Thread: 88 Chevy TBI - Hesitating - need help

Tweet

^^^^^^^^^^^^^

^^^^^^^^^^^^^^^^^^^

How long has this been happening? What has been done to try and fix it? What is the fuel pressure? Have you taken a fuel sample? That truck should have Electronic spark control...is it working correctly? What is the intial timing set at and what is total? Does it have an EGR valve? If so unplug it and see what it does.

Need some more info............on your part

Sounds like timing. Set it by the manual, There's a plug on the firewall that must be disconnected to get the timing right. They will run with the spark off a whole lot, the computer compensates for it, but the maximum advance just isn't there if the dist. is off.

^^^^^^^^^^^^^^^

I think your reading the timing incorrect. I think it should be around 8-10 intial.32 is way too high. When it bogs or hesitates does it backfire or just not take the fuel? Have you checked for an exhaust restriction? Converter plugged? What is your vacuum reading at idle and 2000 rpm? Also what do the plugs look like? and have you look at fuel pressure while under a load not just at idle? How does it run at highway speeds?

^^^^^^^^^^^^

hay there ffm a vary comon problem tn these tbi set ups is the throtle body only has 3 bolts holding them down and they use a vary thin paper gasket if you pop the tbi I bet you will find the gasket burned and dried up vary comon problen on these eng. all the symtems fit give it a try ted

Originally Posted by ted dehaan

hay there ffm a vary comon problem tn these tbi set ups is the throtle body only has 3 bolts holding them down and they use a vary thin paper gasket if you pop the tbi I bet you will find the gasket burned and dried up vary comon problen on these eng. all the symtems fit give it a try ted

That usually causes a High idle issue...Not hestiation.


As for looking at the vacuum, using a vacuum gauge is the best way to tell condition of an gasoline engine. Try and get one and report back....Or take the vehicle to a good automotive repair shop and have them diagnose it instead of throwing parts at it

^^^^^^^^^^^

Originally Posted by FFM

fuel pressure is 8 psi, been happening since I put this engine in. It has same specs as old engine though, same TBI, electronics, etc. All vacuum lines are hooked up properly fuel is fine, clean, new fuel filter. spark control working fine. initial was set to 32, and with it plugged in the cpu advances 4 degrees. totaling 36 degrees. has egr, havent tried unplugging it. will try it.

You need stock timing and 11-12 psi for fuel pressure. Then you can start tunning your computer, very easy. Your stock fuel regulator is also adjustable.

Originally Posted by BigTruckDriver

You need stock timing and 11-12 psi for fuel pressure. Then you can start tunning your computer, very easy. Your stock fuel regulator is also adjustable.

Clue me in on how you "Tune your computer" Never heard of that before

Cam is you biggest problem.... Because the Map sensor is not getting enough vacum reading... It need shortest cam overlap before it will run right on the computer.

Bigtruckdriver is right about the fuel pressure, it's too low. Might want to check your fuel pump.

Originally Posted by FFM

^^^^^^^^^^^

looks like the guy...bailed on everyone after finding out the answer