sbman
Supporting Vendor
Yes it has revved to 2200+ RPM on cold start from time to time. Never a regular thing.
YAIT - Yet another idle thread... (2 Viewers)
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sbman
Supporting Vendor
And I think that when it did that revving (on mine), it was not in any way related to injectors. It was the low idle, rough idle, and eventually a full blow intermittent misfire that the replacement of injectors fixed. Just throwing it out there that it could be a similar issue. Like I said, it's not a popular option to look at injectors, take it or leave it just sharing my experience. Maybe it was not the injectors themselves but the seals at the injector tips where they seal against the intake manifold. They looked OK to me, but I did not do any checking for vacuum leaks there.
Yeah, mine really appreciated some more timing advance. Hope it's the final piece of the puzzle for your
Dirt Ferguson
SILVER Star
I had a similar issue and it was that my MAF sensor connector would come just slightly loose from the sensor housing. It still happens from time to time after extended washboard road driving. My CEL will come on, idle will get rough when in D, and start to dip and become rough.
I shut off the rig, disconnect the battery, firmly press in the MAF connector, fire everything back up and then the rig is back to normal.
Someone posted a thread about adjusting the terminal prongs in the connector so that they are tighter and don't come loose.
Just one more piece of food for thought.
I shut off the rig, disconnect the battery, firmly press in the MAF connector, fire everything back up and then the rig is back to normal.
Someone posted a thread about adjusting the terminal prongs in the connector so that they are tighter and don't come loose.
Just one more piece of food for thought.
Have you checked your VAF connection for corrosion on the contacts?
If you have it apart adding some corrosion inhibitor like ACF50 will help, the actual load through the unit is low so any corrosion has a big negative effect!
Once again, that was my idle problem.
If you have it apart adding some corrosion inhibitor like ACF50 will help, the actual load through the unit is low so any corrosion has a big negative effect!
Once again, that was my idle problem.
U can also pull back the boot and check the values as prescribed in the FSM to eliminate bad connectors.
Just because a connector is plugged in doesn’t mean it’s conducting they way it is supposed to be.
A loose female plug will have issues from a male plug if they are not tight.
CharlieS
GOLD Star
- Thread starter
- #48
This was wrong. I was corrected below. The readings were in spec.
The VAF meter failed on-vehicle inspection.
Only 0.328 k ohms (edited: this is 328 ohms) between VS and E2, where the acceptable resistance range is 200 to 600 ohms.
THA to E2 (maybe idle air temp sensor) was in range at 2.263 k ohms at 73 degrees fahrenheit, where the acceptable resistance is 2-3 k ohms at 68 degrees fahrenheit. Seems in the right ballpark.
Anyone know the part number for the VAF, so I can try to source a used one?
Only
THA to E2 (maybe idle air temp sensor) was in range at 2.263 k ohms at 73 degrees fahrenheit, where the acceptable resistance is 2-3 k ohms at 68 degrees fahrenheit. Seems in the right ballpark.
Anyone know the part number for the VAF, so I can try to source a used one?
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Looks good from here, 0.328 k equates to 328 ohms
ppc
M Go Blue
CharlieS
GOLD Star
- Thread starter
- #53
Door resistance measurement falls in the acceptable reading range at fully open and fully closed.
314 ohms fully closed (should be 200-600 ohms)
68 ohms fully open (should be 20-1200 ohms)
The readings going through the sweep of the range are very non-linear, but a note in the fsm calls that out.
314 ohms fully closed (should be 200-600 ohms)
68 ohms fully open (should be 20-1200 ohms)
The readings going through the sweep of the range are very non-linear, but a note in the fsm calls that out.
FMC80
SILVER Star
You can’t buy one anyway. They’re NLA…have to buy it used or get yours refurbished. I noted I got mine fine at BavRest in my post above.
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CharlieS
GOLD Star
- Thread starter
- #55
@ZackR @OffRoadScott - I finally got a chance to disconnect the O2 sensors and road test it. And it idles like a sewing machine...
What does this tell me?
Does the ECM kick into open loop mode when the O2 sensors are disconnected? If so, doesn't this mean it is basically ignoring the sensor inputs, so it could be any input sensor - O2, ECT, VAF temp circuit, what else?
It seems like if it idles steady as a rock in this condition I am not chasing vacuum leaks anymore... Is that a correct assumption?
The O2 sensors are brand new, Denso units for the 95-97 with the plug trimmed per 'mud guidance, installed in the PAIR openings in the exhaust manifold.
It runs amazingly without the O2 sensors plugged in. Almost enough that I'm tempted to leave them unplugged and live with a CEL. But I really want it to run properly with them connected.
Any guidance or advice?
Note, I used these: Denso 234-4153 Oxygen Sensor https://a.co/d/9Kr0OEQ
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That with enough bandaids, you can't see the problem anymore.
Undo the changes you made that caused the problems in the first place:
Rough idle - my fault, but I don't know what I did
Mea culpa. I changed a lot of stuff at once and am the root of my own problem. But, I don't know what I did to cause it... Before I forget - it is a '94 1FZ-FE with 297k miles. My idle is low and lumpy and i don't know what to troubleshoot. I just got this rig in late spring, I changed the...
forum.ih8mud.com
You 1) didn't start from a known baseline, 2) made a bunch of modifications and 3) are looking everywhere *but* at the modifications.
CharlieS
GOLD Star
- Thread starter
- #57
I'm not reverting to the way it came because it had 300K of worn out components and deferred maintenance.That with enough bandaids, you can't see the problem anymore.
Undo the changes you made that caused the problems in the first place:
Rough idle - my fault, but I don't know what I did
Mea culpa. I changed a lot of stuff at once and am the root of my own problem. But, I don't know what I did to cause it... Before I forget - it is a '94 1FZ-FE with 297k miles. My idle is low and lumpy and i don't know what to troubleshoot. I just got this rig in late spring, I changed the...
You 1) didn't start from a known baseline, 2) made a bunch of modifications and 3) are looking everywhere *but* at the modifications.
I'd love to get some helpful advice from you, but nothing you've posted on my threads has been helpful. Most of it is just mean spirited. Do you have anything nice or helpful to add?
CharlieS
GOLD Star
- Thread starter
- #59
I didn't repin the O2 sensors. I read in this thread (https://forum.ih8mud.com/threads/re...-sensors-for-93-94-1fzs.1178425/post-15033791) that they could be used as is with the plug modified to remove the indexing rib. https://forum.ih8mud.com/threads/re...-sensors-for-93-94-1fzs.1178425/post-14092173
That being said, I'm happy to depin and repin/modify if there is a way to verify what the correct pin out is.
I printed the FSM pages for the O2 sensors and will test them this weekend.
That being said, I'm happy to depin and repin/modify if there is a way to verify what the correct pin out is.
I printed the FSM pages for the O2 sensors and will test them this weekend.
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