disables computer control of the idle. With the IAC disconnected, idle speed is determined by the base mechanical setting of the throttle.
If the TAD solenoid opens and instead of pulling a valve open, it sucks unmetered air, that could make a vacuum leak that would upset the idle speed and quality.Okay. Is that telling me that the IAC is bad (and maybe other things, too)? Hoopty suspects the IAC and so did I at first. However, the code 44 is throwing me a bit. I don't think that code is related to an IAC, but I can see where it could cause a high idle if the TAD is not functioning properly (i.e., improper or no vac). I'm just struggling to see where/how disconnecting the IAC could bring a vac loss/high idle down.
That is, unless, you are saying that if I have a faulty sensor/solenoid that could be causing a vac leak and not necessarily a bad vac hose. I'm still trying to understand this possible multi-concern issue, but are my queries making sense?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?