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Discussion Starter #1
Hi All'
I'm a new member in this club and I have to start a thread right away since I have a lot of issues regarding a hesitation and lack of power on my 1990 GT.

I have a TFS 306 and so far I've been troubleshooting this issue for a while. Here are some of the settings I currently have:

No error codes from EEC IV, stock injectors, new MSD wires, new ECT and ACT sensors, Throttle body plate calibrated at 1 1/2 turns after 0.010", RPM set to 850-900, new EVR, EGR and Idle control valves, TPS set to 0.98 V., clean MAF, and fairly new O2 sensors, good fuel pressure.

This hesitation and lack of power happens only when cold start after she reaches normal temp. runs fine, she even runs fine after 8 hours of being sitting while at work. Please help me finding what the heek is going on. The only things left will be fuel filter, fuel pump, and maybe a vacuum leak? But.....Only at cold start???

Thank you, Nick
 

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Welcome to the Forums, I moved your thread here for help.
 

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welcome to the pages
 

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The Fox isn't so computer controlled that everything will throw a code... leave that for the S197 guys. :D At least with no codes, you know it's something mechanical rather than a sensor or other electrical.
It's common for our cars to be cold natured, I know mine is. Forget about getting in when it's cold and expect to go. Once the temp needle starts coming up, then it'll run ok... does that sound like yours?
 

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Welcome to the fourms.
 

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Welcome to the Forms:wavey

Are you getting any vacuum from the hose on your EGR diaphragm?
Does she idle fast on cold start and idle down on its own after it begins to reach operating temp? Your IAC bypass may be dirty/sticking.

Just a couple of guess...hope this helps some. :bigthumbsup
 

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Discussion Starter #7
Thank you all for the new ideas. I have vacuum at the EGR valve. I ran a test and replaced the EVR anyways just to be safe.

She used to run fine when I had the stock engine even right after cold start but with sooo many changes it acts a bit weird.

I agree that the problem must be mechanical like vacuum leak, etc.

Also another issue I have is that the temperature goes a bit high like 200-205 degrees. I have a 180 deg. thermostat, taurus fan with an FR15 variable speed controller, and 3 row brass radiator.

Any ideas why is getting so hot? (Maybe because I'm runing under-size pullies?) I used to have a griffin aluminum radiator and the temp used to go more or less the same. A few hundred miles ago I replaced the head gaskets because I thought one of them broke but didn't see any indications of that. I installed the heads with ARP studs for better clamping.

Please HELP, Nick
 

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Check these findings!!!
I called a Ford dealer but they don't have the valve in stock and it cost around $300.00 WTF!!! This is unreal, they charge whatever they want!!!

When I got home I applied a generous layer of high vacuum grease to the EGR shaft. This grease is good for temperatures well over 200*C. I used the grease on all the leaks I found during the vacuum leak smoke test. We use this grease at work on high vacuum precision equipment.

Also I found that the TPS was at 0.99 V but if I let the throttle go slowly to idle position the voltage was hanging over 1.0 Volt. So I adjusted it to get about 0.98 V at slow resting throttle plate (Worst scenario) I have to mention that I'm using a good digital meter.

Well this morning at cold start she was much happier (and me too), didn't have backfire and there was hardly no lagging between shifts.

I hope these tips help others dealing with the same issues. I'll keep working on it to better the cold start conditions maybe disconnect the battery so she can adapt to the new conditions, etc. and will post more good results (I hope!!!)


Nick
 
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