PDA

View Full Version : The Incurable Problem?



91 XR7
10-18-2010, 11:32 PM
My hot starting issue continued :mad:

now with All electronic and wiring out of the equations (also ignition).
What would cause a hot start issue on a '91 SC that may possibly mechanical?
Head gaskets? Cracked Heads? Cam sensor Synchronizer out of Sync?

The thing is the car starts within 2 revolutions when cold, and once starts run VERY good with good power/

Pearlbirdsc
10-19-2010, 09:04 AM
I would start with checking for a leaky injector. You may have one or more dripping fuel into the cylinders after you turn the car off. Makes for a very hard start if it hasn't been sitting a long time.

David Neibert
10-19-2010, 12:53 PM
My hot starting issue continued :mad:

now with All electronic and wiring out of the equations (also ignition).
What would cause a hot start issue on a '91 SC that may possibly mechanical?
Head gaskets? Cracked Heads? Cam sensor Synchronizer out of Sync?

The thing is the car starts within 2 revolutions when cold, and once starts run VERY good with good power/

Is the car stock ? If not, please list all mods other than cosmetic stuff. Is this something that started suddenly or gradually got worse ?

David

91 XR7
10-19-2010, 10:03 PM
The Car is 100% stock minus the AC delete Setup (Like you have David?)
I honestly believe it did get progressively worse, it started like 3 summers ago after LONG drives on the free, shut it off to have dinner, get back in was hard to start, but around town, it wasn't bad or as bad, to where it is today i can drive it to work, (28 blocks or @ 1.5 miles?) and it'll still have an issue starting after work (@9 hours) but drive home get into the next morning it instantly starts.. :rolleyes:

And this is the second set of injectors, and when i install them (both sets) i don't have the injectors in the intake, and i turn on the fuel pump, run it for awhile (@ 2-3 minutes) while watching for leaks, and then let them stand for @ 5 or so minutes after shutting the bump off, to no leaks at all

BECERRASC
10-19-2010, 10:53 PM
a different DIS module???

91 XR7
10-20-2010, 01:37 AM
Yep, as of right now, a brand new one is on it

scruffyleg
10-20-2010, 11:24 PM
Last year I was having a hot start issue,if I drove the car for 15 min. or more it would have a hard time starting.The car always turned over really well. I did a lot of searching,nothing worked. About 2 months ago,was at wal-mart getting oil[short drive],went to start car,nothing,so I got a solenoid,still nothing, then I noticed the positive battery cable was very hot. I changed the starter with a new one,have not had an issue since, barely turn the key and it fires right up. Hot or Cold.91 All stock sc thunderbird.

slowpoke
10-21-2010, 02:12 AM
i to had hot start problems last year, it lasted for about 3 months then my head gasket blew out. food for thought. once hot if the gasket has a slight leak it could be letting some coolant into the chamber when hot due to pressure in the cooling system then making it hard to start.

i hope thats not the problem, but you might want to start keeping an eye on your coolant levels. if they start going down you might have a problem.

notime
10-21-2010, 03:22 PM
Please describe your hot start condition clearly. For example, it cranks over fast for 30 seconds before it starts. It cranks over real slow and sounds like its binding. It spits and sputters after it starts when hot...

I have had two fuel pumps go bad. These fuel pumps only showed problems after getting warm. The car would drive normally when cold but after an extended drive the car would act as if it was way down on power. One pump actually quit working while driving but worked after about a 2 hour rest. The other pump would gradually get worse during the drive but never completely quit until you shut it off. If you tried to restart it soon after shutting it off it wouldn't restart. If you let it cool down completely the pump would start working again.

Leaking injectors will cause a long crank and usually misfires after startup due to puddled fuel in the cylinder. It's easy to check for leaky injectors. Pull the fuel rail with the injectors still attached cycle the key a couple times to build pressure. Place paper towels under the injectors and watch for drips. Or you can use a pressure guage to see if the injectors or fuel pump is leaking.


