could be sensor telling the car not to fire...

I know many chrysles cars will exibit the same problems when their crank angle sensors are not talking to the ECU correctly....

Have you checked the crank angle sensor(s)?

 

Hogspeed,

Welcome to my hell..... I have been fighting this same problem for close to a year on my 96 Blazer, and still have not fixed it.[sm=headbang.gif] (Mainly because this is my 'extra' vehicle, not my daily driver).

In searching the net, I have seen this issue posted (and mostimportantly, correctly indentifiedas being linked to rain/humidity), maybe 5 different times over the last few years on different websites. I wonder how many of the other hard/no start issues are the same thing, but people have not linked them to the weather, yet. In either case, I have not seenanyone who has reported a solid root cause in any of the postings.

Also - mycar has only set a P-code once or twice, and then I am not sure this was even the culprit. The vehicle also surges and feelslike it is missing, when driving at ~3000-3500 rpm, with light to moderate load - this happens even when dry,so again I am not sure if itis linked.

Let me start by telling you WHAT IT IS NOT --> (Plugs, wires, cap, rotor, crank sensor, coil, fuel pump, or ignition control module.. Regardless of Brand Name).....I have checked or changed them all.....with the same old problem coming back. I started to have hope about the distributor vents, but them you posted your resultsand there wentthattheory.

Then let me say that I think "Illtww" is onto something with the crank sensor not telling the car to fire. This is my theory also, but why.... I don't know yet.

A few weeks ago, I did a experiment on a hot, dry day, where I used a hose with a finestream of waterand systematically sprayedunder the hood with the sprayer, with the car running.I started low on the engine and worked my way up each side in sections. I did small areas, stopped, turned off the car for a few minutes, and started it back up. I was looking for anything, stumbling whilerunning, hard starts, long starts, no starts, ect.. Eventually I isolated an areain the lower right sideof the engine, where severalwire looms come together, which did affect the car (This is in the general area where the crank sensor wires go into the main harness as well). The carstarting running rougher, and after shuttingdown, ithad long starts, and eventuallywould notstart.

The thing is,the water spray seemed to have a delayed reaction, like it needed time to seep into the convoluted shell, or for some ofitto evaporate off the hot engineblock? The car did not start running rough rightaway, and as I said, the cargot harder to startwith each successive re-start(waiting 1-2 minutes between attempts), until it finallywould not start. Then after the no start, I let it sit for 15-20 minutes to dry up, and then it started & ran fine.

Since then, I have not had the time/energy to dig into the mess of wires which need to be looked at. Not sure if it is a shorted wire, corroded connecter or pins, or a bad ground. But I do know roughly where the problem lies, and I would start with the crank sensor circuit first, since it has all of the symptoms of a crank sensor failure. I expect there is a design or plant build issue which will be discovered, and will be the same issue on many of these older Blazers.

All I ask is that if you ever isolate and fix the issue, please post the results, since you might be helping LOTS of people who are paying for fuel pumps, sensors, ect....unnecessarily.

Sorry for the long post, but I have been fighting this a long time[sm=smiley11.gif]..Thanks.

 

Apparently, this problem is not an isolated problem.

I changed the cap, rotor and wires again. It rained hard the night before and the truck wouldn't start in the AM. After replacing the new parts with another set of new parts (the replaced cap, rotor, wires were new) AND unplugging and spraying with electrical contact cleaner and replugging back in the distributor pickup connector, the truck started and ran fine.

It rained hard the next afternoon. The truck started without a hitch.

I'll have to wait for more rain to give a follow up. I'm guessing that the culprit might have been a poor connection to the pickup via the connector, altho i got spark from the coil wire and 2 plug wires when the truck didn't start (while cranking).

 

Try this, keep in mind WD40 can be flamable.
When it won't start, spray some WD40 around the distributor cap and coil.
Then give it a try, if it starts, swap out the cap and the wires, worked for me for years on early Chrysler Corp. vehicles as atroubleshooting tool.

 

Hogspeed,

Hope the cleaning of the contacts turns out to be the permanent solution,but as you said - you had spark before when it was not starting (as did I).

Ithought I had it solvedearly in the process as well. Iwaited until it absolutely would not start one day due to rain, thenchanged the cap & rotor and5 minutes laterit started right up.Thought I had it licked, but the next time it rained, it was back to the same old no start. (That is why I thought cleaning the vents had some potential).

But just in case this does work....When you said "poor connection to the pickup via the connector", which connector are you talking about- the main coil wire to the'distributor' cap or the 4 way connector on the coil pack?

Thanks again for sharing your info.. and please post with updates if this fixes it permanently.

 

I'm still waiting for some good rain again to report back.

The Distributor pickup has a "plug connector" at the base of the distributor. I unclipped it, cleaned out teh contacts real good, made sure nothing was loose and check to make sure I had a tight, water resistant connection (seal lips on connector were in good shape).

If anything, I would suggest you do this step. Other than Contact Cleaner, it doesn't cost anything and is one less thing in the equation.

 

Looks like the problem is fixed.

It rained again, last night. A good downpour. I went out this morning to try the truck and it started wtihout a hitch.

the last thing I did was on my post from 7/30/07. My guess is that it was either a bad rotor, cap or moisture/poor contact at the distributor pickup connector (even though the cap, rotor and wires were new). Even though i had spark when it wouldn't start, changing these items and cleaning the connector seems to have fixed the problem. It was to the point that if there was any rain at all, the truck wouldn.t start. It got to the point that even if it was very humid and hot in the morning, the truck wouldn't start.

It's fixed.

 

Glad you got it fixed! Post up in a month to let us know if it's still going good!