Fixed it worse,need help please (1 Viewer)

[fiberboy]

Don't mess with the AFM

1992 fj80. Tonight I replaced the plugs,wires, cap, and rotor. Everything went fairly smooth. Now it runs worse. It took about five trys before it would stay running, once it stayed running it is really rough. Its idleing at about 550 to 600 rpm's and the needle jumps back and forth between there. its also blowing alot of soot out the tailpipe. It acts like its missing on one cylinder or maybe the timing is off now? When I rev it up and hold it at about 1200 rpm's it really sounds bad, like its running way rich. Any thoughts would be very appreciated.

 

[Lka1988]

Did you accidentally switch two (or more?) wires?

Edit: Just changing the cap/rotor/wires shouldn't be enough to screw with the timing...

 

[phxtlc]

also check you didn't knock a vac line off or leaned on the air tube and cracked it.

 

[azzzuki]

sounds like u got a wire crossed????

 

[fiberboy]

Checked the wires they are correct 1-6 from front to back. Cap can only go on one way right? #2 on the cap is perpendicular to the Passenger front fender. I'll have to check the air hose, I was trying to be carefull with it. I also attemted to change the PCV valve but could not get it out of the valve cover so I left it.

One more thing to mention. The wire connection on the top of the aire hose close to the air filter, what is that for? I could not get the connection to come off so I removed the screws and didn't like what I saw behind that thing so I put it back together. Would that have messed anything up?

 

[fiberboy]

sounds like u got a wire crossed????

You mean 2 wires swapped or 2 wires crossed over each other?

 

[EricG]

Did you disconnect the battery for this work? What you describe sounds alot like the ECU relearning after the battery has been out - though maybe a bit more extreme then usual.

 

[archie]

Checked the wires they are correct 1-6 from front to back. Cap can only go on one way right? #2 on the cap is perpendicular to the Passenger front fender. I'll have to check the air hose, I was trying to be carefull with it. I also attemted to change the PCV valve but could not get it out of the valve cover so I left it.

One more thing to mention. The wire connection on the top of the aire hose close to the air filter, what is that for? I could not get the connection to come off so I removed the screws and didn't like what I saw behind that thing so I put it back together. Would that have messed anything up?

It is a retangular wire harness that connects near the MAF? those wires pins/connectors inside got pulled back into the wire from the harness and it ran like crap on mine when I changed the filter.

 

[Crusherfied]

Did you disconnect the battery for this work? What you describe sounds alot like the ECU relearning after the battery has been out - though maybe a bit more extreme then usual.

I've heard of this before. Takes a little time for the ECU to catch up.
If your plug wires are in correct order, check to make sure they are pushed onto the plugs all the way.

 

[fiberboy]

I've heard of this before. Takes a little time for the ECU to catch up.
If your plug wires are in correct order, check to make sure they are pushed onto the plugs all the way.

So should i dissconnect the battery and wait a bit then re-connect?

 

[fiberboy]

It is a retangular wire harness that connects near the MAF? those wires pins/connectors inside got pulled back into the wire from the harness and it ran like crap on mine when I changed the filter.

Archie, What kind of PITA was it to get the pins lined back up? I only pulled the connector out a little till I could see what was behind it then pushed it back in.

 

[Koffer]

Make sure to double check the firing order of the plug wires . sounds like one or more are in the wrong place on the cap .
Also nice splice in your avatar

 

[archie]

Archie, What kind of PITA was it to get the pins lined back up? I only pulled the connector out a little till I could see what was behind it then pushed it back in.

Not too hard in my case. Just look carefully in it because it could be pulled back only a little.

 

[jonheld]

Fiberboy,

Something is wrong and has nothing to do with the ECU relearning.

You said you "removed the screws and didn't like what you saw" on the air flow meter (3FE has an AFM not a MAF sensor). That's the box midway in the air intake hose with a horizontal connector that faces forward. Did you touch that BEFORE OR AFTER this problem occurred???

Lets go over a few basics:
1. You should have had to remove the air cleaner hose in order to gain access to the dissy cap. There are 3 vacuum lines that mate with feed through couplings on that hose. 2 small; 1 large. Are they back in the correct positions?

2. Did you use OEM ignition parts or some aftermarket brand? The OEM cap has cylinder numbers and the OEM wires have cylinder numbers and are cut to the correct length. Assuming you can count from 1-6 it would be pretty hard to put them back incorrectly, so let's assume they're correct. AFAIK, the cap can only go on one way, but I've never really tried to put it on wrong. When standing at the right front tire looking at the dissy cap, the word DENSO should be facing you; #4 wire at the lower left position.

3. The dissy cap has 2 breather lines in addition to the 7 wires. Are these back on?

4. Spark plugs in all the way; wires seated correctly on the plugs and dissy cap?

5. If you moved the large air hose during this exercise it is more than likely damaged and allowing unmetered air into the intake screwing the pooch with the ECU. If your vacuum lines are old and crusty it is possible that one has cracked.

