My truck keeps dying!

[jsecrest]

I have a 1989 chevy 1500 5.7 liter v8. Every time I start it my truck will either die automatically or idle like and 90 percent of the time it will eventually die from idle. It also dies when I come to a stop harder than normal. when the engine is at full tempature it starts to level off but still idles horribly and constantly sounds and feels like it about to die. This is starting to become a huge problem. I have ran premium gas as well as treating it with numerous cleaners. The jets or TBI units seem to be spraying just fine but will studder in out as the car is about to die. Any help is greatly appreciated. Thank you

P.S. It might help to know that the weather has been ranging from 30 to about 75 degrees lately.

 

[Scienceman]

Bad Plugs, wires?

 

[simple_gifts]

vacuum leak.

 

[jsecrest]

i forgot to mention i recently replaces all plugs, wires, oil, and distributer cap

 

[ls1mike]

Do you have a check engine light? I had an 88 that did the same thing, it set the light. It was the coolant temp sensor. It needs that to help determine fueling and proper idle.

 

[CourierDriver]

I had that problem on my dodge van , mine would also backfire some, I ran lucas cleaner, heet, mmo, then((( i put stabil in it because it also cleans carbs and injectors, plus it gets rid of water caused by ethanol gas, guess what, it worked. No more dying at idle or running rough. It worked for me, thats all i can tell u. I always go for the simple, I got lucky, thank goodness it was just a water problem

 

[gofastman]

does it have an O2 sensor? replace it if so

 

[AcuraTech]

Need to narrow it down more. Could be anything at this point. First of all find out if it's a spark or fuel problem. Go from there.

 

[tomcat27]

I dont know if your local auto store will scan your engine computer for free... (up here, AutoZone will) start there. then I would start with some basic things that are free. open the throttle plate and clean the back of the plate, the edges of the plate, and the throttle body with carb cleaner and some rags. remove the IAC motor (idle air control - it will be somewhere on the throttle body, held on by two screws, and wires going to it. remove it - and clean the cone-shaped air valve with carb cleaner, rags, q-tips until all the carbon is gone. other than a rough idle, how does it run? check all vacuum lines for cracks...

 

[cjcride]

Was it acting up before you replaced plugs etc?
If not, you may have knocked a sensor wire or vacum hose loose.

 

[JimPghPA]

I would say there is a 80 percent chance that this is your problem.

Check the fine wire that goes from the ignition position sensor to the solid state ignition module. All of this is under the rotor. The thin wires from the pick-up are flexed every time the vacuum advance moves the timing (every time there is any significant change in the manifold vacuum pressure, like change in throttle or load on the engine). Anytime after 50K miles these can go bad, but they usually last 80K miles or more. At first they go intermittent and get worse and worse. All you have to do to test them is to remove the distributer cap and the rotor and find the two thin wires from the pick-up. Very gently move each wire. If one is bad it will already be broken and it will come apart with a slight tug. If this is the case you will have to replace the pick up coil. Mark the exact location that the rotor contact is pointing before removing the distributer. If the vehicle has 80k or more miles you should get a rebuilt distributer for less than 100 dollars. This is because the bearings for the distributer wear out and cause slop that causes slop in the timing. If you want to just replace the pick-up coil be aware that the tolerances required to get this system to work are very tight. Replacement coils come with 1/2 of the metal pathway with the points that align to cause the timing pulse. Even if you do get the correct pick-up coil with the correct part no. that includes the metal with timing pulse points, be aware that the replacement might have too large of a gap and require you to use the old metal part with the new coil. Do not throw the old metal that contains the coil away. You might have to use it. You will have to remove the pin that holds the gear on the bottom of the shaft. Then pull the shaft from the distributer and replace the coil. I replace this part every 50k miles on my 1985 Olds 5.0L so the vehicle is reliable. You will probably require a timing light to set the distributer position. Sometimes the best way to set the timing is to first use a timing light and then fine tune it by driving (test it on hills and or fast accelerations).

 

[CourierDriver]

w o w thats a lot of info

 

[mechanicx]

I think inspecting the pick coil and module wiring is a good idea. A bad connection there can shut down the injector pulse and spark. I think you need to hook up a fuel prssure gauge and check fuel pressure. I would also check the injector resistance against specs.

 

[RH+G]

U need to check ur fuel pressure. My money is either your tbi needs a rebuild with new gaskets and a new fuel pressure regulator or ur fuel pump is getting weak.

 

[Falcon_LS]

Did you check the TPS?

 

[CourierDriver]

go for the simple, the dodge dealer told me i needed an o2 sensor, on the Web it says that 9outof10 o2 sensors are fine. I had all kind of codes come up, the backfiring, rough idle, stalling,,was a water problem, look up ethanol gas on the Web, its a bad problem.........my 2 cents again........so I used Stabil and all is well now.

 

[ChiTDI]

If the engine runs well under load but won't idle, there is an Air Idle Control motor in the fi system that you could check.
You can spend a fortune replacing parts until it works, probably better to spend on the diagnosis with the meters and gauges.

 

[joel95ex]

OBD1 doesn;t tell yo much on a scan. my buddy had one and we replaced, plugs, O2 sensors etc. and it turned out to be the fuel pressure regulator....I would have that checked. all the other little stuff being bad may make it run bad, but it will still run. a fuel press reg. or Ignition control module will make it die.....

 

[mechtech2]

cjcride has the most important first question: Did it start this after you worked on it?
Other than that, it sure sounds like a vacuum leak. All lines and their connections should be checked and fixed. Esp the PCV system - all of it , not just the valve. Brake booster lines and diaphram, too. Intake and manifolding.
CLean your MAF with spray MAF cleaner.