Hot Start Problem- 95 Disco.......

skrufy

Well-known member
Nov 26, 2004
53
0
good evening......

the Perpetrator: 95 Disco 3.9L, 90k miles
Air temp: mid 60s
Altitude: 8100 ft.

Problem: intermittant hot start problem, no OBD 1 fault codes, no CEL- Check Engine Light

I own: LR Discovery Workshop Manual, Electrics Manual, lots of tools- always looking for a meager excuse to buy more.......... consider myself to be a pretty decent mechanic, with
lots of room for more knowledge.....

I have:

- load tested the battery- good, connections clean......
-all fuses are good......
-all wires and connections appear to be good under the hood.....
-within the last 6 months: new plugs, spark plug wires......
-Dist. cap/rotor appear to be good, no cracks.....
-cleaned stepper valve and seat....... replaced breather tube from the stepper to the
plenum because I cracked it- old- getting it off.......
-cleaned/checked all vacuum/breather lines to Plenam/fuel injection
system, including the T- connecter pipe off the rt. valve cover breather/filter to the
plenam......
-checked/cleaned the same inlet for the above breather tube on the plenam, per the LR
Manual.......
-cleaned/checked the Mass Airflow Sensor, including removal of the screen to better
spray carb cleaner into the sensor air sample hole- gently dried with compressed air-
this tip received courtesy of Mike Ray, 25+ yr LR mechanic, now Service Manager at
Royal LR/Jag, Tucson, Az. The slightest bit of oil, dirt, etc on this type of hot/cold
wire MAF sensor will drive the ECU- engine control unit- nuts.......
-cleaned the plenum intake and butterfly valve while the MAF was out of the way......
-pulled the vacuum hose off the fuel pressure regulator, no gas leaks with the engine off
or running, so the reg, so far, appears to be good...... no holes in diaphram....
-replaced the vacuum line- distributor to the plenum- was okay, but always thought LRs
line was brittle and wimpy....... blew out the vacuum inlet on the plenum- was clean...
-fresh gas, run regular in it- or whatever they're calling reg gas these days- not much
chance of pinging at this altitude.......


I haven't yet: (tomorrow maybe......)

-will replace my Amsoil foam air filter with a stock paper one for now- see above MAF
comments, per Mike Ray..... the slightest atomization of the foam oil on the air
sensor..... goodbye Amsoil and K&N foam filters????.......
-checked the fuel pressure at the fuel filter in the r/rear wheel well, per LR manual- need
to go buy a fuel pressure test kit/gage- yea! another tool..... pressure should be in the
39-45 psi range, higher with engine on, with no pressure drop for several hours= bad
check valve on fuel pump= new pump.......
-if the pump is good, I guess the next step is to check the fuel pressure at the fuel rail, if
the pressure drops off, I hope it's a bad fuel pressure regulator- looks easy to
replace, if not, then I must have a leaky injector somewhere- that looks like a pain to
remove the plenum, airbox, and fuel rails to remove the injectors to have them
cleaned/refurished.........

Have spent the day chasing this problem- in the morning, it cranks right up...... but after
it heats up from running errands, etc., it intermittantly won't start- tries to run, real rough, then quits...... had to wait about an hour the other night for it??- whatever component- to
cool down before it would run again.......
After having done all the above stuff, it would run /crank just fine, and couldn't dupli-
cate the problem...... until of course, it was dark, pouring down rain, and I had to go pick
up my son from football practice.... at that time, it had been run about a half hour earlier
without a problem.......
I've tried the on/off of the ignition switch 3/4times trick to no avail when it won't run.
I also had a start problem last winter when it was dead cold outside- 0-32f, mostly fixed that by putting a 60watt bulb under the hood at night, then letting it warm up for 10 minutes or so. Never before have I had a start problem with it in the warmer months.....


Anyway- your thoughts/comments please! there have been somewhat similar threads on
dweb before, but none that I could find like mine, or maybe I didn't dig deep enough.....

Am I on the right track, other things to try?? Like the rest of you, I have better things to do than chase some Lucas nightmare........ I like to work on the LR and other vehicles when I want to, and not because I have to......

thanks once again for dweb, and all the info that is so willingly shared!

skrufy
in the high country, Arizona
 
Oct 27, 2004
3,000
4
Cold start issue. Let me look for my post. There is a cold start update for your Rover.
It's a new PROM,Bosch starter with larger cables, and a couple of adjustments.

I'll find it.
 

skrufy

Well-known member
Nov 26, 2004
53
0
Thanks for the replies guys.......

for Chris St Louis-

I did a search and found your post for Service bulletin #19/13/96/US- thank you!

questions:

- the updated starter LR #ERR6087K- is this a starter used on a later LR of some type?
I would like to cross reference it to a US GMC/Ford/etc unit if possible to maybe
save a little cash if possible by going to my local parts store.... the nearest LR
dealer to me is over 3.5hrs driving time........

- same question for the battery cables- I assume I can use some monster cables from
a Ford or GMC truck, assumeing I want to take the time to aquire and mod. them to
fit, etc- might be too much hassle......

-can I change the PROM only, and achieve the same thing??

-I assume you have to reset the base idle because of the new PROM??



Today- I still haven't had the opportunity to check the fuel pressure- awaiting tester......

The cold weather here is one it's way, so I have to get this fixed ASAP...... typical Dec/Jan
here never gets above 32f/0c......

Anybody heard of a block heater that really works for the Disco- I mean easy install and
no leaks?? My Ford Excursion has the 7.3l TD, with factory block heater in the oil pan
works real well.......

Again, talks for all the help......

Tim
Alpine, Az.
 

