Part 2 of troubleshooting. Engine randomly dies - Defender Source
Defender Source  

Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions


Reply
 
Thread Tools
  #1  
Old February 17th, 2015, 06:19 PM
sflash868's Avatar
sflash868
Status: Offline
Stephan Laputka
1995 D-90 SW
Member
 
Join Date: Jan 2004
Location: San Francisco, CA
Posts: 972
Part 2 of troubleshooting. Engine randomly dies

So this is a follow up on an earlier thread ( http://www.defendersource.com/forum/...ad.php?t=53612 ) I started but I seem to have fixed the symptoms from that conversation and now there is a new issue, which I assume is related.

Quick synopsis: this is my brothers 94 ST that had problems with running rich, stumbling engine, stalling, poor performance etc. Since posting that thread, I've changed:

1. Swapped ECUs
2. o2 sensors
3. Fuel temp sensor
4. distributor cap
5. Mass Air flow meter
6. checked ignition timing

Since doing this, it drives better, doesn't stumble anymore and the smell of rich exhaust is gone but now it randomly shuts off and won't restart. I don't mean it stumbles, coughs then dies. it goes from driving and revving fine fine to just turning off like someone turned the key. I've only gotten it to do this after idling for at least 3-4 minutes. It will crank but it won't restart. I've checked spark at the plugs and ignition seems fine. Turn the key to on and the fuel pump comes on for 2-3 seconds as normal. If I walk away from the car and come back 30 mins later without touching a thing, it fires up like nothing happened. There are no codes being thrown and the engine has no other observable issue.

1. Bad ground.. it wouldn't turn over after dying or run again 30 mins later
2. Ignition switch.. wouldn't turn over after dying nor would it prevent it from starting
3. Fuel pump dying.. might explain why it randomly dies but once it turns back on and pressurizes the engine should fire
4. Clogged filter.. would cause poor performance not a random stall
5. Ignition amplifier.. wouldn't prevent it from starting

Any suggestions would be much appreciated.
__________________
Land Rovers are by far the best looking 4x4 on the back of a flatbed...
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old February 17th, 2015, 07:41 PM
leastonce's Avatar
leastonce
Status: Offline
Jason England
D-90 White 95 SW #65
Site Team
 
Join Date: Jul 2009
Location: NYC
Posts: 6,078
Registry
Quote:
Originally Posted by sflash868 View Post
So this is a follow up on an earlier thread ( http://www.defendersource.com/forum/...ad.php?t=53612 ) I started but I seem to have fixed the symptoms from that conversation and now there is a new issue, which I assume is related.

Quick synopsis: this is my brothers 94 ST that had problems with running rich, stumbling engine, stalling, poor performance etc. Since posting that thread, I've changed:

1. Swapped ECUs
2. o2 sensors
3. Fuel temp sensor
4. distributor cap
5. Mass Air flow meter
6. checked ignition timing

Since doing this, it drives better, doesn't stumble anymore and the smell of rich exhaust is gone but now it randomly shuts off and won't restart. I don't mean it stumbles, coughs then dies. it goes from driving and revving fine fine to just turning off like someone turned the key. I've only gotten it to do this after idling for at least 3-4 minutes. It will crank but it won't restart. I've checked spark at the plugs and ignition seems fine. Turn the key to on and the fuel pump comes on for 2-3 seconds as normal. If I walk away from the car and come back 30 mins later without touching a thing, it fires up like nothing happened. There are no codes being thrown and the engine has no other observable issue.

1. Bad ground.. it wouldn't turn over after dying or run again 30 mins later
2. Ignition switch.. wouldn't turn over after dying nor would it prevent it from starting
3. Fuel pump dying.. might explain why it randomly dies but once it turns back on and pressurizes the engine should fire
4. Clogged filter.. would cause poor performance not a random stall
5. Ignition amplifier.. wouldn't prevent it from starting

Any suggestions would be much appreciated.
3.5 suggestions ....

AICV - not mentioned in the previous thread ... if this is sticky it can cause all sorts of issues. Clean with carb cleaner and or put in a replacement from Autozone for $52.

