Different Suburban...different problem

Sorry if I am starting to sound needy.... but I keep running into odd problems!

I am helping a friend fix a '99 Suburban. The truck was running rough so we scanned it and it said that it had a miss-fire on cylinder #6. Decided to do a valve job and discovered that it actually had a cracked head. replaced the head and completed the valve job, and put it all back together again. It started right up, but the check engine light came on. It sounded OK at idle but would not run well when it was driven. Attached the scan tool, but it won't even connect to the computer. It doesn't seem to know that it is attached to the port. I checked the scanner on another vehicle and it is working fine.

I am assuming that we missed a ground or something, but we can't find one that isn't connected. Any ideas on what connection might still let the engine run (badly) but turn off the OBD port? I know that there is only one signal wire to the port, but we wouldn't have disconnected that. What might we be forgetting?

The OBD2 port might be dead because the cigarette lighter fuse is blown. BTDT.

I know when I did a motor swap in a 99 or 00 burb, I kept having a cam/crank problem, but I found out they just weren't sync'd in yet on a loaded decel.

Does it have the crossfire cap on it? Those are notorious to carbon track and not fire the plugs in the right order. Plus putting the plug wires on wrong. BTDT too.

We have checked all of the fuses at least twice. It has a new cap, wires and plugs. I'll check the cigarette lighter fuse again. If it is on the same circuit as the OBD2 Port it can't hurt!

It sure seems like the running issue is related to the computer, but we have also used two computers and both give the same results.

Are you sure the dizzy is installed correctly? Those electronic deals in those are very finicky to where they get placed. You can't advance or retard the timing, as it is all computer controlled.

I am pretty sure that it is in right. There isn't much room to move it more than a couple of degrees in either direction, and it was put back in the same position that it was it when we removed it, and the engine wasn't turned over.

If your scanner is decent, somewhere you will find a "Cam Synch" pid. That is your distributor position. That needs to be as close to zero as you can get it. Anything over 10 degrees, and you'll start to see crossfiring.

I think there are some grounds on the back of the heads.

The problem is my scanner won't tell me anything. I am trying to figure out why it won't connect!

try a different car yet to make sure the scanner isn't bad?

yep. The scanner is fine.

Hmm, you might try making sure the computer has a good ground. Check the ODB2 port for ground as well.

ODB2 pinout: http://forums.pelicanparts.com/uploads2/OBDII%20port1070929671.jpg

using a multimeter, check for continuity between pin4 and the battery negative terminal. I say batt negative since that way you know all the wiring inbetween is good. Check the resistance, make sure it's low. Same at the computer. If there's a high resistance, then you've got a bad ground.

Just a shot in the dark. Hope it helps.

In reply to dculberson:

I think you are on the right track. I can't get the link to open, but I'll look an see if I can find the OBD2 port pinout.

Thanks for all the help guys! It turns out that even though we had checked the fuses ... twice, knowing that the OBD2 port was powered by the cigarette lighter fuse payed off! We hadn't pulled the fuse just checked continuity and for some reason that one checked out OK but was blown.

Now we can read the codes. It has 2 codes, one is an O2 sensor which we had already suspected, and the other is a crankshaft sensor (P1345 I think). I didn't even know this engine had a crank sensor. I'll look it up, but where the heck is it on the '99 350?

Thanks again, at least now I'm not throwing darts in the dark.

Found the Crankshaft Position sensor. Hopefully this will solve the problems. Thanks.

P1345 is proving to be more of a problem than I thought! I think that we have the timing off just a little and I can't find a Grassroots way to set it. The truck runs great now but the check engine light keeps coming on and throws p1345. From what I have found that means that is a misalignment between the cam and the crank. My scanner shows total advance but not the cam variance. (sorry I don't remember what this is called.)

Is there any way to make the code go away without taking it to a stealership?

Gimme a few min....

DISTRIBUTOR REPLACEMENT

REMOVAL PROCEDURE

NOTE: There are two procedures available to install the distributor.

Use Installation Procedure 1 when the crankshaft has NOT been rotated from the original position.

Use Installation Procedure 2 when any of the following components are removed:

The intake manifold. The cylinder head. The camshaft. The timing chain or sprockets. The complete engine. If the Malfunction Indicator Lamp turns on, and a DTC code P1345 sets after installing the distributor, this indicates an incorrectly installed distributor.

Engine damage or distributor damage may occur. Use Procedure 2 in order to install the distributor.

INSTALLATION PROCEDURE 2

IMPORTANT: Rotate the number 1 cylinder to Top Dead Center (TDC) of the compression stroke. The engine front cover has 2 alignment tabs and the crankshaft balancer has 2 alignment marks (spaced 90 degrees apart) which are used for positioning number 1 piston at Top Dead Center (TDC) . With the piston on the compression stroke and at top dead center, the crankshaft balancer alignment mark (1) must align with the engine front cover tab (2) and the crankshaft balancer alignment mark (4) must align with the engine front cover tab (3).

