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Running rich but can't seem to figure it out. 98 3.0L


stanleyb308

Member
Joined
Oct 31, 2022
Messages
14
City
Milan, IN
Vehicle Year
98
Transmission
Automatic
I bout this ranger cheap and it would barely run. I replaced the IAC valve first and it started right up and idled smooth. Unfortunately it was obivous pretty quick it was burning coolant. I had read the 3.0l was proned to cracking heads so I pulled them off and had them checked. Sure enough both were cracked. Reinstalled new remaned heads. Once everything was back together it seems to be running very rich. I have low power and it stutters pretty hard at around 2k RPM. The previous owner threw a bunch of parts at it. CPS, cam syrncronize(I verfied it was properly aligned), crank position sensor, plugs and wires, and coil pack. While working on it there were things that lead me to believe the enigne had been pulled before. I'm to the point were I'm curious if it is possible I puchased the wrong heads since they were ordered based off the VIN and/or if the original ECM doesnt match the engine that was installed. Is this possible? I'm at my wits end with it. I would greatly appreciate any help! Thank you in advance!

Side note it does throw a few codes I dont remember the numbers off the top of my head but they are rich codes for both banks and a #1 missfire. The only thing I havent checked it fuel pressure is also worth noting
 
welcome to the site!

i have no idea because i don't know much about the 3.0 so hopefully someone comes along to help soon
 
I doubt you got the "wrong" heads. if you did they wouldnt of bolted on or some other glareing incompatiabilty would of been there.

What year is it? The ECM can make more of a difference on say an 03 then a 92.

Id be looking into that missfire. You could have a stuck open injector thats causing all of this
 
It is a 98. The missfire is also a little strange. The plug is getting good spark. I ended up throwing a new injector in it. When I hooked the battery back up it ran on all 6 for about 90 seconds and startin missing again. That is repeatable also. It's one of the main reasons I'm leaning toward the ECM. I probably should have mentioned that in the original post.
 
Welcome to the site. the codes are the first thing to check. OBD II is a pretty reliable system, that's why the parts guys sell you the part right away. You still need to do the flow chart to verify the bad part though.
 
is it a flex fuel? FF will have an alcohol sensor in the fuel line , below the drivers area.
have access to an IR thermometer? they can tell you which cylinders are not up to temperature./ not firing.

new heads? how much was the valve lash preload?
 
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You can't get the wrong heads for a 3.0l Vulcan, 1986 to 2008 are intechangeable
Even FF or gas only work, or the different valve stem sizes

But whats the 8 digit in your VIN, that will tell you what the COMPUTER is for, FF or gas only
Flex Fuel(FF) is V
Gas only is U

The Computer for gas only(U) will need smaller injectors or engine WILL run richer than it should
FF(V) had larger injectors
So if someone swapped in a complete FF 3.0l engine with injectors into a VIN "U" vehicle then that would be the issue

So whats the 8th digit of VIN?


If VIN has a V as 8th digit, then +1 on the Flex Fuel sensor but it WILL set a code, so WRITE DOWN all the codes and post them

Sample code list here: https://www.therangerstation.com/tech/obd-ii_trouble_codes/

SAMPLE, and there are alot but NOT all of them, lol, which is why EXACT code numbers matter alot
And why "I think it was XXXX............." really doesn't help much at all, lol
 
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You can't get the wrong heads for a 3.0l Vulcan, 1986 to 2008 are intechangeable
Even FF or gas only work, or the different valve stem sizes

But whats the 8 digit in your VIN, that will tell you what the COMPUTER is for, FF or gas only
Flex Fuel(FF) is V
Gas only is U

The Computer for gas only(U) will need smaller injectors or engine WILL run richer than it should
FF(V) had larger injectors
So if someone swapped in a complete FF 3.0l engine with injectors into a VIN "U" vehicle then that would be the issue

So whats the 8th digit of VIN?


If VIN has a V as 8th digit, then +1 on the Flex Fuel sensor but it WILL set a code, so WRITE DOWN all the codes and post them

Sample code list here: https://www.therangerstation.com/tech/obd-ii_trouble_codes/

SAMPLE, and there are alot but NOT all of them, lol, which is why EXACT code numbers matter alot
And why "I think it was XXXX............." really doesn't help much at all, lol


The 8th digit is U. The Codes are P0172 system too rich bank 1, P0175 system to rich bank 2, P0301 missfire detected cylinder 1.
 
is it a flex fuel? FF will have an alcohol sensor in the fuel line , below the drivers area.
have access to an IR thermometer? they can tell you which cylinders are not up to temperature./ not firing.

new heads? how much was the valve lash?


It is a gas engine according to the VIN. According to the Haynes manual the hydraulic lifters don't require adjusting so I never checked. It recomemed checking the height of the valve stems which I did. Its been a over a month ago so I dont remember the measurement exactly but the tolereance was 1/32" and they were all within the spec.
 
in this case "lash" was a poor choice of words, lets use preload instead.
I was more inquiring about how much more the rocker bolts were tightened after the slack was taken up.
the lash/preload isn't adjustable, you tighten it all down. works great if all the parts are in spec.
if any of the parts are substantially different than stock it's possible to compress the lifters too much.
 
You said you got a replacement injector, do you have the info on it, model number/part number?
Did you order it for 1998 3.0l VIN "U" or diid FF or gas only even come up?


Rich on both banks is unusual
You will eventually have to test fuel pressure just to take it off the table, before replacing Computer
65psi is maximum, in 1998 Fuel Pressure Regulator(FPR) is in the gas tank, fuel pump is capable of 85+psi, and if FPR wasn't working the higher pressure would set Rich codes on both banks, same as injectors that are too large
 
You said you got a replacement injector, do you have the info on it, model number/part number?
Did you order it for 1998 3.0l VIN "U" or diid FF or gas only even come up?


Rich on both banks is unusual
You will eventually have to test fuel pressure just to take it off the table, before replacing Computer
65psi is maximum, in 1998 Fuel Pressure Regulator(FPR) is in the gas tank, fuel pump is capable of 85+psi, and if FPR wasn't working the higher pressure would set Rich codes on both banks, same as injectors that are too large


The issue never even came up. This afternoon I'm going to swap the number 1 and 2 injectors and see if the issue follows suit. It will tell me something one way or another but ole girl is currently chugging gas.
 
See if you can find a part number on the injectors
 
See if you can find a part number on the injectors

Well when I swapped them the miss followed. The tips of the injectors are different all together. Wish I would have checked a working injector back when I replaced the one. It was the same as the one I removed....
XL5E-B2A(Functioning Injector)
01G5058(Nonfuctioning)
The one on the right is the style I seem to need. Could be possible the engine and computer were swapped out of a flex fuel truck. I didn't get anywhere trying to run down the numbers on the computer but it is definitely not 20+ years old.
 

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You said you got a replacement injector, do you have the info on it, model number/part number?
Did you order it for 1998 3.0l VIN "U" or diid FF or gas only even come up?


Rich on both banks is unusual
You will eventually have to test fuel pressure just to take it off the table, before replacing Computer
65psi is maximum, in 1998 Fuel Pressure Regulator(FPR) is in the gas tank, fuel pump is capable of 85+psi, and if FPR wasn't working the higher pressure would set Rich codes on both banks, same as injectors that are too large

Checked the fuel pressure this morning at the rail. It was 60psi with key on engine off and the pressure only dropped about 2psi after 10 minutes. Engine running it was right around 65psi.
 

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