95 b4000 starting issue

[95bajaguy]

goodmorning everyone,

I am having a issue with my 95 b4000 (4.0) that is getting worse and worse. after sitting overnight it has trouble starting up the next morning. this is a every day thing. whenever i crank it it will sputter a bit and idle low for about 5 seconds then it will return to normal and run great. remember, tbis is ONLY when its cold. I live in South Texas so it doesn't get cold enough to cause problems. thismorming however it sputtered and bogged for about 2 seconds then i got a backfire and it died. after trying again i finally got it going. it has a new fuel pump and relay. fairly new spark plugs. i know alot about my truck but i am stumped here.. if anyone has any tips or ideas of what could be causing this, it would be much appreciated. like i said it is getting worse and worse.

thanks and keep on truckin

 

[Tedybear]

goodmorning everyone,

I am having a issue with my 95 b4000 (4.0) that is getting worse and worse. after sitting overnight it has trouble starting up the next morning. this is a every day thing. whenever i crank it it will sputter a bit and idle low for about 5 seconds then it will return to normal and run great. remember, tbis is ONLY when its cold. I live in South Texas so it doesn't get cold enough to cause problems. thismorming however it sputtered and bogged for about 2 seconds then i got a backfire and it died. after trying again i finally got it going. it has a new fuel pump and relay. fairly new spark plugs. i know alot about my truck but i am stumped here.. if anyone has any tips or ideas of what could be causing this, it would be much appreciated. like i said it is getting worse and worse.

thanks and keep on truckin

Look into changing your coolant temp sensor for the ECU (and not the gauge on the cluster)

If the temp sensor gives bad info to the ECU/PCM it won't get a cold start mixture anywhere near correct.

Not saying that's the cause....but it's a cheap and fairly simple part to address. Also sense the truck is OBD-1? There's not a simple way to check the coolant temp sensor operation like OBD-2 would have with a live data reading. (Sure you can do resistance measurement checks with a DMV. But you'll need to know temp=resistance readings to measure it correctly. Might be around here somewhere? But it's a 20 year old sensor, and nothing lasts forever.)

S-

 

[95bajaguy]

Look into changing your coolant temp sensor for the ECU (and not the gauge on the cluster)

If the temp sensor gives bad info to the ECU/PCM it won't get a cold start mixture anywhere near correct.

Not saying that's the cause....but it's a cheap and fairly simple part to address. Also sense the truck is OBD-1? There's not a simple way to check the coolant temp sensor operation like OBD-2 would have with a live data reading. (Sure you can do resistance measurement checks with a DMV. But you'll need to know temp=resistance readings to measure it correctly. Might be around here somewhere? But it's a 20 year old sensor, and nothing lasts forever.)

S-

thanks tedy, i will look into that. also it is a obd-II. i use scanners on it often. i will let you know tomorrow if that sensor does it

 

[Tedybear]

thanks tedy, i will look into that. also it is a obd-II. i use scanners on it often. i will let you know tomorrow if that sensor does it

Interesting. OBD-2 should have been '96 and newer. (we have the 95. It's got the port, but it's still EEC-4 under the hood. port has power, but no computer connection)

If that's the case- I'd go into the data for engine coolant when it's stone cold and not running. See what the computer thinks the temp is for the engine. Should be easier using live data to track things down.

S-

 

[95bajaguy]

Interesting. OBD-2 should have been '96 and newer. (we have the 95. It's got the port, but it's still EEC-4 under the hood. port has power, but no computer connection)

If that's the case- I'd go into the data for engine coolant when it's stone cold and not running. See what the computer thinks the temp is for the engine. Should be easier using live data to track things down.

S-

i dont know if its because its a mazda or what but i was suprised by it too. i guess i got lucky. do i need a fancy diagnostic scanner for that?

 

[Tedybear]

i dont know if its because its a mazda or what but i was suprised by it too. i guess i got lucky. do i need a fancy diagnostic scanner for that?

Cost is pretty reasonable at places like Harbor Freight Tools for a basic one. Keep in mind, you've got 2 threads about the same issue.

Ron's got some sage advice about the fuel system that should be checked into. One of the forum moderators might want to consider combining these into one thread to avoid confusion.

S-

 

[95bajaguy]

Cost is pretty reasonable at places like Harbor Freight Tools for a basic one. Keep in mind, you've got 2 threads about the same issue.

Ron's got some sage advice about the fuel system that should be checked into. One of the forum moderators might want to consider combining these into one thread to avoid confusion.

S-

my bad, forum noob mistake.