History: 130,000 miles. I have tuned the van up ( new plugs, Dist cap, wires, rotor ). It ran great for a couple of weeks, then developed the same problem: misfires in the morning for the first 15 minutes or so, then smoothes out, also hard starts. I replaced the coil. Worked great for 2 weeks, then same problem again. I had the car diagnosed: they said dirty injectors, but if it were dirty injectors, that wouldn't explain why the car ran great after the tune up and coil. I am having difficulty in trying to assess this as an electrical problem or a fuel problem. The fuel pump was replaced 3 years ago ( 85,000 miles ) and the filter. I can hear the pump making it's characteristic whine. I don't get it. ...any suggestions would be appreciated. Thanks.

The 4.3L engine is very fussy when it comes to plugs, distributor cap, rotor, fuel pressure and leakdown rate. What brand of parts did you use and what is the fuel pressure and leakdown rate? Is the SES, (Service Engine Soon) light on?

The 4.3L engine is very fussy when it comes to plugs, distributor cap, rotor, fuel pressure and leakdown rate. What brand of parts did you use and what is the fuel pressure and leakdown rate? Is the SES, (Service Engine Soon) light on?

Thanks for your response.

I got the parts from Auto Zone, and I don't remember exactly what brand they were, other than I got the most expensive, thinking that they were better. I may have a box or two laying around, I'll check tonight. The SES is NOT on. I do not know what the fuel pressure is since I'm a shade tree mechanic from the 60s before cars got smart. I did read on another forum however, about a person who had hard start problems 'priming' the fuel system pressure by turning the key on/off several times before starting to make sure that pressure was sufficient. I did this and it worked perfectly. I am convinced that this is at least a major part of the problem. This person was also advised that a dirty/clogged fuel filter could cause the system to need more pressure. I have tried to change the fuel filter with no success. I have used 4 different types of rust remover/penetrating oils and though it seems free of rust now, it won't budge. I am afraid that I will twist and break the line if I force it, and yet the only other option I know of is to do exactly that and replace all the lines from the engine back. I read of one fellow who stated that he had found an inline splice kit for the filter, but I don't know of any. I want to look at the simple fixes first, before I dump a barrel of money into major stuff.....like the Firestone mechanics, who admitting they were slow on work wanted $2,600 to replace the fuel injectors.

AC Delco 41-993 with a gap of .060 for the plugs. AC Delco for the distributor cap. If you're replacing the wires, Autolite 96871 is the part number. AC Delco wires are just as good, but they are almost 3 times the price.

If cycling the key helps with starting, that's an indication of low fuel pressure. There is a service port in the steel pressure line next to the distributor for checking fuel pressure. Harbor Freight has an inexpensive and adequate fuel pressure tester for under $20. Key on, engine off, fuel pump running, fuel pressure must be 60psi to 66psi. Pressure must remain above 55psi for 3 to 5 minutes after the pump shuts off.

Before you tackle the fuel filter, have two of these on hand: http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Fuel-Line-Connectors,-Retainers-&-Repair-Kits-Dorman_9110026-P_1252_R%7CGRPFUELAMS_202657471___

The fuel injectors are not a common problem on these engines. It's not a bad idea to put a bottle of injector cleaner in the tank every month or two though.

I used the Delco 41-993 plugs with a .060 gap. On the cap, rotor and coil, I used the brand 'Duralast'. I assume that's the Autozone generic. On the wires, I used the Autolite 96871

What others are saying that I have been reading is that this engine is finiky about using only Delco parts.....and that is something I didn't know. I may just go ahead and replace that coil with a Delco one.

I have been running injector cleaner through for the last 4 tanks...1 can of seafoam, and 3 containers of Lucas fuel treatment/injector cleaner.

The interesting thing about this missing out, is that it only does it during the first 10 minutes or so each morning....once I've been driving for a while it stops.

I'm going to be taking a long road trip this fall in the desert and I don't want it quitting on me then...so I'd like to find out what the heck is going on. I'm going to replace the fuel filter with the cut-in kits, and new Delco stuff.....once the filter is replaced, if it still needs to be primed in the AM, then I'll check the pressure as per your suggestion...BTW: could you give me a link on the unit you're talking about? They're showing several, including one under $20 that says it doesn't work with GM systems.

Thanks for your help.

You should be OK with the coil, but you might want to use an AC Delco distributor cap and rotor. When you replace it, be sure to put silicone dielectric grease on all terminals, inside and out, of the cap. The parts store will have the grease.

