Completed Project My 98 super charged EX

[GRNMACHINE]

Good job! Everything you put your mind to you get done fast! That sure is a lot of green

I agree! I like it-you should make some kits for those of us that dont get around to getting things done as fast or as well. Puddle lights have been on my wish list along with Superlift kit for too many years.

 

[4pointslow]

Uh Oh

I was planning to go racing today, Atco Raceway was supposed to be open. They closed due to cold temperatures and no sun on the track. Soon as they canceled, the sun came out. Figures.

So I decided to mess around with the various tuners I have (X3,X4). I was experimenting with the data logging functions when I noticed that one bank was adding a lot of fuel. Like 30%! The truck had become a little shaky at Idle. I have a factory scan tool called the WDS that works on vehicles up to 2005, It was replaced by the IDS which is the current factory scan tool.

I did what was called the power balance test. It showed an intermittent misfire on number 4 cyl. See picture below. Anyway in case anyone was wondering, the misfire monitor in the PCM would not have noticed it because I have a quick disconnect switch on the battery that I disconnect when I park the truck in the garage. When the pcm looses battery power it has to go through misfire profile correction (drive up to 60 mph, decel to 40 no braking, do it 3-4 times) before it could detect misfires. So no code but the WDS showed the misfire and which cylinder it was. Just have to find out is it compression, spark, or air/fuel mixture that is messed up on that cylinder.

I did a relative compression test with the WDS. You crank the engine over and the WDS uses the RPM signal to see if any cylinder is easier to crank through the compression stroke. If there was a cyl with low compression the engine would speed up instead of slow down when that cyl was on the compression stroke. Anyway, it passed the test and even listening to it I noticed that it sounded uniform while cranking.

I looked at something called Injector Fault Pids. When looking at data from the PCM with the WDS, you can select them and see if there are any electrical problems with the injectors. When the key is on battery power goes from the ignition switch to the injectors, it goes through them, out the ground and to the PCM. When the PCM is not grounding the injectors it expects to see battery voltage on that injector control/ground circuit. When the PCM is grounding the injector it expects to see 0 volts. If it see's anything other than expected then the PID will read "yes", stating that there is a fault. I looked at them with the key on engine off and with the engine running. No faults. I also placed my finger on the injector number 4 and felt it clicking.

I have a tool from snap on (MT2700) that measures the voltage going through spark plug wires. It is inductive so you just clamp it around each wire one at a time and turn a dial until a red led starts blinking, then read the spark KV (kilo volts). All readings looked like 10,000 volts. I changed the spark plug in cyl number 4 . Problem still there. The WDS has spark tests too, I will do them tomorrow. I will also be doing a fuel injector flow test using the WDS. It gives a nice graph of relative flow of each injector. Then I could still do a manual compression test, running compression test etc. And I have a lab scope with amps probe if nothing shows up with all that.

I doubt this will be something simple, and sometimes test results can be misleading or just not helpful at all. One thing for sure, tomorrow is going to be interesting. Good thing I am off work for three weeks.

 

[Dono]

I hate it when all the tests look fine, but there is definitely an issue.
We are all interested in the troubleshooting as you work to the result.

 

[4pointslow]

Defective Technician

So I was thinking that compression and spark were good according to the WDS tests. I figured it must be something to do with the injector on cyl number 4.
So first test I tried to do today was the injector flow test. To get there in the WDS you have to do the fuel pressure leakdown test. It passed, fuel pressure was good (already knew that, 2 gauges) and held long enough to access the other fuel tests.

Injector flow test would not run correctly. The WDS came up with an error code for all injector data, it was "ID". That happens when the pressure drops too much before the injector is even turned on. We are talking tenths of a psi. I have noticed that the Mallory fuel pressure regulator doesn't hold as tight as the factory one when the pump is off. I was considering trying to raise my fuel pressure a little because if the WDS did not like the pressure reading itself, it may do the same thing. Finicky scan tool.

