chevelle74us

Hi Guys,

I have a 1999 Chevy Express 2500 Series cargo van with the 305 V8. It has just over 100k and up until last week ran like a top.

Background info: I bought the van used about a year ago and basically use it to store tools and the occasional side job. That being said, it rarely gets driven. I‘ve gone two month stretches without even starting it and it always fires right up and runs smoothly in all weather conditions

Situation: Last week I decided to take the van out to pick up some materials at the Home Depot. I noticed immediately that the speedometer was marking close to double my actual speed. In fact, when I’d approach highway speeds, the speedometer would be pegged and the engine would bog as if I were bumping the governor. I also noticed that the ABS light turned on. I drove another 8-10 miles down the road not being able to exceed 50 and as I pulled into the parking lot the engine shut off. I coasted the van into a parking spot and tried to start it but all it would do is crank with the occasional hesitation as if it wanted to start.

I got the van towed home and tried to start it several more times but it would just crank as before.


I read on the net that these vans can have wacky issues related to the ECU that is caused by moisture and corrosion. After reading a few posts where other folks have described the same symptoms and had it corrected by replacing the ECU, I went ahead and pulled mine out to see if it looked like moister could possibly be getting in there.

Here’s the old one.




It looked pretty bad so I ordered a replacement ECU off of ebay from a company called SpareECU. I sent them my VIN# and they flashed the ECU to work with my van. The cost was $75 shipped, so I figured even if it wasn’t the ECU, I was still doing preventative maintenance.

New one




After replacing the ECU I attempted to start the van. The van sounds like it wants to start but quickly dies.

I removed the inside engine cover to inspect the ignition system and the wires and cap looked new. I popped the cap off and did see some oxidation on the terminals so went ahead and replaced the cap and rotor.

I replaced the terminals on my battery cables with some nice new ones and hooked the jump box up to make sure I had as much cranking power as possible but still no dice. It would crank, start and die immediately.

(fuel gauge read 3/8 full and I added another 5 gallons of fuel to make sure that there was actually fuel in there and not just a sticking fuel gauge)



Here’s a video I made. Hopefully you can get some insight form it. Thanks!

tsbrewers

you might have to do a security re-learn. It basically makes the computer and the van like each other again. It normally takes about 45 minutes.

BTW, this is an educated guess. I had to do this when I had my van's computer swapped with a custom tune. Mine is an '06 so I don't know for sure if yours is the same.

1. Insert key, attempt to start the vehicle and leave the key in the ON position.
   In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take about 10-12 minutes. make sure to turn off all accessories like radio, headlights, etc.
2. When the Security light goes OFF, turn the ignition to the OFF position.
   Leave ignition OFF for 45 Seconds.
3. Attempt to start the vehicle again and leave the key in the ON position.
   In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take about 10-12 minutes.
4. Turn the ignition to the OFF position for 45 Seconds.
5. Attempt to start the vehicle again and leave the key in the ON position.
   In some vehicles, the Battery and Security light will blink for several seconds, and then shut off. Then the Security light will then remain ON. Leave the ignition ON until the Security light goes OFF. This will take about 10-12 minutes
6. Once this entire procedure has been completed (three times) your vehicle will start on the fourth attempt.

You might have to also bring it to a mechanic that can do a crank/case relearn. Dealer will probably charge you $100 for that, so try to find a good normal mechanic with a scan tool. It takes about 30 seconds to do that relearn, so a normal mechanic is likely to only charge $10-30. If you do the steps above (and it works) then you get a check engine light, you will need the crank relearn. Go to the mechanic and tell them you need a crank relearn on your GM van since you replaced the PCM. They should know what needs to be done.

Again, that is after doing the above steps and assuming that worked.

chevelle74us

tsbrewers, you were right on the money about the security re-learn! I looked up the re-learn procedure for my year (which only varies slightly from yours) and after three 10 minute cycles the re-lean proceedure was complete and she fired right up!

And just like you said, my MIL light came on with a P1336 code. I took the van out and other than the MIL light she performed just as before.

Thank you VERY much!

Here's the link to the procedure I used to perform the re-learn
http://ww2.justanswer.com/uploads/KA...nute_steps.jpg

Here's another video clip
[/URL]

tsbrewers

good, i am glad it worked. It sounds like it purrs like a kitten.

Now to get the crank relearned and you are set. I think there is a way to do it without a scanner, but it takes a good stretch of road and quite a bit of time. Much easier to spend the $30 at a good mechanic.

Brew

Oulderfauder

tsbrewers
I do not have this old a vehicle, mines a 2007, but if I ever have an serious issue like this I hope you see it and have an answer. You are a pro. Job well done.

fidde74

Sounds like my van to...wont start..all lights in my ...at my speedometer are on..everything from security, airbag...gauge etc...and my instrument dies and gos up again...found that an enginefuse was bad..and when i change that one all this wrongs with the car came..and the fan also works now at full speed with egition off..thats wierd!!have a chevy express conversion Hitop 2003 and it feels sad that i have only had it for a mounth..and the vans in sweden arent cheap..mine cost like 25 000$ Can this mailfunction be of the fuse that whent bad???