The more descriptive you can be of your symptoms the more accurate your help will be.

91 XR7
10-21-2010, 06:12 PM
Last year I was having a hot start issue,if I drove the car for 15 min. or more it would have a hard time starting. I changed the starter with a new one,have not had an issue since, barely turn the key and it fires right up. Hot or Cold.91 All stock sc thunderbird.

When you turn the key to the `Start' position (IE turning over) the engine spins over the same Cold or Hot, there's no difference, and it does it with out any strain (sounds the same as before this issue arised, and like my '89 XR7, ect) I guess i truely can't rule it out as a possibility thou, and now if the guy i gave my spare too still has it.......


i to had hot start problems last year, it lasted for about 3 months then my head gasket blew out. food for thought. once hot if the gasket has a slight leak it could be letting some coolant into the chamber when hot due to pressure in the cooling system then making it hard to start.


Well i've only driving this car during the summer months (@ 6 months total in the last two previous years, didn't drive it this summer except for 2 days) and it's being doing it the whole time, and i didn't noticed any change in coolant level or change in oil color or level.


Please describe your hot start condition clearly. For example, it cranks over fast for 30 seconds before it starts. It cranks over real slow and sounds like its binding. It spits and sputters after it starts when hot...

Leaking injectors will cause a long crank and usually misfires after startup due to puddled fuel in the cylinder. It's easy to check for leaky injectors. Pull the fuel rail with the injectors still attached cycle the key a couple times to build pressure. Place paper towels under the injectors and watch for drips. Or you can use a pressure guage to see if the injectors or fuel pump is leaking.


Well if you like to search for `hot start issue' under my alias, you'll find least TWO threads started by me on this issue and will really cover all grounds as to what is wrong. But to forgo that......

first thing in the morning i get into the car, it starts nearly instantly (depending where the vane is on the cam sensor) usually 2 full revolutions at the most. And it runs great, i can drive it too work like @ 28 blocks or 1 mile away, shut it off, come out afterwork and it'll crank over (turn over/key in the `start' position) just like in the morning
After maybe 5-8 or so seconds of cranking it over (key in the start position) if i'm lucky it'll have a hint of struggle firing and will catch and rev up to the typical Start RPM (13000rpm) and settle back down to @800rpm after like 15-20 seconds? but when it catches it does puff out abit of smoke (usually a sweetish unburnt fuel burnt oil smell )
BUT if i'm unlucky, after 5+ seconds of cranking it has in the past `caught' but would idle at around 400-500rpms, and would stay there, you can walk off come back @ 5 or so minutes later, it'll still be idling there, and as you can guess, yes it idles like ~~~ at that RPM. but there is usually a small amount of smoke that starts to come out the tails pipes then, Goes have a sweetish unburnt fuel burnt oil smell :o to get it to stop running like this, you have to just very touch the throttle and it'll catch and run as if nothing is wrong.. heck you can even turn the Air bleed screw on the TB to be able to get it to get out of this state too

Please look at the second paragraph of post #4 of this thread in regards to the injectors, thank you :)

and Fuel pressure is good, and it has no issues building it up to the correct pressure as soon as the key is turned to the run poisition and keeping it there..

TbirdSCFan
10-21-2010, 06:36 PM
It sounds like you have the cam sensor unplugged. Does it bog when trying to start?
If so, you can work around the problem by turning the key off and retrying the start. Eventually the EEC will guess at the right coil and it should start/run as smooth as ever.

If this isn't the case, I would suggest you check the fuel pressure at the rail. The pump, and perhaps a clogged filter, or the FPR might be causing a problem. (Hmmm.. nevermind if you've already checked it.)

Oh, and lets not overlook something obvious (or maybe NOT so obvious). Be sure the plug wires are fully seated on the plugs. When they are pushed onto the plug, there will be a slight click/snap feel to it. If you don't notice it, keep at it until you do. A bit of boot grease will help.

