Help- quits when put in drive

[SubBob]

'88 sub, 350, auto trans, 4WD, 1/2 ton

Truck will idle all day long in park/neutral. Will rev up good too. But when it's warmed up and put in gear it immediately begins to surge and after a little bit it will die. Don't have any trouble codes - flashes 12 only.

Replaced the following:
fuel pump & filter, MAPS, IAC, O2 sensor, distributor, plugs & wires, EGR, battery, injectors, (think that's all)

Also have set timing, checked alternator, used throttle body cleaner, knocked plug out of catalytic converter.

Nothing I have done so far has made the least bit of change. Tried driving it but won't run long enough to set codes(?).

You guys got any ideas that will fix this thing?

Will add that there is a more than slight hesitation/miss when accelerating. (This is while in park/neutral). When you first put in drive it's
'OK" for a few seconds before it starts surgeing. Acts like it's trying to find the right idle speed.

EDIT (9-7-04)
In my original post I said the engine is surging. After paying a little more attention that probably should say cutting out or missing. Seems to me it is idling way down or cutting out then picking up rpm's to normal idle. In doing so the truck will lunge a little.

[454malibuwagon]

check the converter in the tranny, it should have a lock up converter and it sounds like it is staying locked up, there should be an electrical connection on the side of the tranny, unplug that and that should unlock the converter, leave it unplugged and then see if it will keep running in gear then

[SubBob]

Originally Posted by 454malibuwagon

check the converter in the tranny, it should have a lock up converter and it sounds like it is staying locked up, there should be an electrical connection on the side of the tranny, unplug that and that should unlock the converter, leave it unplugged and then see if it will keep running in gear then

........didn't work. Unplugged 4 prong connection. Only one I seen. No difference.

[BeerMonkeY]

try seeing how much vlotage is goin to your coil, my jeep did the same thing (it has a 350 in it) i found a bad connection goin to the 12v plug on my cap and it turns out the coil was only getting like 7 volts so it was making enough spark to let it idle but so as it got a load on it it would die

[SubBob]

Originally Posted by BeerMonkeY

try seeing how much vlotage is goin to your coil, my jeep did the same thing (it has a 350 in it) i found a bad connection goin to the 12v plug on my cap and it turns out the coil was only getting like 7 volts so it was making enough spark to let it idle but so as it got a load on it it would die

......not sure how to check that. I looked at the Chilton's manual but it didn't give me any ideas on how to check. How did you do that?

Also (for all) in my original post I said the engine is surging. After paying a little more attention that probably should say cutting out or missing. Seems to me it is idling way down or cutting out then picking up rpm's to normal idle. In doing so the truck will lunge a little.

[f.monroe]

One of our TBI equipped company trucks was doing the same thing. It turned out to be a Throttle position sensor but the first one we bought was bad out of the box.
Frank

[somery]

engine vacuum always goes down before it goes back up when you accelerate...to operate the engine needs to counter earths 14.7 psi by running at 15 psi or higher. maybe you have an intake manifold or throttle body vacuum leak? see if you can get a hold of a vacuum guage and connect it to the vacuum going to the pcv valve. cap the open connection to keep dirt from sucking in notice how vacuum goes down to like 5 or something...this might be what you are feeling in idle change.....if you can't get one try spraying wd-40 around base of intake where it mates to engine block(while engine is running) and if engine runs better then drops then you got a leak? or does this not apply to non carboraters (i got a carb)

[SubBob]

Originally Posted by somery

engine vacuum always goes down before it goes back up when you accelerate...to operate the engine needs to counter earths 14.7 psi by running at 15 psi or higher. maybe you have an intake manifold or throttle body vacuum leak? see if you can get a hold of a vacuum guage and connect it to the vacuum going to the pcv valve. cap the open connection to keep dirt from sucking in notice how vacuum goes down to like 5 or something...this might be what you are feeling in idle change.....if you can't get one try spraying wd-40 around base of intake where it mates to engine block(while engine is running) and if engine runs better then drops then you got a leak? or does this not apply to non carboraters (i got a carb)

Don't believe it to be a vaccum leak. When I disconnect MAPS vaccum line the engine will immedialtey die. Also, if the TBI gasket were leaking the engine would idle fast. At least that what it did before (on this truck and an '89 i ton I own. Also, the PVC hose has blown off the TBI a couple of times when the engine has backfired when I tried to keep if from dieing after drive was engaged. When it came off the engine would idle fast till it was reconnected and then it idled down to normal.

[f.monroe]

Have you plugged the vacuum line to the EGR and driven it with the EGR disconnected? It will kick up a code after about 15 miles of driving but might help to isolate the problem.Frank

[SubBob]

Originally Posted by f.monroe

Have you plugged the vacuum line to the EGR and driven it with the EGR disconnected? It will kick up a code after about 15 miles of driving but might help to isolate the problem.Frank

Drive it 15 miles.......this thing barely makes it down the drive and back. Got it out on the road a few days a go. Went about about a mile and came back. Missed and carried on the whole time. Don't think it got past 40 going uphill. Died about 3-4 times on the way back. Put it back in "Park" and run just fine.

[f.monroe]

Did you set the timing with a timing light? If so ,the marmonic balancer might have spun causing a false setting.Advance the distributor without a light hooked up until it clatters under a load and then back it off a little. If it doesnt change anything you can always reset it with a light. I would also check all chassis and engine grounds. Especially the grounds at the battery .
Frank

[gchemist]

Is the "base" timing "0"??

