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Tune Up Advice

2K views 11 replies 11 participants last post by  Ragland 
#1 ·
I have had my D90 (1995) for aobut 2 years, bought it with 40K, put on about 10k miles. Recently it has been running rough (sort of 'skipping' when it idles), rough starts (especially when its raining or wet out), and a fuel smell when you shut it off (and I think its getting poorer than normal gas milage).

Also, the shop here in boston wants to do a "Fuel Injection Service", which involves hooking up a device to essentially clean out the system with a fluid.

Oh yeah, noticed that some type of sensor on a coolant hose (righ on the front of the engine) isn't plugged into anything. its a wide hose, right behind the fan belt. Anyone seen that before?

This is the first service that its had since I have had it and the first time I have gone to this shop (Boston Roverland), so I am a bit nervous.

Thanks
 
#3 ·
bbusino said:
I have had my D90 (1995) for aobut 2 years, bought it with 40K, put on about 10k miles. Recently it has been running rough (sort of 'skipping' when it idles), rough starts (especially when its raining or wet out), and a fuel smell when you shut it off (and I think its getting poorer than normal gas milage).

Also, the shop here in boston wants to do a "Fuel Injection Service", which involves hooking up a device to essentially clean out the system with a fluid.

Oh yeah, noticed that some type of sensor on a coolant hose (righ on the front of the engine) isn't plugged into anything. its a wide hose, right behind the fan belt. Anyone seen that before?

This is the first service that its had since I have had it and the first time I have gone to this shop (Boston Roverland), so I am a bit nervous.

Thanks
Before doing much, I would replace (one at a time, to see which one makes a difference):
- air filter
- spark plugs
- spark plug wires
- rotor cap
- solenoid
 
#4 · (Edited)
bbusino said:
Oh yeah, noticed that some type of sensor on a coolant hose (righ on the front of the engine) isn't plugged into anything. its a wide hose, right behind the fan belt. Anyone seen that before?

Thanks
The temperature sensor in the thermostat housing (engine end of the top Radiator hose) is hooked up to the airconditioning harness. If you have no air conditioning then the sensor will not be connected to anything.
 
#8 · (Edited)
evilfij said:
You can do all of a tune up at home. "Fuel injection service" does not really do much in my experience.

Plugs, rotor, cap and wires should fix your truck. Probably $100-150 in parts and an hour of labor at home.
If you go the Genuine LR route for parts, expect to pay close to 200 bucks :eek: , well at least that's the RN and stealership price...

It easy to do...while your in there you can give the motor a look-over, check for leaks and what-not...oh yeah...and have a couple of brews while doing so...

Cheers...
 
#9 ·
mdmccallum said:
Or does their computer do something we can't do at home?
Not as far as I can tell. In theory yes, in practice, no. The 4.0L ECU is the one doing the work. If it's doing it, there is nothing to do. In your case, clean the exhaust return pipe & flame arrester, check for air leaks on the intake.
No rotor/distributor cap on the 4.0L.

I run a fuel injector/valve cleaner once every 10K miles to be on the safe side. But I hear that the problem is more on the exhaust valve anyway, so nothing that can be done there.

Follow-up Post:

bbusino said:
I have had my D90 (1995) for aobut 2 years, bought it with 40K, put on about 10k miles. Recently it has been running rough (sort of 'skipping' when it idles), rough starts (especially when its raining or wet out), and a fuel smell when you shut it off (and I think its getting poorer than normal gas milage).
If the "standard" tune-up does not help in your case, you might want to consider replacing the O2 sensors. I heard that sometimes the '93-'95 Defender ECU does not (can not?) detect a bad oxygen sensor and mpg will go down the drain (and poor power/performance). Obviously, those are not cheap, so consider this a last thing to do. But I think the standard "tune up" will do it excellent.
 
#10 ·
Before going nutty with the injector servicing, I'd do the normal tune-up stuff first. New air and fuel filters, when was the last time you checked the plugs and wires? It's little and easy stuff to do. But because you are mentioning a fuel smell, there is a possibility that the injectors ARE clogged. When you drive it, is it a lot of short trips? or occasional long trips?

As to the injector cleaning itself, a good additive cleaner is just as good as anything that just squirts fluid through. For a serious cleaning, the best option is to send the injectors out for an ultrasonic cleaning. When you get that type of service done, they actually do flow testing and pattern checking, as well as tearing them apart to put new seals and screens in. I've been reading a lot into that lately, and will probably send mine out soon. I'm most likely going to go with this shop ( http://www.cruzinperformance.com/injsteps.html ) since they actually give you the before and after data sheets. Price isn't bad either, $130 for the whole set + shipping.

Oh, and I haven't followed up on that other post yet, but she's running again finally. But still needs some tweaking, acting really sluggish and burbling out the exhaust when I shift. But starts right up.
 
#11 ·
Fuel injector cleaning is worth the effort. I had mine done about 2 months ago at a local NAPA, they supplied me with the before and after flow test chart, they were all dribblers. This is on my 1995 D-90 with 150k miles. It starts easier and has more power, I can run up a highway grade to work in 5th that used to require down shifting to 4th.
 
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