XR7 Dave
10-21-2010, 06:48 PM
Have you ever opened the throttle all the way to the floor during any of these hard starts?

91 XR7
10-21-2010, 10:13 PM
It sounds like you have the cam sensor unplugged. Does it bog when trying to start?

Oh, and lets not overlook something obvious (or maybe NOT so obvious). Be sure the plug wires are fully seated on the plugs.

Nope Cam sensor isn't unplugged.. TRUST me :) I even made a DIS relocation setup (now removed again) and it had the issue both ways (oh and the Cam Sensor is a Brand New Ford unit)

When i resealed from the heads forward, and have good access to the plugs wires, i did double check them, and they were all good and seated.

As you guessed, i did check all aspect of the Fuel system ;)


Have you ever opened the throttle all the way to the floor during any of these hard starts?

Dave, I have never gotten it to the floor when it has this issue.. Before i turn the key to `start' i have my foot resting on the Accelerator Pedal, and once it doesn't Catch with in 2-3 revolutions, i can just barely push the Accelerator Pedal (maybe just enough to open the Throttle body blade abit) and it'll fire up.. it's almost like the Idle Air Controller isn't opening in my book, BUT i check all aspects of that circuit, even different Idle air controllers, But what would cause it to work all of a sudden after it gets running?

I even bought a IAC tester.. and if use it to start the car, it'll start every time? (but that may be coincidence and the car would of started as normal?)

you know one thing i don't remember of this whole thing thou.. when it's hard to start if i stop turning it over, and try again if it'll start as normal.. I may try it this weekend?

XR7 Dave
10-21-2010, 10:24 PM
You should never rest your foot on the gas pedal while turning the key on. During this time is when the EEC is learning base TPS voltage. Having your foot on the gas during this time screws up this initial setting.

If the car doesn't start within 2 cranks of the motor, without releasing the key, press the throttle to the floor. If the motor then starts, this indicates an excessive fuel condition. At least knowing if it has too much fuel or not enough would be a starting point in determining the cause.

The fact that it seems to start better on the 2nd try indicates a possible lack of fuel condition. Does fuel pressure remain high when engine is warm? I know you said you tested it, but you did not say if you tested it during a no start condition.

91 XR7
10-21-2010, 10:41 PM
You should never rest your foot on the gas pedal while turning the key on. During this time is when the EEC is learning base TPS voltage. Having your foot on the gas during this time screws up this initial setting.

If the car doesn't start within 2 cranks of the motor, without releasing the key, press the throttle to the floor. If the motor then starts, this indicates an excessive fuel condition. At least knowing if it has too much fuel or not enough would be a starting point in determining the cause.

The fact that it seems to start better on the 2nd try indicates a possible lack of fuel condition. Does fuel pressure remain high when engine is warm? I know you said you tested it, but you did not say if you tested it during a no start condition.

I'm pretty sure that when i had my foot on the gas pedal, that no movement was done at the throttle body, but typically my foot isn't even on the gas when i'm trying to start my cars, unless it was carburated with a Finicky Choke :o
If the car hasn't started after 2 or 3 revolutions if i open the throttle up a hair it will typically start as stated earlier :o
I'm not 100% sure if it starts better on the second try, since i honestly do not remember that, or trying it :(
Fuel pressures where tested KOER and KOEO, Cold and Hot, and even when it was hard to start and always almost instantly came up to the correct pressure every time the key was turned to the `run' position. Leak down was with in specs, if not better then what is said in the Ford Shop manual
and Injectors like i said, have been tested for leakage, i think @ 10+ minutes at @40psi there should be a leak, and if you can come back after say 15-20 minutes of shutting off the car and have it have an issue starting up again.. i think there should be a reasonably decent leak at a injector to cause that problem..
And that's the other thing, usually within 10 minutes of shutting the car off, it'll start no problems..

