Cold start problem

[fusion1620]

Hello!
I have a 91 Ranger with the 4.0l engine. The truck will not start when it's cold? It cranks over fine. Fuel pump sounds good and I have pressure at the rail. Not getting any pop at all.. I assume that its a spark problem...

Weird thing is, that if I push start the truck it starts right up. Then if I turn it off and try to start it again, it starts right up every time. She just does not want to start up after sitting. Any ideas? Thanks!!

 

[97RangerXLT]

Neutral safety switch.

AJ

 

[adsm08]

Neutral safety switch.

AJ

That would keep it from cranking.

 

[n_grimm]

Looking at the Haynes manual, it appears there is more than one set of contacts in the clutch switch. Seems like one feeds the starter and the other provides a signal to the ecm, which would control the injectors. May be worth looking into since I don't see anything else that would change when you push start it with the clutch pedal up.

 

[trail B2]

Is your starter speed good sometimes it needs to turn over faster when its cold.Try jump starting it to see if that helps for diagnosis.

 

[xkotyx]

i had about the same problem. check the plug wires. mine had fell against my exhaust manifold and was shorting out on the manifold when i cranked it. for some reason it hardly gave me problems when it was warm. but it was terrible in the cold.

 

[martin]

Sounds like a similar problem to mine. Problem is it's hard to diagnose as once it's started it seems to be ok until it sits for a few hours and you really need another person to turn the key while you check stuff. whenever I had the opportunity to use another person to help diagnose the thing it would start before I had a chance to check much. I didn't bother about chasing the problem too much with mine as I used to go home for the winter, but now I'm stuck here for the winter time I'm just going to park it for four months, I suspect the problem might be the air temp sensor or water temp sensor but I don't know what the spec is for them, If someone knows the specs perhaps they might post them.

 

[doorgunner]

Looking at the Haynes manual, it appears there is more than one set of contacts in the clutch switch. Seems like one feeds the starter and the other provides a signal to the ecm, which would control the injectors. May be worth looking into since I don't see anything else that would change when you push start it with the clutch pedal up.

hmmmmmmmm.......good to know....no volts to ecm.....no volts to injectors....can you hear the injectors clicking with a mechanics stethescope...even though it's got fuel at the rail--the injectors might not be getting voltage to make em squirt....

 

[n_grimm]

Sounds like a similar problem to mine. Problem is it's hard to diagnose as once it's started it seems to be ok until it sits for a few hours and you really need another person to turn the key while you check stuff. whenever I had the opportunity to use another person to help diagnose the thing it would start before I had a chance to check much. I didn't bother about chasing the problem too much with mine as I used to go home for the winter, but now I'm stuck here for the winter time I'm just going to park it for four months, I suspect the problem might be the air temp sensor or water temp sensor but I don't know what the spec is for them, If someone knows the specs perhaps they might post them.

Not sure it this will help with the OP's problem but the coolant sensor should read about 3 volts at 70*F and about 4 volts at 32*F Here is a link to the charts: http://fordfuelinjection.com/index.php?p=28
One thing that made mine harder to start when cold was that the ignition timing was at TDC instead of 10-12* I suspect a previous owner may have adjusted it without unplugging the SPOUT.

 

[martin]

The four liter is edis ' no mechanical distributor ' so it's essentially not adjustable.

 

[Legend]

If the battery is getting weak, terminals corroded, cables frayed.... Then when cranking the voltage may be reduced enough to screw up the computer, injectors or fail to generate spark. Push starting it could unload the electrical system enough that other stuff still works. The battery is certainly weaker when it's cold, so if some of the other things listed are a problem, they are aggravated when it's cold.

Stick a voltmeter on the 12V at the cigarette lighter for instance and see what it does when you crank the engine. Once you have run the engine for a few seconds the cranking load is much less than right out of the box. I'll bet you can see the difference between the first cold morning start and the second one, no matter how you got it started.

 

[fusion1620]

Looking at the Haynes manual, it appears there is more than one set of contacts in the clutch switch. Seems like one feeds the starter and the other provides a signal to the ecm, which would control the injectors. May be worth looking into since I don't see anything else that would change when you push start it with the clutch pedal up.

I will check into it. The clutch pedal in my ranger went out recently. I replaced both the master and the slave. It was a real pain to get the pedal to work again. Had to reverse bleed the system by pushing fluid into the slave until all the air came up through the top. Now I have to push the pedal hard all the way to the floor before the stater will engage. Maybe its not triggering the ECM though... I probably have to bleed the system again and check the switch...... This is most likely the problem. Thanks A lot for all the responses!!

 

[fusion1620]

The weird thing is that the truck runs great. Once I push start it, it starts up every time and runs fine. Untill I let it sit for awhile..

However, I have noticed that ever since the cold start problem showed up, Even though it starts with the key after a push, It is not the same as before. It used to start up great after the first or second crank. Now it starts up on like the 3rd or 4th crank and just kind of starts. Not as good.. Could it be the cold start injector?

I need to check for spark and injector pulse and see were i'm at........

 

[97RangerXLT]

What Adsm08 says is true, the neutral safety switch *should* disengage the starter, but I wonder if it is a double pole double throw switch and half of it has gone bad...

Everything you have indicated seems to point to a safety interlock in the clutch system...

AJ

 

[fusion1620]

Well got stuck at club the other night.. I need to figure this out.. It's not getting spark when I try to start it. Like I said, if I push start, it will start right up. Let it run for awhile, then the key works again. Checked for power at the coil. Seems good. Changed the switch on the clutch pedal. Still not working. Help!