Where to start 94 3.0 running extremely rich. (1 Viewer)

[5speed addict]

So this low mile 1994 3.0 truck that’s been abused has shown up at my house, dumping fuel and making soot like a diesel. It’s a friends and I’m trying to help him get it going

View attachment 3431280

So far what I know:

The guy he got it from put a bunch of Chinese/reman parts on it trying to fix something and was unsuccessful so sold it. So far I think he put in a new aftermarket? ECU numbers on the board don’t match the case and it’s obviously been removed before, airflow meter? looks aftermarket (the one on the airbox), and “Chinese distributor that wasn’t letting the timing be adjusted past 5 degrees” according to a shop that specializes in Toyotas that declined to go through diagnosing the truck (this is 2nd hand info to me and important details are probably lost in transit)

Ac compressor is toast, it locked up and threw the belt on his way over and when you turn on the ac it was popping the efi fuse so I unplugged the wires. the ac will be a problem for later


So far what I’ve done:

Removed crackhead audio install and the rats nest of wiring from that.

Run the cel codes and it gives a code 31 so I need to figure out where to start.

Currently thinking I’d prefer to start diagnosing the truck with some oem parts and not the remans so hopefully can snag a ecu distributor and airflow meter from a junkyard or part out. Also thinking a New denso o2 sensor

 

[gnob]

make sure the o2 sensor wire isn't shorted to ground.

 

[Dumpolina]

So this low mile 1994 3.0 truck that’s been abused has shown up at my house, dumping fuel and making soot like a diesel. It’s a friends and I’m trying to help him get it going View attachment 3431279View attachment 3431280

So far what I know:

The guy he got it from put a bunch of Chinese/reman parts on it trying to fix something and was unsuccessful so sold it. So far I think he put in a new aftermarket? ECU numbers on the board don’t match the case and it’s obviously been removed before, airflow meter? looks aftermarket (the one on the airbox), and “Chinese distributor that wasn’t letting the timing be adjusted past 5 degrees” according to a shop that specializes in Toyotas that declined to go through diagnosing the truck (this is 2nd hand info to me and important details are probably lost in transit)

Ac compressor is toast, it locked up and threw the belt on his way over and when you turn on the ac it was popping the efi fuse so I unplugged the wires. the ac will be a problem for later


So far what I’ve done:

Removed crackhead audio install and the rats nest of wiring from that.

Run the cel codes and it gives a code 31 so I need to figure out where to start.

Currently thinking I’d prefer to start diagnosing the truck with some oem parts and not the remans so hopefully can snag a ecu distributor and airflow meter from a junkyard or part out. Also thinking a New denso o2 sensor

Holy cow! You saw there's a 1990 4runner at upull? I have not seen it yet. I have that running 1990 4Runner at Mauser's place in Edgewood you could take distributor from, but need to keep that engine complete in the end. It has a chinese intake IIRC

 

[pappy]

I think you are on the right track with the Ox sensor. While OEM is the way to go, I would not pass on aftermarket Denso when available. Same quality for less money.

 

[5speed addict]

Holy cow! You saw there's a 1990 4runner at upull? I have not seen it yet. I have that running 1990 4Runner at Mauser's place in Edgewood you could take distributor from, but need to keep that engine complete in the end. It has a chinese intake IIRC

found all the parts im thinking of swapping around from a guy who did a 3.4 swap. ecu, airbox, distributor

I think you are on the right track with the Ox sensor. While OEM is the way to go, I would not pass on aftermarket Denso when available. Same quality for less money.

yes going to use an aftermarket denso for any sensors replaced on the truck. wonder how its going to run with the o2 unplugged, will report back shortly (it didnt like me unplugging the o2)

 

[pappy]

found all the parts im thinking of swapping around from a guy who did a 3.4 swap.

3.4 is the right answer and the solution to the 3.0.

 

[5speed addict]

3.4 is the right answer and the solution to the 3.0.

if it was my truck I would already have the swap harness on order and a donor 3.4 vehicle in the driveway and I’d be hunting for a front axle it’s a really good thing this isn’t my truck!

