[Billy33]

Hard to crank with a rough idle. Seems to be flooding. We have already tried injection cleaner. When cold it will crank up and run fine but when it get warm starts cutting out and idles real rough. Need help.......Thanks

[1st & 2nd GENGuy]

Should be able to get trouble codes from the computer.

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68SS ZZ4, 4sp T-10, 12 bolt, getting painted

78Z28, 330hp vortec, TH350, 10 bolt (just finished)

[Billy33]

We got information off the internet telling me how to jump the pins and the "12" flashing code and came up with 5 flashes after the "12" which gave us code no. 17 I think. Please tell me if I am doing it wrong? But 17 seems to be unlikely "RPM signal malfunction". Any suggestions?

<BLOCKQUOTE>quote:</font><HR>Originally posted by 1st & 2nd GENGuy:
Should be able to get trouble codes from the computer.

<HR></BLOCKQUOTE>

[davidpozzi]

What is the fuel pressure doing? You may have a bad pressure regulator.
The code is flashed like morse code. 5 flashes can not give a code of 17. That would require a flash of 1, then a pause, then seven flashes. That is a total of eight flashes!

Take note of where the pause is, how many flashes before, how many after?
The first code is for no distributor signal. This is because the engine is not running. I think it's 42 and repeats 3 times, then any trouble codes, then repeats 3 times again.

[This message has been edited by davidpozzi (edited 02-21-2000).]

[camaroguy]

I would bet it is either the MAF sensor or lack of fuel pressure. The code will be 34.
Please check fuel pressure first. I learned the hard way by going out and buying a MAF first. It ended up being my fuel pump. The MAF was reading lean and telling the computer that it was the problem. I've owned several tuneport's and it's always been one or the other.

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67 SS
70 Z/28

[Goose]

I've got a '90 IROC 305 TPI and have had some of your same problems. I had only one malfunction code which indicated a malfunctioning oxy sensor. I replaced it, but problems remained. I then checked fuel pressure and found only 20psi. I was able to rule out the fuel regulator. Now the fun begins.

[davidpozzi]

If you have to pull the tank, get the rear as high as you can. The filler neck is very long, and one piece attached to the tank. Buy a new sock screen for the pump.

[Billy33]

After figuring out the code, thanks davidpozzi, I got a 15,22,33 and 34. After checking the fuel pressure I'll move on to the MAF.

[davidpozzi]

15-coolant temp low
22-throttle position sensor signal voltage low.
23-manifold temp sensor circut low
34- map sensor signal voltage low.
Check your grounds, the engine and computer. check bat voltage. All these circuts can't be bad.

[JimM]

right u r David. All these are in the same harness. I bet they use a common ground or power wire, which is no longer grounded (or powered). Time to get a schematic.

[Jay621]

try lowering your idle also check your timing and make sure you vacuum hoses are in the right place

[bighaas79]

i could be wrong but don't all those pull off the same 5 volt ref feed?

[Oldrocker]

Originally Posted by bighaas79

i could be wrong but don't all those pull off the same 5 volt ref feed?

They don't according to the wiring diagram, but it would be a good idea to check the 5 volt reference to the MAP and TPS and check the computer grounds. The temp sensors only have a signal and ground. If you don't find any bad grounds, my bet would be a bad computer, but I wouldn't replace it without confirming it first.