sudden loss of power

[TJay]

Hi all, I figured I'd better say hello to everyone so nobody thought I was just a dumba** troll or something, anyhoo figured maybe one of you guys or gals might have run into this problem before and could give me a hint or two. I was coming back from camping out on the trunk road west of Rocky on Sunday and it happened twice. First time I was in 4th gear at about 70 km/h it lost power but only for a second then hit the highway and 5th, same thing. After that I drove all the way to Rimbey to drop my trailer, then home at Bashaw without a hiccup. It is a '97 Disco 4.0 and I was pulling a 13' Trillium, although it did do it once shortly after I bought it in February. Don't know if anyone is familiar with the truck but I bought it from Marco in Westlock. It's in pretty decent shape with the usual maintenance issues, swivel ball seals, shocks, dirty intake system etc, but not too bad on rust (ya I hate fixing rust). Any thoughts?

[Red90]

Are you saying it completely dies or just drops in power?  If completely, I would guess an intermittent electrical fault that could be in one of many locations....  Until it fails more permanently all you can do is hunt around for anything that looks obviously damaged or loose.

[TJay]

Nope doesn't die, it's like there is no fuel/air/spark but only for about a second. I've had the intake system apart and cleaned with intake cleaner (not carb) which helped with the idle although I'm clean everything right down to the intake manifold because idle drops down to around 300 at every stop. I've checked all the wiring I can get at and all looks good.Have to work at noon so won't get a chance to check much 'till later.

[Matt H]

Coil packs are known to give this symptom when they are on their way out. At first it happens only under high output/high heat conditions (like towing) but as time go's on it happens more frequently until it happens all the time.

If you have access to an OBD2 scanner check for misfire codes.

Test the coil packs carefully with a multimeter. If you are not sure how to do this a 2 sec Google search will turn up lots of detailed instructions that are applicable to almost all automotive spark ign systems.

Check that you have a really good strong spark at each plug. Test wires and inspect plugs.

Check these things properly. don't just throw a new coil pack at it and see what happens.

Bad news- changing the pack can be a real PITA.
Good news- it's not as bad as changing a coil pack in a D2.

[binch]

"Bad news- changing the pack can be a real PITA.
Good news- it's not as bad as changing a coil pack in a D2. "

ROFL

[TJay]

Thanks Matt, I never even thought of the coil haven't had problems with those since back in the 80's. Now if I can only remember who borrowed my multimeter, or it's a quick trip to PAL.
I got the Torque pro app on android which seems to work pretty good and check for codes this morning. Is there any chance it may be from an O2 or cat?
I've gotten an O2 code a while ago and the left cat went from a slight rattle to full blown about a week ago.
If it could be the cat any suggestions for replacement?

[Matt H]

CAT problems will usually trigger emissions codes (and CEL) before you notice any running problems.

[RWAYOUT]

If it triggers a misfire code, then great. It will need to happen more than once to do it. P300 will be muliple misfires. So that would make it harder.
If the coil ( s ) are getting weak, the missfire will be problematic as they get hot . A Coil Tester will show which coil is the problem child or if its not firing a steady rate, or a plug wire issue.
Also , how old are the plugs and what gap are they at?

Another possible issue could be a Crank Sensor.

[TJay]

Couldn't find my multimeter so had to go to Red Deer for a new one so hooked up the Torque pro app and the truck hiccuped a few miles out of town.
It was only up to about 80 C and it doesn't last long enough to pull a code.
I did check for codes about half way and got P1187 and P1193 pending.
I checked the coil, wires and plugs ( all gapped properly and looked good )
Don't know how old the plugs are but the wires appear to be fairly new.
It doesn't seem to be a heat related problem because this time it was fairly cold.
To possibly better describe how it acts, its as if you took your foot off the throttle then put it right back on.
I'm heading out camping tomorrow 'till Sunday so I will see if I can get it to trigger a code ( hope I don't get stranded ).  :-\

[Matt H]

Have you checked the fuel filter or fuel pump pressure?

Filter testing involves destroying the old filter but at least you will see if it is clogged or not and the fuel pressure should be 33.8-38.5psi, if memory serves. A poor/corroded electrical connection at fuel pump harness connector is also not unheard of.

I suppose it could be a faulty injector but I would start with a new fuel filter and work from there. There is a long list of things it could be so start with the simple/maintenance stuff first and work your way up.

[pechanec]

definitely check wiring harness plug at fuel pump. its a piece of crap and an ongoing issue on my 97. good news is a wiggle will often solve the issue.

[TJay]

Well three days of camping & fishing and I couldn't get the durn thing to hiccup even once.
Out west of Sundre and the trunk road was rough even went on a few trails bounced it around pretty good.
Maybe checking the plugs, wires and coil appeased Lucas' ghost I don't know.
Since I've only had it for about 6 months I'm still going to keep checking things.
I have a new fuel filter to put on, Matt, so I'll rip the old one apart just 'cause and check the pump wiring, pechanec.

NOW I have to track down why the brake lights decided to go awol on me Sunday afternoon, aah the joys of an old rover.

Tom