Check the lead from the coil to the ECU ( its the one that has the chicklet in line near the MAF sensor. If this is loose it will cause the engine to stall and not start. Is your coil genuine? The proper spec puts out 9v which the ECU expects ... non-genuine and mallory seem to output 12v which causes issues.

Plug leads ... check the resistance on each lead ... they should be the same ... I had a bad lead that cause some pretty major issues ...

if someone has an old school oscilloscope it can detect all the ignition related issues ... a Rover Gauge could be useful to look at the IACV position.
__________________
Quote:
Soapy water / KY jelly, etc. is is basically a must. Yes, good idea to remove trim panels - only takes 5 more minutes to do so.
Car Camping Collective founding member and Chief Executive Officer
Cat Camping Collective founding member and Chief Executive Officer
Reply With Quote
  #3  
Old February 17th, 2015, 07:52 PM
sflash868's Avatar
sflash868
Status: Offline
Stephan Laputka
1995 D-90 SW
Member
 
Join Date: Jan 2004
Location: San Francisco, CA
Posts: 972
Quote:
Originally Posted by leastonce View Post
3.5 suggestions ....

AICV - not mentioned in the previous thread ... if this is sticky it can cause all sorts of issues. Clean with carb cleaner and or put in a replacement from Autozone for $52.

Check the lead from the coil to the ECU ( its the one that has the chicklet in line near the MAF sensor. If this is loose it will cause the engine to stall and not start. Is your coil genuine? The proper spec puts out 9v which the ECU expects ... non-genuine and mallory seem to output 12v which causes issues.

Plug leads ... check the resistance on each lead ... they should be the same ... I had a bad lead that cause some pretty major issues ...

if someone has an old school oscilloscope it can detect all the ignition related issues ... a Rover Gauge could be useful to look at the IACV position.
Sorry, forgot to mention that.. I did already change out the AICV. The coil is original. not only OEM i think it's the original that came on the car. I'll check the connection on that MAF wire, i haven't looked at that yet. As for the leads, wouldn't an issue like that cause performance issues that slowly get worse vs. acting like an on/off switch? Is there anything I should be looking at related to temperature? Seems it only happens after the car warms up... (to be clear though, it's not overheating.. needle is left of center)
__________________
Land Rovers are by far the best looking 4x4 on the back of a flatbed...
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old February 17th, 2015, 08:06 PM
leastonce's Avatar
leastonce
Status: Offline
Jason England
D-90 White 95 SW #65
Site Team
 
Join Date: Jul 2009
Location: NYC
Posts: 6,078
Registry
That wire from the coil tells the ECU that the engine is firing ... it signals that the ECU can keep the fuel pump on and fire the injectors.

If it's problematic it will kill the engine like you describe.
__________________
Quote:
Soapy water / KY jelly, etc. is is basically a must. Yes, good idea to remove trim panels - only takes 5 more minutes to do so.
Car Camping Collective founding member and Chief Executive Officer
Cat Camping Collective founding member and Chief Executive Officer
Reply With Quote
  #5  
Old February 17th, 2015, 08:14 PM
brutus147
Status: Offline
Todd
94 Defender 90
Member
 
Join Date: Mar 2013
Location: Alexandria, VA USA
Posts: 20
Engine on my 94 would cut out after about 2hrs on the road. After it cooled down...it would start and be fine until things had a chance to come up to temp again. After about a month of troubleshooting...replaced the ignition coil. It's been fine since.

Todd
Reply With Quote
  #6  
Old February 23rd, 2015, 02:49 PM
sflash868's Avatar
sflash868
Status: Offline
Stephan Laputka
1995 D-90 SW
Member
 
Join Date: Jan 2004
Location: San Francisco, CA
Posts: 972
I checked the connections off the coil and everything was tight. I'm going to replace the coil anyway since the terminals don't look all that great. I noticed on AB's site that there are a number of different coil options (3) at different price points. I figured the Bosch is the one to go with but any opinions?
__________________
Land Rovers are by far the best looking 4x4 on the back of a flatbed...
Reply With Quote
  #7  
Old February 23rd, 2015, 03:13 PM
leastonce's Avatar
leastonce
Status: Offline
Jason England
D-90 White 95 SW #65
Site Team
 
Join Date: Jul 2009
Location: NYC
Posts: 6,078
Registry
Bosch is the one most people would recommend.

