dwayneellis2003

I'm changing the spark plug wires on my '94 Z28 auto, and up until I reached the passenger side of the engine, it wasn't too bad. Also, now I can't remember how I was able to reach the #2 plug either. I got to it last time top-side, by moving the line that goes into the manifold on that side, by bending it backwards. I'm worried that if I bend it back again, since I've already straightened it back out once, that I might break it. Do I need to take something off of the engine to make the passenger side plug wires easier to reach? I just didn't expect it to be this much harder than my '92 was, I guess.

mike2

you should remove the alt.

dwayneellis2003

I did, and was able to reach all of the plugs....#2 was broken all the way through to the base and the top half of the plug was still stuck in the wire, and #8 had apparently popped off, so no wonder the car was running rough.......the car had an oil leak around the heads and so I installed new piston rings, heads, all new gaskets from the block up, and an intake manifold about year back and never replaced the passenger side wires. They got all caked up with oil and dirt and I was going to replace them all and clean the block up while I was at it.

Now that the plugs are done, do you have any tips on replacing the wires on the passenger side? I found a guide that says to remove the starter, tensioner, alternator and power steering pump, and route them OEM. Surely there is an easier way than this? I mean, I know it's gonna be kind of a pain, but this seems like overkill. I've messed with it for a few hours today, and the biggest problem is that I can't sufficiently reach the plugs wires to the opti.

SnakeOiler

All I ever did was loosen the PS pump and drop the Ypipe and routed OEM.

dwayneellis2003

Man I'm half tempted to just sell this thing, because I always get cut up when I work on it. Can you loosen the PS pump without having to remove the entire bracket, just to reach the opti?

slomarao

i did it drunk it 3.5 hrs when i was 19 for my first time. Take the alt off, loosen the cooling fans, drop y pipe.

bw_hunter

Yes, you reach the bolts through holes in the pulley.

7 out of 8 aren't that hard to reach once you move the stuff out of the way. That #2 is a pain in the tail but can be gotten if you move the AIR tube.

People often try to leave the Y-pipe in place on stock manifolds for fear of breaking the bolts. I think it's easier to fix those broken bolts than try and reach around everything.

dwayneellis2003

Alright, well I'm gonna try again in a minute, by removing the starter, the alternator and the power steering pump. The bottom right bolt, looking at the tensioner from the bottom, has a completely smooth head apparently, and so I was hoping to avoid removing the bracket / tensioner. I guess I can try the Y-pipe removal.

mike2

dwayneellis2003
I've picked up aset of wires you can put on anthing.Cut each to length,crimp on the ends (put the boot on first) and there you go. Bringlots of zip ties and keep them away from hot spots. I do this everytime .Untill its time to change the AC.comp.
Do you use two U-joints ahead of youre socket....works for me.

Injuneer

You shouldn't have to remove the serpentine belt tensioner. When my engine was still totally stock, the only thing I pulled on top was the alternator. Left the PS pump in place. Didn't drop the Y-pipe, didn't drop the starter.

FastandBlue

And I have always done it while leaving everything on AND I routed 8.5s. But I can squeeze my elbow between the exhaust and frame/suspension okay. So yeah, It took me 4 hours that way.

dwayneellis2003

Well, the reason why I have to drop the starter and the Y-pipes now apparently, is because I can't get my wrists past the starter and my elbow through the exhaust, no matter what angle I use. The alternator HAD to be removed for me to get the #2 plug, but I finally did it. My main thing is that I can't reach the opti on the passenger side at all. I can get my index and middle finger through the gap, and only touch the bottom two plug wires to the opti. If I could just get to that, I could route them just fine though. Either way, when I DO get the wires on, anyone wanna buy a Z28? haha

dwayneellis2003

OK, so don't laugh at this because I don't know how in the hell this happened all of a sudden. First off, I finally figured out the easiest way for me to reach all of the plug wires, even though it required removing the alternator and the power steering pump (not the lines). I got in a hurry and had to remove the alternator, but If I had to do it again, I would now say that I can do the job in about 45 minutes, an hour if I'm doing the plugs too. Bear with me now:

