One last shot... Breaking up!

[BoostedSUV]

Re: One last shot... Breaking up!

Very doubtful. As many times as you have changed the plugs, all the paint would have to be gone by now. A grounding issue with plugs would be a work or no work situation not cause a rpm specific problem.

As long as I have access to Ted's shop & equipment, I'm serious about picking up the truck.

My next target would be getting a perfect ground to the back of the head. I don't think it is the problem, but it would be one more thing crossed off the list.

Looks like there are some nice weather days next week, but you will be gone. Maybe a nice day to have your truck towed.

I have until next Sat AM to mess with it after that it will be in the driveway if anyone wants it! lol

 

[kentuc]

Re: One last shot... Breaking up!

I once had a Turbo Buick. Similar problem. Found out it had an 8 cylinder reluctor ring in the distributor. A scope picked it up.

 

[BoostedSUV]

Re: One last shot... Breaking up!

I once had a Turbo Buick. Similar problem. Found out it had an 8 cylinder reluctor ring in the distributor. A scope picked it up.

Scoped the distributor and didn't pick up anything unusual. Not sure what a reluctor ring is?

 

[turboj91]

Re: One last shot... Breaking up!

I once had a Turbo Buick. Similar problem. Found out it had an 8 cylinder reluctor ring in the distributor. A scope picked it up.[/QUO

Don't take this the wrong way as almost any suggestion is appreciated but, I hope you did not think that was his actual problem. I know it is a very long thread to read but there is no way that is his problem. (not that I have figured it out either).

Matt, pm me your phone number and lmk when is a good time to call.

lmk what is dave millers shop as well. I'm curious.

 

[meyers2211]

Re: One last shot... Breaking up!

Dig, Nolan suggested an Ignition missfire causing a lean symptom or false lean reading. I agree with you, since the wideband is a stand alone unit and shows lean as well it's not a false reasing.

FP does rise with boost and fall with vacuum as normal. I watched the gauge at all rpm levels and it does not drop at all, it is consistant with boost/vacuum. So I agree it's not fuel delivery..

I will try unplugging the O2 sensor and see what happens as well as checking the purple signal wire that used for the A/F guage I took out. It appeared to be good but I will look closer.

i agree an ignition misfire will show lean spikes on the wideband

 

[SloGN]

Re: One last shot... Breaking up!

OK


IHave done some brainstorming here (smell the smoke) Matt states that the problem arrived shortly after the engine was reinstalled back into the truck. correct?


Is it possible that one could have gotten the injector harness on back wards and it's firing the injectors out of phase?


I understand that it's a bank/batch fire set-up but if the o2 sensor is looking for a certain delivery time of the fuel/air misture being burnt based on left/right bank firing order it may could have a problem.





I ran into a very strange problem on a lt-1 in a hot rod one time. where the painless wiring harness had been wired wrong and they had the o2 sensors pinned wrong causing all sorts of issues from running rich as hell to very lean.

 

[BoostedSUV]

Re: One last shot... Breaking up!

I've had the motor out 4 times and just swapped in the new injectors. I really doubt I got the harness wrong.

I did look at it carefully when I swapped the injectors a few weeks ago and each plug is clearly marked. I made sure everything went whre it's suposed to.

I haven't had a chance to even look at the truck in a few days (damn world series/rain/etc). Hopefully the yankees can win it already so I can get back to work on it :tup:

 

[BoostedSUV]

Re: One last shot... Breaking up!

well tonight I pulled off the ALT bracket and ground all the paint off the bolt bosses and the head/block where they make contact. I also moved my ground cable off the battery to the front of the head which seemed to be a more solid ground. I pulled off the front intake bolt and engine lift bracket and cleaned up that area for the ground to engine harness.

I disconnected everything off of the battery except for the bare minimum and tried it that way. Truck still broke up and I still showed crazy high voltage at the junction block. Next I disconnected the MSD from the junction block and wired the truck up factory to the coil and tried again. Truck was still breaking up but I had a steady 14.2 volts at the junction block that matched the battery and the ALT.

Made no difference but why is the MSD making a erratic voltage readings at the power wire? Bad MSD ground? Back feeding through coil harness?

 

[TYTILIDIE]

Re: One last shot... Breaking up!

14.2 sounds normal in those places to me.

 

[BoostedSUV]

Re: One last shot... Breaking up!

14.2 sounds normal in those places to me.

Yes 14.2 is normal but when I had MSD 6A connected I was showing 17-19 volts bouncing around at the junction block which is where I had the power feed for the MSD.

Another thing I noticed is when I OHM test all the grounds the all seem to be pretty solid but when I start up the truck I seem to get drastic differences in my readings from when truck is off....

 

[SloGN]

Re: One last shot... Breaking up!

Do you have a stock dist that you can install in the truck? I'm really thinking it's a miss fire issue and that it may be in the dist. i understand it's a msd unit. but did you install the msd unit in the motor the first time you rebuilt it? if so it may have been bad the entire time.


On other thing to try is run the truck with the est wire bypass to see if the timing starts jumping around. witht eh est wire by passed the timing should stay rock solid @ 0 degrees and never move unless something is causing it to move around. you can watch this using a timing light and free revving the engine while in park.


