2.5L Cold Start Problem

[Yardbird]

Hi. I've been looking at Rangers for the last few weeks and just got a 2000 Extended Cab, Stick Shift, 2WD, with 160K miles, so this is my first post. The truck is okay for its age but I have one issue that I need to deal with ASAP. It starts fine when it's warmed up but when it's cold it bucks and dies. I have to hold the key in Start position to get it running. Don't really want to do that and possibly break teeth on the ring gear, plus it stresses the motor. Seems like an ignition problem, maybe firing way too early. The little used car lot I bought it from thought it was a problem with the aftermarket alarm system, but I don't know about that. (Seems a stretch, though I wouldn't mind pulling the thing out just to eliminate any problems with it.) Thanks for any feedback/suggestions/etc.

 

[RonD]

Welcome to The Ranger Station
No, alarm issue doesn't sound right to me either.

A few things can cause cold start issues.

Fuel injected engines can not use a regular "choke" like a carb could, no jets to suck the extra fuel from.

So they use a "choke mode" in the computer software to set high idle(via IAC valve), rich fuel mix(open injectors longer), and advanced timing(coil control from computer).

Now all this is triggered by the coolant temperature, the temperature is "read" from the ECT(engine coolant temp) sensor hooked to the computer, this is a simple two wire resistance sensor and only used by the computer.
Dashboard temp gauge uses a one wire "sender", they look similar but are not the same nor are they connected together, so 2 wire = computer, 1 wire = dash gauge

On the 4cyl I think the ECT sensor is towards the front of the engine, drivers side just below the head on the block.
But not sure on the 2000
This sensor is easy to test with an OHM meter or volt meter
Look here:
http://oldfuelinjection.com/?p=28

ECT sensors rarely fail, but not never fail.
If the ECT sensor was "reading" engine warm all the time then computer wouldn't know there was a problem, so no CEL(check engine light)
But engine would run poorly until it actually warmed up a bit.


Check a few spark plugs make sure they are the correct ones for your engine, and are in good shape.
If ECT sensor is working then engine should run rich at start up, this could cause fuel fouling if plug spark is not hot enough, so until spark plug heats up you get misfires.

Another issue that is easy to test for is leaking fuel pressure.
Fuel injected engine fuel pumps are not on all the time, the computer turns them on and off according to RPM, throttle and speed.
When key is turned to ON the fuel pump will come on for 2 seconds then shut off.
It will not start again unless engine starts and runs for a bit.
If there was a small pressure leak in the fuel system and truck sits for a few hours, engine now cold, then when you go to start it the pressure would be too low and engine wouldn't start well, the 2 seconds isn't enough to restore full pressure.
So the test:
Turn key to ON, count to 3
Turn key OFF
Repeat 3 times
Then try to start engine

If it starts right up and seems normal then you have a pressure leak, next step would be "where is it leaking?"

 

[Yardbird]

Wow. Excellent. Thanks, Ron. Great info. Do you think any of those issues would show up in a computer scan? Is there an adequate scanner I could buy to use myself? Something that wouldn't cost much more than a scan would at an indy shop.

 

[RonD]

You can buy Bluetooth interface OBDII plug ins then see any codes and watch real time data on a smart phone, I or android, usually under $30 for the interface, app is free for most but check first.

Yes you would see the ECT temp real time, and if it showed 180degF on a cold engine you would have found one problem.

Spark and fuel pressure wouldn't be part of OBDII and wouldn't generate specific codes, you might get misfire codes but you already know that is happening.

 

[Road Angels]

2.5L ect is on the back of the head on the intake side, drivers side

 

[Yardbird]

I've been looking at ScanTool.net for scanners and stuff and they have both ScanMaster and ScanXL software. These seem more useable/comprehensive than the free software that comes with a lot of code readers. ScanXL has a plug-in (extra license fee) for Ford Extended codes and I was wondering if that would be useful for the 2000 2.5L. Thanks again.

 

[Yardbird]

Further developments

So I took Ron's suggestion of pressurizing the fuel system but it didn't help. I can let the truck sit for 48 hours and it starts ok as long as it doesn't get too cold. I also noticed that it wants to stall if I punch it when it's idling.

I got the ScanXL Pro package with the Ford Extended codes. It has codes I don't even understand, but it does have a basic set of gauges to start with. I checked the engine coolant temp sensor and the ambient air temp sensor and they both have appropriate readings. I doubled checked by disconnecting them and the scanner showed -40 F for both.

So, yeah, it's time change the plugs but it seems like a pain. Any tips, tricks, or threads I should check out?

 

[Kenneth S]

On my brothers 92 I jack up the drivers side (put a jack stand under it) and get to the spark plugs through the fenderwell (along with a universal, and some extensions).