blazer k5 1990 stalls
 

i have a strange problem with my engine that i can't put my finger on it.
my 90' blazer stalls randomly in several situations:

-it stalled for five times when i tried to park the truck in reverse. when i first stopped it stalled, then when i tried to start it again it failed for three times and then when i finally got in the parking space it stalled for one more time.

-on another situation i was cruzing about 90 kph on a highway and suddenly i felt like the engine is suffocating, the rpm dropped, the speed dropped and after about four seconds it came back to normal. that happened twice over about one kilometer. throughout the whole thing i didn't changed the gas paddle position.

-on another day i got in the truck and started it, the engine was idling while i was putting my seat belt , tuning the radio and etc (something like 2 minutes) when i put it in D the engine stalled immediately.

-on another situation i was standing in a red light, when i started pushing the gas paddle i felt like the engine have no power, the truck budged for a few meters and then it stalled again.

-and the most common of them all, i drive the truck like always and the engine stalls with no warning at all, like i switched it off myself.

in all of the situations the engine will start right up when i give it a go.
the lights on the dash won't change when the engine is stalling.
i hope i could get some direction from you guys, thanks in advance!
by the way in the last two weeks the truck stalled for more than 20 times..

Yarin.

Possible fuel delivery issue? Fuel filter in good shape?

my experience tells me that fuel problem usually won't shut down the engine with such ease. my shut downs were smooth as if you just simply turned the switch off.

either the fuel pump, iyac, or the alternator.

iyac?
and about the fuel pump and the alternator, is there any way to check them?

can i hear more options guys? this problem is really strange and gives me no rest.

Fuel pressure test??? You need an inline adapter fitting to test the fuel pressure on a TBI engine.

You can remove the alternator and have it tested at most autoparts stores.

I'd run through what has been suggested rather than waiting on more responses. The responses you have been given are pretty much right on the money...

IAC == Idle Air Control which is the air valve on the side of the throttle body.

If you do not already have a repair manual for your truck, I would highly suggest the investment. If you can find a FSM (factory service manual), definitely go that route. I just picked up a '90 R/V GM fullsize manual on eBay for $20 delivered since I am putting a Suburban motor in my '74. A manual will help you run through the suggestions made.

well swartlkk, with all do respect i didn't mean to upset you, but my logic tells me that a fuel problem is out of the question because the spray pattern is perfect.
the alternator was tested already, but here as well my logic tells me that if the alternator was bad then i wouldn't get any charge to the battery, is that right?
the iac valve, i replaced it six months age with a brand new one. the reason i asked again it's because the guy above you wrote iyac and i didn't understood what he was talking about.
as for the manuals i already took your advice and bought me those manuals, the should arrive any day now.
now, please believe me that i don't just sit around and wait for answers from you guys. i have this truck for two years and this problem is there from day one.
this issue makes this truck unreliable off road because i never know when it will strike me next.
I'm truly trying to keep the thread informative but i do need as much help as possible, the k5's are quite rare in Israel and mechanics usually won't even consider touching my truck, so I'm on my own on this one.
if i may, i would like to add some new info about this problem that might help - when i cruse on a high way, and the gas paddle is steady the truck suddenly feels like it wants to come to a stop, it doesn't feel like brakes applying, it feels like the engine is suffocating and within a few seconds it releases and the truck continues to ride as usual. this happened to me twice today and a few more times last week, I'm 100% sure that the two problems are connected.

thanks in advance, Yarin.

You aren't upsetting me at all, but why did you wait until now to let us in on all of this information? If you don't tell us what you have already done, we'll likely just be wasting your time. None of us are mind readers...

How is the ignition system? Good spark? Proper timing? How about the EGR system?

What have you checked/tried to remedy this problem? Or have you just lived with it for the past 2 years?

well, about the ignition the only thing i did was to replace the spark cables. it was about a year ago.
to tell you the truth i read about the EGR system but i don't really know where to find it in my truck.
what else i checked? well like i said the IAC valve is new. someone told me to check for vacuum leaks so I'm planning to replace most of the lines with new ones.
i read around here about leaking from the TBI base, so i still need to get a rebuilt kit for that (it's kinda hard to find it in Israel, but it does exist here).
i've also been told to check the ignition module, but i haven't found someone who was able to do that for me around here.
i've also been told to check the coil and the distributor but it seems to me that a problem like this should come all the time if a part like the coil or the distributor were bad, instead it as random as it can get.
i hope i gave you some leads with this, if i'll remember anything else i'll write it down.

Thank you very much, Yarin