93L: Check Engine Light --> Dies + Then Cranks Great But Won't Start

[SiliconSoul]

I had intermittent stalling problems at one point (and no check engine light) which ultimately (car quit altogether) was tracked down to a faulty dizzie cam sensor pickup. Only the EFI engines feature this built-in counterintuitive device, and as Bobstad found out a couple of years ago, a new-purchase dizzie can break the bank. Other gizmos that can give you oddball problems are the VAF and the O2 sensor.

Inertesting Bert, I didn't realize out cars had a cam sensor. Love the fact it doesn't throw a code!

[Spike]

I'ma put this in here, though it was on a carbed Chevy Sprint without computer, ect.

It's been 95% fixed now, though it does it once in a while. Drive it on a warm day (but sometimes cold days!), get it up to operating temp, shut it off. Come back 5min+ later. Crank crank crank won't start. Pump the pedal like nuts (dunno if you can even do this with EFI), and it will start and die quickly. Hold pedal down, ram it in first, get it moving. It'll buck, but it'll drive. Get on flat piece of road/hill, put trans in neutral, shut off engine, coast. Turn back on 30 seconds later and voila drives normal.

Vapor lock or clogged fuel jets was the cause, though I replaced my lines and cleaned the jets at the same time. I can't say for sure which it was.

Which leads me to the question.. could the fuel injectors be clogged? Possibly a car with only 50k miles sat for a very long time, was started up, pieces of crud from the fuel filter went up into the injectors, causing them to *sometimes* get clogged, requiring the engine to be shut off and the crud to have time to float down to the bottom again.

[Twistiva]

Bad gas. Drain the tank of the separated water/gas mix from using ethanol fuel (poison). Then, fill up with a tank of non-ethanol super and watch the problem disappear.

Brave -

Would be nice, but the previous owner had this same issue for quite awhile, ie, burned through multiple tanks of gas. Plus, I myself have burned through 2 separate tanks of gas....1 topped off in Granby, CO and the other somewhere in Kansas. So....bad gas would be doubtful?....think he drove it a fair amount in the last 4-6 weeks and all without any problems.

Next time it acts up, unplug your Engine Coolant Tempatutre sensor and see if it makes a difference.

Silicon -

I read your post on the ECT sensor on the previous owner's thread that I hyperlinked to on the first page of this thread. Talked to a parts guy at an O'Reilly's the day before yesterday and he said he had a similar ECT sensor issue with his girlfriend's car. Cost me about $17. Now I gotta change it and see if that fixes it. Which leads me to my next question....

where in the heck is the ECT sensor? I don't have a 93 shop manual. I do have an 88 shop manual. Same place? I confess I am just starting to dig into this / do my own 'due dilligence' but if anyone wants to holler out, pls do! If I understand it right, there are 2 temp sensors?....one near the thermostat and one somewhere else?

[SiliconSoul]

It's fairly easy to get to. It's just back and between the last two fuel injectors near the passenger side. It should be green, at least mine was. I removed my air silencer on the valve cover to get to it, but I don't think you need to. The trickest part to it was removing the little metal clip that holds the ECT connector in place. I lost one in my gravel driveway when I popped off. Just use a little tiny flat head screwdriver to pry out the metal clip, then the connector will easily separate. Use a socket to remove the sensor from the head.

Something important - I think I remember reading something about a problem caused by people putting teflon tape on the sensor when they put it in. This causes a bad ground that then screws up the signal. I could be completely talking out of my rear here, but something to keep in mind!

*Edit - There are two sensors, but one is only for the temperature gauge in your gauge cluster. I think that is a one wire connector located on the front of the engine by the distributor.

[Twistiva]

It's fairly easy to get to. It's just back and between the last two fuel injectors near the passenger side. It should be green, at least mine was. I removed my air silencer on the valve cover to get to it, but I don't think you need to. The trickest part to it was removing the little metal clip that holds the ECT connector in place. I lost one in my gravel driveway when I popped off. Just use a little tiny flat head screwdriver to pry out the metal clip, then the connector will easily separate. Use a socket to remove the sensor from the head.

Something important - I think I remember reading something about a problem caused by people putting teflon tape on the sensor when they put it in. This causes a bad ground that then screws up the signal. I could be completely talking out of my rear here, but something to keep in mind!

*Edit - There are two sensors, but one is only for the temperature gauge in your gauge cluster. I think that is a one wire connector located on the front of the engine by the distributor.

When tightening, does the Engine Coolant Temperature sensor need to be torqued to a certain torque range or 'just get it snug'? (Sorry, no '93 shop manual. Tried to find it in my '88 shop manual. No luck.)

[SiliconSoul]

Does it have a proper range - yup. Do I use your method? Yup!

Do 'er until snug, and as long as there are no leaks your golden.

[bravekozak]

I will repeat what I said before. The coolant temp sensor threads are straight. It seals with an O-ring. Just pinch that rubber good and you shouldn't have any leaks. It is not necessary to crush it into submission.

[Twistiva]

Does it have a proper range - yup. Do I use your method? Yup!

Do 'er until snug, and as long as there are no leaks your golden.

I will repeat what I said before. The coolant temp sensor threads are straight. It seals with an O-ring. Just pinch that rubber good and you shouldn't have any leaks. It is not necessary to crush it into submission.

Silicon - OK, that'll work for me.

