98 Amigo Looses power on Acceleration


#1

My husband and I just recently (probably a little over a month ago) received a 1998 Isuzu Amigo 2.2 5 speed from a friend as a gift. We had some issues with it and discovered the spark plug wires were in the wrong order on the coil pack. We fixed this and the car ran great for about a day then started bogging down and eventually wouldn’t start at all. We discovered at this point that there was a blown head gasket so we took apart the head sanded it down, cleaned everything replaced all the gaskets when putting it back together. We also found at the same time that the timing was off so we fixed that as well. After putting everything back together the car ran awesome for about 2 1/2 days and now when we go to drive it we turn it on it idles fine no issues but when we go to drive it once we put it into gear and press the gas sometimes we have power and sometimes there is no power. It comes and goes and when it is there it runs great but then we loose power again. We have tried replacing carburetor cleaning all the parts and spark plugs rechecking the torque on bolts on the head and nothing seems to work. And now there is a clicking noise coming from what seems like the exhaust side of the motor. Does anyone have an idea as to what this is? My husband and I are on a very limited income and so we have to fix this ourselves. Thank you for any response!


#2

Suggest to do a compression check. You may have a sticking valve.


#3

Boy?

I don’t know where to start?

The first thing I’m going to ask is, were NEW head bolts used when reinstalling the head, and were they torqued to spec?

The second thing I’m going to ask is, what do you mean when you say that you took apart the head and sanded it down?

Tester


#4

We have tried replacing carburetor…

That must have gone poorly, since this vehicle is fuel injected.


#5

The source I’m looking at says the same thing, a 2.2 L 4 banger electronic fuel injected engine. OP is perhaps thinking the part that they cleaned is a carburetor, but it is actually something else instead. Maybe the throttle body. Either that or OP is outside the USA. Where are you and where does your Amiga hail from OP?

Presuming this is actually a fuel injected engine, my second guess – a sticky valve being the first – with an intermittant bogging down during acceleration symptom would be a problem from among the following

  • fuel pressure, most likely
  • fuel filter
  • engine air filter
  • cat, to less likely

#6

1- yes you are right it is the throttle body, my mistake put the wrong word

2-no we did not use new head bolts, the kit for all the gaskets we bought did not come with them and as how we had no vehicle to drive to get any we were forced to reuse. We did however torque them down to specs from Haynes manual on the vehicle

3- as for the sanding when we took the head off it was uneven so we sanded it down until it was flat. We have had no leaks what so ever since putting it all back together.

I will run your suggestions by my hubby and see what he says. Thank you all


#7

It sounds like you are on the right track, doing the best you can as diy’ers. Usually when replacing the head gasket the head is taken to a professional machine shop for flattening the gasket surface area. They have a machine that does this job very accurately. I’m not sure how much that costs, but I’d guess it is a fairly reasonable fee if all you need is the flattening done, sometimes also called “skimming” I think.

There’s no fundamental reason why using an abrasive like you did wouldn’t work too, but it’s a tricky job using sandpaper I imagine to get it as flat (straight) as the manufacture’s spec for the engine-rebuild requires. Not having a visible leak isn’t the same thing as the head gasket isn’t leaking. A leak can occur internally, for example between the cylinder under compression and the coolant jacket. That could cause a loss of performance and drivability problems.

Some head bolts can be re-used, and others not so much. If they are the torque-to-yield type, I don’t think those are recommended to be re-used. I’m not sure what the symptom would be if you re-used them though, maybe difficult to achieve the correct amount of tightening, uniform over the entire head/block interface.

I continue to think a compression check might be next on your agenda.


#8

I agree with Tester; where to start. That ticking on the exhaust side could be an exhaust manifold gasket giving up. Keep in mind that a cylinder head can warp in more than one plane. The exhaust and intake manifold flanges can warp along with the head gasket surface.

What would I do as a first step if the car was in my hands? I would connect a vacuum gauge to it and get a feel for what’s going on with the engine. A vacuum gauge can point out low compression, vacuum leaks, timing off, clogged exhaust, etc, etc.

Maybe this loss of power is a flaky fuel pump which is intermittent. Those can be fine one moment or dead and not running the next. Sometimes there is an inbetween with very sluggish running.