Isuzu Amigo Frequently Asked Questions, FAQs

FAQs

Isuzu Amigo Frequently Asked Questions
by dallas nunn

The first generation Isuzu Amigo was first released in the US in 1989 and was built until 1994. It came in 2 trim levels S, and XS, 4x4 or 2x4, and either a 2.3l carbureted or a 2.6l fuel injected engine. The second gen Isuzu Amigo was released in 1998 and also comes in 4x4, or 4x2. The second gens come in either soft-top or hardtop and can be had with either a 2.2l 4cylinder or a 3.2 V6. Here are some of the most frequently asked questions about the Amigo.

1. What size tires can I fit on my truck?

For 1st gens you can fit up to a 32 x 11.5 x 15 tire on the stock rims without rubbing or lifting. To run anything larger you will need to lift the truck AND trim the wheel wells.

On second gens you can fit a 265/70R16 without rubbing and if you trim the fender flare very slightly at the rear corner you can fit a 265/75R16. This is comparable to a 32x10.5. If you keep the stock 16" rims you can fit a 32" metric tire but if you go to 15" wheels you can only fit a 31x10.5 because of the width.

2. What lifts are available for my Amigo, and how high can I go?

There are two commercially marketed 3" suspension lifts for the 1st gen Amigo from Calmini and Darlington Off-Road. They both use the same techniques for lifting the front by cranking up the torsion bars, and they both come with replacement shackles for the rear. The Calmini kit uses an add-a-leaf in back and DOR uses totally new spring packs. You can also lift your truck about 2.5" by simply cranking the front torsion bars and putting in an add-a-leaf in the rear. There is also a 3" body lift that is marketed by Performance Accessories that includes all the brackets for front bumper radiator air duct and seat belt relocations. This lift cannot be used with an auto transmission and you will need to extend and rebend the shifters on the manual tranny.

Calmini has just recently come out with a 3" lift for the 2nd gen Amigos that includes all the pieces you could ever need to lift your newer Amigo. DOR has also just released a lift for second gen Amigos and if it follows the DOR standards in construction it should be nothing less than great. The other option you have is what is known as the CP lift. This is pretty much a do it yourself lift that involves cranking the front torsion bars and buying new longer springs and shocks for the rear. You can lift your truck anywhere from 1" to 4" this way depending on the springs you choose. Instructions for this lift are provided in the "lifting a late model Isuzu" section on the 4x4wire.com Isuzu main page.

For more information on these lifts you can go to the manufacturer pages at: www.calmini.com and www.darlington-off-road.bigstep.com

3. What axles do I have in my Amigo?

The 89-94 Amigos came with these axle options:
4x4- Rear Isuzu Corporate 12 bolt, Front Isuzu Corporate 10 bolt
4x2 with 2.6L engine- Isuzu Corporate 12 bolt
4x2 with 2.3L engine- Isuzu Corporate 10 bolt

The 98 and newer Amigos come with these axles:
Rear- Dana 44
Front- modified Isuzu 10 bolt
Some of the new Amigos came from the factory with a limited slip differential in the rear, this would be identified by a G80 code on the option id plate under the hood.

4. What are my gear ratios, and what is my crawl ratio?

The early Amigos with 4x4 all came with 4.55:1 axle gear ratios, 2.28:1 4lo transfer case gear ratios and a 3.767 1st gear in the tranny. Here is a list of the combined gear ratios to find your final gearing. Also added in are the numbers for the upgraded gear sets for the front and rear axles.

3.767 x 2.28 x 4.55 = 39.1:1
3.767 x 2.28 x 4.77 = 41.0:1
3.767 x 2.28 x 5.38 = 46.2:1
Here are these same figures but with the tera low t-case gears added into the mix for an even lower gearing.
3.767 x 3.07 x 4.55 = 52.6:1
3.767 x 3.07 x 4.77 = 55.2:1
3.767 x 3.07 x 5.38 = 62.2:1

5. How can I get more power out of my engine?

The first gen Amigo was pretty underpowered even with the larger 2.6 engine, but there are a few things you can do to help.

EXHAUST
The first thing many people look at is the exhaust. The early Amigos came with a really complex very restrictive exhaust system. Your first option is the complete cat back system from Calmini. The second option is to take your truck to a good exhaust shop where you can have a very nice 2-1/4" exhaust built that will not only be straighter and more free flowing but will be much higher up and less likely to get damaged off road. Expect to pay about $300, money very well spent in my opinion. It made a big difference on my Amigo. Both Calmini and Pacesetter offer headers for the 2.6 as well.
INTAKE
Next many people look at the intake, you can get a complete intake system with a cone filter from Calmini or Injen, or just put in a K&N stock replacement filter, either one will help a bit. If you want to just stick a cone filter on the end of the MAF the inlet is 3-1/4" so order a filter with that size opening in it.
CAMS
You can get higher performance cams from Calmini and Delta, which have been tried by a number of people with good results. Calmini is a totally new cam and Delta is a regrind of either your old cam or you can have them send you a cam and then send them yours back. To do this you have to pay a core charge in addition to the price of the cam. Calmini only offers a mid-high cam where as delta offers a low and a mid-high cam as well as a stock replacement. All of the power gains mentioned here are either seat of the pants estimates by those who have installed these cams, or manufacturer claims. No real dyno tests have been done so there is no way to tell where you actually gain power in the rev range other than by using the "butt dyno".
OTHER
A few people have changed out their stock ignition system to a performance one such as an MSD or Jacobs with some success. There are also some minor gains from doing smaller things like high performance spark plug wires and platinum plugs, etc. Do not expect to make any huge difference in power on your 4 cylinder Amigo. All of the above modifications will get you extra power but none of them will boost your little 2.6 from 120HP to 300HP, it's just not possible.

