What problems will I encounter by converting from a 6.5 liter diesel to a 350 or 454 gas engine? I wonder about the wiring harness etc. any help would be appreciated. I am sick of my 6.5. been working on it ever since I got it. thanks for any help.http://www.dieselplace.com/forum/smileys/Big%20Smile.gifhttp://www.dieselplace.com/forum/smileys/Hug.gifhttp://www.dieselplace.com/forum/smileys/Cool.gif oh, Im talking about a 96 silveradohttp://www.dieselplace.com/forum/smileys/Clap.gif

Fuel pump, flywheel, starter, exhaust





for a '96 equivilent gasser the wiring harness, ECM and matching engine


What's your plan on the 6.5L parts?Edited by: quantum mechanic

whatcha doing with the old 6.5 you take out?


Let me know if you decide to follow thru with this idea and want to sell the old 6.5 engine


as far as converting over to a gasser, Your best bet would be to get a truck and engine complete from a salvage yard, maybe one thats been rearended or something. eveything should swap over easier that way.


OR go find you a gasser truck and sell yours

I'm with Bowtie, sell what you have and buy what you would like to have, will be much easier in the short and long run.
That's alot of work ahead of you to get that done. Did you think of which way you where going to go, carburated or EFI Vortec with OBD2 certified? If you went carb, which ignition system, OBD2-donor vehicle only and complete unit.
Brakeshoe

I am also interested in the old 6.5. I have a fresh rebuilt 350 4 bolt with carb I can trade. I am located in Athens, Tx.


hrjack99@hotmail.com

if you want a nice gas go buy a vortec 350, 97 or 98

too much plastic in the vortec. go earlier 90's just before vortec.

You might have trouble getting an inspection with a motor that's older than the truck. Unless your cousin's inspecting it, that is.

my 96 vortec was great with good power, and it sounds like he wants some power, I wouldn't buy anything older than the 96 and I would really be looking for like a 00-02 with a 6.0 in it.


But thats just me http://www.dieselplace.com/forum/smileys/HiHi.gifEdited by: bowtie

my old 95 and my grandpa's 88 350's dont have any power compared to a 97 or 98 vortec and the vortec's get about twice the mileage.

I've found the Vortecs to get exactly the same mileage as TBIs, and to be less reliable as the "spider" of low pressure fuel lines and poppets tends to fail at regular intervals . . . to the point that California's Air Resources Board has required GM to replace the fuel injection system with a different one when it fails on a California truck. When it's working it does make 25% more power than TBI though.

the 96 and newer vortec power increse over the 95 and older 350 is mostly from the move to a roller camshaft. before my 95 6.5 tahoe I owned a 97 5.7 and if you want to be satisfied with gas power i recomend you go with the 454 (if you can afford the gas). I drive off-road alot and the 5.7 was not enough for me.

Hello people, thanks for the responses. I think I'll go with the "go buy what you want" idea. I've wasted a lot of time over the years changing my vehicle to something else. Like all the column shift automatics I've changed to 4-speeds. Just a waste of time. as for the 6.5 I'm still diagonising it. I still want it back on the road. If I decide to trash it, I'll post it for y'all.


Good Day!!

my 95 350 TBI got 10-11 mpg. my buddies 97 350 MPI gets 15-16. i guess there must have been something wrong with mine.

Billy,


Did you ever say what's wrong with your's? I'd like a chance to call it.

