Start, no start, start no start

[gmhowe]

My 85 with less than a 1000 miles on the new engine has its own issues. One day it will start up fine after 2-3 tries and then next day will drain the battery cranking but no start. go back a couple of days later and it will start again after 2-3 times then next day crank till battery is dead. Has a new fuei pump in it also. Driving me crazy since my 96 CE is in the body shop when some JO decided not to make a left turn and backed his trailer hitch into the front of it.
any help would be appreciated
Gordon

[tonylong]

Did the new engine include up to date injectors (Bosch design III), or original type multec's? I ask because the multecs are not ethanol tolerant and they can rot their o-rings on ethanol and give starting and other running problems.

[vetteboy86]

You need to evaluate the situation systematically. Identifying what is going on when the motor will not start will allow you to fix what is going on. Next time you have a no start condition, check for adequate fuel by doing a pressure test, and also check for adequate spark. Either one of the two isn't happening.

[CAJUN C4]

Change / Check the Ignition Module and Pick up Module in Distributor

My 84' did the exact same thing.

see http://www.autozone.com/autozone/cat...&parentId=62-0

Very Much Overlooked Part.


Good Luck

[gmhowe]

Ok got it running with new fuel pump, checked fuel pressure it slowly climbed up to 48 lbs when running and turn it off it slowly went all the way back to 0 lbs. but it runs. I was told the pressure should jump up to the working psi and after turning if off would hold about 20 lbs.
And yes all new injectors were installed also, along with new fuel filter. and all the other stuff for rebuilding.
Just curious about the slow climbing while running and what would cause that.

[gmjunkie]

Ok got it running with new fuel pump, checked fuel pressure it slowly climbed up to 48 lbs when running and turn it off it slowly went all the way back to 0 lbs. but it runs. I was told the pressure should jump up to the working psi and after turning if off would hold about 20 lbs.
And yes all new injectors were installed also, along with new fuel filter. and all the other stuff for rebuilding.
Just curious about the slow climbing while running and what would cause that.

Fuel pressure on a 85-91 L98 should run 34-39 lb at keying up!!
If its building slow and it's reaching 48 lb you most likely have a faulty fuel pressure regulator or restricted fuel return line!
Maybe Both!

[Paul W. Sammarco]

Hey, folks - I'm new here. Could someone please tell me how to start a new thread. I have a problem with the headlamps. I'd like to post it and see if someone can help bail me out. Thanks. Paul

[vetteboy86]

Hi There, Welcome to CAC

Navigate to the C4 Tech and performance page, and near the top of the page should be a button "New Thread". Click this button and you will be able to create a new thread, very much like posting a reply like you have already done.

[gmhowe]

Finally figured it out, it was the gasket under the Fuel Sending unit where it goes into the gas tank. Replaced it and all is better, thanx for all the help.
Gordon

[boomdriver]

Did you install the new sock on the new fuel pump? That screen is the first "filter" that fuel has to pass thru. A dirty sock will give intermittent run, stall, run symptoms.
Slow to build pressure sounds like a filter issue, or even a crimped line. It SHOULD build 35 to 40 lbs just by turning the key, and do that instantly. After shut down it should hold near normal pressure for as long as 1/2 hr...or even longer.

How was the tank access gasket effecting the fuel pressure? Is there another gasket that I've been overlooking?

[roger longman]

I can't figure that out either ! Roger.

[gmhowe]

Yes new sock on with the new fuel filter, I don't know how it was affecting it, but after putting on a new gasket all is better. The old one was pretty dried out, guess the rubber had finally crapped out.