1997 'Hoe runs rough after top end rebuild

[frustrated'hoeowner]

I am new here and this is a first posting anywhere so bear with me.

I have a 1997 tahoe 350 5.7L 4 door 2wd. Has just over 141K on it. A head gasket blew and cracked a head so i bought new heads online as well as a full gasket set, cap, rotor, wires, spark plugs.

After banging head repeatedly on not getting the dist in right, and getting a million dtc's and not running right if at all, someone finally pointed me in the right direction. I lined the marks on the gear to the shaft while being set at tdc on compression stroke. Once dist was set right it hesitated starting (mainly from a dead battery i suppose) but once it started it ran great and no dtc's! drove about 5 miles and other than a weak brake pedal i was thrilled. I had also burned a hole in #1 wire so once back from test run i put new set on. started it up and immediately got a code; i beleive p1345. along with a couple of others. At one point it wouldnt start w/o foot on throttle. late last night it decided to not even turn over, just get a click even with jumper cables.

since rebuild of top end i have gotten dtc's for just about every electrical component there is and most went away.

Prior to blown head gasket i had not a single problem with it. Now i am at a loss as to what to do or where to start.

Please help, this has taken entirely too many hours and headaches! I just want to be done! BTW i have limited income so maybe its time to cut loses?

Sorry for the long post just figured easier to post all info that i know. Thanks guys.

 

[SunlitComet]

First and foremost fix the 1345 code first. It means the correlation of the cam and crank sensor is out of alignment by more then 2 degrees in either direction which if it goes to far out starts misfiring problems. Easy to fix but you need a scanner that can read "cam_retard". does not have to be an expensive one either.


BY any chance do you live in the bay area in California. I have a laptop based scanner system that reads that and a lot of other stuff.

What other codes do you still have? Some may be affected by the P1345 code.

 

[frustrated'hoeowner]

At this moment I think the only other code is p0300. From what I found that is the code for misfire w/o a specific cylider. there was a code that popped up in correlation to a map sensor. I forget the trouble code associated.

I live about 30 min south of fresno, so no I am not terribly close to the bay area. Where should I start in correcting the 1345 code?
Could I be a tooth off when I stabbed the dist.? I dont have a scanner capable of showing cam retard nor do I personally know someone who does. Have been told I need the timing set by computer but dont know if this is correct or how expensive that would be.

Thanks again

 

[SunlitComet]

A good scanner like mine can read the cylinder misfire history and sow you which ones are acting up. A The p1345 code is easy to do. With a scanner that reads the cam_retard you raise the rpm to above 1000 and adjust the distributor until the reading say 0.0 degrees + or - 2.0 degrees.So you really have 4 degrees of play. There should be some scanners for less then $200 bucks at the parts stores that read it. It is usually considered to a a "GM Enhanced Perimeters" Reading. Ignition timings is completely controlled by the computer and you should not worry about it except for making sure the p1345 is taking care of. See what you stores have for scanner model numbers and look at the manufactures website or call to verify it will read those perimeters. If you can't get any of that, Lets assume your teething is correct and get me a pic here of the current orientation of cap and wires and see if we can't guess you to a better setting. If you go to far off worst case is it won't run. So we will move it a few degrees at a time but I would like to see how it looks now to find out how far off you might be.

---------- Post added at 03:40 PM ---------- Previous post was at 03:39 PM ----------

One more thing give me the # and address of a local oreily's or kragen And I can help you get a good scanner if you want. I could look at there stock and do some homework for you.

 

[frustrated'hoeowner]

ok. sorry about the delay in replying. I had starter issues and have been working on getting this resolved. So i took care of the p1345 code and now it is mostly running. It is still difficult to start but runs decent after that and got to the point that it is driveable but it does want to die when put in gear. And I did notice that my spark plugs are extremely fouled after replacing them only about 20 miles ago. They have lots of carbon build up and was wondering if that was from the 1345 code and running the vehicle in that config? They are the bosch platinum +4 that are non-gappable.

Another issue popped too. When the a/c is turned on the engine starts to diesel and turns up the P0108 code which I found out is the map sensor and then dies. What do I do about that? It is close to being done but i find myself still banging my head on the wall.

 

[SunlitComet]

use regular AcDelco platinum's With a single ground electrode. p1345 code, if distributor was really far off, can contribute to misfires but the Bosch plugs are killing the efficiency of you burn. delco plug 41-993.


Ignore the p108 until your spark issue has improved. MAF errors can pop up when the combustion is not right. After you replace the plugs reset the computer and try it again.

 

[frustrated'hoeowner]

Just curiosity but how to bad plugs cause MAP errors?


So just to summmarize what you said, theoretically I could be done if I get the right plugs? That SHOULD be the only culprit that stands in my way?

 

[SunlitComet]

When all the sensors are read there is certain criteria for each code that must be met in order for a code to be popped.

Your would see this combustion as rich and if it sees this variable and others in a way that you are really using gas but the airflow does not seem to be lining up with that it may pop a MAF error on you. It would have to be a really screwed up sensor or a weak ignition of which it can not test. The same thing happened when my fuel spider was malfunctioning. After the spider fix the MAF lined up with all other data and replacement was not needed even though I had a code for it.

It is not definite your MAF is fine and could probably use some cleaning too but logic leads be to dictate that unless your ignition coil has failed really bad those plugs can't get the energy they need to fire as advertised. There are not tested on every engine around. That why they usually include a money back guarantee.

 

[gpracer1]

Get a nice bright flashlight and spend 20 minutes looking at every connector, every GROUND, and every vacuum hose on the engine front to back. You may just find something simple or loose.

 

[frustrated'hoeowner]

Im not getting a MAF error I am getting MAP errors. The only time I het a MAF error is when it isnt connected. But I do consistently get the Manifold Absolute Pressure error at different times.
What causes those and what do I do about it?

Thanks again for all your help in troubleshooting this.

@gpracer1- Thanks for the idea.