Have you measure the voltage from the coil to see if it's failing?

The best way would be to measure the voltage at the ECU plug ( remove the back ) ... if the coil is not sending a pulse then the ECU won't attempt to run.

Given this voltage is a pulse it's easier to see with a test light. When cranking you should see the light flash. If you measure the voltage then it should be around 9v although the ECU will run at lower ... down to about 7v from memory.

While it's probably good to change the coli if it's old it would be better to have a before and after measure to see that it actually fixed the problem.
__________________
Quote:
Soapy water / KY jelly, etc. is is basically a must. Yes, good idea to remove trim panels - only takes 5 more minutes to do so.
Car Camping Collective founding member and Chief Executive Officer
Cat Camping Collective founding member and Chief Executive Officer
Reply With Quote
  #8  
Old February 23rd, 2015, 04:15 PM
Roverlab
Status: Online
Trevor Griffiths
85 110, 92 110, 92 RR, 06 LR3
Member
 
Join Date: Jan 2008
Location: Elizabethotwn, PA
Posts: 1,647
Ignition module still on the distributor housing, or has it been relocated? I know you said you had spark when it wouldn't restart, but I'm curious about the module....
__________________
Roverlab is now British 4x4 Specialists.
Email is
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Same place, new dogs.
Reply With Quote
  #9  
Old February 23rd, 2015, 04:27 PM
cellulararrest's Avatar
cellulararrest
Status: Offline
Chris Snyder
1994 D90 #614 | '07 L322 SC
Member
 
Join Date: Feb 2006
Location: Newburyport, MA
Posts: 1,544
On my range rover when I first bought it (Doug can attest to this) it would cut out just like you shut the ignition off seemingly randomly but almost always when the engine was warm. Sometimes it would start back up after a few minutes. Or sometimes not until about half an hour or so went by.

It turned out to be the ignition amplifier. This was on a 95 (so it's relocated from the side of the dizzy) but it still failed. I swapped it with a good spare I had and the problem never came back.

You say you have spark when it won't start, however. Which would seem to point away from the ignition amp. But the symptoms sound very similar.
Reply With Quote
  #10  
Old February 23rd, 2015, 04:49 PM
cellulararrest's Avatar
cellulararrest
Status: Offline
Chris Snyder
1994 D90 #614 | '07 L322 SC
Member
 
Join Date: Feb 2006
Location: Newburyport, MA
Posts: 1,544
Quote:
5. Ignition amplifier.. wouldn't prevent it from starting
I'm curious why you say this is the case
Reply With Quote
  #11  
Old February 24th, 2015, 12:35 AM
sflash868's Avatar
sflash868
Status: Offline
Stephan Laputka
1995 D-90 SW
Member
 
Join Date: Jan 2004
Location: San Francisco, CA
Posts: 972
I'll admit that my understanding of the ignition amplifier isn't great but I thought if I was getting spark at the plugs then the amplifier could be ruled out as a symptom of preventing the engine from actually starting since it opens the ignition circuit? Once it's running, I get the thing could cut out and cause a stumble, stalling, poor performance etc. but if I get spark it should start, right? (assuming the amplifier was the issue)

The ignition amplifier on this car is original. It's still on the distributor. I think if i'm doing the coil, it would be good measure to relocate it while i'm there. Other than spark at the plug, all the symptoms fit.
__________________
Land Rovers are by far the best looking 4x4 on the back of a flatbed...
Reply With Quote
Reply

Lower Navigation
Go Back   Defender Source > Defender & Series Technical Discussions > Defender Technical Discussions

Tags
engine, part

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
200tdi cutting out randomly BRAB Defender Technical Discussions 5 September 2nd, 2014 02:06 PM
Truck randomly dies... dlane Defender Technical Discussions 12 July 20th, 2011 12:23 PM
D90 randomly stalls when placed to neutral danb.taylor Defender Technical Discussions 2 May 9th, 2007 09:03 AM
Engine Dies: Fuel Pump & ECU Relays? jimngo Defender Technical Discussions 4 October 15th, 2006 01:25 PM
engine dies going downhill?? P1CR Defender Technical Discussions 1 April 16th, 2004 04:08 PM


All times are GMT -5. The time now is 11:43 AM.


Copyright