My '94 Z28 Auto has 136k miles on it and the engine was rebuilt at 100k. The new intake and heads were installed at 125k. The VATS module was replaced at 136k (my other post about why the car wouldn't start) and SUPPOSEDLY the ECM and/or PCM were reprogrammed at the same time, at the GM dealership I had it serviced at After the VATS module was replaced, the dealership called me and said my fuel pump died and they replaced it and that the car was ready. $2500 later, it's running like it was when I got it.....Normal but with a slight miss, and a "shudder" between 55-65 MPH, but otherwise perfect with the exception of the AC compressor not working. I replaced the plugs with some old AC Delco's that just looked like older versions of the factory plugs, which were still in the engine, along with the factory wires as well. The engine ran fine after that, but because 2 of the 8 plugs looked like they had longer threads, I used those for about a week and got a new set of AC Delco double platinum's from Autozone because they were supposedly OEM matched, and they worked fine in other Z28's. Well, when I finally got those plugs gapped to .050, as per the sticker on the radiator shroud, and got the new wires hooked up and routed OEM and nowhere NEAR anything hot, I connect the battery and start the car. It runs like crap for about 3 seconds, and then idles up to 1100RPM for about 15 seconds, then drops to 900-1000 RPM range......sometimes, it'll stay in the 1100-1300RPM range for almost a minute, but it'll level out. I'm pretty sure my TPS sensor is fine, because it was before I replaced the plugs and wires. In fact, the only thing wrong with the car before I started all this was that my "ABS Inop" light was on, and sometimes when I turn the key on, my "Low Oil" light stays on, but turning the key off and back on makes it go away usually. I've been thinking that the sending unit is going, because physically, it looks like it's in bad shape and it's damaged. My oil gauge works fine, but sometimes stays in high range, although after replacing the plugs and wires, it'll actually favor the mid-range mostly and only increases when I mash the gas pedal. Also, I should mention that the older AC Delco's worked better when gapped to .045 instead of .050. I'm thinking I should do the same thing to the new plugs as well.

Here's the fun part:
I've been using an "Innova 1403 CAN OBDI & II ScanTool" on this car for the past 2 days to monitor the codes. This computer claims it can read '94 Z28's, but mine has a trick to it apparently. My 8th digit of my VIN is "P" and my 4th digit is "F". When the reader asks for the 8th digit, use "F" instead of "P". If you use "P", the scanner will NEVER link up, and say that the computer is not responding, no matter what you do, Even IF Link Authorization is successful. I used "F" and then when it said reading codes, I gave it 30 seconds, and then unplugged the ALDL cable from the diagnostic port. I know you're not supposed to do this with the key on, trust me. Once the ALDL cable was unplugged, the tester said " codes read successfully " and now give me a list between 25-28 DTC's......I didn't figure out the trick with the scanner until after I replaced the plugs, so I don't know if they were there before I ever started the job or not, but the car ran perfectly. here is a list of the DTC's along with their descriptions:

DTC 41 - Brake Switch Test fail ("ABS Inop" light, I'm sure)
DTC 58 - Transmission Temperature High (before the car was ever started, it's NOT hot)
DTC 83 - Torque Converter Clutch Solenoid Fail
DTC 82 - Shift Solenoid A Fail
DTC 81 - Shift Solenoid B Fail
DTC 79 - Transmission Hot (I physically checked it even after I ran it, it's fine.)
DTC 78 - Turbo Wastegate Error (WTF?)
DTC 77 - MNP Switch
DTC 76 - Resume/Accel Switch Fault (my cruise wasn't working, I'm sure that's why)
DTC 75 - System Volts Low (TRUE, battery was low, but the jump-pak wasn't)
DTC 92 - ACB modifier out of limits for Cylinder 2
DTC 91 - ACB modifier out of limits for Cylinder 1
DTC 89 - Maximum Adaptation And Long Shift
DTC 88 - Timing Offset Error
DTC 87 - High Ratio
DTC 86 - Low Ratio
DTC 85 - Ratio-Undefined Region
DTC 89 - Maximum Adaptation And Long Shift
DTC 88 - Timing Offset Error
DTC 87 - High Ratio
DTC 86 - Low Ratio
DTC 99 - Pedal Position 2 (5 volt reference fault)
DTC 98 - ACB modifier out of limits for Cylinder 8
DTC 97 - ACB modifier out of limits for Cylinder 7
DTC 95 - ACB modifier out of limits for Cylinder 5

