soapy water is a better conductor of electrons than reg water so you will see a lighning show in a dark garage etc

and i dont think it will work if you disconnect the ICM as it is what tells the ECM/PCM to fire the injectors (most cars are like this) so you need to disconnect the coils only

and yes you should see a nice cone of misty fuel dropplets if you see a solid stream that inj needs to be cleaned
some inj will have 2+ streams in a cone pattern but doesnt attomize the spray that will be a marginal inj spray.

I rec the vacume line trick on the coil terminals first as it is the easiest to see what cylinder might be contributing the least power to running the engine--sometimes it's best to unplug the Idle air control motor at a decent idle speed so the ECM/PCM wont raise the idle to correct for a "missing" spark when you cancel it with a ground wire/test light (this wont damage your test light-mines been doing it fer years!)
BTW the vacume line rubber contains carbon so it will conduct the spark through it to you ignition cables and the spark will leap to your ground/testlight when you bring it close to the vacum line to cancel the cylinder.

What really sux is ya cant just drive it over to my garage and we can chug beers while diagnosing/fixing it
anyways i hope this helps you more!
James

OK, here's the deal...

Today, I had hooked up the laptop and got a CODE 32.
This is the EGR.
What got me surprised by this code is that I had already replaced the EGR Valve and Solenoid. I've already check the vacuum lines in the engine compartment. Sprayed some carb cleaner all over every one of them and nothing changed.

So I read this wonderful little article The Lowdown on Code 32 (EGR). And it says:


So it looks like this is what is in store for me? I ran some seafoam through the car...that certainly should have cleaned the injectors up. When I replaced the EGR valve, I did notice quite a bit of carbon build-up in the intake. So do I have to remove the entire intake?

Has anyone ever cleaned the carbon out? Let me know...

Thanks,
TOC Admin
Brando

are you sure that thats not a history code (from some point in the past?) it wouldnt cause backfiring unless it was stuck wide open creating a vacum leak of sorts that would tend to cause backfiring through the intake more than the exhaust. clogged egr passages will afect your ability to pass emmisions more than it would affect engine running (like deleting the EGR entirely) disconnect batt power to clear the egr code and run her to see what relevant codes pop up if any (87's are stone age as far as self diagnostics-look at how few codes they have to ID problems)
good luck man,

James

BTW seafoam wont clean the injectors properly seafoam will remove carbon deposits inside the engine but only a cleaner that goes through the injector (like Chevron with Techron--i use two bottles at less than 1/4 tank for it to be really concentrated) and even then if a particilate is in the injector only ultrasonic cleaning and reverse flowing the inj will clean it properly.

james

Well I finally got around to measuring the voltage to the TPS (thanks for keeping the topic alive, Brando) and I'm not even sure if I measured it right because the readings were so low. I unplugged the TPS and measured the voltage at the prongs on the plug. First it gave me a .042 v reading at idle, then after I let the car run for a while and warm up it gave me an even lower reading .025. That's why I'm not even sure I measured correctly. Help.

to properly measure Tps voltage you will need a couple of T pins to backprobe the wires-the orange 5V reference the signal wire and the ground!
you will see on the signal wire.3-.5V at closed throttle and 4.5-5V at WOT
the 5 v supply should have constant 5 v at key on engine on/or off
amulti meter will help but it will not show you any voltage dropoffs/glitches from a bad carbon track! a graphing digital multimeter is needed or a Digital storage occiliscope.
have you fixed any part of your problems yet?
james

I found that backprobing was unnecessary because I got the same readings either way. The wire colors in my car are black (ground), blue (signal), and gray (5v). I figure the black wire is ground because I got little or no voltage reading from it. At idle the blue wire again gave me a 0.04 volt reading at idle. I have neither a graphing digital multimeter or a digital storage oscilloscope, nor do I feel like spending that amount of money for either instrument. I have not fixed any part of the problem because I don't know what is causing the problem.

you need to measure the voltage at the blue wire with the connector plugged in! othewise the 5v reference cant go throught the wiper arm and reach the signal wire to go to the TPS.

you WILL need to backprobe!
with it backprobed check for voltage drop across the TPS ground (plugged in Key on) and the Batt neg terminal.
also make sure that the 5 v referenc still has 5 v with (plugged in) key on.
then you will need to check the voltage on the signal wire (you guessed it, plugged in) with the key on, at closed throttle (see specs above fer this) and at WOT and inbetween (where any dropouts/glittches would cause a running problem similar to a missfire in certain instances.

to do the Glitch test you will need a digital graphing multimeter with glitchcapture (my MAC tools unit cost me $650) or a DSO with enough Mega samples a second...
you will not be able to see a glitch on a multi meter.
so maybe it's time to take it to a mechanic for proper diagnosis with the tools needed (a new TPS might be cheaper though.....)

I am starting to think that we need more details on the missifre, what conditions, engine load, weather etc....

Good luck!

James