98 chevrolet blazer V6 please help


#1

What would cause my truck to have a long turnover start, a really rough idle, and a loss of power after idling at a stop light for about a minute?

This problem gets worse as the truck warms up. It feels as if i’m not getting power from all 6 cylinders but this goes away after about 20 feet of acceleration. The truck has never not started. It just has to turn over for about 5 to 10 seconds before it fires up. I changed the spark plugs and wires thinking it was that and then i tried the fuel filter and it wasn’t that either. has anyone else had this problem?


#2

@Keebler

The extended start makes me think you’ve got a fuel pressure problem. The good news is your engine has a fuel pressure test port, so it’s easy to hook up a gauge.

Changing the plugs, wires, and fuel filter was a good first step, and good maintenance, anyways

Check engine light on?

If there’s any codes, please post them. Parts stores will usually read them for free

But if there’s not any codes, the first thing I’d do is hook up that fuel pressure gauge.

An injector balance test will determine if you have a leaking and/or partially plugged poppet-style injector. But this test requires a fuel pressure gauge AND a high-level scan tool, which non-pros will typically not have.


#3

ya the check engine light is not on so no error codes. and i know that like autozone lets you rent parts so ill see if the have a fuel pressure test gauge to borrow.

i have also been told that these might be symptoms of a failing distributer cap/rotor. what is your opinion on this?

also, my muffler is pretty shotty and in need of changing. is being loud and obnoxious the only major issue when it comes to a rusty muffler?


#4

@Keebler

“failing distributer cap/rotor”

Didn’t you replace these when you replaced the plugs and wires?

Based on your description, I don’t think the distributor cap and rotor are the problem


#5

I’m guessing dB is correct, a fuel problem of some kind. If that doesn’t pan out … hmmm … you know I’ve never seen your vehicle, let alone put any test instruments on it, never put it on a lift, right, so you know everything I say is just a guess? Ok, given all that … hmmm … when you say it seems to lack power until after 20 feet of acceleration, then it seems to catch and go like it should. hmm … . that could be an ignition timing problem. The timing changes with engine rpm and load so maybe at idle the timing is off, but it get back to spot on once you start to accelerate.

You also say you have some exhaust issues. Modern cars just don’t run well with exhaust issues for some reason. Before investing any more resources I recommend getting the exhaust system up to snuff first. And make sure the intake manifold vacuum reading at idle is correct once the exhaust system is fixed. Be sure there aren’t any exhaust leaks at all, especially in the vincinity of O2 sensors.


#6

This is another vote for checking your fuel pressure. The symptoms you have stated sound like the classic failing fuel pump.


#7

I second and third the mention of fuel pressure measurement. If you find it to be normal and must proceed to the next suspect beyond a leaky FPR fuel pressure regulator… The problems with the FPR you will learn soon…and its location…

You may find the fuel pump in the tank faulty…but they usually just die and dont work. Make sure when you turn the ignition all the way on…that you hear the telltale HISS of the pump in Prime mode…it should prime for about 2-3 seconds…if you do not hear this…you are onto the problem…which could be a failing FP Relay… Id consider you very lucky if that fixed you up. Methinks it might be everyones favorite insect to hate…The Dreaded Spider.

If you need to proceed further… I hate to even mention it…but…the fuel injection Spider could be acting up. Do a search for your Yr make n model…about the “Fuel injection Spider” Its a well known…mayhem inducing item that affects many many of the same engine out there in the world. Ive had to replace many of them. Sometimes when you unplug the huge electrical connection that goes to this part on the engine…it behaves nicely for a while without any other repairs…so it may be useful to simply unplug and re-plug in that connection a few times…just for giggles.

Hope its not your Spider…not too hard to do…just not something you go around wishing would fail. Plenty of info out there on this Spider I mention. But you have many things to test PRIOR to getting to the spider. See below for some good info on the topic. I have these documents all over the place from prior replacement jobs Ive had to diagnose and perform.

Good Luck

http://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/testing-the-spider-fuel-injector-1

Blackbird


#8

Actually, the cost to replace the “spider” is quite reasonable. A few hundred bucks for the part

And a few hours labor

The good news is that if you buy a new “spider” it will be slightly more modern. If you google that link, it will probably have pictures


#9

Yeah its not too bad to change the Spider…for us. Many people look at disconnecting the battery as a daunting task however. lol. Not sure the mechanical ability here. By no means is this “Beginner Time” to tackle this replacement properly. I dont find it too bad meself and have done more than a few.

Blackbird