[SubBob]

f.monroe - Yes, timing was set with a light (w/ timing wire unplugged on drivers side of engine compartment). Advanced timing as suggested - no change ( also retard - no change) Will check grounds.

bisquik65 - have already installed a new distributor.

gchemist - Yes base timing is set at "0". Have also set in several advance & retard positions, with no difference.

[somery]

with the harmonic balancer on top dead center of the compression stroke, does the rotor under the dist. cap point toward the number one cylinder (or whatever your manual says?) if not say so and i'll post how...( i wrote bunch of stuff already but internet connection closed and lost it all )

[somery]

just reading what i wrote again....if you say it goes on 0 then i guess its not a tooth off like i was thinking. if you have a haynes manual or whatever does the rotor AND the number one wire on the cap (again, on TDC) point to the same place as the black dot in the picture in the book? maybe you are 180 degrees off? no wait--i don't think it'd run, but i am thinking its off and the plugs are just off with it to compensate. it really does sound like some kind of distributor error. no chance of crossed wires, eh? if yours is like mine i had it at about 5 o' clock for the number one wire start. if your number one plug wire is on the side facing toward the firewall then you may be compensating for being 180 off. sorry im babbling i don't know what you know...

[somery]

also have you tried putting the timing light on all of the wires to see with one is missing? (you know, just shine the light on anything...not for timing guage reasons....)

[somery]

also is your fuel filter in backwards?

[SubBob]

somery
1) Yes, rotor is toward #1

2) Rotor & #1 are roughly in the 5 o'clock position.

3) Will give it a shot!

4) No.

See next post

[SubBob]

A short history of problem

This problem started (or became apparent) after the Suburban was parked for a while. Prior to that the only thing was that sometimes while driving 55MPH, it would "spit" (maybe quit) just for a split second, Check Engine light would come on for a few seconds and go out. Wasn't much of problem. Just would do that occassionally. I then parked it for a couple of months. Didn't even start it. When I did this problem started. While idleing, the rpm's would go up and down. When you tried to drive it, it would buck and jump and just about quit. Didn't have time to fool with at the time so it sat a while longer. When I did get to it I first thought it to be the fuel filter and then the fuel pump. No change. I then found out the battery was bad and got a new one. Had alternater checked at parts store. It was OK. If I remember correctly (old age is starting to get in the way) this is when the truck would idle "OK", but couldn't drive it. That's when I started checking and replacing parts (see original post). Not one of these has made even the very slightest of change in the problem. One thing I forgot was that I put new ends on the battery cables due to corrosion. Cut cables off a little to assure corrosion didn't go deep into the cables. Cut off no more than an inch to where copper was clean and shiny. This didn't make any difference. So here I am. I have done or already had done the things mentioned in the replys to my original post except check grounds (don't where they all are. Hope Chilton manual is clear on this), check coil voltage (don't know how and book don't say how) and use timing light to check for location of miss or misses. I how to do these this weekend.

Thanks

[somery]

i don't think its the grounds because this would cause the car to not start, ect....voltage check? i dunno about your situation because you mentioned it missed anyway idleing....
i think you have stuck valves....auto zone (am i allowed to say that?) has a free rent a tool service -- get a compression guage and test each cylinder....in fact you may have more than one with zero compression because it seems serious enough that you can't move. i got a valve job for about $250 at a machine shop.

[somery]

my truck sat for a year without a start because the previous owner passed away and one of the valves were stuck...

[somery]

hey i have another idea....the second time you let it sit, it wasn't that long, (oil gums up the valves) so maybe its can be unstuck...go to an autoparts store and buy you some Marvel Mystery Oil....its a red bottle and i think its for gummed up valves. read the bottle and run it a while see if you can free up one valve and maybe then you can be moveable enough to take it to a shop so you dont have to do so much work yourself (it IS fun tho)....you said it missed before so that may have been just one stuck valve (which will act like a bad plug) maybe it was just sticking some of the time. but doing the work is a lot of trouble (you gotta take pictures and label before you dismantle!!) but you just have to take everything off the top of the engine, then the intake manifold (which hides some head bolts) then the heads come off...make sure you take the bolts out in the right order if you are doing your own valve job, so that you don't warp the heads. if you go to a machine shop, they charge a little for each bad valve, but crack checks and warp fixing is covered in the main charge. keep me posted! i wanna hear more!

[SubBob]

Hadn't really thought about a stuck valve(s). No noise. Worth a shot. If any are stuck I've got a 2 lb sledge that should unstick them. (Just kiddin') I'm familiar w/ Marvel Mystery Oil. Was considering a compression check as one of the next steps. Gotta get a new starter, I think I burnt this one up starting it so much. I'll post what I find out. I got a lot of things on the agenda so it may take a while, so be patient.

Thanks

[f.monroe]

I was wondering if you have checked the cat converter .I noticed that you pulled the plug but it may be clogged. Crank it and feel the exhaust before and after the cat. If it stays cool to the touch after the cat converter, it might be plugged. Since these only use one cat it will affect the scavenging of the cylinders and will not run well under a load. The reason I mentioned the grounds is because we had a truck that did the same thing after a new battery was installed. They did not reinstall the ground wire that went to the core support and it caused similar problems until we hooked the wire up .We could unhook the wire and the problem was right back. It would be a little troublesome but you could cut the exhaust before the cat .If it made no change ,I am sure you could slide a cheap exhaust coupling over the cut or have a muffler shop weld it up for a few dollars.
Good Luck!