I understand that's a common problem on this van, the plenum gasket leak. I hear you can also test it by disconnecting the PCV valve from the hose on and putting your finger on the hose I believe and checking the vacuum. We no longer have any misfire codes. I'm not worried about the plenum gasket at this moment. PCV valve is new.

HeyYou, we have fuel, we have spark and my son says injectors are working. It seems any number of sensors could be causing issues. I'd assume they'd throw a code unless they are just out of spec for some reason. It seems like EVERY sensor for this vehicle starts at $60 so we are hesitating to throw any thing else on it. So short term fuel trim indicates it's burning rich at idle at normal operating temps. Long term fuel is at 0 but maybe it's not set any thing after letting the car run for a few minutes? So, could a MAP sensor cause a start issue and possibly rich engine at least during idle 5 or so minutes after starting? I'd assume a rich reading right after starting would be set after potentially flooding the engine during no start conditions, but after letting it run until it got up to normal operating temps I'd assume any rich reading would be corrected IF the vehicle was running normal. MAP shows a MAP (inHg) reading of 13.6. Is that normal? Anybody know? Also, we have been calling local shops to get it in but it appears that either the dealerships won't touch it or the shops are backed up a couple weeks. Very frustrating.

 

At cold startup, the PCM just runs off tables, and ignores the O2 sensors.... and it *should* add a bit of fuel during cranking.

MAP should read about 29 inches ignition on, engine NOT running. (assuming you are close to sea level....)

 

Ok, we picked up a noid tester and checked the injectors. They appear to be working. I can't read data on my scanner unless the vehicle is running so I'm unsure about live data. Is there another way to test the MAP sensor? Also pulled a plug to inspect. My son did this but I wanted to make sure. Yes, they appear very good though slightly fuel fowled. Oil smells like gas and so does the plug though I suspect that's going to happen when you crank the vehicle for minutes and minutes at any given time with a no start condition. So they noid lights would flash once, pause then flash a steady pulse while turning the car over. I am assuming that delay is normal?

 

Ok, I finally got it to read the live data in auxiliary mode! I kept getting a system not supported error message on our scan tool. If I'm reading this correctly ignition on with engine not running or being cranked I have an 28.6 on the MAP. Temp is reading correctly. It's 64* here at the moment. We are about 200 above sea level if that's of any assistance. Please see the pics:

 

I was able to retrieve live data while cranking as well. Same readings. Not sure if that helps, but I'd assume to see at least a change in MAP right?

 

Everything looks pretty normal there, and yes, map value should decrease pretty significantly while cranking.

 

Ok, first we have not dismissed a possible ignition switch replacement. It was ordered but hasn't arrived yet. Decided to go back over and test for fuel/spark/ignition.

We can get it to start but holding the fuel peddle to the floor for several minutes while cranking until it starts hitting then pumping the gas until it starts. This takes 2-3 minutes of non stop cranking.

We cleaned the idle air control valve and boy, it runs awesome and more quiet now! However, that didn't fix our no start issue..... Still no start after sitting.

Pulled a spark plug again as I hadn't looked at them personally, but my son did. They look pretty new but does appear to have some fouling from running rich.

Purchased a Noid tester to re-verify after using a test light. All injectors are running fine.

Purchased a fuel compression tester. 45 PSI on Aux and 50 PSI on crank when starting on the fuel rail.

Live data shows, after driving the van under different conditions and speeds for at least 20 miles and over 25 minutes that the O2 sensors show the vehicle is running a little rich, idle runs around 800+/- RPMS. MAP within specs. Temp sensor correct. Fuel trim still looks to be a little rich.

Replaced the distributor cap and button just because the other showed a little fouling. I thought it looked ok, but it was advised to us by a 40 year veteran mechanic after seeing it.

Just an update. We have spark, we have fuel, injectors are working...... The plot thickens.

 

Also, forgot that my son performed an ignition switch test for voltage drop while cranking I believe using a voltmeter on 3 wires on the switch. He says it passed the test. Maybe this might ring a bell for someone? I'm unfamiliar with this test so I am unsure if this clears the switch for fault or not. Just thought I'd mention it.

 

So, everything testable is lookin' good. The starting issue then has to be either too much, or not enough fuel. Given that it will start if you hold the gas pedal on the floor, that would imply 'too much'.... How fast does fuel pressure bleed off with the engine not running?

 

So it takes about 6 hours or so for this to happen of letting the vehicle sit. Previous to using the fuel gauge we had fuel on the rail before aux or cranking that shot out pretty decent when tested. It seemed a wee bit less pressure than when we placed it in aux mode and cranked. I'll see about testing it after it sits and get a PSI reading then.

We thought we had it figured out this weekend. We were checking wiring harnesses around the distributor including the crank shaft sensor. We had some pretty fouled grounding wires on the block we removed and cleaned. Inspected the crank shaft sensor harness. Then hooked the car up to jump it and it instantly started. Mind you, the battery wasn't low when we did this, but we jumped it as a precaution because repeated cranking will eventually deplete the battery when we attempt to start. Waiting 5.5 hours and it started, waiting 5.5 hours and it started, waited another 5.5 hours and it started but at the 6 hour mark when my son went to leave work....same issue. Originally it appeared to go down after 4 hours thus the 5.5 hour testing. It might just be a coincidence but it seems that we get a quicker start or more instant start when we've screwed with the distributor cap (we just replaced it). Seems like a wiring issue, but am at odds. I guess the question might be why are we possibly getting too much fuel? Why do we need to hold the peddle to the floor initially to start and yet when the vehicle runs and we've put some miles on it, it shows to be running a bit rich? And idle seems to be no less that 750 rps but more in the 800s range? Is that normal? I miss when cars were simple....and mechanical.