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No start...again

Reply #15 –
Not that this is your answer, but it sounds similar to the prob I had when I bought my truck so going to share that experience

91 F250 351 EFI
Ran cold, ALWAYS ran cold gauge read cold, heater blew cold, but the truck ran fine. Talked to the previous owner who said it had always run cold, that’s just where it ran.

BS! So I change the thermostat, nothing else just remove the old one (was broken in two pieces) nothing came off that motor other than the thermostat housing and some coolant loss. Reinstalled the new Thermostat and gasket, refilled the radiator, started it up and it ran fine till it warmed up. Then all hell broke loose on that thing, bucking and kicking, spewing coolant out the overflow, Died and wouldn’t start.
I was thinking WTF how ya blow a engine up changing a thermostat?
Let it cool off again, then it started fine.
Let it warm up and it shuddered a bit as it got warmer then leveled off and has been fine for months now.

Best answer I could come up with from the sources I used was that the computer had adapted over the years to the cold running temperature. Once the temp rose up from the new thermostat it OD’d the computer and freaked it out. It needed a few starts for it to adjust itself. At the suggestion of somebody I removed the battery cable and let it sit over night then started it again just to be sure.

Never did find a better answer, but like I said, truck runs great and get’s warm
:birdsmily:   Objects In Mirror Appear to be Loosing  :birdsmily:

No start...again

Reply #16 –
Fuel pump or pip/tfi

No start...again

Reply #17 –
Any possibility of the ECU causing it? I may buy a second one just to try and sell if it isn't the problem. I have yet to reset the computer after last night's issue as it didn't seem related but its certainly possible, especially since there was still some air in the system until last night.

I need to get the problem to happen again so I have time to test the PIP signal at the ECU (have it hanging back out now so the wire is accessible...whichever it is, I forget - pin 56 or something like that). To me it certainly looks like no injector pulse but if I can get it into a no spark condition, it'd explain a lot. Otherwise, I can just pull a spark plug when it happens and look for fuel or lack of.

I need to find a way to reproduce it though! Trying to loosen up connectors a little still allows it to start right up - black connector on intake, coil, and tfi module cable all seem like they are making great contact. ECU's harness is screwed in all the way.

Sadly, I must work until probably 7pm tonight so I can't test much until tomorrow. I'll give it a try though - let it idle for 5 minutes, put into drive, and hope it surges/dies. I'm so tired and frustrated right now, I'm losing my ability to think straight and diagnose these things in the proper order.

1) Get to die...needs to happen. I need ideas on ways to make this happen and not something that won't help me.

2) Check for spark at a plug. If none, check at coil. Move towards ignition switch or towards distributor depending on condition.
3) Check for PIP signal at ECU since its already in the car and yanked out. If none, test at TFI module. If yes, check at an injector? Depending on what I find, move towards whatever is logical.
4) If for some reason these both test out, I won't be able to get a fuel pressure reading at the moment as my gauge isn't with me. Every time in the past we've tested it though, it read 38-39psi, don't remember what it read when running. This at start should be plenty though and it doesn't bleed off very quickly (maybe at 30psi after an hour iirc)
1988 Thunderbird Sport

No start...again

Reply #18 –
Disconnect the SPOUT and take the ECU out of the spark equation.

No start...again

Reply #19 –
Quote from: softtouch;199338
Disconnect the SPOUT and take the ECU out of the spark equation.


Not quite, the injector pulse to the EEC is picked up from the same output that fires the coil...

No start...again

Reply #20 –
Yeah, I'm not sure if its easy to test the computer. When the PIP signal gets to the computer, does it send anything back out on another wire I can test?

I picked up a Motorcraft TFI module and pickup coil "just in case" so I'll have it on hand if I get the problem reproduced and it points to one of the two being bad. The dealership even price matched and surpassed the price on the Motorcraft parts to what Partsamerica had on their site so I saved $70 or so over what they were charing. The guy remembered a call earlier in the day from me about these and mentioned something about a lower price elsewhere and pricematching it so I said what the hell, sure. Got the pair for $200. Hopefully I won't need them though...

