Engine losing power temporarily - Defender Source
Defender Source  

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


Reply
 
Thread Tools
  #1  
Old August 9th, 2015, 07:34 PM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
Engine losing power temporarily

Been having a recurring intermittent issue I can't wrap my head around. Thought it might be bad gas but need advice. I have a 1994 NAS Def 90 with stock 3.9L V8.

Issue: on occasion the vehicle suddenly stutters and loses power dramatically but does not actually stall. It can happen at highway speeds and lower speeds. Some times just for a minute or less sometimes a few minutes.

The car runs like it is not getting air out the exhaust almost like someone stuck a banana in the tail pipe. Sounds very muffled and runs on limited power even if floored for a while then goes fine again.

I noticed twice that when it did this and I got a look underneath the cat converters seem very hot (more than normal actually one was glowing red) and I smelled a slight burning smell.

When I shut the engine off, it starts right up and is perfectly fine until it happens again (could be weeks before it happens again).

What I have changed recently (within past 8-10 months) as new parts:
Fuel filter
Fuel pump
Fuel pump relay
Fuel lines
spark plugs, distributor, tune up
Throttle position switch
Cat converters and exhaust
Cleaned out MAF
K&N air filter
Snorkle

What I haven't changed:
O2 sensors

Any thoughts? I don't know what "bad gas" symptoms are like but a few said it could be that.

Any advice would be appreciated!
Thanks,
Will
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old August 9th, 2015, 07:47 PM
javelinadave
Status: Offline
-
-
Member
 
Join Date: Sep 2003
Location: -
Posts: 5,394
Quote:
Originally Posted by wmatos1001 View Post
The car runs like it is not getting air out the exhaust almost like someone stuck a banana in the tail pipe.

Have you seen this guy hanging around your truck?



Good luck with finding the fix.
Reply With Quote
  #3  
Old August 9th, 2015, 07:55 PM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
ha! good one
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old August 9th, 2015, 10:25 PM
navydevildoc's Avatar
navydevildoc
Status: Offline
Neill Thornton
1984 D90 300 Tdi / 1965 Series IIA
Site Team
 
Join Date: Nov 2010
Location: San Diego, CA
Posts: 1,586
Registry
Coil comes to mind to me... the red hot cats mean it's running lean, which runs hotter. How's your engine temps? Does the little code box display anything after one of these episodes?
__________________
"It doesn't swoop, curve, or look like it's going fast when it's parked. It never looks like it's going fast. It doesn't go fast." - Richard Hammond, BBC Top Gear


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #5  
Old August 9th, 2015, 11:12 PM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
Engine temp seems fine nothing unusual there. I hadn't thought to check code usually too focused on the issue. Silly question what is a coil?
Reply With Quote
  #6  
Old August 10th, 2015, 01:12 AM
Rocky's Avatar
Rocky
Status: Offline
Chris
72 + D1 drivetrain
Member
 
Join Date: Sep 2006
Location: Colonies Aka Boston
Posts: 8,664
Quote:
Originally Posted by wmatos1001 View Post
Engine temp seems fine nothing unusual there. I hadn't thought to check code usually too focused on the issue. Silly question what is a coil?
It looks like a thin but tell version of a can of soda, with a large ignition style wire coming out of it. This large wire goes to the distributor. It's mounted inside the engine bay on the fender
Reply With Quote
  #7  
Old August 10th, 2015, 03:30 AM
navydevildoc's Avatar
navydevildoc
Status: Offline
Neill Thornton
1984 D90 300 Tdi / 1965 Series IIA
Site Team
 
Join Date: Nov 2010
Location: San Diego, CA
Posts: 1,586
Registry
Quote:
Originally Posted by Rocky View Post
It looks like a thin but tell version of a can of soda, with a large ignition style wire coming out of it. This large wire goes to the distributor. It's mounted inside the engine bay on the fender
The important part is that the coil provides the high voltage juice to fire your spark plugs. They are also notorious for having issues once they heat up. Poor current production from the coil = less electricity for the spark plug = no cylinders firing correctly.
__________________
"It doesn't swoop, curve, or look like it's going fast when it's parked. It never looks like it's going fast. It doesn't go fast." - Richard Hammond, BBC Top Gear


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #8  
Old August 10th, 2015, 08:15 AM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
Thank you both I will look into that and see if it needs replacing. Appreciate the advice!
Reply With Quote
  #9  
Old August 10th, 2015, 08:55 AM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
I ended up finding a new OEM Bosch Coil on line for a good price and also decided to get two new O2 sensors and replace those as well. I have heard they recommend replacing those between 60k and 90k miles. I bought mine with 117k miles on it and don't know that they have been changed (may be original). So while I'm at it I might as well do those as I understand it could also be causing the problem. Doesn't look like my code reader is working.

