Hi guys,I have a 1989 4.3 liter. Yesterday after work it wouldn't crank,just turn. This morning it fired off beautifully,drove 30 miles,cut off,fired again. Then it wouldn't fire anymore. I'm getting spark and I have no check engine light so I suspect fuel pump. I've got a fuel pressure gauge but have no idea how to properly test it. What is the proper fuel pressure I need to look for at start up and then leakdown? Basically what's the number I need to look for to be able to either know or not know it's the pump? Also if there's a specific way/method to test it other than hooking it up and hitting the ignition. Thanks in advance and god bless. By the way I do have the adapter needed to make a test port

 

Get some carb cleaner and spray it into your intake as the vehicle is being turned over (dont use starting fluid, it is VERY volatile and could ignite if you have a spark issue on a plug wire)
If it tries to start or does start for a second while doing that, you than know that it is indeed most likely a fuel issue. If it does not try to start or start for a couple seconds the issue is not the fuel and it is in the ignition system.

 

If I've got spark then what else would be a culprit without setting off the check engine light? I think it's important to add that I'm on the third fuel pump in two years that I got from Oreileys. So it wouldn't be shocking if it was the pump.

 

What brand pumps? pretty much the only good ones out there are acdelco or delphi. Airtex, spectra are crap

 

Pretty sure it's a Delphi. Whatever oreileys knock off is. I've put three in in a two year span,so it wouldn't surprise me if it were the pump. But I don't want to replace the pump if it's not the culprit

 

is your tank dirty maybe?

 

Ok so here's the update.....I got it to fire off with the carb cleaner. While its runnining it runs great,no hesitation,no sluggish acceleration or rough idle. Some days it'll crank and run like it's supposed to. But every now and then it'll only crank with the carb cleaner. I've checked both injectors and they're both firing normal. I'm guessing its going to be the fuel pump that is the culprit.

 

Hi guys,I've got a head scratcher! 1989 4.3 liter will only crank using starter fluid. It runs great while cranked,no skips or hesitation and great response to accelerator. I've replaced the pump and filter but still no change. Every once in a while it will start on It's own with no fluid after a short period of time after I shut it off. I took the AIC off and cleaned it,checked vacuum lines and connections and still no change. I also took the ignition coil off my other s10 and no change. I'm completely stumped on this one,anyone got any suggestions?

 

I'm no mechanic but when mine did this I put Seafoam in a tank of gas and took it out for an hour long drive. No problems since then.

 

Sounds like fuel pump is not being pulsed (primed) by the ECM for the 2 seconds after the key is turned on, but fuel pump does come on with oil pressure and stays running when you start it with another source of fuel. Why this would be? not sure on an 89. would have to look at wiring schematics.