throttle body ignition question
 

hi,
i have an 87 chevy c10 with a 350 and throttle body ignition. on cold starts the motor has to turn over four or five times before it actually starts. warm starts it fires right up. the motor runs well otherwise. it's got 120,000 miles.
the throttle body has been rebuilt and i installed a rebuild kit. i was wondering if this cranking problem could be a caused by a leaky check valve. does the fuel pump have a check valve built in? should i consider installing a new fuel pump?
thanks

Re: throttle body ignition question
 

fuel pump could be getting weak. upgrading to a tpi (camaro/firebird) or vortec (96-02 gm p/u) is a nice upgrade and a "drop in". other thing to check is the fuel pump relay, if it has failed long crank times are common because fuel pump power is fed through a +3psi oil pressure switch ie: oil prssure needs to build so switch can close. once you have these sorted another mod is to braze up the pressure relief port that is under the regulator. you will have to disassemble the injector pod to get to this. i recommend getting a TBI gasket set (ac delco makes one). the injector o-rings need to be sound or the fuel pressure will bleed off and negate the mod.

i know this is a lot but you can also mod your stock regulator you want to aim for 13-14.5.psi. the factory spec "9-13" is BS. if you cant achieve this you can put a washer under the regulator spring.

Re: throttle body ignition question
 

hi,
thanks for the response. i did put in the gasket kit and a new fuel regulator. didn't have the nerve to add a washing under the regulator spring.
on a new pump, i've heard of installing the pump inline with the fuel filter, outside the fuel tank. (to save the trouble of dropping the tank.) any thoughts on whether or not this is a good idea?

Re: throttle body ignition question
 

im not a fan, they are noisy and don't last as long as a pump that lives most of its life submerged in fuel. i don't see what the big deal on dropping the tank is? drive around until empty, a few bolts and lines and the tank is out. if the tank is empty i just lower by hand and reverse for install. if you decide to replace the pump make sure to install a new sock/strainer.

Re: throttle body ignition question
 

ok thanks. i've changed the in tank primary pump on several volvo 240's over the years. you don't have to drop the tank for that though.

Re: throttle body ignition question
 

ON cold start, the ECM fires the fuel pump for 2 seconds, then once the oil switch sees pressure it powers the fuel pump. Major fuel drainback, failed relay or wiring, or a weak pump can cause the issue. My trick was turning the key on but not cranking, have someone listen for the pump running, if it doesn't, the relay or wiring is an issue. A way to overcome the fuel leakdown or weak pump is key on but do't crank for 2 seconds, key of for 2 sec, then key on for a second then crank. Basically get 2 cycles of fuel pump priming.

Re: throttle body ignition question
 

sorry for the delay replying. the problem was the relay. thanks to all for the info, sure is great to be able to come here fro advice.