Lino

Well-known member
Nov 19, 2004
46
0
After you do the bosch starter mod and the rest of it check and make sure the timing is correct.
I live in Canada and after the mod it worked great but it started better after we retimed it.
We get it bad up here -40 degress celsius and i have a factory block heater which i don't use. It starts fine. Just do the MOD.

Lino
 
Oct 27, 2004
3,000
4
skrufy said:
Thanks for the replies guys.......

for Chris St Louis-

I did a search and found your post for Service bulletin #19/13/96/US- thank you!

questions:

- the updated starter LR #ERR6087K- is this a starter used on a later LR of some type?
I would like to cross reference it to a US GMC/Ford/etc unit if possible to maybe
save a little cash if possible by going to my local parts store.... the nearest LR
dealer to me is over 3.5hrs driving time........

Not sure. Could be. I just bought on though from Rovers North for less then $200 if I recall.
- same question for the battery cables- I assume I can use some monster cables from
a Ford or GMC truck, assumeing I want to take the time to aquire and mod. them to
fit, etc- might be too much hassle......
Yep, the cables are just bigger 2 or 0 gauge.
-can I change the PROM only, and achieve the same thing??

I know some guys have. The starter is to get the RPM over 50 when cold. In canada, its a recall but only to change the chip.

Of course, on mine I replaced it all.;)
-I assume you have to reset the base idle because of the new PROM??

You do, but not because of the PROM so much, but jsut becuase almost all of them are set wrong.
Again, talks for all the help......

Your welcome, happy to help.
 

macklow

Well-known member
May 3, 2004
398
0
Las Vegas, NV
I changed the chip for under $20 (bought chip at dealer). Fixed the cold start problem on my '95; it wouldn't start if ambient was under 40F or so.

I have original everything on the engine (starter, battery cables, injectors, etc.) and have over 200k on it. I thought I was going to have to do a head or long block replacement... thanks to dweb and chris, my "rebuild" cost under $20.
 
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Rocky

Well-known member
Apr 23, 2004
2,178
7
Red Sox Nation
I think you are most likely looking at a dying coil. Us 95 owners are so old fashioned we have just one of them.
Typical symptoms of coil failure include failure to start when hot. The coil has likely overheated, perhaps when it lost its coolant. Given enough time it cools off and bingo can provide enough spark to run the truck
 

jims95

Well-known member
Apr 20, 2004
203
1
Upland, California
Last year, my 1995 Range Rover Classic 3.9L, with 134K miles (original fuel injectors) developed hard starting/flooding after being warmed up, and sitting for a few minutes to an hour later. I had a mechanic check the fuel pressure on the intake manifold when running and after turning off the engine. Turned out that the fuel pressure was dropping too fast after turning off the engine, which means a leaking fuel injector. I ordered a new set from Five-O Motorsports in Lakewood, California (great price and service). I found out when I changed them that I had 3 fuel injectors on the passenger side that were leaking. The new injectors cured the problem and runs great.

Hope this helps.

Jim Lupinetti :D
 

skrufy

Well-known member
Nov 26, 2004
53
0
Good evening to all-

Have been real busy doing other stuff, so a late reply to my solution to my hot start problem- 95 disco......

Problem was two fold:

Fuel pressure was way low at 28 psi- should have been 39-45 psi- no leak down of pressure after 30-40 minutes or so, but still low....... checked pressure with old fuel filter with about 19k miles on it- 28psi, and then with new filter-still 28 psi...... replaced fuel pump with a Carter P74006- fuel filter: forget the number, but it's a Chevy or GM filter- see the Tech Listings for compatable parts= works good.... and cheap..... Carter pump was $71, fuel filter about $9....... vs OEM LR pump at $350 vs Brit. Pacific's OEM at $230......

#2: fuel temp sensor on fuel injection rail was bad- $42 at British Pacific...... the LR manuals don't give the resistance values (in ohms), but I think the Test Book does- Test Book is the LR lap top computer that the LR dealers plug into your LR....... anyway, the after market computer repair programs do give the values- in this case Mitchell's- about
$8-9k initial costs to repair shops, with annual updates running around $1000..... anyway, the resistance was way too high- at about 2000ohms: for the fuel temp that I had at about 150-160f, should have been down around 300-400 ohms- the sensor was telling the ECM "I'm cold, give me lots of gas to start......" = flooding the engine- when added to the low fuel pressure, caused all my problems......... I know that last statement seems a bit confusing, but I diffinately identified two separate problems, the major one the fuel pump, and I have had a cold-dead of winter start problem as well- and the other the fuel temp sensor ( not to be confused with the coolant temp sensor......). Most diesel engines have
a fuel temp sensor, but most gas engines do not as a mechanic/shop owner buddy of mine has told me....... LR has added one for some reason- perhaps Chris St. Louis or someone else can tell us- hopefully..... I like to find the problem , instead of shotgunning = lots of $$ replacing lots of stuff not really relating to the problem- but you hope it does...

Don't have all the sensor values in front of me, but will post them to this thread to help someone else in the future........

have ordered the cold weather update PROM chip for the ECM from the dealer, but have nor received it yet- will post that info also in a week or so- thanks to Chris St-Louis for the cold weather info posted earlier in this thread.....

that's all for now! no start problems!......

Tim Timmins
Alpine, Az.
 
S

ShaunP

Guest
Fuel temp sensor and water temp have the same resistance. Fuel temp is to monitor under hood temp, ecu leans out for hot start as a result of high fuel temp. Very common hot start fault, perhaps I should have put more detail in my first post. The fuel temp sensor also plays a role in the thremo fans running after switch off. For the thermos to run the water must be 230* and fuel temp 158* This will cause the fans to run for 10 min after switch off.
14*f =9200 ohm
32 =5800
68=2500
104=1200
140=600
176=350
212=180
these are + or - 100ohm at the cold end to 50 at the hot end.
 
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