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Discussion Starter #1
I have been having a quite a few issues with my 1990 chevy k1500. Its got a new engine, and and all sensors on the engine are new along with the spark control module, cap rotor and wires. The problem im having is when its cold it will start up just fine but after it is warmed up and shut the engine off for about a half hour to an hour it will crank fire once and then die right away and then wont start until i unplug the temperature sensor. then it will fire up with a little persuasion.
 

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It's possible that your temperature sensor is bad out of the box use an ohm meter to test the specs should be available in your mitchel manual or from a dealer.
 

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Discussion Starter #5
ive replaced it twice thinking that it might have been a bad sensor and it wasnt ill check the ohms through the sensor tommorrow ive also tried to trace the wires back to the computer but didnt find any spots where it might ground out
 

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Discussion Starter #6
i was thinking that maybe the chip in the computer it self could have dust in it or isnt getting the connection it should have what do you guys think this is a good possibility
 

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Discussion Starter #8
i believe its not getting enough fuel when im trying to start it up the exhaust dosent smell rich or anything
 

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It sounds like it's too lean.
When you unplug the temp sensor it adds fuel and allows it to start.

You should read the TPS voltage at idle and slowly open it up and watc the reading.
You should be at about .54 volts at idle and increase to almost 5V at WOT.
It should go up smoothly not jump around.

If the TPS is too high then it will go into clear flood mode on cranking and reduce the fuel amount. Causing a hard start. Of course the temp sensor can also cause the problem if it reads too high a temp.
If too low of a temp you get extra fuel...rich/flood.
 

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Discussion Starter #10 (Edited)
i checked the throttle positioning sensor and it gave me some weird readings. at idle it was 3.17 volts and as i pressed the thorttle down the reading went down to 2.25 volts. The thing is its a brand new sensor. i think ill replace it this weekend and see if it helps. thanks guys.
 

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Make sure your 5V is good and that you read near 0 ohms to ground on the other.
 

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Discussion Starter #12
ok i check the 5 volt reference its fine 5.0 even and the ohms are 0. but i double checked what i did the other day and i checked the blue wire to the black wire and it was correct i think i did it wrong the other day. i think that the tps is fine. any other ideas
 

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Do you own a lap top?
Can you solder?

If so then you can pick up about $6 worth of parts from radioshack and make a data cable to record the data from your engine anytime the key is on.

You can also download the winaldl program for free.
That is the easiest way tosee what is happening. (see sig)

You can also read the voltages at the map sensor. It's output is also used to determine fuel.

How about fuel pressure? have you stuck a gauge on it to see if it's good at idle and while revving the engine? Should stay the same.

When did you replace the fuel filter last?
 

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Discussion Starter #14 (Edited)
well i do have a laptop which connectors do i need to hook it up to laptop. i have stuck a fuel pressure guage on it and it was fine. I replaced it when i put the fuel pump in. then about a month later. its only been a couple weeks. when you put the wire together from the obd port to the 9 pin connector do u need to have a 12 volt power supply.
 

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did you go to the FAQ's in the FI forum link in my sig?

It's all step by step from making the cable to viewing the data.
Even programming a chip if you get that far.

And what are you calling fine?
 

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Discussion Starter #16
today i had a mechanic come out and help me out with it we hooked the dignostic scanner up and the only thing that was off was the tps. I put the stock one back on since it still worked fine we got it to be at .55 at idle and it works smoothly rest of the way. and that fixed its rough idle but as for the tough starting when its warm it didnt help any. i have him checking to see if he can think of anything that might be making it do this. The fuel pressure was right around about 11.5 psi. thanks for your help if you have any more ideas please let me know.
 

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11.5psi is at the bottom of normal--11 to 13 is factory spec.
 

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Discussion Starter #18
I looked at autozone's website and it said that anything between 9-13 psi was in operating range
 

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Goes to show you, don't always believe what you find with Google.
You are correct, according to my GM '94 C/K Truck motor manual.:D
 

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Discussion Starter #20
does anybody else have any more ideas i cant think of anything else. Unless the fuel regulator isnt right but i replaced it a couple months ago.
 
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