 

[fiberboy]

Fiberboy,

Something is wrong and has nothing to do with the ECU relearning.

You said you "removed the screws and didn't like what you saw" on the air flow meter (3FE has an AFM not a MAF sensor). That's the box midway in the air intake hose with a horizontal connector that faces forward. Did you touch that BEFORE OR AFTER this problem occurred???

Lets go over a few basics:
1. You should have had to remove the air cleaner hose in order to gain access to the dissy cap. There are 3 vacuum lines that mate with feed through couplings on that hose. 2 small; 1 large. Are they back in the correct positions?

2. Did you use OEM ignition parts or some aftermarket brand? The OEM cap has cylinder numbers and the OEM wires have cylinder numbers and are cut to the correct length. Assuming you can count from 1-6 it would be pretty hard to put them back incorrectly, so let's assume they're correct. AFAIK, the cap can only go on one way, but I've never really tried to put it on wrong. When standing at the right front tire looking at the dissy cap, the word DENSO should be facing you; #4 wire at the lower left position.

3. The dissy cap has 2 breather lines in addition to the 7 wires. Are these back on?

4. Spark plugs in all the way; wires seated correctly on the plugs and dissy cap?

5. If you moved the large air hose during this exercise it is more than likely damaged and allowing unmetered air into the intake screwing the pooch with the ECU. If your vacuum lines are old and crusty it is possible that one has cracked.

I attempted to remove the AFM sensor before I put the new parts in. Again I just pulled it back a bit and then pushed it back in a replaced the screws.

I did remove the air cleaner hoses, but was very careful with everything as I have read enough posts about that subject. But I guess its possible I could have damged one of them

All hoses are back on and in the correct place. Distributor is on correctly. I will double check the wires again.

All parts are OEM and ordered from C-Dan.

If it turns out to be a vacuum line how do you find the bad one?

If its just the ECU re-learning, how long will it take?

 

[EricG]

If its just the ECU re-learning, how long will it take?

A few start cycles and some driving - less then a day.

But I would take a hard look at your intake hose - if that is cracked, it could do what you're describing also.

If you got the OEM parts, I doubt you got the wires on the wrong plugs - if I recall correctly, everything is marked pretty well. Worth a look of course.

 

[phxtlc]

Checked the wires they are correct 1-6 from front to back. Cap can only go on one way right? #2 on the cap is perpendicular to the Passenger front fender. I'll have to check the air hose, I was trying to be carefull with it. I also attemted to change the PCV valve but could not get it out of the valve cover so I left it.

One more thing to mention. The wire connection on the top of the aire hose close to the air filter, what is that for? I could not get the connection to come off so I removed the screws and didn't like what I saw behind that thing so I put it back together. Would that have messed anything up?

"didn't like what you saw" ugh that in my exp that connector is very moody. Did you have the battery disconnected when you were messing with this? I had a dealer screw this connector up and it burned the ECU up. Hopefully it's something else!

 

[fiberboy]

Ok, Just got home from Church and I'm going to go and double check everything. I'll keep you all posted.

 

[jonheld]

I attempted to remove the AFM sensor before I put the new parts in. Again I just pulled it back a bit and then pushed it back in a replaced the screws.

I did remove the air cleaner hoses, but was very careful with everything as I have read enough posts about that subject. But I guess its possible I could have damged one of them

All hoses are back on and in the correct place. Distributor is on correctly. I will double check the wires again.

All parts are OEM and ordered from C-Dan.

If it turns out to be a vacuum line how do you find the bad one?

If its just the ECU re-learning, how long will it take?

OK. It is VERY likely you screwed the pooch on the AFM. The AFM module contains a switch that fires the fuel pump. If it was somehow misaligned it would explain the difficult starting. In addition if the ECU is getting the wrong signals from the AFM it will cause all sorts of woe and strife.

The ECU "re-learning" would have zero effect on starting the truck. The ECU relearns air/fuel mixtrues under different throttle openings and at different loads, etc. I've swapped out ECUs and have had my battery out for weeks at a time. She starts right up always. You have a problem here. This is not typical at all.

IIRC, with a cold motor at startup, vacuum is not in play. As the motor warms it will idle increasingly rough.

That doesn't sound right after reading it. It's the O2 sensors that are not in play during warm up. I forget what happens when vacuum is faulty at cold start up.

 

[FrankTorres]

I'm with Jon on this.
I see a broken AFM in my 3EF crystal ball...

You are not the first to do this.

Most likely you broke the soldered connection inside the AFM circuit board when you removed the screws and pulled it out.

Now you will need to cut the black plastic top off the AFM to see the damage.
Do a search on repairing a broken AFM.

Good luck. Toyota should have never put screws there.