Now the whole time I was wondering if I could have messed up the wires to the injectors. I know all too well that to err is human. Having fixed many things that other people messed up on their own cars is kind of a specialty of mine. Working for Goodyear I had customers that tried to get there cars running better but in the process made them worse. I had to learn to figure out what they did wrong, fix it, then diagnose the first problem that caused the running problem in the first place. I actually enjoyed it after a while, it kept my mind occupied. I too have made a lot of mistakes myself along the way, and I learn from them. Usually.

Anyway, I pulled up the injector fault pids again and unplugged cyl number 4 to make the fault pid read "yes fault". I was somewhat surprised and relieved when I saw number 5 read yes fault. Relieved that I was not going to have to remove the injectors to replace them. As I was unplugging the real number 5 injector, it dawned on me that I engraved the cyl number on each connector. I looked at it and saw the 4 on it and had to laugh. So what had happened was that I just plugged 4 into 5 and 5 into 4. Even with the number on the connectors I still got it wrong. lol. Must have been the Captain Morgan.
Now just think, this has been messed up since I did the head studs and redid the wiring. I even ran a 12.93 with 2 injectors crossed. If they were not crossed I bet it would have run a 12.92. lol.

 

[Dono]

Im amazed it ran so well.
With a firing order of 1-4-2-5-3-6 that would mean fuel would be hanging around quite a while at the firing cylinder.

I'm glad it was an easy fix. And its great to see you are human also.

Awesome tools btw.

 

[4pointslow]

tools

Thanks! I love diagnostic tools!
I am amazed I didn't burn a valve, that cylinder had to be a little short on fuel.
I wonder how much that methanol helped out, being sprayed centrally in the intake.

 

[CDW6212R]

Whew, just take a brief time to be thankful you found it, move on and forget about it.

Ditto, great tools to have there. Well done.

 

[4pointslow]

Wideband bung extender

Last week while messing around with some data logging, I had the truck running so long in park without driving it that the Wideband O2 sensor overheated. It starts flashing all different readings that you know are not correct. The datalog reflects the same erroneous A/F readings and is unusable to tune with.

I have had this experience a few times before and most of the time just shut it off and let it cool down and it goes back to normal. Once it never went back to normal, I guess I burned out the sensor from overheating. I replaced the sensor and all was fine (part number Bosch 17014).

So to try to eliminate the problem I installed a bung extender from Innovate, since I am using their LC1 wideband sensor set up. We will see in the future if it does the job or not.

 

[4pointslow]

Went to Atco Raceway last night

Got to the track last night.
First run, wheels broke loose off the line, ran a 14 second.
Second run, tried the other lane, wheels broke loose 13.93.
Third run, set my tire pressures lower, wheels broke loose 13.75.
Started thinking, something is wrong here. Control Trac automatic 4WD must not be working. No flashing 4X4 lights. Feels like I been here before.(2009)
(more to come)

 

[4pointslow]

Automatic 4WD not working

So my auto 4WD was not working, no flashing lights though so it took me three runs to figure it out. The Auto 4WD is supposed to lock the front drive shaft in when I floor it from the starting line. This happened once before.

You have to have a scan tool that can access the GEM module. I choose the NGS because It is faster to use for these things. Once into the GEM you go to PIDs, that is where the data is. You want to look at Hallpower, that is the power supply(10v) to the driveshaft speed sensors that are Hall Effect sensors(put out a square wave signal). Hallpower should be on as soon as the "GEM wakes up" My hallpower was off, the GEM was protecting itself. A road test showed the front and rear driveshaft speed sensors(TRA_FSP and TRA_RSP) reading 0 all the time. VSS worked since it is from the ABS module which gets it signal from the rear differential speed sensor.

There was also a code stored in the GEM, it had to be cleared to reset the module so it would turn the hallpower back on. Of course you have to fix it first or it wont come back on. The problem was a shorted driveshaft speed sensor.

 

[4pointslow]

Sensor

The Front driveshaft speed sensor went bad the last time so I was glad it was the rear one this time. I had a spare that was sitting in another transfercase in my garage.

