Sputter! Sputter!!
 

This is weird. If I try to start my Blazer by turning the key normally,it doesn't want to start . I have to try several times. If I turn the key fast like snatching it, it cranks right away first time. Idles fine. When I accelerate , it stutters and hesitates really bad. If I really get on it, It almost wants to cut off, Especially if I power brake. I've changed fuel filter,plugs,and rotor button.Previous owner changed fuel pump,plug wires and cap. Says they have about 9k on them. But said when he checked pressure he was only getting about 10 psi. My question is could this be causing all my problems or does it sound like an ignition problem as well? Bad distributor and pump? When I cruise, It runs fine, only when under load does it sputter and sounds like all 6 cylinders aren't firing. Any Ideas? Thanks in advance!! By the way - no codes all checks fine - code 12

Sounds like a fuel pressure issue to me. I am not sure what the psi is supposed to be on the TBI, but I am sure it should be more then 10. Was the filter plugged bad when you changed it? A severely plugged fuel filter can kill a pump.

I would also look into the fuel pressure regulator.

Filter was not plugged bad. Had some black stuff come out when I knocked it on a table. TBI was taken off and completely cleaned, injectors cleaned professionally, fuel pressure regulator rebuilt . All this done by ASE technician who previously owned the truck. Checked all sensors - good. He said it ran fine for about 8k miles after he changed fuel pump (from Advance) . Only sputtered a little bit under load. Maybe a cheap weak pump?? Or maybe not getting correct voltage - I don't know.

Did you try to blow through the filter at all? That is how I test them out. If I can blow through it in the flow direction easily, it isn't that bad. If I have a hard time getting any air though it, it is very bad and could damage the pump.


I would check to see what the fuel pressure is supposed to be at and go from there. Might have to call a dealer if you can't find it on here or in a book ( if you have one )

yes i did the blow test. easily blowed out fuel. I'll check to see what my fuel pressure is suppose to be but i think it suppose to be around 16psi on tbi but not sure.

8-10psi for TBI so that part sounds good.

Almost sounds like a timing problem. Have you verified the timing?

Yes timing was off when I purchased the vehicle. It was at 6 degrees. Checked Haynes manual and it said it needs to be set at 0. So I set it at 0. (with the timing wire underneath passenger floor disconnected)I'm wondering if it could be the coil or the distributor itself. Cap,wires and rotor are new. Distributor looks rusty underneath cap. Truck cruises along good when up to speed. Would'nt a timing or ignition problem make it run rough all the time and not just under load?

Not necessarily. Timing will change with load. In pre-computer controlled distributors, this was accomplished with the vacuum advance in combination with mechanical advance. The vacuum advance was based on the engine load as a function of manifold pressure. Mechanical advance was a function of RPM and modified via weights and springs.

Ok , that's over my head. Thanks for the info. Do you have any suggestions on what I should check? I thought it could have been fuel pressure but since you said 10psi should be good, I now think it must be an issue with firing and misfiring. I did set the timing, but could it be off again? Maybe computer? But i am getting code 12 and that's it. I'm stumped and almost to the point of just replacing the distributor and coil but that wouldn't be very economical! I really don't have time to take to a mechanic because I drive this truck daily.Any ideas and help is greatlly appreciated! Thanks. Maybe I should pull the distributor and check for a worn gear. I've read about this in other posts.

OH CRAP!! #6 and #4 plug wire crossed!
 

I unplugged the #4 and #6 plug wire and the engine didn't run any different! Tha's not good! Anyway,in a hurry,I plugged the wires back in crossed. Drove about 4 miles - ran terrible- knew exactly what was wrong. pulled out Haynes manual and routed plug wires correctly. Unplugged battery for a few minutes to reset any codes. Now truck will not start at all. Did I cause any damage?

Check and make sure that the brown wire below the glove box and underneath the carpet is not disconnected. (Controls Timing Advance). You could also time the vehical using vacuumn gage and tack along with the timing light. Goal is to obtain highest vacuumn and the best idle speed.(Adjust all timing with the brown wire disconnected) This will optimize your timing.