Sometimes I will actually get a code more than once, but then again, I'm not surprised it's running like crap. The Evap line or whatever that comes out of the top of the on the passenger side, has apparently come off of whatever it was connected to on the other end, which I'm assuming was the block, considering that I'd have to remove so much just to be able to SEE what it goes to. There is a little bit of smoke coming from the engine compartment now, for obvious reasons, but it's not bad and nothing around that leak of I'm assuming is exhaust recirculation, would get hot enough to damage anything. At least, it didn't yesterday. I can see how there would be codes, due to the exhaust recirculation leak, the Resume/Accel switch not working (because cruise isn't), the brake switch test fail (ABS Inop light), system volts low could be happening. The "ACB modifier out of limits for Cylinder x" makes me think, because it's only throwing the code for Cylinders 1,2,5,7 and 8, then Cylinders 3,4 and 6 must be gapped properly. I'm thinking this is an incorrect gap (gap would be the modifier, and obviously it's out of specs according to the ECM, which is VERY likely because the last plugs had to be set to .045 instead of .050, and these are at .049 -.050.) The wires are seated perfectly, and everything is routed perfectly. I don't understand the other codes though, but as I said, I don't know if these are fresh. I disconnected the battery, obviously, the whole time I was messing with the car, so I'm assuming the ECM is clear and that these codes are fresh and real. I'm currently deep charging the battery, because even though it's only about 3 months old, it's dead already, so while it's charging, I'm going to be looking for shorts and tracing wires, while I've already got the dash out.

I'm starting to think that maybe I should just leave this car alone. Every time I even look at it, something breaks and it costs me $$$$. Also, apparently I need new door hinges and latches too :'(

Injuneer

Many of those codes are not functional on the LT1 PCM. Many have generic descriptions that are not correct for your engine. Check each one against Shoebox's LT1-specific code list:

http://shbox.com/1/Dtcs.htm

Injuneer

DTC 41 can prevent the engine from starting. Focus on that one.

You indicate the engine idles high at startup. That's normal. The PCM increase the idle speed for cold start.

When the oil pressure gauge goes all the way to the max, high pressure, its because the signal from the sensor was lost, wire is off, etc.

The difference between a plug gapped at 0.045" and 0.050" should not be noticeable. How did you gap the AC Delco platinums? Are you sure you didn't loosen the platinum pucks? They have a tendency to fall off, and leave the plugs with a huge gap, that eventually turns into a misfire, and will typically cause the plug wire to fail, as that wire arcs to another wire.

Do you mean the rubber hose that runs from the passenger side of the throttle body, to the passenger side valve cover? If so, that is simply the air supply line for the PCV system:

http://www.injuneer.com/images/photo.../DCP04254a.jpg

The EVAP system is the solenoid on the bracket on the passenger side of the intake manifold. If that has loose connections, you may have a vacuum leak as a result. From Shoebox:

http://shbox.com/1/evap_sol.jpg

http://shbox.com/1/1995_evap.jpg

Which hose is not connected to anything?

Your comments about the "ACB modifier...." are completely off base. The code description isn't valid, and the PCM can not measure the plug gap. And there is no misfire detection, or individual cylinder analysis in OBD-I.