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
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