Chevy & GMC Vans

hello folks, my name is Luke and i am joining this web site because i have always had good
luck getting help and info from people that are owners of certain vehicles. i have a 86
monte carlo CL custom that my son and I built and i am a member of the national monte carlo
association. but my problem now is with my wifes 94 astro XLT 2wd 4.3 TBI started having a
hesitation from start all the way up to cruizing speed, almost a misfire.
right now i am stuck because it will not start. in feb of this year i replaced the intake
gasket, complete tune up, plugs,wires,dist cap/rotor,starting module,coil,idleair valve,
TPS, EGR "gasket/Screen" and all was good up until 2 weeks ago. then the starteling started.
a week ago sunday i decided to replace the spark plugs, did the passenger side and tried to
start and it did not. since then i have went through 2 sets of plugs "filing them out" a new
set of plug wires, cap/rotor, coil, and distributor. reset timing using 2nd
timing mark on balancer as the book said just in case but this
thing will not fire up. i have spark and good cones of gas but when i try to start it
makes a good attempt then upon stalling a puff of vapor/smoke comes out of the TBI holes
that smell like oil, not burnt oil, just like oil. this van we've had for 5 years, we bought
it with 86K on it and now she has 155K, it has been maintained religiously, it is my wifes
baby. i am at a total loss... i need some point of direction to check next... she treates
this van like i treat my show car. can someone give some input no mater how bad the news
might be.. cam toasted? even worse motor?
i do appreciate any input and thank you in advance
Luke

the hesitation you mentioned makes me think you need to take a look at your fuel pump. My 87 started doing the same thing.

The fuel pump was working but just not putting out enough pressure.

At 155k, if you have not replaced the fuel pump already, its probably time to do so.

When someone is cranking the engine over pound on the bottom of the fuel tank with your fist. If it starts up the fuel pump is bad. The pounding on the tank will usually jolt the pump loose. Just remember his only works one time so do not shut the engine off until it is somewhere it can be fixed.

Also since you pulled the distributor once, make sure you found TDC for the power stroke, not the exhaust stroke. Typically to check, you find TDC and wire it up, if it does not run then pull the distributor out again and give it a 180 turn then wire up and it will start. Well it will start if that is the problem anyway.

i have got fuel to the TBI, haven't done a pressure test yet. my issue now is i noticed a hiss coming from the drivers side valve cover and when i took the valve cover off a piece of one of the valve seals was laying in the head. i think the seal that is rubber in the intake valve seal right with the metal retainer around it. also when i'm cranking the motor over i do not see any oil coming to the top of the head. or won't it come up until the engine is running. i did some testing of wire ends and noticed that the oil pressure sending unit has constant power, is that correct? this is driving me crazy

on the 94 TBI do i still go by the old method compression stroke dist pointing at #1 drop the dist in pointing rotor at number 1 cylinder, both valves closed. also why do i have 2 timing marks on balancer. i have a S-10 book that says disregard 1st mark go with 2nd just don't know if that goes the same with Astro's
thanks

Check the ECM A and B fuses under the dash. Then check the fuel pressure at the rail. Don't go by sight...may not be enough pressure to start. You can also check the ECM wire harness that runs from the passenger side kick panel to the fire wall just in front of the doghouse cover on the pass side. It then goes over the top of the right side valve cover. You are looking for burned or melted wires.

I can't answer on the timing stuff.

Well figured it out, would help if I 1 put the dist back in at TDC, note go by first timing mark on the balancer not second mark. Also on my fan shroud there was a sticker that said to unplug single wire adjacent to dist while setting time . Took a minute to find but it is a single wire running along the back of engine outside of the harness cover near the dist with a straight pig tail like whats on some O2 sensors. Also while the dist was out again pulled EGR and it was stuck open, wasn’t like that before? So in the end my original problem is fixed. whether it was the plugs,wires,cap,rotor,dist,egr the issue is fixed so for what it’s worth hope my problem and resolution helps someone else that’s great. this may only apply to 4.3 Vortec TBI vin W
Thanks
Luke

Luke-did you replace the EGR gasket with a help section screened one???.That is a $8.00 investment that will come back to ten fold over the yrs.With mine I also replaced the bolts with lock tighted studs that I found the exhaust studs from a Ford exhaust fit.I sure does make that inside bolt a hell of alot easier when your putting it back together.Just my two cents worth.

oh ya, replaced gasket, if it's coming off and there a gasket it will be replaced. when i originally did the intake gasket everything got replaced in the way, i was really surprised when it started acting up a few weeks ago. she always has ran like a champ, but i still have to deal with a intake valve gasket is missing the retainer around it. have done them before not fun with heads on but do-able
thanks
Luke