Rotate the crankshaft balancer clockwise until the alignment marks on the crankshaft balancer are aligned with the tabs on the engine front cover and the number 1 piston is at top dead center of the compression stroke.

Align white paint mark on the bottom stem of the distributor, and the pre-drilled indent hole in the bottom of the gear (3). NOTE: The OBD II ignition system distributor driven gear and rotor may be installed in multiple positions. In order to avoid mistakes, mark the distributor on the following components in order to ensure the same mounting position upon reassembly:

The distributor driven gear The distributor shaft The rotor holes Installing the driven gear 180 degrees out of alignment, or locating the rotor in the wrong holes, will cause a no-start condition. Premature engine wear or damage may result.

With the gear in this position, the rotor segment should be positioned as shown for a V6 engine (1) or V8 engine (2). The alignment will not be exact. If the driven gear is installed incorrectly, the dimple will be approximately 180 degrees opposite of the rotor segment when the gear is installed in the distributor. Using a long screw driver, align the oil pump drive shaft to the drive tab of the distributor.

Guide the distributor into the engine. Ensure that the spark plug towers are perpendicular to the centerline of the engine.

Once the distributor is fully seated, the rotor segment should be aligned with the pointer cast into the distributor base. This pointer may have a 6 cast into it, indicating that the distributor is to be used on a 6 cylinder engine or a 8 cast into it, indicating that the distributor is to be used on a 8 cylinder engine. If the rotor segment does not come within a few degrees of the pointer, the gear mesh between the distributor and the camshaft may be off a tooth or more. If this is the case, repeat the procedure again in order to achieve proper alignment. NOTE: Refer to Fastener Notice in Service Precautions.

Install the distributor mounting clamp bolt. Tighten Tighten the distributor clamp bolt to 25 N.m (18 lb ft) .

Install the distributor cap. Install two NEW distributor cap screws. Tighten Tighten the screws to 2.4 N.m (21 lb in) .

Install the electrical connector to the distributor. Install the spark plug wires to the distributor cap.

Install the ignition coil wire. The wire must not touch anything like the dip stick. Rubbing will make a ground/short after time of use.

For V8 engines, connect a scan tool.

Monitor the Camshaft Retard Offset value. Refer to Computers and Control Systems Camshaft Retard Offset Adjustment. IMPORTANT: If the Malfunction Indicator lamp is turned on after installing the distributor, and a DTC P1345 is found, the distributor has been installed incorrectly.

Refer to Installation Procedure 2 for proper distributor installation.

Stolen from Alldata.....

In reply to Ranger50:

Thanks, I found that also! I have spent WAY more time researching this that I wanted! The problem is, after you have followed those instructions it tells you to set the Cam Retard to plus or minus 2 degrees from 0. The problem is I don't have and can't find a scanner that supports "cam retard" and there doesn't seem to be a grassroots workaround!! Spending all morning on Google has shown me that there are more questions about this subject than answers. The only solution that I can see is to hunt and peck by twisting the distributor until the check engine light doesn't come on. since there is only 2 degrees of tolerance each way, I could possibly go right past the sweet spot and not know it! I'd rather do it right, but shy of spending $500 on a new scan tool that I only need for a friend's truck, I am stumped!

When I did that one swap, I just made sure the cap was 90 degrees to the motor and the oil pump drive was the same. Doing that, I had no problems. I know it doesn't normally apply with OBD2, but disconnect the battery for a time. This will clear the cam crank relationship and not throw the P1345, until you have "reset" the, in Chrysler-speak, the adaptive numerator. This is the value the PCM uses to establish timing chain wear, dizzy "offset", etc... to fire the injex and plugs. I know for Chrysler, you are either "in-sync" or "out-of-sync". Could that be the same for your scanner or is it more of a code reader with freeze frame?

But on the surface to me, sounds like you need to restab the dizzy, reset the adaptives on a test drive, and see if the code returns.

We had planned try try the distributor one tooth in either direction, but I am now thinking that is probably too much. The truck runs fine right now, it just throws the code. I would think moving the distributor past the tooth it is in now would hurt the way it runs. Using the old twist the distributor until it runs best method, I can tell that one direction seems too advanced, because it starts harder when the motor is warm, but the other direction it starts fine.

My scanner allows you to see some functions real-time, just not cam retard.

No grassroots way to fix this short of slowly clocking the distributor (not the gear but the distributor) in small increments and hoping you get within 2 degrees.

Otherwise you have to do a relearn on the CPS sensor and thats only possible on a high end scantool or dealership tool.