Dorealdeal

Try a 97 ford e350 with a 460! I find my express 3500 with a 8.1 a dream compared to that thing. Takes me about two hours on the 8.1, I use a sparkplug socket with a short well 3/4 on its hex. I do two from the wheel wells on each side.

GOFOAD

So an update is in order. After the re-flash She is running like a champ. One problem, after sitting for more than a couple of hours and especially overnight. She won't start without a shot of Surestart. After that She is smooth as silk. I can start it 10 times in a row with no problem. But let Her sit for 4+ hours and She begs for a spray of Surestart. My Mechanic is on holidays for 2 weeks and I am leaving for the annual Boy's fishing trip next weekend which involves a 6 hour drive, then She sits for a week and then a 6 hour return drive. A couple of years ago my Safari van crapped out for the return trip and we had to pile the Boy's into my buddy's small car (5 Guys) and I rode with the tow truck all the way home. I still haven't lived that one down. Fuel pump BTW for the second time in 5 years. Now I have the Express and i'm hoping we are not headed to ANOTHER fuel pump issue.

locodave

I'm wondering if the coolant temp sensor is bad. Not giving a reading the engine is cold.

GOFOAD

Wouldn't that sensor show a code? Thanks i will look into it.

canucklehead

Aren't there 2 coolant sensors. 1 for the bcm, and one for the gauge.
Gauge one may not show a code.

locodave

The coolant temp sensor for the engine control module tells the engines computer go into open or closed loop.

Throw a code? Might not if it's giving a reading. Open and closed loop means. On a cold engine you get open loop. Basic engine running, extra rich-ness you need on a cold engine to run. No sensor input like the O2's,ect. Like the old days with a carb that the choke came on. Gradually it comes off as the engine got warmed up.

Once warmed up, you go into closed loop. No extra fuel, no fast idle. All the sensors come into play. Giving info to the ECM to fine tune it for running.

When you get it started cold. Do you have the fast idle that gradually goes to a normal idle? If not? That would be my clue.

This is a general graph on how they work, cold to warmed up.



Is the throttle plate clean or carboned up. Have a fuel pressure tester? Free tool rental from autozone? Watch the pressure when you turn the key on when cold, not start. Then look at the pressure when trying to start it.

In doing research, I see a lot of posts on a loose ground by the thermostat housing. And the electrical fuel pump connector in front of the fuel tank. Under the van, becomes burnt or corroded.

GOFOAD

Surprize, surprize surprize!!! After all the bull**** it turns out it was the fuel pump after all. I nursed it all the way up North with the boys for our annual fishing trip using the Surestart fluid down her throat everytime. After getting back and letting her sit a few weaks out of frustration I replaced the coolant temp. sensor as suggested here. Then I replaced the intake temp. sensor just in case. still nothing. Finally gave up and had her towed to a real mechanic. Lo and behold it WAS the fuel pump after all. God Dam GM fuel pumps. I have replaced the fuel pump on my Safari van twice. Keep telling the Wife not to let it get below a quarter of a tank since the pump is cooled with the fuel. But hey its done now and she starts up as soon as i look at her.

canucklehead

That is strange, as a fuel pump failure means it won't run at all. Getting it to fire on surestart would not keep it running.
I hope that your mechanic is not throwing parts at this issue.
When you turn on the key, the fuel pump should run a 3-4 seconds to prime the system. If you don't hear that...then it is seized. You can hammer on the underside of the tank to dislodge it, and that will usually get you down the road.

GOFOAD

Well in it's early stages of death it was probably a pressure thing on startup. then after getting back and sitting for a month She wouldn't start at all. that's when i took her to a shop. Just from the symptoms and what i was driving the mechanic laughed and kept saying fuel pump, fuel pump, fuel pump all the time. He said to go pick one up and we will go from there. sure enough new fuel pump in and She is back to smooth and steady. Just like when my Bus @ work has any problem the standard response from the Mechanic is " just do a battery reset" fuel pump is the answer with any starting or fuel related issue. It's a GM thing especially the vans and Jimmys that used anything from the 4.3 up to the 5.7 Litre engine.

canucklehead

I had to do the FP on my 2002 with the vortec 5.7. I did the hammer on the tank thing to get it running to avoid the tow, and got if fixed. I used a bosch pump instead of oem, and have had no issues since.....touch wood....lol.
The one trick I have heard is to not run below 1/4 tank for very long. The gas in the tank cools the pump......