On a related note, are the distributors in our cars different than the Mustang's? Cast iron vs steel gears? Just curious. I'm using the distributor that came from the HO motor along with the thing's cam.
1988 Thunderbird Sport

No start...again

Reply #21 –
I'll throw this one out there. may not even help.
Any chance of water freezing in the fuel line? I remember you said it was 25 deg.
[SIGPIC][/SIGPIC]
***** Project "EVOLUTION" 1987 Cougar LS  & 1985 Cougar Convertible *****
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5.0 HO 306 roller block, machined GT-40P heads, Wiseco dished forged pistons, Eagle forged floating I-beam connecting rods, Lunati pushrods, ARP bolts, Scorpion aluminum 1.6 rockers, Comp Cams Magnum 266HR, Explorer intake, 65mm TB, MAF Conversion, 19# injectors, Ford Racing stainless P-headers, 2-1/2" cat-less exhaust w/ Flowtech Afterburner lers , SC AOD with 2800 BDR torque converter, 3.73 T-Lok rear, CHE rear control arms, full 2-1/2" frame w/1" jacking rails & seat supports, Rear disk brakes, Turbine wheels, All original interior w/ floor shift upgrade .......
Pretty much every panel on my 87 is new, rebuilt, or re constructed. :D
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No start...again

Reply #22 –
Quote from: TurboCoupe50;199344
Not quite, the injector pulse to the EEC is picked up from the same output that fires the coil...

 I'm not sure what you are saying here.

The TFI fires the coil when it gets the SPOUT (Spark Out) pulse from the EEC.
Disconnect the SPOUT and the TFI fires the coil without any output from the EEC.

No start...again

Reply #23 –
Okay, well, I didn't get too far yet and I'm waiting for the engine to get cold again/reset the computer. After idling for 2 minutes, I put into drive, it bounced up and down like 50 rpm's for ~30 seconds before it got worse and worse and died. Trying to start the car sounded like it tried to fire a few more times before it died completely and just spun doing nothing. This time holding the gas pedal down and cranking it brought it back to life, put it into drive, it surged a couple times +/- 50 rpm's and settled at ~800 rpm's...and wouldn't die again.

I still need to verify but I only think it happens when the engine's cold...so right direction to look next? I only got to test the flickering at the coil's connector when turning over before I got it running again.

edit:
Got it back together, idle and rpm transitions are much smoother again like it was on Sunday. Into drive, it settled at an rpm and stayed there. Still need to get an accurate reading of the transmission fluid level as it still wants to slip - a job for tomorrow while trying to reproduce the problem again. I should have almost all afternoon to diagnose - and in the daylight. I think the problem is still there but masked by the computer relearning what it wants to do.
1988 Thunderbird Sport

No start...again

Reply #24 –
Quote from: softtouch;199388
I'm not sure what you are saying here.

The TFI fires the coil when it gets the SPOUT (Spark Out) pulse from the EEC.
Disconnect the SPOUT and the TFI fires the coil without any output from the EEC.


OK, so what has killing the advance have to do with his problem??? Timing is static till the engine fires, then it is advanced...

No start...again

Reply #25 –
Quote from: TurboCoupe50;199442
OK, so what has killing the advance have to do with his problem??? Timing is static till the engine fires, then it is advanced...


Missing SPOUT pulses from the EEC = no spark.
SPOUT unplugged = spark at base timing.

No start...again

Reply #26 –
We have a 91 Ford F150 that kinda sorta not really does the same thing.  Every blue moon when the planets are aligned it will start right up and run great.  After a few minutes it dies and wont start for another year or two.  I've measured the fuel pressure at the rail and it reads 50lbs when the engine isn't running and it has a strong spark.
One 88

No start...again

Reply #27 –
No luck so far today in killing it again. I'm having a little trouble adjusting the idle as restarting the car after setting it makes the thing surge so I bump it up, the computer compensates by closing the IAC, and I'm back where I started. Not enough surging to kill it, but enough still. Maybe I am supposed to be setting the idle in drive instead of in park? Don't remember. I'll be putting a few miles on it in a few minutes to get the computer learndid.

Did codes again with the engine still cool, got codes 21 and 33 which is to be expected.
1988 Thunderbird Sport

No start...again

Reply #28 –
Put some miles on it...with 2.73's performs the same as the SO motor did off the line. Haven't taken it on the freeway yet and done any WOT runs but so far the thing feels exactly like the old motor at speeds below 50mph. I'm sure the stock exhaust manifolds and pipes are holding it back some but whatever, as long as it'll run for now and get me through emissions in the next few weeks. Fluids are all still good but I can still hear bubbles in the heater core.

...it still won't die.
1988 Thunderbird Sport

No start...again

Reply #29 –
Quote from: softtouch;199522
Missing SPOUT pulses from the EEC = no spark.
SPOUT unplugged = spark at base timing.


LOL if you say so... In my book missing is same as none...

I've fired a coil from a TFI dist, with them both on the work bench, using a 12v power supply... Not a EEC in sight...