HELLO QUANTUM MECHANIC....I HAVEN'T FOUND OUT FOR SURE WHAT IS WRONG YET...A MECHANIC IS GOING TO LOOK AT IT AGAIN MONDAY, HE THINKS THE INJECTOR PUMP IS PROBABLY BAD, BUT, HE SAID IT IS DOING SOMETHING FUNNY TOO, THINKS IT MIGHT HAVE SOMETHING TO DO WITH THE FACTORY ALARM SYSTEM...I TRIED TO EXPLAIN IN MY FIRST POST WHAT IT WAS DOING...IT DIED A MILLION TIMES....WITH THE FIRST PUMP...THE ORIGINAL that was on it WHEN I BOUGHT THE TRUCK...IT DIED AND DIED, FINALLY WOULDN'T START AT ALL. THEN I PUT ONE ON IT THAT I GOT FROM A MECHANIC THAT WORKED AT A CHEVY DEALERSHIP, A USED ONE THAT HE THOUGHT WAS OK....IT RAN FINE FOR MAYBE A COUPLE OF WEEKS, THEN IT STARTED DYING LIKE THE FIRST ONE...NOW, WHEN THE FIRST PUMP STARTED DYING...I COULD JUST PUT THE TRANNY IN NEUTRAL, TURN OFF THE IGNITION AND IT WOULD START RIGHT BACK UP...THEN IT GOT WORSE AND FINALLY WOULDN'T START AT ALL. WHEN I PUT THE USED ONE ON, IT RAN FINE FOR A WHILE, THEN STARTED DOING THE SAME THING...BUT, NOW, I HAD THE PMD OFF THE PUMP AND IT WAS ACCESSIBLE, SO I STARTED CHANGING THEM TOO...I HAD ABOUT FOUR OF THEM, MAYBE FIVE TOTAL, AND EVERY TIME IT WOULD DIE, WHEN IT WOULD'T START AGAIN WITH THIS PMD, I WOULD CHANGE THE PMD, AND IT WOULD RUN AGAIN. THEN THE NEXT TIME IT DIED, I CHANGED THE PMD AGAIN, PUT THE ONE ON THAT IT DIED WITH THE LAST TIME, AND IT WOULD RUN ON IT NOW. OVER AND OVER, I CHANGED THE PMD'S...FINALLY IT WOULDN'T RUN ON ANY OF THEM. LEFT ME ON THE ROAD IN THE RAIN...HARD RAIN TOO. REMEMBER IT WELL. SO, THEN I GAVE UP AND STARTED MY SEARCH FOR A MECHANIC TO HELP ME...BEING A POOR CONSTRUCTION WORKER, I SEARCHED FOR A CHEAP MECHANIC. I FOUND ABOUT THREE. I THINK THIS FOURTH ONE MIGHT BE A GOOD ONE. HE HAS ALREADY LOOKED AT IT LAST FRIDAY, AND DIDN'T HAVE TIME TO LOOK LONG, AND WILL RETURN MONDAY. I'VE ALWAYS FELT IT WAS SOMETHING TO DO WITH THE WIRING HARNESS...SINCE THE PUMP SEEMED TO WORK FINE WITH THE DIFFERENT PMDS. THEN, IN THE END, BEFORE I STARTED SEARCHING FOR A MECHANIC, I TRIED A PMD THAT WAS DEFINATELY GOOD, AND IT WOUDLN'T START WITH THIS ONE....SO, HERE I AM..I THOUGHT I HAD A DIAGONIS SET UP WITH A DEALERSHIP IN TYLER...TOLD ME THAT THEY HAD A "BREAKOUT BOX" WHICH I'M TOLD IS NECESSARY TO REALLY DIAGONIS THE WIRING HARNESS...THEY TOLD ME THAT THEY WOULD DIAGONIS IT FOR $67.50 AN HOUR, AND ALL BUT PROMISED ME THAT THEY COULD DO IT IN ONE HOUR OR LESS..MOST LIKELY NOT MORE THAN TWO HOURS...SO, I LOADED IT ON A TRAILER, DELIVERED IT 50 MILES AND WHILE MY DAD WAS UNLOADING THE TRUCK, I WAS INSIDE TALKING TO THE ?APPOINTMENT? KEEPER, WHICH I FOUND OUT WAS THE ONE I HAD BEEN TALKING TO ALL THE TIME, (TWICE I CALLED TO MAKE SURE THERE WERE NO MISCOMMUNICATION), AND WHILE I WAS TALKING TO HIM, THE REAL MECHANIC CAME UP AND WANTED TO KNOW WHAT WAS GOING ON, AND AFTER EXPLAINING TO HIM WHAT HAD TRANSPIRED AND WHAT I HAD BEEN TOLD, HE INFORMED ME THAT I HAD BEEN LIED TO, THAT THERE WAS NO WAY HE COULD CHECK IT OUT IN ONE HOUR OR EVEN A DAY...SAID IT WAS GOING TO COST ME A BIG BUNDLE OF BUCKS TO FIND OUT WHAT WAS WRONG WITH THE MOTOR....SAID HE WOULDN'T JUST DIAGONSIS IT FOR ME ANYWAY. HE HAD TO FIX IT TOO....FIRST THING HE WANTED TO DO WAS CLEAN THE FUEL SYSTEM, TANKS, LINES ETC....THAT WAS GOING TO COST $3500.00...MAN, THE TRUCK ISN'T WORTH A LOT MORE THAN THAT. SO, I BROUGHT IT HOME, AFTER RAISING A LOT OF RUCKUS.....I'VE HAD TWO MECHANICS THAT CALL THEMSELVES THE BEST IN THE WORLD DO EVERYTHING THEY CAN DO TO IT AND BOTH GAVE UP, SAID IT WAS REALLY RARE THAT THEY COULDN'T FIX ONE...SO NOW, I'VE TURNED TO THE INTERNET, WHICH I PROBABLY SHOULD'VE DONE IN THE FIRST PLACE....I CAN'T JUST GIVE THE TRUCK TO A MECHANIC WITH AN OPEN CHECKBOOK TO DRAIN ME DRY....I'VE HAD IT ON ABOUT THREE DIFFERENT SNAPON HAND HELD SCANNERS....I JUST GIVE UP....I JUST HOPE THE ALARM SYSTEM HAS SOMETHING TO DO WITH IT...HOPE IT IS ALL THAT IS WRONG WITH IT, BUT I DON'T THINK SO...SO, HERE I AM BEGGING FOR HELP.....WHOEVER GIVES ME A PROPER DIAGONIS IS GONNA GET PAID FROM ME TOO, I GUARANTEE IT....BY THE WAY, I HAVE A HOME PHONE PLAN IN WHICH