I have seen a video online on how to replace a later model with 4 o2 sensors and it looks pretty simple. Any trick to doing this that I'm missing? I don't have stock cats but assume it is the same concept as stock?
Reply With Quote
  #10  
Old August 10th, 2015, 11:16 AM
flippedrover's Avatar
flippedrover
Status: Offline
Tyler
'94 D-90
Member
 
Join Date: Dec 2003
Location: Ashburn,va
Posts: 3,112
I'd also check your cats to see if one is starting to clog
__________________
Can't you feel 'em circlin' (closin'in) honey?
Can't you feel 'em swimmin' around?
You got fins to the left, fins to the right,
and you're the only bait in town.
You got fins to the left, fins to the right,
and you're the only girl in town.

Jimmy Buffett


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote
  #11  
Old August 10th, 2015, 12:03 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:
Originally Posted by wmatos1001 View Post
I ended up finding a new OEM Bosch Coil on line for a good price and also decided to get two new O2 sensors and replace those as well. I have heard they recommend replacing those between 60k and 90k miles. I bought mine with 117k miles on it and don't know that they have been changed (may be original). So while I'm at it I might as well do those as I understand it could also be causing the problem. Doesn't look like my code reader is working.

I have seen a video online on how to replace a later model with 4 o2 sensors and it looks pretty simple. Any trick to doing this that I'm missing? I don't have stock cats but assume it is the same concept as stock?
The code reader will only display something if the check engine light is on. And, at least on my truck, occasionally I'll pop a check engine light with no code at all. Go figure - Sorry I didn't see this earlier. I have the stock coil from my truck sitting in the basement I took out at ~60k miles.

I like the catalytic convertor thought, but would surprised if that's the issue if they're not rattling at all. As far as replacing the O2 sensors, it's pretty easy (a flare nut wrench makes it easier). Just make sure you spray with PB Blaster or something equivalent. Sometimes they come out easier with the exhaust hot, sometimes not.

------ Follow up post added August 10th, 2015 01:04 PM ------

I do have rovergauge all setup if you want to check out how your O2 trim looks. But I'm not sure how helpful that'll be in this case.
Reply With Quote
  #12  
Old August 10th, 2015, 12:10 PM
Ren Ching's Avatar
Ren Ching
Status: Offline
Skinny Pete
'84 90 "Yamelo"/'88 RRC "Chewbacca"
Member
 
Join Date: Mar 2007
Location: Downtown
Posts: 4,696
Registry
Ignition is cutting out, probably due to a bad amplifier or amplifier wiring. When it cuts out you are dumping raw fuel into those new cats which is what is causing them to glow. Won't take long to damage the cats.
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Present:
1960 SII 109"- "Red Square"
1984 90 Tdi- "Yamelo"
1988 RRC- "Chewbacca"
1987 RRC- "Chewy 2"
2008 RRS SC- "The Supersofa"

Past:
1959 SII 88"- "The Little Green Beastie" last seen in NY
1972 SIII 88"- "GreenHELL" now in NC
1988 90 "Eric the Half a Bee" half a truck, sold for parts
1991 RRC- never got a name- long since recycled
Reply With Quote
  #13  
Old August 10th, 2015, 12:57 PM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
Quote:
Originally Posted by Ren Ching View Post
Ignition is cutting out, probably due to a bad amplifier or amplifier wiring. When it cuts out you are dumping raw fuel into those new cats which is what is causing them to glow. Won't take long to damage the cats.
That's good to know as well. Would you recommend taking the cats out when replacing the O2 sensors? And when looking into the cats is there something in particular I should be looking for? Like burnt fuel?

It has happened in total about 5 times never for very long (a minute or two) so I'm hoping these brand news and expensive cats are okay?!?

Thanks!
Reply With Quote
  #14  
Old August 10th, 2015, 02:25 PM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
Quote:
Originally Posted by Ren Ching View Post
Ignition is cutting out, probably due to a bad amplifier or amplifier wiring. When it cuts out you are dumping raw fuel into those new cats which is what is causing them to glow. Won't take long to damage the cats.
I ordered a new 3pin ignition amplifier module as well (Lucas) so thanks for the advice. Prior owner looks to have done the popular remount of this module to the same location on side wall as the Coil to keep it away from excessive heat. So since I am replacing the coil and this is on the same mount now made sense to replace as well and just cancel that possibility out

Thanks for the advice.
Reply With Quote
  #15  
Old August 10th, 2015, 02:52 PM
MonLand
Status: Offline
Loic Fabro
95 D90 - 96 Disco -06 LR3
Member
 