6. How do I get the O2 sensor light to turn off after I change the sensor?

The O2 light is programmed from the factory at certain mileage intervals, so even if you change your sensor before the light comes on, it will still turn on when you hit the correct mileage. To turn off the light you have to take off the instrument cluster. On the back next to the Speedo cable input there will be two holes that are connected by a trace on the circuit board. One will have a screw in it the other will not. All you do is switch the screw from one hole to the other and the light will turn off. You will have to repeat this process every 90k miles, as this is when the computer is programmed to turn the light on.

7. Why does my check engine light keep coming on?

The check engine light is one of the most useless gauges known to man. Unless it stays on for a long period of time (say, several days) don't even pay attention to it, and even then, don't worry about it much.... Only worry if it's FLASHING, That indicates a serious problem. It'll come on as it pleases (due to some test that it might fail, like for instance, riding the brake while it's in gear, which you may tend to do off-road) but it goes off only after certain conditions are consistently met, and only after a certain number of on-off key cycles. The check engine light used to actually mean something on older cars and trucks but now it's pretty much entirely emissions related.

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EXHAUST
The first thing many people look at is the exhaust. The early Amigos came with a really complex very restrictive exhaust system. If you take your truck to a good exhaust shop you can have a very nice 2-1/4" exhaust built that will not only be straighter and more free flowing but will be much higher up and less likely to get damaged off road. Expect to pay about $300, money very well spent in my opinion. It made a big difference on my Amigo. Both Calmini and Pacesetter offer headers for the 2.6 as well.
CALMINI also makes an entire cat-back exhaust for Amigos and most other Isuzus.

CAMS
With little to no actual dyno experience on thse reported mid-high vs. low gains, I'd rather see verbiage in there something like: 'Folks who have installed the cams report....' or 'The vendor reports...' I just hate to report something based only on seat-of-the-pants feel....

All of the above modifications will get you extra power but none of them will boost your little 2.6 from 120HP to 300HP, it's just not possible.
Well put!

2nd-gen Amigos, 265/75R16's are 32x10.50. If you stick with the 16" rims, you can fit a metric 32" tire on there, but if you go to 15" rims, the best you can do is a 31x10.50R15. It's the width that gets you, not necessarily the height.

Calmins 3" Susp: also comes with new front upper a-arms, SS brake lines, HD Torsion bars, Urthane bushings, bump stop extenders (who needs them).

Perf mod: There is a replacement ECU chip as well but I don't know if anyone has tried it.

Lockers: Don't forget lockers.. ARB, Lock-rite, MECA, Powertrax?

Easy enough:

Final Drive = (Tranny Ratio) x (Transfer Case Ratio) x (Axle Ratio)

First Gen manual Amigos and pickups all have the MUA5 tranny with a 3.767 first gear and a 2.28 transfer case ratio. TTBOMK, they were only available with 4.55 gears stock, though some have upgraded to 4.77s.

Therefore, the following permutations exist:
3.767 x 2.28 x 4.55 = 39.1:1
3.767 x 2.28 x 4.77 = 41.0:1
3.767 x 2.28 x 5.38 = 46.2:1
or, with Tera gears:
3.767 x 3.07 x 4.55 = 52.6:1
3.767 x 3.07 x 4.77 = 55.2:1
3.767 x 3.07 x 5.38 = 62.2:1
If you have a swapped in tranny (like a Toyota), then figure your crawl out yourselves, ya slow-moving bums!

What are they called and where?
Amigo - Mu - Trooper - Rodeo - Jackaroo - Bighorn - etc. . .

2nd Gens...

To keep your fog lights on with high or low beams, is an easy procedure.

To start with, pop off the carrier that holds the three switches to the left of the steering wheel using a flathead on the bottom of the carrier about a quarter inch off the two bottom corners and it will fall right out.

From there, snip the Yellow/Red wire (#4, second from the end) in the diagram.

Then ground the tail of the switch (the wire coming out of the switch), I grounded mine to the cigarette lighter. The ground wire on the cigarette lighter is the wire that attaches to the side of the back of the lighter.

Put everything back together and now you will be able to run your fogs on with high and low beams.