Brave - The Engine Coolant Temp sensor I bought has a brass washer on it / no rubber. Regardless, will "not crush into submission". (I don't recall you saying that before on this thread but it still made me smile.)

[Twistiva]

OK, the plot thickens. I really think I found the culprit but I have 2 other questions:

Likely problem: Three times today my 93L would crank great but not start. A parts guy at my local O'Reilly's said he thought it might be a bad Engine Coolant Temperature (ECT) sensor. His girlfriend's car had a bad ECT sensor where the sensor would 'think' it was hot and turn off her engine and would not restart. If he poured water on the ECT sensor he could get her car to start immediately. So....when it wouldn't start today I also poured moderately cool water right on the ECT housing (I did not bother pulling it out of the engine head to pour water directly on the probe, I just poured it on the ECT housing) and the car started right up all 3 times. So the engine 'thinks' it is hot when it is not (there's no way a 1 1/2 minute drive to Ace Hardware would overheat the engine) but pouring water on it does in fact allow it to start? Weird. Any good ideas?

Question 1: When I put a jumper wire in the STI (Self-Test Input) code-retrieval plug (the plug is white in the picture and my jumper wire is white) and connected the alligiator clip to bare metal, then turned the key to "ON" (but not to the "Start" position) like directed in the 1st post in the thread below, I expected to see a 9-flash ECT error code on the CEL (Check Engine Light) and got.....nothing; the CEL illuminated like it's supposed to in a normal engine start sequence but the CEL did NOT flash at all. Any ideas why?

http://www.fordfestiva.com/forums/showthread.php?17417-Retrieving-Trouble-Codes-from-OBD-I-Systems

Question 2: So, when I did not get the CEL to flash I wondered if maybe it's because the code is dumped when you turn off the engine. So I started the car, connected the jumper wire to the STI pigtail plug and when I connected the aligator clip to the mare metal bolt stud the wire sparked slightly and the car immediately died. It did this 3 times. What the heck is going on?

STI Terminal To Ground via Jumper Cable.jpg

[SiliconSoul]

Just replace the friggen sensor!!! I promise you its that part. Mine was corroded inside causing a bad intermittent connection.

[Twistiva]

Just replace the friggen sensor!!! I promise you its that part. Mine was corroded inside causing a bad intermittent connection.

Silicon -

Yeah, I'm going to do that.

But I still want to know why it doesn't show the ECT error code on the CEL and why the stupid car dies when I connect the jumper wire from the STI to ground.

I'd also like to know why an ECT sensor that incorrectly 'thinks' the engine is too hot then lets the engine start when you literally cool it down.

[SiliconSoul]

From this thread : http://www.fordfestiva.com/forums/sh...ght=diagnostic

Don't test for codes while the engine is running. BAD. I ran out to test mine with a low voltage test light to see what would happen, and sure enough something was trying to put a LOT of juice through the STI. My car didn't die, but it stumbled until I disconnected it.

I don't know exactly how the computer is seeing the ECT data when it sends either a really low or no signal (Because of the bad corroded wire inside) but I would guess it thinks its very cold, so it turns the "choke" on and floods the engine with fuel. That's probably why mine would be just fine one minute, then I would park and come back to a no start condition. The contraction of cooling down must cause a connection inside the ECT too shift. The only way it would get going was by holding down the gas pedal which causes the computer (I think our cars do it) to turn down the injectors (dwell time) to un-flood the engine.

Like I said, just change the friggen thing!

[Twistiva]

SiliconSoul -

(Don't do the jumper wire STI test with the engine running.....got it! Thanks!)

Hey, I changed the ECT sensor (and thanks for confirming where it was and telling me to be careful with that small spring clip....you're right, that clip was the hardest part of swapping the ECT) but....

The bad news: I swapped the ECT sensor, fired it up (it started immediately) but then I left it running to see if it would putter out and die (like it did twice the day I ran errands after work) while I was putting away tools, washing up, etc. I went back outside after about 20-30 minutes and it had died. At about 15 minutes it was still idling nice and quiet and the temp gauge was about 1/3 of the way from "C" to "H" (higher than I expected but it's Oklahoma in the summer with zero wind today) but at ~ 20-30 minutes it had died and....once again would crank very strong but not even a hint of catching / starting.

The good news: once again I slowly dribbled some moderately cool water directly on the ECT sensor (2 20 oz. bottles versus just one like earlier today since I knew the engine was this time in fact fairly warm) and it started up immediately. So....the good news is, I once again confirmed it has to do with the ECT sensor....either getting too hot or thinking it's too hot.Could it be the wiring to the ECT sensor that's bad? If so, how does water on the ECT housing affect the wiring? Maybe I just happened to buy a bad ECT sensor?

Anyone got any ideas?

[Twistiva]

Just replace the friggen sensor!!! I promise you its that part. Mine was corroded inside causing a bad intermittent connection.

BTW, I checked the inside of the ECT wiring receptacle and the connectors were nice and shiny and clean, not even a hint of corrosion. There's enough water/antifreeze in the radiator and the oil is only slightly less than "F". I also heard the radiator 'overheat' fan kick on at least twice while I was cleaning up my tools.

[SiliconSoul]

It looks like I owe you a drink... sorry man.

Have you tried a wiggle test on the wire? Do you have a temperature gun you can use to test the temperature is correct? No damage anywhere else up the wire to the harness that water would maybe dribble down to and make a better connection?