Quad 4 Still doesn't run right!!!

[94CutlassSLCoupe]

Ok, so i've been working on the new '90 Quad 4...

 

So far I have:

1) used the ignition system and computer from the other car

2) changed the spark plugs

3) tried the TPS from the other car

4) Removed timing cover and checked camshaft timing

5) checked fuel filter (it was new)

6) checked compression (even 140 in each cylinder as i suspect i either didn't turn it over enough to get a higher reading or my shit compression tester can't hold more than that)

 

The car still runs, but when i take out the spark plugs, 1&4 had carbon on them and 2&3 looked just like i took them out of the box. The car just won't rev up and doesn't idle for shit (runs really rough)

 

I did a resistance check on the injectors and I got 2.5 or so ohms on all of them, which is the same as one injector i tested quick while i was at the junkyard on another quad 4. It seems to have a decent amount of fuel pressure at the rail because it sprays pretty good if you turn the key on and then off quickly and check it.

 

HELP!!!

 

I gotta go back to MI tomorrow afternoon and i want to at least get this car to run!

[94CutlassSLCoupe]

oh yeah and No trouble codes

[mihela816]

An Injector balance test is in order. That will point out problems with injector flow that can't be diagnosed with a simple resistance check.

[slick]

You probably will not find any answers on here. I would visit the Quad 4 forum. That would be your best bet.

[94CutlassSLCoupe]

already have

[slick]

already have

 

No luck? Do you have a scanner or access to a scanner? You may be able to pull engine data from it.

[Slade901]

Most Quad 4 engines I've seen when you have this problem is usually related to the Ignition Coil Housing Cover around $60 failing. Next possible problem is with the ignition coils itself. 3rd would be the ICM (Ignition Control Module).

 

The way I test most Quad engine is to use a spare spark plug wires since this engine uses a DIS (Direct Ignition System). I then use the spark tester and pinpoint if I have a sparks. Again, it's mostly the Ignition Coil Housing Cover is the problem.

[94CutlassSLCoupe]

Most Quad 4 engines I've seen when you have this problem is usually related to the Ignition Coil Housing Cover around $60 failing. Next possible problem is with the ignition coils itself. 3rd would be the ICM (Ignition Control Module).

 

The way I test most Quad engine is to use a spare spark plug wires since this engine uses a DIS (Direct Ignition System). I then use the spark tester and pinpoint if I have a sparks. Again, it's mostly the Ignition Coil Housing Cover is the problem.

 

I used the ENTIRE IDI cover (anything that's on that size of the engine harness connector), computer, etc from our other car which is mechanically identical and it didn't help. The other car runs perfect, in fact, my dad drove her to Philadelphia on tuesday! haha

[Canada]

You need to check actual pressure with a gauge.....even 10 psi will come out of the valve at a good clip.

[turby]

Swap the computers and see what that does. A guy at work had the exact symptoms you have and it was the computer.

[94CutlassSLCoupe]

Swap the computers and see what that does. A guy at work had the exact symptoms you have and it was the computer.

 

I did already...i'll try the pressure gage when i get home in two weeks

[turby]

Swap the computers and see what that does. A guy at work had the exact symptoms you have and it was the computer.

 

I did already...i'll try the pressure gage when i get home in two weeks

 

Sorry, I missed that in your original post.

[94CutlassSLCoupe]

ok, came home, checked the pressure...a good steady 41psi with the key on and it goes down when the engine is idling...i'm lost on this thing!!! arrgh