Compression was great as of a few weeks ago. But thank you for reminding me to pull my distributor cap and clean it. It had thick white deposits on all of the contacts as well black on the (graphite?) post. After I cleaned it this morning, she fired first try under the same conditions that she was previously giving me trouble. I've done this a couple times over the past 6 months, seems like my distributor contacts are fouling too quickly. Any thoughts?

EDIT: A clean distributor help my new cold start issues but the problem is still persisting when warm after sitting a couple hours or so. Same issue of cranking, firing for a second then dying. Will start on its own but starting fluid makes it happen faster. Holding the throttle open does not seem to improve the starting but I will try it some more.

 

Going to order some parts so that I can hook up a fuel pressure gauge. Any thoughts/field tests in the meantime?

Still thinking of ordering some new OEM sensors. Whenever the engine is anything but ice cold, it has trouble finding the right idle on startup. Cold, it fires an immediately revs right to 1000RPM (edit: more like 1200 until its done with cold idle.) and stays there. Hot, when it does stay running, it fires and sorta slowly chugs its way up and eventually settles on 1000. Seems like if it hit it with ether right before a hot start it gets rid of the chug-a-lug. Don't know if that's useful info but there ya go.

 

Bryce - before wasting your money on new sensors, there are specs in the FSM for them. There is a temp sensor for the ECU, temp sensor for the gauge, and one for the cold start injector. Obviously the gauge one isn't causing you this issue, but I would pull all of them, clean the really well, and then test them. You can put them in the freezer for a bit, put them in warm water, and test the resistance of them as those temps.

I do not know much about the 3.0, but I assume it has an idle air control valve similar to the 22re. Do you get a cold idle? There are also tests in the FSM that involve pinching the hose from the IACV at cold to verify that it is working. I'd do those tests plus clean and test the sensors before just replacing expensive OEM sensors.

 

Cory do you know if the specs are the same for the 1988 sensors as the ones in the 1993 service manual? I know the array itself is different in my engine versus the one shown in the FSM. But thats good advice I will check the resistances when I'm home from visiting family. That and install a fuel pressure gauge. Today I got the chance to drive all day and stop for few hours at a time, I used starting fluid each time and never got a hard start so I suppose I'll see what happens with the fuel pressure gauge.

 

I have a little hesitation on mine under these same parameters. I'm also leaning towards injectors and/or fpr @ 265k on the clock. Let us know what u discover.

 

Revisiting because I finally got around to testing my fuel pressure. In spec while running and the regulator is in spec but the fuel pressure drops to 0 within 5 seconds of shut off.

Any advice here?

Its still is mainly only hard to start when sitting for a specific time (2 to 3 hours OR overnight) even though it never maintains fuel pressure when off. So I'm not sure what that means but maybe someone else knows.

 

Believe it or not, there is a spec on that: stay above 21psi for at least 5 minutes. http://web.archive.org/web/201003261...87fuelpump.pdf But that's not your problem. It might mean you have to crank a little more if you try to start it within 5 minutes, but even if that's the case it's so little you're not noticing it. I doubt anyone's truck holds pressure for an hour. (Mine will stay above 21psi for only about 3 minutes.) Why does yours? Probably a bad check valve in the fuel pump, or maybe a leaky FPR. But if you're getting the correct pressure numbers (at idle, and off), that isn't it.

No one has mentioned ignition timing. A timing light is only $30 and you should have one anyway. I'd check that. It COULD cause your problem.

 

scope, I see what you mean. I plugged the fuel return line to rule out the regulator and still got the same pressure drop, and I've tried a new fuel pump as well to rule out a check valve issue. In my mind whats happening is the injector(s) are leaking into the engine and when hot, enough of the fuel is vaporized to keep dry and when sitting overnight it also has a chance to dry out. I think this is why i have a "lukewarm" start issue. I have a timing light and have checked a number of times. I have also checked valve timing and that is good too.

 

I once "feared" leaking injectors, so here's what I did to check: https://www.yotatech.com/forums/f116.../#post52330847
You have to remove the plenum, but not much else.

Don't forget the temporary fuel return line.

My problem was NOT a leaking injector.

 

Thats a great idea, man. My buddy has a borescope we're gonna use to look at the injectors tonight but if that doesn't pan out ill try your idea.

 

Borescope? Let us know how you do that. The injectors don't go into the cylinder, but the lower intake manifold.

 

Just lifted the plenum enough to slide the camera in. As far as we could tell none of the injectors are leaking. So I don’t know what’s happening to my fuel pressure at shutoff but like scope said, I suppose that isn’t my hard start problem.

 

Pull the vacuum line off the fuel pressure regulator and make sure its dry. Another issue I've seen before is a leak in the line that comes off of the fuel pump. Its the same as an "external" leak but you'll never see it because it leaks inside the fuel tank.

 

So something I have noticed is that my CSI only seems to spray on the first crank attempt. SO if I put the key in and crank it will spray, but once the key is turned to "ON" if i crank it subsequent times the CSI wont spray. BUT if I cycle the key all the way off before cranking again it will spray again. My thermo time switch checked out as far as the FSM is concerned.

When cold, the CSI fires even if the thermo time switch is disconnected???? but only on the first crank or after I cycle the key.
When the engine is hot it doesn't spray at all regardless of the thermo switch being connected or disconnected.
If I unplug the time switch AND ground the injector (STJ) it will spray every time without having to cycle the key.

This morning was icy maybe in the 20/30s and it was a no start until my buddy gave it ether while I cranked, fired right up. I didn't cycle the key at that point because I didn't know it made a difference for the CSI but I'll test that idea these next few mornings.

 

Checked a bunch of voltages at the ECU per the FSM and everything looked good. Also, took out the aftermarket fuel pump I had installed at one point and replaced with an older OEM pump I had. Started well this morning but it was not very cold out. Had a long crank after sitting for 2 hours and got it to start by grounding the STJ wire (green w/ red stripe coming off of the thermo time switch) and forcing the cold start injector to fire. I wouldn't have thought the CSI needed to fire as my engine was considerably warm. Might be something to try as there have been a couple other posters on here having problems like me. I had previously tested my thermo switch with hot/cold water and cleaned the contacts but I guess it is still defective or I have a short somewhere. A new one is close to 200 bucks and I am probably going to start getting things together for a 3.4 swap so I am not looking to sink much more time into chasing this hard start issue, so for now I think I'm just going to throw a toggle on the STJ wire and feed it into the cab for when I'm having hard starts. I'll post again when I figure out if this solved my issue.

 

Yeah this solved my issue. Something in the CSI/thermo time circuit was/is off. The injector behaves super odd on its own but things are working alright with the toggle installed. Thanks to everyone who chimed in to help!