95 cHEVY 3.5L TBI cranks excessive when left overnight

n01tk · Post by **n01tk** » Sat Jun 30, 2012 1:17 am

My 95 C/K 3500 turns over 10 times or more if it has not been started in the last 12 hrs. Before putting key to start position, I wait 5 secs with the key in the on position ( can hear the fuel pump running) and then turn it over. Once it starts the one time it starts quickly and runs very smoothly for the rest of the day. Goes into closed loop when up to operating temp.
Tried noid light when cold and noid light flashes but not brightly ( how bright should it be?) New fuel pump, lines, filter, TBI, and tbs. Any ideas?

EagleMark · Post by **EagleMark** » Wed Jul 04, 2012 2:57 am

Really sounds like a fuel pump relay issue, but you can hear pump run with key on? Can you test for pump on at crank? If there is not enough power to trigger relay during crank then it will have to build oil pressure to trigger relay...

n01tk · Post by **n01tk** » Fri Jul 06, 2012 3:37 am

Have not got back out to garage to try this but I think this will be worthwhile test. Thanks for the reply.

n01tk · Post by **n01tk** » Sun Jul 08, 2012 6:09 am

Yes I can hear fuel pump running when key is in "on" position. I monitored voltage at pump when cranking, 10.5 vdc. This is what the battery drops to when cranking. Is this too low? It has a new battery which has a trickle charger continuously connected when in the shop. The voltage is 12.3 with key in on position, drops to 10.5 while cranking and up to 14.1 when running.
Another strange occurance is the fuel pump runs 22 sec when the key is put to "on" position. If I turn the key off, wait 10 sec and try again, the pump will run 22 sec again. (This maybe due to the truck having a hot fuel module, not yet sure.) Any other reasons why the ECM would increase this prime time, the fuel pressure is @ the TBI in one sec. (11psi)?

EagleMark · Post by **EagleMark** » Sun Jul 08, 2012 8:02 am

If it's the truck in your avatar chances are is has the hot start fuel module. This is not the reason for long crank times though.

Voltages are fine, 10.5 crank is not unreasonable, since tha battry is new maybe have them load test it? Could have a weak cell that is not showing up with 12.3 voltage.

But if the relay is old/worn/failing it could be turning off during crank. Then you would have to build oil pressure to energize fuel pump. Check power from relay to pump during crank and see if it goes off?

You may be able to check it at pin G of ALDL port.
http://www.gearhead-efi.com/Fuel-Inject ... 1331394709