 

[WristPin]

3.4 best case fix. In the mean time establish the basics:
Compression test: is it even holding air? Is fuel dumping into your oil? You could also drain the oil and look for fuel at the bottom of the pan.

Long start/crank to run? Would indicate possibly leaking injectors. Or somewhat unrelated to your symptoms-bad fuel pump.

The o2 will normally throw a code if there’s a problem. It’s 4 wire right?

It could possibly have bad timing- too advanced. Spark or chain timing could cause this.

Does it fall on its face on acceleration? Restricted air? a clogged air box seems unlikely.

 

[5speed addict]

3.4 best case fix. In the mean time establish the basics:
Compression test: is it even holding air? Is fuel dumping into your oil? You could also drain the oil and look for fuel at the bottom of the pan.

Long start/crank to run? Would indicate possibly leaking injectors. Or somewhat unrelated to your symptoms-bad fuel pump.

The o2 will normally throw a code if there’s a problem. It’s 4 wire right?

It could possibly have bad timing- too advanced. Spark or chain timing could cause this.

Does it fall on its face on acceleration? Restricted air? a clogged air box seems unlikely.

Need to compression test

90% sure fuel is in the oil, fuel is misting out the exhaust so it has to be getting in the oil

Starts easy, only had Long cranks a few times

O2 probably not the issue, without looking not sure if 4wire or not

Timing is suspect, I don’t have a timing light to verify but the shop my friend took it to said the aftermarket distributor wasn’t letting them set the timing properly. It’s fully maxed out on the adjuster slide so I’m wondering if it’s skipped timing

It accelerates poorly then hits a wall, air filter is a little dirty but not clogged

It’s giving the cel code 31 which i think is ecu/airbox thingy related

 

[gnob]

dizzy shouldn't be maxed out.
check the belt and set the dizzy correctly. make sure the tps is set properly or you won't be able to time it either.
aftermarket afm always a little sus

 

[Mauser]

I had a problem with the kid's 4runner flooding when started. It ended up being the AFM.

The return spring for the flap in the afm was weak. When the engine was started the flap would fly open for a second and cause the engine to flood. If I was able to get it started it would run extremely rich and smoke. I found a video on youtube showing how to add tension to the spring and that fixed the problem.

 

[WristPin]

I had a problem with the kid's 4runner flooding when started. It ended up being the AFM.

The return spring for the flap in the afm was weak. When the engine was started the flap would fly open for a second and cause the engine to flood. If I was able to get it started it would run extremely rich and smoke. I found a video on youtube showing how to add tension to the spring and that fixed the problem.

No s***?! That’s a new one to me!

 

[WristPin]

Need to compression test

90% sure fuel is in the oil, fuel is misting out the exhaust so it has to be getting in the oil

Starts easy, only had Long cranks a few times

O2 probably not the issue, without looking not sure if 4wire or not

Timing is suspect, I don’t have a timing light to verify but the shop my friend took it to said the aftermarket distributor wasn’t letting them set the timing properly. It’s fully maxed out on the adjuster slide so I’m wondering if it’s skipped timing

It accelerates poorly then hits a wall, air filter is a little dirty but not clogged

It’s giving the cel code 31 which i think is ecu/airbox thingy related

Beyond checking compression & inspecting fuel in oil, that’s it. We await your conclusion.

 

[5speed addict]

About a month ago I found a 3.0 4runner torn apart in the junkyard and someone had already pulled the afm and the distributor and left them in the back, easy enough for me so I grabbed them.

Today got it put in and timed, truck runs great for how bad the plugs look. My friend who owns the truck wanted to learn to work on cars so I just supervised and helped as needed. The distributor immediately fixed it even with the timing eyeballed, hit it with the timing light and got it dialed in.

 

[Dumpolina]

About a month ago I found a 3.0 4runner torn apart in the junkyard and someone had already pulled the afm and the distributor and left them in the back, easy enough for me so I grabbed them.View attachment 3501981
Today got it put in and timed, truck runs great for how bad the plugs look. My friend who owns the truck wanted to learn to work on cars so I just supervised and helped as needed. The distributor immediately fixed it even with the timing eyeballed, hit it with the timing light and got it dialed in.

Excellent! Thanks for the update on how you resolved this