First post and my trucks problem "stalling"

[PanamaExpat]

Hello to everyone:

This is my first post so I will use it as my introductory post and my first question about my truck. I have a 1994 Mazda/Ranger B4000 with the 4 liter in it. I bought it a little over a month ago and have done several things to it already. I know my transmission is shot but am expecting a new one to arrive from USA this coming week.

The problem I am having seems to run in spells. Start the truck in the morning and it revs up to 12 or 1300 then dies. After 2 or 3 restarts we're off to the races and can generally get to the job site without further incident. Shut off the truck and let it sit for a few minutes then need to go pick up materials and it is the same thing. Starts up, revs a bit high then dies. after it goes through this it drops back to about 650 rpm with AC on and for the most part runs fine. Every now and then it will stall at a traffic light and will go through the same procedure. Before it dies it acts like the computer is hunting the proper idle as it will drop into the 400s then pull back up to about 1200 and just seems to get lost then dies. After a couple of restarts and little driving it goes back to normal.

To date because of info I have read on this forum. I have done the following:

Cleaned MAF

Checked TPS

Replaced IAC

Searched for vacuum leaks (none found)

Switched around the fuel pump relays

Replaced air filter (same time as MAF clean)

Noticed some wild voltage fluctuations when turning on AC and other accessories. Cleaned chassis grounds. (had this problem on Mustang, Lincoln, and old F250 a few years back) Voltages now back to normal.

Have not:

Checked ECU codes (don't have USB adapter)

Changed fuel filters (doesn't give indication of fuel starvation at speed)

Changed intake manifold. Since problem is intermittent not sure if this could be the case.

I have notice that there is a different ECU (has JY marker on it indicating is from an Explorer) in the vehicle so I am presuming the previous owner was having the same issue.

This truck was shipped in by a local dealer from the USA. So I do not know anything about it's past life or owners. But, I sure could use a couple pointers on what to look for next.

Sorry for the long post but this problem is really becoming a bother.

 

[nitrofan1]

Welcome to TRS!

You have one of "those" issues that will drive someone nuts trying to find. I know it's a long shot but you may need to replace the computer again. This doesn't sound like a mechanical issue but an electronic one. Since you replaced all the parts that may cause this already and I doubt it's a fuel delivery issue I'm betting either the computer is bad or it's the wrong one for the truck.

Pull the computer and see if it still has the O.E. Ford serial number on it. If it does post it back on a reply. I work at a parts store and can tell you what it is supposed to fit.

Let's go from there. Other members will reply with their opinions as well I'm sure!

 

[adsm08]

Are the problems worse when it is wet out?

 

[AgPete139]

If the fuel filter has never or rarely been replaced, it could even be so clogged that it doesn't help this. I have noticed the fuel filter making a slight difference in my truck, and you could try this as well. A few dollars and about 5 minutes to switch out the filter underneath the driverside frame rail is a basic maintenance item anyways,

I find it really odd that the IAC did not help, and the MAF didn't do anything either. The constant high & low searching does indicate an electrical issue. If you have a multimeter, you could check the ohm load across the spark plug wires, which should not exceed 9000 Ω. If it's higher from the spark plug boot to the cap boot, replace it.

Have you also checked the gapping on your spark plugs? 0.54" is your gapping.

This will be easier than replacing your ECU or harnesses first...



Pete

 

[PanamaExpat]

Hello again:

Sorry I never got back but I came down with one of our wonderful tropical flu bugs. That set me back for over a week and then I had to catch up the honey-do list before I was allowed to play with my truck some more. Now that I have the time it is raining cats and dogs. Oh well..... As soon as the rain lets off I will go take a look at the suggestions that you guys made and will reply this time.

 

[straycat]

Hello to everyone:

This is my first post so I will use it as my introductory post and my first question about my truck. I have a 1994 Mazda/Ranger B4000 with the 4 liter in it. I bought it a little over a month ago and have done several things to it already. I know my transmission is shot but am expecting a new one to arrive from USA this coming week.

The problem I am having seems to run in spells. Start the truck in the morning and it revs up to 12 or 1300 then dies. After 2 or 3 restarts we're off to the races and can generally get to the job site without further incident. Shut off the truck and let it sit for a few minutes then need to go pick up materials and it is the same thing. Starts up, revs a bit high then dies. after it goes through this it drops back to about 650 rpm with AC on and for the most part runs fine. Every now and then it will stall at a traffic light and will go through the same procedure. Before it dies it acts like the computer is hunting the proper idle as it will drop into the 400s then pull back up to about 1200 and just seems to get lost then dies. After a couple of restarts and little driving it goes back to normal.

To date because of info I have read on this forum. I have done the following:

Cleaned MAF

Checked TPS

Replaced IAC

Searched for vacuum leaks (none found)

Switched around the fuel pump relays

Replaced air filter (same time as MAF clean)

Noticed some wild voltage fluctuations when turning on AC and other accessories. Cleaned chassis grounds. (had this problem on Mustang, Lincoln, and old F250 a few years back) Voltages now back to normal.

Have not:

Checked ECU codes (don't have USB adapter)

Changed fuel filters (doesn't give indication of fuel starvation at speed)

Changed intake manifold. Since problem is intermittent not sure if this could be the case.

I have notice that there is a different ECU (has JY marker on it indicating is from an Explorer) in the vehicle so I am presuming the previous owner was having the same issue.

This truck was shipped in by a local dealer from the USA. So I do not know anything about it's past life or owners. But, I sure could use a couple pointers on what to look for next.

Sorry for the long post but this problem is really becoming a bother.

Hello, Bro!! Welcome to our site. Panama, eh? Man, I was over there for Operation Just Cause back in Dec 89. Really neat country. You have some great people over there!!!
One thing about the issue you are having...it might be some water in the gas tank. I helped out a buddy two months ago who was having a stalling issue with his 2001 Nissan truck. I put on a new fuel filter for him. When I took off his old filter there was some goop in there. I drained and removed his tank and we saw there was a bit of water in it. He said the truck ran great before the last fill up and then it started stalling after about 20 miles. He would get it to start after a few trys and then he would drive it and it hesitated a bit and then shut off at traffic lights and when coming to a stop. You might want to check that out. He said he never saw any engine lights or codes come up. But it is running just fine still he said the other day when he called me.