the 96 and newer vortec power increse over the 95 and older 350 is mostly from the move to a roller camshaft. before my 95 6.5 tahoe I owned a 97 5.7 and if you want to be satisfied with gas power i recomend you go with the 454 (if you can afford the gas). I drive off-road alot and the 5.7 was not enough for me.
They had roller cams before the Vortec motors.

What year is it? F or S engine? How does it die? suddenly, or can you feel it coming like when the fuel pressure is too low?


Also, PM hrjack99. he's in your area and he's good with electrical.Edited by: quantum mechanic

BIlly, Where in Texas are You ? I'm in SW OK are we close?


Won't start as in not turning over or not firing off? Lift pump working ?


you could try this with a jumper wire and truck off just to see if lift pump works and then see if it will start


http://www.dieselplace.com/forum/uploads/Z6F_DCP_0471.JPGEdited by: bowtie

Hello,


i am in northeast tex....edgewood, canton..and the motor is a 96, turns over fine, lift pump is working fine, has been changed, but the old one was ok too, I changed it because one of my "master mechanics" suggested it. grasping at straws....when the motor was running, it died instantly...just like turning off the key. as for a "F" or "S" engine...i don't know what that means...the motor has had three pumps on it. "Injector pumps"...the original one (#1) lasted a long time,(210,000miles) the second one i put on was taken off a truck at a dealership, the mechanic thought it was ok after all, (it was a warranty change only died once or twice i guess and the owner enforced the warranty) and the third one (on it now) was a rebuilt one i bought from, i think it was "Midwest Supply" in some state up north. had it shipped to me. the motor did exactly the same thing with every pump. it would run fine for a while, (maybe several months after changing the pump both times) then it would start dying again, with absoutely no pattern. nothing consistency. And, like I said, on the second two pumps, i was able to change the PMD's, I bought several and changed them a million times. when it would die, i'd change the PMD, it would run again. some time later, it would die again, would not run on the present one, i would change it, it would crank right back up. over and over....this is why I have thought it was an electrical prob....like someting was just telling the injector pump to stop working. then i woudl change the PMD, and "confuse" the electrical system? that is what one of the master mech's told me. Heck I don't know. right now, it is waiting at my brothers muffler shop for the mechanic at the dealership to come back and look at it again. he said it might have something to do with the alarm system. http://www.dieselplace.com/forum/smileys/HiHi.gif He's the one i bought the first "used" injector pump from. also he's the first one to come up with the alarm system idea. Man, I've changed everything that can be changed. Even the wiring harness that connects to the back of the pump and the PMD...i've taken the fuse box apart at the cowl, and checked for bad connections....lift pump. many other things that i can't recall now. but the only thing i haven't changed again is the injector pump. maybe that would have done it. I just figured that since the pump would work when i changed the PMD. there was nothing wrong with it.(doesn't matter anymore) but, then there is something electrical in the pump, and the lady at "tyler fuel injectors" said since i wasn't using additives, that the pump was bad. i don't know. the only way to actually check the pump is to deliver it to them, they will put it on a machine for a couple of hundred bucks, and test it. maybe I should've done that. I"m open for suggestions. as for the lift pump, you can hear it running when the key is turned on. it has fire to it as well. lights the tester. Thanks for ya'lls responses. I appreciate the information.http://www.dieselplace.com/forum/smileys/Big Smile.gif

Ignition switches are known to cause electrical stalling in these trucks. ~$25 to get a fresh one. not at all hard to put on. A bad + connection on the passengerside battery will do the same.


Fuel pressure issues will stall it too. Have you ever opened the filter air bleed while the engine's running? It should shoot out fuel, not die.


F or S will be the 8th VIN and indicate HD or LD, EGR or non-EGR.

