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No cold start - rpm drops when slowing

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Old Oct 29, 2009 | 10:04 AM
  #1  
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No cold start - rpm drops when slowing

I put a tpi from an 86 camaro on a 350 bored 60 over, with a mild cam and headers. Ever since putting this on the engine I have basically had the same two issues - it will not start when cold (air temp) and when slowing (stop signs or whatever) the rpm's drop to 400 or lower. I've replaced the cts, iac, tps and have reset them. Replaced the ecm, no difference (was lucky to have the parts store take it back). Once the engine is warm, it will start fine, and run fine - except for dropping the rpms. Pulled the plugs, they are fine. All the sensors are new. A mechanic tried a new maf sensor, with no change. Why will this not start cold, and does so when warm? Are the two issues related? I hope this is not one of those repeated questions... I searched for answers before listing this thread. thanks so much - kip
ps- opening the throttle will start the car when its cold, and it idles and runs terribly, and of course opening the throttle picks up the rpms when they drop. Is this a too rich issue?
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Old Oct 29, 2009 | 01:12 PM
  #2  
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Re: No cold start - rpm drops when slowing

UPdate: I checked the fuel pressure this afternoon. With the key first on, the pressure went up to 40. With the key still on (engine not running) the pressure started to drop like crazy. Within three to four minutes, it was down to the low 20's. I pulled out the ninth injector, and it was dry. With it out, I got the pressure back up to 40, and watched to see if any fuel came out - none. Is the only option left to tear this tpi apart again, and see if any of the other injectors are leaking? I can not see fuel leaking anywhere else, nor smell it. Any other reasons for the pressure to drop like this? thanks - kip
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Old Oct 29, 2009 | 01:58 PM
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Re: No cold start - rpm drops when slowing

OK, this time I got the pressure back up to 40, crimped both the fuel lines and its holding a steady 40. It appearently was dropping back through the return line to the tank. So, still don't know what the issue is. Any ideas???
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Old Oct 29, 2009 | 07:43 PM
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From: N. Illinois
Car: 92 GTA/ 00 TA
Engine: 383/350
Transmission: 700R4/T-56
Re: No cold start - rpm drops when slowing

If the pressure holds when you crimp the return line, it only leaves the regulator as the problem.
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