SabrToothSqrl

i hope you got it for a good price for all that; sounds fun to do yourself, but I dont know if Id have the time...

my 1995 for sale doesn't have any problems like that cough cough...

get some pics of all this chaos...

bronzebogen

DarylH, thank you so much for chiming in with some info! I feel better already.

So when we had it at the dealer yesterday they checked all the small stuff, compression, vacuum, SP wires, cap, rotor, dist. gears, etc... They also checked the EGR valve to make sure it was working as well as the PCV valve which is working as well.

Come to find out after I went to a mechanic in town that this car has had this problem for a while. The previous owner put over $2500 into trying to get it to run with an indie mechanic!

They tried the lower intake seals, new ECM (PCM), new alternator and removing the cat on that side and replacing it with a straight pipe. New cap, wires, rotor and plugs also. Also found they put in a brand new transmission too!

Poor guy gave up in disgust, but I'm not going to. This thing is going to run right!

Something else an old timer suggested while I was in the shop asking questions was that the fuel could be leaking out where the injector hose goes into the manifold. There was no seal there when I pulled the old fuel body out and the dealer couldn't find them in their parts catalog, but I'm wondering if there's supposed to be some O rings there because there aren't any right now...

I'm going out to see if I can check the wires running from the cam sensor and the crank sensor now.

Thanks for your advice again DarylH and hopefully some other Chevy addicts might have some ideas too!

bronzebogen

I got it for $1500 with brand new Toyo tires. It's in excellent condition otherwise. NO rattles, tight ride... New trans... Has a brand new $700 front cattle guard too. Dang I'm getting upset that I can't figure this out, it's such an awesome truck!

I'll post some pics soon. Didn't take any of the upper intake while off, but the link to the other thread on my original post shows a good photo of that.

bronzebogen

So an update on The Situation:

Checked the wires to cam sensor and crank sensor. Seemed to be fine with visual inspection. While working around the wire harness jiggling it a little while running to see if anything changes, I got a shock from one of the ignition wires. Yow! So got new ones (these are pretty new) and no change.

Questions for any GM elites lurking:

1. When testing the intake manifold vacuum (plugging valve cover holes and measuring vacuum at dipstick) I've heard there should actually be pressure blowing out of the tube. Is this true? Because there's niether vacuum or pressure blowing out of mine.
2. I found some exhaust leaks. Nothing really major, but they're there. First one is at the doughnut on the driver side bank just before the o2 sensor #1. Second is just before second o2 sensor where they removed the cat previously. Could this cause or contribute to the issues?
3. There is a humming sound from the rear when engine is running. I assume this to be the fuel pump. How loud is too loud?
4. Pulled the EGR off, seems to be working. BUT, I noticed that the hole from the upper intake manifold to the lower intake manifold doesn't line up all the way! The holes are about half in half out. Is this normal?
5. If all I'm getting is a misfire code and no CEL, wouldn't it be reasonable to assume I'm not dealing with an electrical problem?

Sorry for so many questions, but this is turning into a documentary of fixing a problem that more than one local tech has claimed to be a demon possessed car. I intend to exorcise it once and for all... with a little help!

bronzebogen

Another update:

After pulling the plugs, it's become apparent that this problem is isolated to the left (driver) side. The pass. side plugs are clean and healthy looking, the driver side are full of soot. No oil or water, just soot. It's running rich on one bank only.

Pulled # 3 plug wire to look at spark. Good, healthy blue spark that appears to be in sync with the motor's timing.

This eliminates a lot of problems I think. It couldn't be fuel pressure, cam sensor or crank sensor now right? (of course it feels like I'm almost talking to myself here, but maybe some other poor soul is going through the same thing and this thread is helping them out).

UPDATE: So I pulled the fuel injection body plug out and with some electrical cleaner and a pick, cleaned out the contacts on the plug. It seems to not be bogging down now at all, but it's backfiring something fierce! It's like this thing is trying with all it's might to fire correctly on all cylinders, but something just keeps it down.

What in the world...?

bronzebogen

Well, I'm pretty much ready to give up on this thing. It's got me beat.

Took it out for a drive because it got the power back, but was backfiring. Quit running. After a little while, it started, but now there's a knock in the engine and a squeak from the water pump.

Wonder where one can find a decent used 5.7?

in2pro

double check your firing order, if you replaced the wires make sure they are all back in the correct order esp at the cap, a mis-wired v8 can idle fairly smooth if the right wires are out of order...
also make sure the wires are ran correctly they should cross as little as possible and use a harness seperator

bronzebogen

Checked the firing order a couple hundred times at least...

in2pro

just a thought, check and make sure the previous owner didn't add a power chip or tuner to the vehicle...
make sure the fresh air intake is clear all the way to the throttle body,
check and properly clean the MAF sensor.
pickup an inexpensive code reader and clear and go from there, keep the info coming as it helps everyone get on the same line of thinking...

in fact do a recap of what has been done so far and we can work off of the latest and greatest...

I would also start getting suspicious of O2 sensors being more then 10yo at this point.

bronzebogen

in2pro,

Thanks for the input! My posts contain all that I've done so far after searching these forums tirelessly...

Replaced by previous owner trying to fix the problem:What I've done:Now there is a knock from somewhere and the engine keeps backfiring.

So there's the info!