Ranger starts-then-dies, then restarts fine.

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560
Location
st louis, mo
So I think I got my other problem fixed. I replaced the original fuel pump because of my truck's start-then-die behavior, but the replacement pump(s) were cheap and I think they didn't work well. Here is the problem: 1997 Ford Ranger 2.3L engine, manual transmission If you turn the key on to start the truck, after it has been sitting for more than a very short length of time, it will initially start, rev up a bit, then die. After that, if you try to restart, it will start right up and run fine. If you turn the key to "ON" for a couple of seconds and wait, then start the truck, it starts and runs without dying. Sounds like a fuel pump losing pressure, right? Here are the things I've replaced that have had no effect on this behavior: Fuel pump x 3 Fuel filter x 2 Fuel injectors Fuel pressure regulator IACV With a pressure gauge on the fuel rail, no loss in fuel pressure is seen during the start-then-die event. In fact, the fuel pressure seems to increase as the engine dies (vacuum operated pressure regulator). My guess is that there is maybe a tiny leak somewhere in the system and that causes the fuel pressure in the system to leak out -- and air to leak in (?). Then, the injectors get hit with a little bubble of air that makes the car die. I guess the thing to do would be to get a UV dye for the fuel system and see if that will show any leaks.
 
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8,301
Location
Grand Rapids, MI
I have something similar happen with my Camaro. When it sits for a while and when it's cooler out, it'll start fine then run really rough, misfire/backfire and sometimes stall. After about 30 seconds or so the revs will come up and it'll run fairly well. I've tried replacing the idle air control valve, no dice there. Tried running some fuel injector cleaner, nothing. EGR valve was also replaced but no change there. It has always used premium gas and has pretty low miles for the year. I had a similar problem with my old Firebird and it was the mass airflow sensor. I'll probably be looking at that next. Just thought I'd mention it as something you might want to take a look at as well. I've only driven the car a few hundred miles this year so far, so I haven't really been hunting down the check engine lights but mine is on with multiple codes as well. I believe two of them were for the O2 sensors. Weirdly, mine doesn't act up when it's warmer out (i.e. over 60 degrees).
 

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Messages
560
Location
st louis, mo
Okay, I have figured out that THIS IS NOT A FUEL DELIVERY PROBLEM, as least as far as I can tell. Scenario 1: with the engine running, shut the engine off. Leave key "off" for one minute. Attempt to start. Engine starts for one second, then dies. An immediate attempt to restart is successful. Scenario 2: with the engine running, shut the engine off. Turn the key back on with the engine off. Wait one minute. Attempt to start. Engine starts and runs fine. Note that in Scenario 2, the fuel pump is not running when key on engine off after the first two seconds.
 

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Messages
560
Location
st louis, mo
Test: jammed the throttle partly open, still starts and dies. Test: with MAF disconnected, it won't idle, runs very lean.
 
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1,269
Location
Brittany / Canada
Running lean with MAF disconnected? Could it be a vacuum leak somewhere? Had it been a Barchetta, I would have pointed the TDC and camshafts sensors, but I don't know on that Ford.
 

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Messages
560
Location
st louis, mo
Tell me more about the crank or cam sensors. I saw someone recommend that for an Audi with a similar issue. Thing is, other than the start-die, restart hassle the truck seems to run fine, no CEL. Idle isn't real smooth, but it's ok.
 
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1,269
Location
Brittany / Canada
I can only talk about the Hitachi injection system in the Barchetta, sorry. Such behavior in that particular car would be associated with a failing crank sensor, or camshaft sensor, or both, as the system is able to somewhat recuperate missing or corrupted data. Disconnecting the MAF sensor would bypass some sensors, but the camshaft sensor would still be needed. Anyway, different engine, so no real point there wink Rough idle could also point to a vacuum leak somewhere, a pernicious one difficult to see. I don't know if you can look at fuel trims on that car?
 

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Messages
560
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st louis, mo
So I replaced the head on this engine last week, and this perplexing problem is gone now.

The original head (270k+ miles) was suffering from receded valves; they would cause the truck to misfire and possibly stall after it had been revved up.
 

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Messages
560
Location
st louis, mo
I had replaced the upper-to-lower gasket previously, but not the lower-to-head gasket. I don't think it was leaking, because I did a lot of work trying to find a leak when I had some odd fuel trims. But anything is possible.

At the time I did the head, I also replaced the crank sensor because I busted the old one. Also replaced the water pump, crank seal, plug wires, and cam seal.

I had a really weird issue that baffled me for days: after I put it all together, I got a P0102 (MAF signal low) code and it wouldn't idle. I cleaned the MAF and also tried replacing it with an aftermarket MAF I had on hand. Still no MAF reading. I checked the wires for continuity and no shorts to ground. All good. I guessed it was the PCM and ordered one from eBay.

I measured voltage out of the MAF. Nearly zero volts. Could my MAF really be bad? Did my MAF fail dead and the aftermarket MAF I had also failed coincidentally at the same time I was replacing the head? Finally out of ideas, I grabbed a junkyard MAF and put it in -- works perfectly. Now, it *could* be that there was some fault in the short piece of cable that runs from the MAF to the connector on the wiring harness. But I dunno, I tested that cable and everything seems right on it. I could do a part swap with the old MAF on the new connector to find out but I'm not curious enough.
 
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