Hello,


i don't have the truck here to check the vin, I did change the ignition wiring harness in the steering column. not the switch. Have opened the fuel bleeder many times, it never died. I haven't really focused on the battery passenger side battery cables, though. However, once, the truck wouldn't turn over, I drove 40 miles one way to buy a starter, left my old one as a core. after changing the starter, I found a bad connection on the passenger side battery. Man, did I feel stupid...I called the place back and told him the story, and he saved the core for 8 months. it was 8 months when the mechanic burned the bushing out of the end of the rebuilt one, I went back and got my core back. The rebuilt one I left was under warranty, so he fixed it for me..all i have to do is take him a core and get it back....I've taken the positive sides of both batteries off many times, when doing different things, but I don't think I"ve ever actually taken off the neg sides of either one..except when I changed the batteries...a long time ago....darn, what if that is it. Interesting....gonna check it out tomorrow...however, would that make it not crank, but turn over fine?seems like it wouln't turn over good with a bad connection...and what about the ignition switch...I've not changed it, just the harness......no, actually, I think I did change the switch at the same time I changed the wiring harness...but, I don't remember for sure. I'll do some checking. tomorrow afternoon after Chris gets off work, he is gonna check about the alarm system again for me. He is a mechanic at a dealership, checking after work. I'm hoping....however, as I remember the alarm system (I never use it) has a switch below the dash, and when it is turned on, the starter won't kick in..just makes the horn blow when you try to crank it...I don't know if it could be causing a problem or not. seems like it wouldn't turn over if that is it. but maybe it would do something else...like make it not run......I will definately check the battery connections...first thing in the morning actually...gonna make it my main project.....the truck is about 30 miles from my home, but, if it works, it'll be worth traveling a 10000000000000000 miles...thanks for the info.....(still searching)http://www.dieselplace.com/forum/smileys/Approve.gifOH YEAH, I JUST TALKED TO MY SONIN LAW, WHO'S BEEN AROUND OVER MOST OF THIS TRUCK PROBLEM, AND HE REMINDED ME THAT THE "GREATEST DIESEL MECHANIC IN THE WORLD" (THE ONE THAT BURNED THE BUSHING OUT OF MY STARTER BY CRANKING ON IT SO LONG) ABSOUTELY CLEANED ALL THE BATTERY CABLES, AND IT RAN FOR ABOUT MOST OF THE DAY WITHOUT PROBLEMS, BUT STARTED AGAIN QUICKLY...ACTUALLY THE SAME DAY, i TOOK IT BACK TO HIM AND HE STARTED CHEKCING ALL THE WIRING...( DON'T KNOW IF HE WAS CAPABLE OR NOT NOW) THE THIRD MECHANIC (FRIEND OF MY BROTHERS) LOOKED AT IT, AND WOULDN'T EVEN MESS WITH IT BECAUSE "SOMEBODY HAS BEEN CUTTING INTO WIRES LIKE HE'D NEVER SEEN"...I FIGURE IT WAS THE ONE "GREATEST IN THE WORLD"...NOW THAT I THINK ABOUT IT, MAYBE IT IS ACTUALLY SOMETHING TO DO WITH THE CABLES...MAYBE NOT THE CONNECTONS, BUT MAYBE THE CABLE ITSELF.....I PROBABLY NEED TO CHECK FURTHER ON THAT ASPECT....THANKS A MILLION!!!!ALSO, AS FOR BLEEDING THE FUEL...I BLED THE VALVE MANY TIMES, THE FILTER I LOOSENED SEVERAL TIMES IN THE BEGINNING TO BLEED IT BUT NEITHER SEEMED TO HELP...THANKS!Edited by: BilllyH

Anywires grounding out could stall the engine as well. Bad connections on the wiring harness, especially the FSD harness/ground will stall the engine. Any splices should be sodered.

OK, I'M GONNA CHECK OUT THAT............NOW, I DON'T KNOW WHAT WIRING HARNESS YOU ARE TALKING ABOUT, FSD. IS THAT ON THE BATTERY CONNECTION?

Hey Billy, check the tension on the connector at the harness for the pump. Theres a 4 pin connector that I've seen the pins loose and cause an intermittent problem. Is there any codes?

some alarm systems do have an ignition kill circuit. are you getting any codes out of that thing?

well, i guess the "ignition kill circuit" would probably be what mine is since the ignition won't work when the alarm is on....haven't seen any codes about it though. however, I haven't had a scanner on it in a long time.

I have a viper alarm with the IGN. kill. It doesn't crank when Ign. kill is activated.


When your stalled, have you ever checked for vacuum pressure on the fuel tank? It will make the fuel stop comming.

haven't checked vacumn pressure.....I don't understand...will you explain?

If you have a gasoline cap instead of diesel on your truck it will pull a vacuum on the fuel tank and stall the truck.

I have the same cap that has always been on it....it was fine for a long time. I don't think that would change while using the same cap...changing the PMD"S was making it run...

Prior to 96 the only 8cyl. gm gas motors that had roller cams were the corvette, camaro and LT1/LT4