Ok, truck stalled yesterday at a stoplight. Luckily I was able to push the Blazer into a car dealer's parking lot. Truck would crank, but no fire. Checked igintion coil - good,sending 12volts to distributor. Removed cap and rotor button to inspect - good. Put all back together, sprayed ether into TBI and she started - but rough. Able to get her home sputtering and hiccupping badly. Went to Auto zone & bought distributor . Installed,set timing and WA LA!!!!! Blazer fired right up and had plenty of power. No more sputtering and hesitation. Been doing a lot of reading in this forum that has helped me a lot in troubleshooting. Thanks to all you guys I know have a strong,smooth running Blazer. Time to hit the mud!!

Good deal. Did you look over the old distributor? Were you able to determine what it was that caused it to run poorly? I have seen cracked drive sprockets cause weird issues.

Yes , we looked over the distributor before we gave it to autozone for core. It looked rough and rusty. It had some play it it and the gear was a little worn. I'm guessing maybe the pick up coil was bad. But instead of just replacing parts, heck for $99 I just replaced the whole thing.

I'm having similar problems right now with my Jimmy. Same setup as yours, same year. I've already replaced the cap, wires, and rotor...Same symptoms,

I grabbed an ignition module off my brother's K1500 Pickup with a 4.3 also...nothing changed.

So, I pulled out the distributor core. I examined it and noticed the gear on the end. The spin on the gear is arrested quickly. The gear doesn't spin too freely that, and it seems to be in overall bad shape. But the question is, does the gear not spin well or very freely? 'Cause I think I might have solved it...

no, mine didn't turn to freely, it would hang up a bit and not turn smoothly. Also mine had rust build up around the top where those little "nipples" were on the round part that spins around. Sorry I don't know the correct terms. It is the part the ignition module is mounted to and the part above the pick up coil. Did you check your pickup coil?. I was told that part tells when to spark for each cylinder.

Now I'm not so sure my distributor is installed correctly. I made my marks on the old one and installed the new one exactly the same way. Rotor button was in same position. However when i turn the crank to the position on the vibration damper that has the groove and mark for top dead center at 0 degrees, my rotor button is pointing at position 4 on my distributor cap. If I turn it to postion 1 on the cap my mark is about 2-3 inches to the left of the timing plate gauge. The engine runs good,sounds good, but I just don't feel I'm getting full power.Could my distributor be off a few teeth?

I think that Autozone has the proper timing procedure for your truck detailed. I think I remember reading through it not too long ago. I responded to your question in Tim's (hanr3) post.

Ok, so an update to my little problem...

I bought a new distributor shaft with new ICM. Did nothing. Now it won't even fire, period. I also noticed something strange, I think the TB is shooting too much gas into it. I'm getting a strong scent of fuel when it cranks. I haven't checked the ignition coil yet...But might be the problem. It doesn't seem to be getting spark? I'm not entirely sure. I assume if is not firing then their is no spark, which brings me back to the ignition coil...I swear this is becoming a full-fledged nightmare.

Any suggestions?

You did get the distributor reinstalled properly didn't you...? I would go through the whole engine timing procedure to be sure.

I'm doing this by ear...Is it possible its dumping too much gas for the plugs not to keep up due to the off timing? It's possible that it's 180 deg. upside down. How can I tell when it's on the exhaust cycle or compression cycle?

I pull the #1 plug and hold my finger over the spark plug hole while I bump the starter. Having a remote starter switch helps, but a friend can bump the starter while you have your finger over the hole. Just bump it very quickly so as not to spin the engine over too fast.

Before you do this, you will want to pull the coil wire to the distributor so the engine cannot start.

I'm gonna try re timing this beast tomorrow. My friend is bringing the ECM and Injector drivers from his S-10 pickup too. It's just with the unusual amounts of gas being poured into the TB is a bit weird. Possibly the fuel pump relay?

I'm running out of options...

EDIT - Also, When finding TDC, When I'm trying to align the marks on the crank pulley, the timing degree indicator is kind of old and I'm having trouble reading it...There are three triangles of sorts down there. Is the 0 degree mark on the left, middle, or right?

On my truck the 0 is to the right. The balancer has two key slots or "grooves" for timing. They should be at about 1 o'clock and 4 o'clock position with the 1 o'clock at the 0 mark on the timing gauge. Hope this helps.