3.9 no start problem

[thegeekboy]

my 94 has mysteriously died ... hoping someone has an idea as to what is up.

here are the symptoms, and what i've done so far:

it had recently been taking a few more cranks to start

it will turn over dead for 30-50 seconds then stumble once or twice, then repeat. some times it will just turn over completely dead for over a minute. on a few occasions it has started right up, only to be dead again after being off for a few minutes.

it's not an ignition problem. it's got spark .... replaced cap, rotor, and plugs any way.

the fuel pump relay comes on, and the pump pressurizes. i pulled the fuel line at the rail and it's getting fuel ..... how much fuel should flow here ... it seemed ok. i pilled the return line off as well .... after a few seconds of the pump being on, it starts dumping to the return, so it doesn't appear to be the fpr.

during long cranking sessions the pump cycles on and off, this is normal, right.

there is a very light gas smell when cranking

so it seems to be the ecu. i'm i probably looking at a dead ecu. could it just be a bad sensor or something. is there a way to test the ecu, other than swapping it into another rig.

any ideas, i'm stumpped

-anthony

btw. the ecu isn't showing any error codes

 

[flippedrover]

Have you posted to D-90.com?

 

[ptschram]

Did you ever get it started?

 

[RangeRoverHP]

Did you ever get it started?

Guess not.

Sounds kinda like an ECU.
What are your thoughts Paul?

 

[WILL.TILLERY]

No Start

leaky injectors.

 

[ptschram]

I agree with Will that it sounds like badly leaking injectors. BTDT-had to hold the throttle wide open when starting and then it ran rough for a coupla seconds and sorta smoothed out.

In this case, it might be injectors, but I doubt it's the ECU, they tend to be pretty robust.

 

[RangeRoverHP]

Your right. Could be inj leak.
But don't discount the ECU.

 

[JMK]

I have the same motor and am having the same issues. How would one figure out if it were leaky injectors? And what about the ECU?

Thanks

Jeff

 

[ptschram]

I have the same motor and am having the same issues. How would one figure out if it were leaky injectors? And what about the ECU?

Thanks

Jeff

Easiest way to presumptively rule out (or in for that matter) injectors is to hold the throttle wide open when cranking. If the engine fires, runs rough for few seconds and then smooths out, it is likely leaking injectors. You may also notice a loss of fuel pressure in the rail if the vehicle is left to sit standing after shutting the engine down for more than a few hours. A fuel pressure gauge permanently mounted makes this easier . Granted, it could be a failing pressure regulator, but there are ways to check for that as well.

I believe there may be a picture floating around here of my fuel pressure gauge setup on my Disco. Shopgrrl's Rangie will get one as well if the engine ever goes in.

 

[ptschram]

As for ECUs, I have never seen a 14 CU(x) ECU go bad, in one case, a bad coil wire had put secondary voltage into the ECU and the truck is still running in spite of an input that was supposed to receive less than 12 volts having received a few thousand. It did throw a code for complete ECU failure (29?), but it is still running andit was last spring I fixed it.

The older 14 CU ECUs are said to be less robust, but even then, I've only seen one that was even suspect.

 

[RangeRoverHP]

My experience with 14cux ECU's in early D-90 differs a bit. There are few '94-'95 Defenders in my area running around with the original ECU. The symptoms vary from sputter and dies, won't start, or will run great cold but when operating temp is reached they fall on their face.
Just my .02

 

[ptschram]

Whoops! My observations were not restricted solely to Defender applications.

 

[JMK]

Alright this is what happened to me: I drowned the motor. The fix: take the fuse to the fule pump out and start it up. a moment or 2 turn off and replace the fuse.

 

[flyor]

Are the injectors firing? You check this by listening to them while you crank the engine over. You'll need a sthesescope or a long screw driver will do. If not the speed signal may not be coming to the ECU from the coil. If I remember correctly there is an inline resistor between the coil and ECU closer to the ECU. I have had a few of these fail at least on the early RRC.

 

[EMBIBB]

injectors

I just replaced the injectors in my 3.9 and have resolved poor starting issues. Seems the old injectors were clogged and leaking when the engine is shut down. Its an inexpensive fix and hightly recommend.

eddie

 

[Pugsly]

I just replaced the injectors in my 3.9 and have resolved poor starting issues. Seems the old injectors were clogged and leaking when the engine is shut down. Its an inexpensive fix and hightly recommend.

eddie

I concur. I bought Ford Mustang takeoffs (from turbo conversions) from fiveomotorsports.com - they are a direct (and more modern) replacement, and you can replace all 8 for less than the cost of two genuine fuel injectors.

 

[Timmy!!!!!!!]

I concur. I bought Ford Mustang takeoffs (from turbo conversions) from fiveomotorsports.com - they are a direct (and more modern) replacement, and you can replace all 8 for less than the cost of two genuine fuel injectors.

What is the part number?