Join Date: Oct 2003
Location: Herndon, VA - USA
Posts: 1,640
Registry
Be careful.... It is very easy to throw parts (and money) at a problem. You got a lot of advice with all possible solutions to a problem. Just make sure you figure out what problem you are addressing. My advice would be: only fix "one problem" and wait for "another problem" to appear before you try to address it. You don't want to have to chase -two- problems at the same time.
__________________
Quote:
I have an ex MoD and an ex wife. The two no longer conflict with each other.
Quote:
it is not hoarding it is selective collecting
---
MonLand
1995 D90 NAS
1996 Discovery NAS
2006 LR3 NAS (hers, but comfy! :) )
Reply With Quote
  #16  
Old August 10th, 2015, 03:50 PM
Rocky's Avatar
Rocky
Status: Offline
Chris
72 + D1 drivetrain
Member
 
Join Date: Sep 2006
Location: Colonies Aka Boston
Posts: 8,664
Quote:
Originally Posted by MonLand View Post
Be careful.... It is very easy to throw parts (and money) at a problem. You got a lot of advice with all possible solutions to a problem. Just make sure you figure out what problem you are addressing. My advice would be: only fix "one problem" and wait for "another problem" to appear before you try to address it. You don't want to have to chase -two- problems at the same time.
Ain't that the truth.
Sometimes you just have to wait for stuff to break completely to figure out what's wrong.
Took months of on again off again work starting at WR before I figured the Dizzy and rotor were toast.
Reply With Quote
  #17  
Old August 10th, 2015, 04:16 PM
Contractor's Avatar
Contractor
Status: Offline
Will
1969 IIA
Member
 
Join Date: Aug 2013
Location: The South
Posts: 553
Land Rover Defender Forum - Defender & Series Owners Community




Mine ended up being really simple, but pretty much the exact same problem.
Reply With Quote
  #18  
Old August 10th, 2015, 04:58 PM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
Quote:
Originally Posted by MonLand View Post
Be careful.... It is very easy to throw parts (and money) at a problem. You got a lot of advice with all possible solutions to a problem. Just make sure you figure out what problem you are addressing. My advice would be: only fix "one problem" and wait for "another problem" to appear before you try to address it. You don't want to have to chase -two- problems at the same time.
Totally understand and great advice. I do plan on changing one item, drive for a while make sure all is okay before moving on.

------ Follow up post added August 10th, 2015 06:00 PM ------

Quote:
Originally Posted by Contractor View Post
Land Rover Defender Forum - Defender & Series Owners Community




Mine ended up being really simple, but pretty much the exact same problem.
what was the issue on yours?
Reply With Quote
  #19  
Old August 11th, 2015, 09:03 AM
Contractor's Avatar
Contractor
Status: Offline
Will
1969 IIA
Member
 
Join Date: Aug 2013
Location: The South
Posts: 553
Dirty connections on the wiring harness @ the fuse block. Pulled them, cleaned them and put a little grease on them.


For some reason my link did not work, but if you search for threads started by me you can find it. Tons of other good information in the thread.
Reply With Quote
  #20  
Old August 11th, 2015, 07:05 PM
wmatos1001's Avatar
wmatos1001
Status: Offline
William
1994 NAS Defender 90
Member
 
Join Date: Aug 2014
Location: New Hampshire
Posts: 409
Registry
Quote:
Originally Posted by Contractor View Post
Dirty connections on the wiring harness @ the fuse block. Pulled them, cleaned them and put a little grease on them.


For some reason my link did not work, but if you search for threads started by me you can find it. Tons of other good information in the thread.
You know that reminds me. Just yesterday looking at where the coil and amplifier are I was poking around and near the fire wall noticed a block of fuses near the fire wall that was just hanging loose. Looked totally unusual to me and don't recall ever seeing it just hanging like that. I will snap a pic when I have a minute. But is that the fuse block you are referring to? If so I assume it is not just supposed to dangle as a bunch like that and actually be fixed to something like the fire wall/bulk head?
Reply With Quote
Reply

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

Tags
engine

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 losing power mightymo Defender Technical Discussions 8 September 22nd, 2013 11:31 AM
Sealings screw holes temporarily Bryanfor311 Defender Technical Discussions 2 May 22nd, 2012 02:36 PM
Engine running rough temporarily cgalpin Defender Technical Discussions 8 May 13th, 2009 12:45 PM
engine temporarily runs.. help sflash868 Defender Technical Discussions 4 July 31st, 2006 10:59 AM
losing power Ray Bone Defender Technical Discussions 6 September 21st, 2005 07:53 AM


All times are GMT -5. The time now is 09:31 PM.


Copyright