Does any one have or can send me online TSB 95-2 and 95-8?

are they worth reading?

95-2 is on Hesitation/Surge-Light Acceleration 4.9L Engine

95-8 is on 4.9L Engine Noise on Initial Start-up

I of course have both problems.

Thanks in advance

Steve

 

Hey Steve,

I "think" I may have the 95-2 TSB.
Yes, it's worth reading and checking out.
It has to do with checking for a shorting wire in the harness between the PCM and ICM.

Currently my truck is in the shop for the "stumble".
My only copy of that TSB is in the repair shop with the truck.
I'll keep an eye on this thread and if no one replies I'll try and send it to you (if I ever get my truck back).

So far (4 days later) their "wizard" hasn't been able to find/isolate/remedy it.
They were pretty cocky and confident they could find it.
It's been scoped and all.
They're more frustrated than I am at this point and ready to give it back to me unrepaired.

I know my stumble is electrical---coil is arcing, blue light coming out of the plug wire boots (brown powder on boots, coil, wires) --- Disappears above 1500 rpms.

No, it's not wires, cap/rotor, plugs, ICM ---- all brand new (2 sets of each) and all check good, PCM power relay is new and good, yellow wire (in distribution box) making good connection, brand new dizzy and the internal gound (ICM ground) is good, I've even added an extra gound ground strap from the block to the frame.

I've replaced everything (or darned near) under the hood and thinking it's the PCM that's gone bad.

Check under your hood in the dark for a light show.

Good luck and I'll check back,

Bob

 

Bob,

Thanks for the nighttime look to scope things out. I remember hearing that a long time ago, it's amazing the good info you forget.

I spent some more time testing things on Friday and came to the conclusion (along with the blue oval guy at the NAPA store) that I recieved a bad reman ECM. He ordered another one and I should have it on Monday.

I have good continuity for the EGR solenoid but it isn't working. When I put the ECM from a 90 E-250 in the van runs ok, but the engine light come on and I get codes for the bypass and 3rd solenoid that aren't on my van.

It still seems to "load up" and try to stall on light throttle.

I'll post here after I get the new ECM in tomorow. It may solve a world of problems but I'm not going to hold my breath.

I'd still like to see that TSB, if no one else has it.

Thanks

Steve

 

Steve,

Make sure your EGR valve holds vacuum.
The sensor on the end of the EGR valve MUST be sealed AND hold vacuum ---or bleed VERY LITTLE (mine didn't).
THIS IS IMPORTANT !!!!!

Otherwise, the EGR valve will NEVER be positioned at a "correct setting" and the PCM will wack itself out trying to apply vacuum to a leaking EGR valve (amongst other crazy things).

Beg, borrow, or steal a hand held vacuum pump to check for vacuum loss @ the EGR valve !!!!

Just a little tip.

Bob

 

Bob,

I have a pump and the valve is fine. Thanks anyway

Steve

 

Bob I just started reading your posts. Did you get it figured out yet?
The stumble at 14-1500 rpm used to be quite common. In dealership years the 300-6 is getting old so I dont work on them much anymore but I know I used to see quite a few that did that.
Have you tried plugging the vacuum hose to the EGR and driving it to see what happens? They EGR flows too much at that rpm and causes a lean stumble. Usually that cures it but it's not a real fix. If the EGR isnt working you'll set a code because of it. What you can try is to make a block off plate to fit in between the EGR valve and the maniold. Make it the same as the gasket but instead of the big hole for the exhaust to go into the intake just drill a small hole, maybe 1/4". That will still allow the EGR to flow but not so much that it stumbles.
Let me know if you try that and if it helps.

 

Racerguy (Dave),

OH YEAH........
Been there and done that.
Currently I think my truck is "stumbling" because of an electrical problem (I'm quite sure it's electrical).
I'm getting arcing around the coil and out of the ends of the spark plug boots at idle and up to 1200 rpms.
Makes for quite the light show under the hood in the dark !!!
The symptoms are quite puzzling.........
The arcing and sparking disappears above the stumble point (1200 rpms) AND it doesn't happen untill the engine warms up.
I had a previous problem with the alternator circuit --- 3 new alternators NOT charging the system ---- and found that some of the wires going to the instrument cluster (in the 2 connectors) had been moved and installed in the wrong position --- according to the wiring diagrams in my Haynes manual.
Anyhow, to make a LONG story short..... I think (even though I checked it 3 times) there are still some wires in the wrong position in the two connectors that plug into the instrument cluster.
I've done alot of thinking about it......if the ignition system starts to arc and spark ONLY when it's warmed up AND/THEN goes away above 1200 rpms, then there's a good chance that the ignition circuit is somehow tied into or partially tied into, let's say, the engine coolant circuit. ???
If not, then it's probably a faulty PCM.

And as far as the EGR circuit goes....

I've made a couple (just in case I lose one for whatever reason) of EGR restrictor plates.
Yes, they do make the truck run alot better !!!!!!!
My only concern is the fact that the EGR tube and valve may/will at some point clog up AND the truck will be running on an air mixture other than what it was designed to run on. ie. EGR in the air mixture to reduce combustion tempratures (not sure what long term effects that'll have on the engine though).
I'm considering installing a SuperChip just because their "program" (in the PCM) might address the excessive EGR issue.
I'm not looking for more HP, just trying to get rid of the stumble --- of course more ponies would be nice.
I'll start another thread to see if ANYONE has had any luck with that.

Thanks for the reply and sorry for hijacking this thread.
I'll keep everyone updated.

Bob