BLT
03-03-2014, 10:26 AM
My 1991 Previa LE has begun a bit of a rough idle, and had a code for the EGR as well as a lean O2 code. I cleaned the EGR, cleared that up, but the lean code and rough idle returned. However I was making a trip from LA to Dallas, then Austin. In Dallas, suddenly, my van would not start.
A quick look determined that my front fuse box was corroded, right where it connects to the positive cable, a common problem on these. I cleaned that up, and it started, but it was a hard start. After shutting it off it would not restart. Checked for fuel, and I had none. So I dropped the tank to check the pump, it works fine, it's not getting power. Instinctively I went looking for an issue with the fuel pump relay, but unlike most vehicles, it is important to know this van uses a switch in the MAF to close the Circuit Opening relay after started, and the ignition switch closes this relay while cranking. So the van, if you just turn the key on, will not be running the pump like most vehicles do for a few seconds. You gotta jump the fuel pump test connector, located under the driver seat by the computer and diagnostic port, to get fuel pressure. Another post on this forum has pics. So I spent a bit of time chasing a fuel pump wiring issue before realizing this, but after knowing how it works I was able to determine it was fine.
So next I checked spark from the coil, located underneath the car about where the front passenger and sliding door meet, on the frame rail. It has a shield over it, but the coil wire is about 6" long and goes to the distributor. I pulled it off there, and checked, and had a very white spark. I checked by putting a small screwdriver into the wire and, holding the screwdriver with insulated pliers, got the metal shaft about 1/8" away from the metal frame. Then I had a friend crank the engine for just a second.
The spark was a very white/yellow color, not good. Ideally you want to see a blue/white spark, so I determined I must have a weak coil, and bought another for $96 after tax.
Well, this is where the real problem finally revealed itself: When I took the old coil out, the coil wire that runs to the distributor had corroded all the way through at the end connected to the coil! The wires are about 1.5 years old, so still under warranty, but they came from Autozone. Duralast brand. I put the new coil on, because forcing it to fire under bad circumstances can cause it to become weak and I don't want future problems. Then I warrantied the wire, and all is great! Van runs perfect.
So, what I learned, if your van does not start and you want to do a fuel pressure test you HAVE to jump the fuel pump connector or you will waste your time trying to figure out why the relay is not getting the power signal when the key is turned on. Also, don't buy the Duralast wireset. I plan to replace them all in the future with some higher quality ones. When it rains, sometimes I have a misfire; I think that problem is gone for now. Anyways, hopefully this helps someone out there pulling their hair out over a simple fix.
A quick look determined that my front fuse box was corroded, right where it connects to the positive cable, a common problem on these. I cleaned that up, and it started, but it was a hard start. After shutting it off it would not restart. Checked for fuel, and I had none. So I dropped the tank to check the pump, it works fine, it's not getting power. Instinctively I went looking for an issue with the fuel pump relay, but unlike most vehicles, it is important to know this van uses a switch in the MAF to close the Circuit Opening relay after started, and the ignition switch closes this relay while cranking. So the van, if you just turn the key on, will not be running the pump like most vehicles do for a few seconds. You gotta jump the fuel pump test connector, located under the driver seat by the computer and diagnostic port, to get fuel pressure. Another post on this forum has pics. So I spent a bit of time chasing a fuel pump wiring issue before realizing this, but after knowing how it works I was able to determine it was fine.
So next I checked spark from the coil, located underneath the car about where the front passenger and sliding door meet, on the frame rail. It has a shield over it, but the coil wire is about 6" long and goes to the distributor. I pulled it off there, and checked, and had a very white spark. I checked by putting a small screwdriver into the wire and, holding the screwdriver with insulated pliers, got the metal shaft about 1/8" away from the metal frame. Then I had a friend crank the engine for just a second.
The spark was a very white/yellow color, not good. Ideally you want to see a blue/white spark, so I determined I must have a weak coil, and bought another for $96 after tax.
Well, this is where the real problem finally revealed itself: When I took the old coil out, the coil wire that runs to the distributor had corroded all the way through at the end connected to the coil! The wires are about 1.5 years old, so still under warranty, but they came from Autozone. Duralast brand. I put the new coil on, because forcing it to fire under bad circumstances can cause it to become weak and I don't want future problems. Then I warrantied the wire, and all is great! Van runs perfect.
So, what I learned, if your van does not start and you want to do a fuel pressure test you HAVE to jump the fuel pump connector or you will waste your time trying to figure out why the relay is not getting the power signal when the key is turned on. Also, don't buy the Duralast wireset. I plan to replace them all in the future with some higher quality ones. When it rains, sometimes I have a misfire; I think that problem is gone for now. Anyways, hopefully this helps someone out there pulling their hair out over a simple fix.