It used to run beautifully but it sat for about three months and now it wont stay running. When first starting it wont turn over but once you get it to it will not stay idling. If you continually rev the engine it will stay running but it wont idle or stay running at a rev either. The injectors are spraying beautifully and the IAC was replaced. We have also tried using octane boosters just in case the fuel was too old. The spark plugs are fine and there is no sound of misfire. It sounds beautiful when its running. We are running low on ideas so any help would be appreciated.
Use a gage and check proper fuel pressure. With tbi fuel injection, the fuel pressure is 9--13 psi. I have seen fuel injector spray pattern that looked good to me, but, the fuel pressure was half of what it should have been. 5 psi may show a good spray pattern, but, it won't start and run a v8. In my opinion.
Any applicable trouble codes? Your obd1, you should be able to check some codes yourself, if there are any.
SOURCE: I have a 1988 GMC Sierra 1500 that wont stay running
fuel pump,fuel pressure regulator, or vaccume leak,
may also need complete tuneup,or as a last shot the timing gear could be a tooth off
SOURCE: Treated gas for moisture. Got high octane additive.
Even a small amount of bad gas can cause your problem.
So the first thing you need to do is remove your fuel tank so you can drain all of the old fuel out,then remove the fuel sending unit and fuel pump assembly thats in your fuel tank and clean the filter screen, after that you can reinstall the fuel tank,replace your fuel filter and I would have a fuel injector sevice done.
Unless you are very skilled in automotive repair, leave this one to a pro.
SOURCE: I have a 1988 GMC Sierra 1500 that wont stay running
1988 gmc runs for a little but dies. Check your c.t.s that checks the temp. of your coolent and when it fails it tells computor engin is hot, t.p.s takes over closes butterfly and chocks the air to keep engine from runnin to lean. If engine is not hot it will flood and stop runnin then some time will go by befor truck tries to start. May not be probablem but its a thought. c.t.s is located on manifold by top radiator hose neck. My truck was fine than sat had simmilor problem when i went to use again thats what i changed and seems to be back to normal. Hope this helps.
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