If you pull the power wire out of the connector for one sensor and disconnect the battery for a couple of seconds to reset the GEM, and the hallpower comes back on then that is the one that is bad. If the hallpower does not come back on then try pulling out the other power wire and reset the GEM again.

Once you know which one is bad then replace it. I did a resistance test and found 1.7 ohms from the green to the grey wire on the bad one (shorted sensor). The good one was OL from green to grey. (green is power grey is ground, the other wire is speed signal)

Edit: That plastic connector was broken the last time I took it apart, causes no problems.

 

[Dono]

An age thing, not a 'your pushing way more power than your supposed to' thing.
It didn't take you long to sort out. Amazing tools, and the 'know how to use them' one again.

 

[4pointslow]

Hallpower

Yes I have to agree, how old is this truck now? 17 years old, damn that's like 65 in human years. lol.

Last Thursday was a beautiful night for racing, I just happened to have some time off too. Then no A4wd. No warning lights or any signs that there was a malfunction. If I had known about the problem I might have been able to fix it before even going to the track. Trying to launch the truck without A4wd is useless, tires just roast.

I am half tempted to put a LED on that circuit so I know when I loose power on it.

 

[4pointslow]

LED for monitoring Hallpower

The green wire/ Highlighted RED circuit is the hallpower from the GEM to the sensors.
I may be able to tap into that circuit and add a LED to monitor the hallpower.

 

[4pointslow]

Led

On second thought, maybe I will add a LED and a momentary contact switch so it will only be lit when I want to test it. Then I don't have to have an extra LED just sitting there lit up all the time.

 

[CDW6212R]

Good job again finding and fixing it, I appreciate the details of the wiring, NGS tool etc.


BTW, that red plastic locking piece in the connector, it goes in 180* from that, or it did originally. I hadn't put one in backwards before to see if that still worked and would let you remove it faster with a needle nose. Is that what you did there?

 

[4pointslow]

connector

That red piece goes in that way. The two red tabs go into the other side of the connector. When I first pulled the connector apart I thought the red piece had stuck to the wrong side because it looks so weird, but it only goes in one way.
I have another transfer case with both connectors on it since I cut it out at the junkyard, it goes the same way, both are 98's.

 

[CDW6212R]

It looks funny to me, but I haven't done any wiring for about 8 years, my memory is funny.

 

[4pointslow]

No LED for hallpower

I have been doing some rewiring of switches and gauges so I had the radio out and had access to the GEM. I looked closer at the hallpower circuit. It is a 10 volt power supply to the driveshaft speed sensors.
I back probed it with a LED(and 680 ohm resistor) and the voltage dropped from 10 to 9.5 volts. The LED did light up and nothing burnt out. However I did not feel comfortable with the voltage drop on the circuit and feel that the GEM could be damaged with the added current flow on the circuit.

I thought of getting a volt meter gauge and hooking it up to the circuit to monitor hallpower. Volt meters do not allow much current flow through them, they only look at the difference in voltage between one probe and the other, thus the name high impedance(resistance) volt meters. I will look into this more.

 

[CDW6212R]

I have been doing some rewiring of switches and gauges so I had the radio out and had access to the GEM. I looked closer at the hallpower circuit. It is a 10 volt power supply to the driveshaft speed sensors.
I back probed it with a LED(and 680 ohm resistor) and the voltage dropped from 10 to 9.5 volts. The LED did light up and nothing burnt out. However I did not feel comfortable with the voltage drop on the circuit and feel that the GEM could be damaged with the added current flow on the circuit.

I thought of getting a volt meter gauge and hooking it up to the circuit to monitor hallpower. Volt meters do not allow much current flow through them, they only look at the difference in voltage between one probe and the other, thus the name high impedance(resistance) volt meters. I will look into this more.

Good idea, but try the same test using just a relay. See how much one stock relay will take to run(trigger). Run a wire from that GEM circuit to the relay trigger power, and from the other trigger wire, to any ground. That will tell you how much a simple relay would draw from the circuit, and then any load you use will not change that. An LED doesn't take much juice of course, but maybe the relay might be a hair less(it could be more(try the little ones)).