Significant Loss of Power - Help Diagnose

[unclewolfie]

92 Ranger with the aweful 2.3 L. Ya, its always been underpowered, but more recently it has become significantly worse; to the point of having to run up the RPMs and slip the clutch quite a bit just to get it rolling and even then, it will sometimes stumble and backfire. Took it to the local shop and although the fuel filter was almost completely clogged, that didn't solve it. The mechanic said its similar to an issue they used to see with some Nissans, but for some reason they couldn't fix it, nor really figure out what was going on. The mechanic admitted that his shop didn't have the technical info for diagnosing this type of distributorless ignition system. It starts fine and idles fine, and cuises okay, but its when its under any type of load that it just falls flat. Any help, or point me to a resource that will help to diagnose and better understand this type of ignition system; OR could it be something else?

[envious8420]

sounds like a clogged cat converter.
when the truck is running, how much flow is comming from the exhaust pipe?
how about when someone revs it?
if its weak its most likely the cat.
could also be a dirty maf, hows the air filter? any signs of dirt/debris making it past the filter?

[Wicked_Sludge]

cat converters are rarely the problem.

if you do suspect the converter, test it with a vacuum gauge. dont just guess, blow $80+, then find out it wasnt the problem.

id start with basic tune-up items. check the plug gaps, air filter, PCV system, check for vacuum leaks..ect.

pulling the codes will help point us in the right direction (even if the CEL isnt lit, there could be stored codes)

[tom]

Grap a timming light and see if your belt jumped. You may need a new belt.

[unclewolfie]

Okay; had the catalytic converter checked it it checks out okay. Did a diagnostic KOEO and received a code 218. In the book it says this is an "Ignition system (distributor-less) problem - Loss of left side Ignition Diagonostic Monitor (IDM) signal."

On this website it lists it as: (M) IDM signal open or high or left coil pack failure - Ignition Systems

I'm assuming these mean the same thing, just worded differently. In laymens terms; what does this mean? Is this different from a bad Ignition Control Module (ICM)?

[Wicked_Sludge]

the way it looks to me, it could be either a bad coil or a bad control module (the computer has a hard time determining which).

the dealer and many auto parts stores can test the module. if its good, replace the coil. if its bad, replace the module.

[unclewolfie]

Okay; today I had the Ignition Control Module checked out at AutoZone; it checked out okay. I also went ahead and purchased a coil pack (just one). I swapped it in and out with the two old packs, in various combinations, but nothing improved. I guess my next step is to check the timing. From what I understand, there is no adjustment that can be made, since it is distributorless, so if it is something other then 10 degrees, what would I be fixing? How about the timing advancing? I assume if I rev it while watching the timing mark, I should see it advance (I am suspicious that this may be the culprit) what would I fix to remedy the timing not advancing?

[Wicked_Sludge]

since the engine isnt timeable, i would assume there is no way to disable the control module to check base timing. in this case, the timing will probably far advanced from 10* since the computer will be actively controlling it.

you need to pull the timing cover off to check the belt if its jumped.

i'd check the power to the coil to make sure there isnt a fault in the wiring.

[Dave R]

since the engine isnt timeable, i would assume there is no way to disable the control module to check base timing.
You would be assuming wrong, again.

You have to find and remove the SPOUT plug in order to limit the computer to base line ignition timing.

[Wicked_Sludge]

didnt know there was a spout connector on non timeable ignitions.:dntknw:

[unclewolfie]

So, where is/what does it look like? Sorry for all the somewhat simple questions, but I just moved and have not been able to located my manual. If the timing is off, is it always a timing belt that has jumped a tooth? Or, could it be something else? Does the Powertrain Control Module be a cause?

[Dave R]

It been so long since I've worked on a stock set-up that I'm not 100% sure where it is. It SHOULD be somewhere near the ignition module. It'll be a grey or black plug with two wires running out of the opposite side. (not a very good description) There were several posts on the old board about it's location. UGH! :annoyed:

[Wicked_Sludge]

http://i140.photobucket.com/albums/r9/Wicked_Sludge/DSC02677.jpg

http://i140.photobucket.com/albums/r9/Wicked_Sludge/DSC02672.jpg

[Dave R]

That appears to be the plug but I'm guessing that's on a V6.

[Sevensecondsuv]

On my 1990 2.3 it comes out of the wiring harness just above the DIS module (ICM as others have been calling it). Hope that helps.

[Wicked_Sludge]

That appears to be the plug but I'm guessing that's on a V6.

'93 3.0

[Mutant Pony]

The symptoms to me sound like low fuel pressure. Has the pressure been tested?

[wmcclay]

Is this a calif. truck? they are a little different than the other 49

[unclewolfie]

Ah, thanks for the photos; that, along with some additional reading, I found it. Quite obvious, as it does stick out of the wiring harness right next to the ICM. Although I don't have my timing (in between moves and it is packed away at a buddy's house; I know, that was dumb) I did remove the SPOUT connector, started the engine and then when I plugged it back in, the RPMs went back up, like they should. So, I believe I have timing advance; although, I was really thinking that was the problem.

I did run tests for codes again, since I have done a few things. KOEO test now revealed a Power Steering Pressure Switch open connection or circuit failure (code 519). I'm assuming this is unrelated, although interesting.

In running the KOER test, it came up with no problems found.

I'm taking the truck to a recommended mechanic tomorrow (Thursday), as I'm about out of things that I am willing/able to do, unless someone comes up with a new suggestion.

[unclewolfie]

Yay, Hurray, Yippie! FIXED. Not sure it ended up being one specific thing, but the things that were replaced that may have contributed to this problem were; new fuel filter, one new coil and new plugs and wires. The last thing done was the plugs and wires and that really made the final difference. It was believed that one of the plug wires had gone bad. So, there ya go.