I may have mentioned this before i dunno this is a long @$$ post.

 

[BoostedSUV]

Re: One last shot... Breaking up!

Pat I don't have a stock dizzy to put in but I put the MSD in when I did the vortec swap... I had the stock dizzy in the truck the first 3 times the motor came out and this problem kept coming back. I also scoped the distributor with a timing light on all 6 cylinders and did not get any spark fall out the timing was solid even through the breaking up. I feel like everything has been covered! Lol I've just about had enough. I don't want to give up because I'm determined to figure this out but when is enough enough already?

 

[92 Ty 1173]

Re: One last shot... Breaking up!

This is the first I'm reading this, damn 40 pages, can't blame you for giving up. I prolly would of torched the truck by now. Wish I had some input to help but good luck anyway, hope you figure it out.

 

[BoostedSUV]

Re: One last shot... Breaking up!

This is the first I'm reading this, damn 40 pages, can't blame you for giving up. I prolly would of torched the truck by now. Wish I had some input to help but good luck anyway, hope you figure it out.

Lol thanks... If it wasn't for all the money spent and time spent I would have driven it into a lake already! I should have one sick truck with all the parts I've thrown at this thing and I've never really been able to enjoy since I've been chasing problems ever since! If I acheived my goal of an 11sec pass and then this started I probably would have given up!

 

[WyoSyclone]

Re: One last shot... Breaking up!

Gee Matt, looks like there's a concensus!

1. disconnect all aftermarket stuff at battery
2. disconnect and remove MSD
3. See if problem is still there....

Hang in there buddy, you're almost there!

I feel like everything has been covered!

This is where we stopped Matt.... get out there and get that hood up!

 

[BoostedSUV]

Re: One last shot... Breaking up!

This is where we stopped Matt.... get out there and get that hood up!

Rob, post #589... Been there done that

 

[WyoSyclone]

Re: One last shot... Breaking up!

Rob, post #589... Been there done that

Damn, a person leaves for one day and they miss all sorts of stuff around here!

Well, that is progress... you've eliminated a bunch of stuff. The high voltage with the MSD installed is probably the high voltage in the MSD leaking past an internal component.

Was the breakup exactly the same with the MSD both installed, and removed??

 

[BoostedSUV]

Re: One last shot... Breaking up!

Damn, a person leaves for one day and they miss all sorts of stuff around here!

Well, that is progress... you've eliminated a bunch of stuff. The high voltage with the MSD installed is probably the high voltage in the MSD leaking past an internal component.

Was the breakup exactly the same with the MSD both installed, and removed??

It was breaking up regardless but it seemed to break up worse with out the MSD? Could be entirely my imagination though :dunno: I didn't go back and forth a bunch of times to confirm since I was watching the World Series.

I'm going to replace the fusible links off the Alternator tomorrow but I don't think that's my problem. The clock is ticking and ideas are running out :tdown:

 

[turboj91]

Re: One last shot... Breaking up!

Yes 14.2 is normal but when I had MSD 6A connected I was showing 17-19 volts bouncing around at the junction block which is where I had the power feed for the MSD.

Another thing I noticed is when I OHM test all the grounds the all seem to be pretty solid but when I start up the truck I seem to get drastic differences in my readings from when truck is off....

I think I want to go back to one of my ideas and think there is something wrong in the harness and it happened the first time you installed the rebuilt engine. We have alot of harness and it gets moved alot especially if your in the engine bay painting stuff. Something shorted or broke or... If I am understanding correctly, when the truck is off, your proper at 14.2 at the junction but it jumps up when it is started and gets worse when you power up the msd. Are you getting power jumping into a ground circut and then the msd aggravates it even further due to its multiple discharges? Might be time to split the harness? It is a problem that needs to be found and corrected whether it is related to the rpm specific misfire or not. Would be a bonus if you cure one problem and the other is cured at the same time.

I have a friend that is a electrical engineer for Pratt & Whitney and wires up all the test engines. If it comes to it, maybe we can ride down when you get back. Knowing how engineers think, he might see that if you fold down the rear seats that he could fit a jet engine in there and then its all over. Heck, some guy put a jet engine in a VW Bug and drives it on the street.

 

[WyoSyclone]

Re: One last shot... Breaking up!

It was breaking up regardless but it seemed to break up worse with out the MSD? Could be entirely my imagination though :dunno: I didn't go back and forth a bunch of times to confirm since I was watching the World Series.

I'm going to replace the fusible links off the Alternator tomorrow but I don't think that's my problem. The clock is ticking and ideas are running out :tdown:

Well, showing good voltage with the MSD taken out would probably rule out the fusible links.

It's got to be something spark related, or a partially broken wire somewhere. Have you looked under the hood at night while it's breaking up to check for spark leakage? If there is none that would pretty much rule out the plug wires... that leaves you with dizzy, spark coil, or a component inside the dizzy.... those should be easy to rule out if you can find another distributor to put in it.

If it's not that I would think you're looking at a harness issue somehwere. Even so, it seems like it should be traceable.. DM doesn't show any issue so it's probably not between the ECM and engine.... which leaves a voltage supply issue. Can you take the voltmeter and check for proper voltage at different locations as it's breaking up?? Dang I wish I was there to look at it..