Not starting cold unless using starting fluid

I put a fuel pressure gauge on it, turned the key to on and have 60 p.S.I. I then turned the key off and checked and at least 5 minutes went buy and the fuel pressure was at 55 p.S.I.. I then turned key on with out starting and fuel pressure went back to 60 p.S.I. I then starting cranking and pressure was 57 p.S.I. And would fire up for a second and then die. I did this about 10 more times and waited each time for the relay to click when fuel pressure built before cranking and each time it acts like it wants to start, but doesn't. When it finally starts, I can shut it off, and it will start right back up. There is something about letting it cool down after running it that it doesn't want to start. It runs great once it is started also. You just don't want to go somewhere long enough to let it cool down while you are there, or it doesn't start. That's where a little shot of starting fluid does the trick and starts right up and away you go. This thing is killing me.

This has a digital gauges and the gauge panel goes dark while cranking so I really don't know what oil pressure is while cranking. I just had a chance to look at it some more yesterday, its outside right now and weather kept me from messing with it. It didn't even want to start at all even after numerous times until I shot it with a little starting fluid and I actually drove it all over with no starting problems through out the day. I think you might be on to something with the oil pressure sender though. After it had cooled down and temp was at 30 degrees, I turned the key to on and had noticed the temp gauge was maxed out fuel pump came on, fuel pump relay clicked and it did not start, then turned the key to off and back on, heard the fuel pump come on, fuel relay clicked, and it started. It was 40 degrees out today, tried starting, and it fired right up on the second try. While it was running, I pulled the fuel pump relay, and it killed it. I thought I read somewhere it should have stayed running when pulling the fuel relay because the oil pressure sender keeps voltage going to the fuel pump in case the fuel relay goes bad, it just doesn't start again when shut off. I bought a oil pressure sender today and going to install and see what happens. It started 5 or 6 times throughout the day today with no problems, but I'm hoping changing the oil pressure sender does it. Thanks again, I'll let you know.

I've changed the oil pressure sender after the brass elbow it was attached to broke off and made one more thing to fix. It started right up and ran fine, but it was also 60 degrees outside. This morning it was 33 degrees outside and didn't want to start again right away. On first crank it just turned over with no wanting to start, I heard the fuel relay click, fuel pump on, and tried again and it started for a few seconds and died. This continued for about 10 more tries and then it started right up and ran fine. After it ran for about 20 seconds, I shut it off and then tried starting right back up, and it started great. I haven't messed with the egr valve, or changed the fuel pump relay. I do have about 50 p.S.I oil pressure right away when starting, even when it only runs for a few seconds, which reads higher now then before changing the oil pressure sender. I also have a 1994 s10 Blazer which is identical set up as this one and it takes a couple of times maybe when it gets cold out, but not 10 or more times. I checked again also for codes, and nothing.

The spider injector I installed was a reman unit, and I have another 1994 s10 BLAZER that has the same spider and no problems. The problems didn't start on this S10 Blazer until it set about 6 months without being driven daily, and before that it run and started perfect. Since changing the oil pressure sender I noticed that if you just get in and turn the key without letting the fuel pressure build and wait for the fuel relay to click, it will start right up on the first couple of tries. If you let the fuel pressure build and wait for the fuel relay to click and then try starting, it doesn't want to start unless you cycle the back to off and then go right to trying to start it. Maybe its the fuel relay? I also read maybe it could be an exhaust system plugged.?

I always kept between 1/4 and 1/2 tank of gas in it but would drive it enough each month to run this out and put more in. If I think maybe that it will be sitting awhile, I would always pure in some stabil, but it probably would get used up driving it once a month. I'm a real believer in using Lucas fuel additive also, and have had at least 4 trucks go to 150,000 miles without a fuel pump change or any running or starting issues. I will check voltages to the relay again, look at that socket and will change that relay today. I used it to do a run into town last night, 25 degrees out, and I just jumped in and turned the key to start quickly without let fuel pressure build and it started on the 2nd try doing this. One other thing started since changing the oil sender unit is that when slowing down to a stoplight or something, just before coming to a stop, it acts like you hit the kill switch just enough to act like its going to die for a split second, but doesn't, and will only do a couple of times when out driving. Thanks for hanging with me on this Steve.

What do you think about the plugged exhaust idea?

After changing the oil sender unit, it did start better but only if you didn't let fuel pressure build and hear the relay click. And after changing the oil sender it started to get little mini stalls sitting at a light or maybe slowing to a stop, and also noticed that it would do it when the oil pressure would drop at a lower rpm like coming to a stop or at idle. With your idea about the fuel pump relay and reading an article about those relays can cause these little mini stalls but will still allow the vehicle to start and run, , I changed the relay, and it runs great now, and starts like it should. Wow! I believe it was the combo of the oil sender and a barely working fuel pump relay.