94 montero sr engine problem 3.5

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94 montero sr engine problem 3.5

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Mitsubishi Forum >> Mitsubishi Models >> Mitsubishi Montero & Montero Sport >> 94 montero sr engine problem 3.5

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94 montero sr engine problem 3.5 - 2/22/2007 11:57:48 AM

Posts: 2
Joined: 2/22/2007
Status: offline

Im used to get 18mpg @80mph and now im getting 15mpg @ 80mph. Ive also have noticed loss of power climbing a hill i regularly climb i now have to shift out of overdrive to maintain 80 up the hill and recently the egr temp valve popped out and they cleaned up the threads and reinstalled it but i still have an engine noise simular to a disieling sound in the rpm range of 2000 to2200 rpm no noise present before or after that range, engine has 226,000 miles and spark plugs have 76,000 on them timing belt has 46,000 miles on it and i have always ran regular gas instead of high octane.And it uses about 1.5 qts of oil in 3000 miles

Maybe the engine is just wearing out !

Any ideas what going on here with my power and fuel economy?

Post #: 1

RE: 94 montero sr engine problem 3.5 - 2/22/2007 12:06:42 PM

contourcrazy

Posts: 9
Joined: 1/15/2007
Status: offline

I would say that it is trying to age a little. lmao

(in reply to gj)

Post #: 2

RE: 94 montero sr engine problem 3.5 - 2/22/2007 12:34:18 PM

off roader

Posts: 419
Joined: 10/20/2005
Status: offline

Timing belt won't be an issue. Still too young and only affects timing. If it's screwed up, you'll experience worse affects.

I suspect the plugs (& plug wires?) having 76k on them might have something to do with your problem.

Also, I've heard running lower than rated octane my have long term effects on the motor. Perhaps this is one of those.

_____________________________

1990 3.0L SOHC V6 4 Door Montero
Custom bumpers, rocker panel protection & skids
Built for wheeling.

1989 3.0L SOHC V6 2 Door Montero
Off road virgin... about to change that <GRIN>

(in reply to gj)

Post #: 3

RE: 94 montero sr engine problem 3.5 - 2/23/2007 1:13:51 AM

matthew_m75

Posts: 46
Joined: 2/17/2007
Status: offline

if ur engine is consuming 1.5 every 3000 miles and its been 76,000 miles since ur plugs were replaced then its very likely you have one or more oil fouled spark plugs. i would defineatley start at the spark plugs and wires since its a cheap fix. but if your EGR is damaged or causing a vaccume leak it could cause a change in performance and gas mileage. but also as a mechanic i would have to say as long as your owners mmanual says you can use 87 octane then it shouldn't effect anything but i wouldn't recomend using cheap fuels regularly like arco, suppose this is mostly opinion but using chevorn or shell regularly can go a long way.
although you have probably already done this some other possible causes could be the air filter, fuel filter, or dirty fuel injector(s)

(in reply to off roader)

Post #: 4

RE: 94 montero sr engine problem 3.5 - 2/23/2007 1:55:41 AM

acapulco36

Posts: 2
Joined: 5/23/2005
Status: offline

What about the ignition coils. I had one go bad on a 96 sr and the miss was at a specific rpm level, can not recall any diesel sound though, but it may be worth
checking out.

(in reply to matthew_m75)

Post #: 5

RE: 94 montero sr engine problem 3.5 - 2/23/2007 10:51:50 AM

Winshawn

Posts: 269
Joined: 1/31/2005
Status: offline

Is the diesel sound, "pre-detonation" or "pinging" "knocking"? Try a tank of high octane and see if it gets better. You might have carbon built up in your cylinders, which can cause pre-detonation. There are various methods to help remove carbon build up in your cylinders. Look it up on the internet.

I don't think 1 qt per 2000 miles would affect your spark plugs. I would not worry until your consumption gets worse than 1qt per 1k miles.

_____________________________

'90 Montero (sold-sadly)
'95 Montero LS (166k) - my car
'03 Montero Limited (36k) - wife's car

(in reply to acapulco36)

Post #: 6

RE: 94 montero sr engine problem 3.5 - 2/23/2007 11:38:52 AM

off roader

Posts: 419
Joined: 10/20/2005
Status: offline

quote:

ORIGINAL: Winshawn
...
I don't think 1 qt per 2000 miles would affect your spark plugs. I would not worry until your consumption gets worse than 1qt per 1k miles.

It may be loss due to valve guide seal wear as well.

(in reply to Winshawn)

Post #: 7

RE: 94 montero sr engine problem 3.5 - 2/25/2007 2:52:03 AM

mxmikie