While the cap is off, check the vent in the distributor base. It's about 1/4" in diameter and has a screen in it. It's there to vent the distributor and reduce the possibility of condensation forming on the underside of the cap. If the screen gets clogged, it can't ventilate the distributor. Excess condensation inside the cap can cause a misfire until the cap dries out, usually only takes a few minutes of driving. There is a TSB from General Motors that instructs you to remove the vent/screen completely.


Here's the link to the tester: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92699

Thanks, Old Master.

I have replaced the coil, dist cap and rotor with Delco parts....but before I replaced the cap and rotor, I started it with the shroud off ( engine compartment open ). There was an incredible rattling racket ( skreeky-creeky sound ) coming from the dist cap and when I touched it, a lot of vibration too. As I ran it, it quieted down, but still made some noise I considered to be unusual. Fearing that perhaps a rotor screw had worked itself loose and damaged the interior, I took off the old cap, but there didn't appear to be anything wrong. I took the rotor off and noticed some very fine metal dust in the distributor. When I put the new Delco parts on, and fired it up again ( after sitting for a night ) it started right up without any fuel pressure priming. It had a small bit of noise like the old one, but vanished quickly enough...however, I'm thinking that I need a new distributor....I don't think I ought to hear ANY noise coming from the dist, plus I don't like the metal dust in there...no clue as to what is going on there....but it is obvious that the culprit has been apprehended...LOL....what do you know about this sort of problem?

That's a fine piece of investigative work you've done there! A slight amount of axial play in the distributor shaft is normal, but there should be no perceivable radial play. Distributor bushings do wear and can cause the rotor to contact the terminals inside the cap while the engine is running. That might be the dust you noticed. Inspect the cap and rotor terminals and you might just confirm that. Make sure you mark the rotor position before you remove the distributor. http://files.automotiveforums.com/gallery/showphoto.php?photo=51302 It is absolutely critical that the new distributor and rotor are in the exact same position. If not, the PCM will set a P1345 DTC and the SES light will come on. Keep us posted.

...is there a distributor brand preference for this vehicle that you know of?

AC Delco is recognized as the "preferred" brand, but as long as you use a reputable brand of reman, or a new one, you should be fine.

Thanks!

The old dist cap has a whitish substance on the leading edge of each terminal where the rotor would touch as though it has been burnt ( like a spark plug ), and the old rotor has a burnt front edge.

When the distributor cap and rotor are replaced, a small dab of silicone dielectric grease is applied to each terminal, inside and out, of the cap. When the engine is running, current flows through the grease and it crystalizes, perfectly normal.

History: 130,000 miles. I have tuned the van up ( new plugs, Dist cap, wires, rotor ). It ran great for a couple of weeks, then developed the same problem: misfires in the morning for the first 15 minutes or so, then smoothes out, also hard starts. I replaced the coil. Worked great for 2 weeks, then same problem again. I had the car diagnosed: they said dirty injectors, but if it were dirty injectors, that wouldn't explain why the car ran great after the tune up and coil. I am having difficulty in trying to assess this as an electrical problem or a fuel problem. The fuel pump was replaced 3 years ago ( 85,000 miles ) and the filter. I can hear the pump making it's characteristic whine. I don't get it. ...any suggestions would be appreciated. Thanks.
I had a simular situation on one of my older Astro Vans. It turned out that one of my plug wires either slowly rubbed or melted and it would arc intermittently especially when it was cold. You can imagine the frustration level i was experiencing. Once the sun went down and I was in nearly pitch dark, I cranked it one last time and saw a spark that leaped from the plug wire to the exhaust manifold--Problem solved.. With your doghouse off --try cranking it up after sunset in pitch dark and take a good look. The Old Master might be laughing but hey it can't hurt--it's quick and free!

Thanks 94&92 for your response. When I tuned it up several months ago, that exact thing was of concern to me seeing how close those wires come to the heads and covers. I made sure that wouldn't happen by enclosing the wires with plastic flex shielding....but it makes a lot sense.

That wasn't/isn't my problem however, it was in fact a worn out distributor. My cost: 300 bucks for a new Delco unit, which in looking at it, one has a difficult time understanding WHY that piece costs so much....but then again, it wasn't Ford that needed the bailout either, but that is another subject.....LOLOLOL

The van runs great now, and hopefully that is the end of that problem.

BTW: the later model Astros don't have a doghouse, unfortunately. The engine has to be removed from the bottom along with the entire front suspension assembly and a piece of the frame......LOLOLOL.....what was I saying about GM earlier?

....The Old Master might be laughing but hey it can't hurt--it's quick and free!

Not laughing a bit... that's a simple thing to diagnose with a scope, but without one, working in the dark is the next best thing... been there, and done that!