TbirdSCFan
10-22-2010, 01:39 PM
OK.. I give. At this point I would start throwing parts at it. But not just willy-nilly.

Have you tried a different EEC? Oh... and how about your ECT sensor? Might try swapping it out for a new/different one. Maybe the EEC thinks its already hot and needs no extra fuel? For that matter, ACT sensor, MAF? Just some ideas.

91 XR7
10-23-2010, 12:25 AM
Replace or swapped out for another:


EEC (Used from running car)
IAT Sensor (New)
ECT sensor (New)
IAC (Used from running car)
TPS Sensor (Used from a running car)
Cam Sensor (New)
Crank Sensor (New)
MAF Sensor (Used from a running car)
MAP sensor (Used from a running car, and tested both <got a tester>)
O2 Sensors (New)
Dis Module (New)
Sparkplug wires (New)
Sparkplugs (New)

Note: `used from a running car' = from a car with no issues at all at starting, running and is stone cold reliable

Electrical wise, there's a 4ga wire going from the battery directly to the engine from the battery, and another from the battery to the chassis. Also a 4ga wire going to the Alternator (Positive) to the Battery.
Majority of the EEC wiring seems to be good, all sensors are getting good ground path, or positive voltage (5V or 12V dependent on which)

Hence why i said what can cause this issue that's not electronic/electrical:o Head gasket seems the most logical but it show no other signs of a HG failure, and would it have failed completely by now (after driving it for 12 months, with the last year being started an ran for @15 minute or more every other weekend?

XR7 Dave
10-23-2010, 10:12 AM
If the car consistently starts by adding throttle during crank that is an indication of too much fuel during crank, or not enough air.

Suggested test 1: Warm car to condition where you know it will have trouble starting and shut it off. Disconnect battery to clear adaptive memory. Reconnect battery and without touching anything else, attempt a restart.

Suggested test 2: Warm car to condition where you know it will have trouble starting and shut it off. Place a thin piece of cardboard under the throttle stop to give it just slightly more throttle opening. Then after waiting at least 10 seconds and without touching the throttle, attempt to start. See what happens.

91 XR7
10-23-2010, 02:29 PM
The car does seem to consistently start with a little bit of throttle (IE more air) when it has issues starting.. But to add on to it

With in 10-15 minutes of shutting off the car, the car will start usually with out an issue, it's usually after 15 minutes or Greater that it'll have an issue starting, and seems longer you wait, the more likely it'll have an issue and more Severe it is?

91 XR7
10-24-2010, 06:55 PM
This weekend i didn't get any real chance to work on the Bird, Between my Computer getting a virus/Malware/whatever and my Parents computer failing, among other things, time was hard to come by in working on my `toys' but i got this Friday off, so if it's not a down pour i'll try working on it.. maybe put insurance on it for the weekend so i can try more at my home instead of it's home :o

BUT i tried my IAC tester/controller on it, was able to get a 2000rpm fast idle out of the IAC and down to a stalling out. it's also a nice way to get the car to warm up without having to be in the car :) But as soon as i got to that point (Car warmed up) i only had like a 5-10 minute window to do any testing, and i tried pulling the EEC fuse (G) and when i tried to start it, it didn't seem to have any issues.. but the thing is it may of also still been in that time frame after shutting it off that it won't have an issue restarting

Breadsax
04-04-2011, 12:38 PM
I have very similar symptoms as you in the same scenarios.

Did you replace your IAC with a Motorcraft unit? I did not use a Motorcraft IAC and I'm wondering if this is causing me problems.

Another interesting thing that seems to help is whether or not I shut the car off immediately after parking. If I do shut it off right away, it seems to fire right up compared to letting it idle before shutting her off.

Likewise, when I know she's hot, I turn the key immediately to cranking it instead of letting the fuel pump kick in. If I do this, it starts better with no sputtering/low rpm.

Hope this helps.