1996 Disco 1 - Hard Starting?

[wsy]

My 1996 Disco I is developing a starting problem. Sometimes it starts, sometimes it doesn't. The engine spins just fine, (I even get oil pressure!); it feels like it's ALMOST ready to run, but it often doesn't quite kick in.

Diagnostics so far. Spark seems good ( AAAIIIEEEESHUTITOFF!!!! ) . Slight smell of gas out of the tailpipe when not starting. I replaced the plugs and plug wires with OEM from Rovers North; no change. Cleaned the K&N air filter; no change. If I just turn the key to the third click I can hear the fuel pump buzz away (however, the fuel pump does seem to sound considerably noisier than it did when I bought the car new ten years ago. (130Kmiles on it). I can hear the fuel pump as being slightly louder than the engine exhaust sound when I stand at the back of the truck with the engine running. (is there a way to test the fuel pump?) The diagnostic system display under the passenger seat says "everything is just fine".

The only pertinent things have been changed on the truck are both oxygen sensors have been changed and the exhaust system aft of the catalyst Y-pipe has been changed over to a stainless from Rovers North (twice - first rusted out, but RN got me a new one for free). Replaced the distributor cap and rotor too. Battery is fine; engine spins over no problem. Everything else on the truck is pretty much as it came from the factory (original coil, original fuel pump, original MAF).

This no-start happens mostly/only when the truck hasn't been run for a few days. If it's only been a few hours, then it rarely has any problem.

Clues? Suggestions?

 

[joey]

Fuel injectors sound like they need replaced.... when is the last time you changed the fuel filter? Also if you can hear the fuel pump over the exhaust, start shopping for one.

 

[wsy]

I haven't replaced the fuel filter; I have one in the parts kit but I haven't noticed any signs of fuel starvation even at 90+MPH _once it's running_, so I doubt that fuel starvation is the cause at that point.

Ditto on the fuel injectors, either. Once it's running for a ten seconds or so, it's all grand.
Is there any way to test 'em or is this a "shotgun debugging" situation here? If so, it
sounds like an _expensive_ debugging test.

Although, sometimes when it does start, it sounds like it's missing on a few cylinders for a few seconds. Hmmm... you might be onto something there. Thanks.

I agree on the fuel pump; it's getting noisy but it's always been noisy and it's hard to rememeber what it "used to sound like" for a strong comparison. Can the fuel tank be changed without draining/dropping the fuel tank (I don't have my LR Disco manuals here with me)?

(thanks on the fuel pump advice. I will get one into stock ASAP, and start pricing out injector kits as well).

Any other ideas out there, especially tests that I can do ?
-Bill

 

[Discosid]

The Fuel Filter should be changed at 50000 miles of 4 year if its only been done once back then I would replace.
The pump will last on most LR's up to about 90 to 100 thousand I would replace that too. A noisy pump doesn’t necessarily mean a lose of pressure it means the unit is on it last leg. If it goes out when on the road your screwed. (Access hole under the carpet in the back)
I replace mine at 125K the Brushes on the motor had about a 1/8 of an inch left on them. You can rebuild them but that’s an other story.
As for the not start problem try the temp sensor behind the Distributor, not the fuel temp sensor the water. Unplug it se if it will start (this will pull the CE light so you’ll have to reset it)

 

[Moose]

Slow leak in an injector will result in the engine effectively flooding itself -- that's why the hard time getting a start, and sluggishness for a little bit after a start. Once you burn off the excess fuel, things are fine.

I'd bet it's injectors leaking. You can get them checked through companies that probably exist in your area (look for diesel engine diagnostic places), and IIRC there are cross-refererenced parts from GM (???).

 

[wsy]

Last night I had at it again for a little while. Mantra: "Air, fuel, spark". It didn't want to start, but it seemed closer to starting with full throttle open (as in it rattled on a bit afterwards, which is pretty close to running). I popped the MAF tube off the air filter, Put my hand over it. Yeah, sucking air. Big surprise.

Fuel: Gave it a shot of starting fluid (ether). Well, more than a shot. No joy, not even a rattle onward. So, plenty of fuel. Maybe too-plenty- as it didn't rattle onward as in case 1 (full throttle cranking without ether).

Spark: Lots of nice big fat hot sparks at the end of the coil lead. Not so much at the plug ends (do OEM wires go out of their way to suck?). But definitely spark.

The telling case is that when I tried starting at full throttle instead of foot-off-the-gas, and it came *closer* to starting, as in it rattled on for a while after I stopped cranking. Which really does substantiate the idea that the fuel injectors are leaking. (and also explains the continual loss of fuel mileage - I'm down to 10), With throttle wide open, if there is partial flooding, the larger air flow would tend to lean the mixture toward "better".

OK, I am starting to believe that it's the fuel injectors. and boy, is the fuel pump getting loud. I think I will make a call to Rover's North today, and get some parts.

I wonder if it's worth diagnosing *which* injector is leaking, or just replacing them all. At 130,000 miles it's no fun to think about doing them one at a time over the next year. Opinion on one-at-a-time versus do-em-all? A new fuel pump is definitely on the menu- it's getting *loud*.

Thanks bunches! I think this is starting to get sorted out. You are all gentlemen and scholars.

-Bill

 

[wsy]

I checked my factory manuals, and they suggest that checking the spark plugs to find the one that's sooted up is the right way to find the leaking injector (leaky injector runs a cylinder overrich, and so carbons up the spark plug).

I did that. Some are more sooted than others, but none are really sooted... that is, I didn't feel bad about putting any of them back into the engine.

Suggestions? -- Bill

 

[wsy]

Oh, and I'm a ****. The truck has 140,000 miles on it, not 130,000 miles.

Any opinion on whether it's worth replacing all the injectors at once or to do it one at a time?
-Bill

 

[Moose]

Do 'em all at once.

 

[wsy]

Fixed... I feel STOOPID

OK, now it starts. I feel soooo STOOOOPID.

What got replaced:
Fuel tank (recall)
Fuel pump (140 Kmiles, was getting noisy anyway, and heck, it was out)
fuel filter
distributor vacuum advance (was leaking pretty badly)
distributor rotor
EFI engine coolant temperature sensor
serpentine fan belt
spark plug wires
air filter (ditched the K&N and reverted to stock LR part on list member advice)

What got repaired/cleaned
engine MAF sensor cleaned
minor vacuum leaks on power brake booster, evap canister, and heater vac valve
power steering pump suction hose leak (only found it when replacing fan belt; it has
been leaking for years; tighened hose clamp now it's fine)

What the real problem was:
Distributor cap - small carbon button in the middle was worn down to about 3/16", it
should stick out by about 3/8", causing weak/no spark till it heated up. :-(

Cost of what got replaced: $ 594 (not counting the recall on the fuel tank)
Cost of what was broke: $18 (and I now have a spare!)
Having a Land Rover that starts: Priceless