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1992 4.9L auto F-150 Starts Stalls, runs rough rev'd and kept in gear to keep going

Kaajot

Micro Machine Manager
The 6.0 Update Fix

Hi all-

We put the new ECM in -- it now runs just fine, although there is a check engine light still and we cannot get the KOER to run. It pauses after initial setup and says "Cannot detect Injector" or something like that. I did not take a picture of the print out.

It does not even start going through different rpms or get to pumping the break, steering the wheel, etc. It literally cannot detect something and hangs there.

Could this have something to do with calibrating the EEC-IV?

As stated, it's running pretty well so far. I'd dare say it's running almost as good as when I first picked it up.

Also, the old ECM did have a busted capacitor. So that was the correct diagnosis. The TPS, IAC, Coolant Temp IAT, etc are all reading correctly now.

Ideas about how to fix so we can pull the remaining engine codes from KOER?
 

Kaajot

Micro Machine Manager
Edit:

Error code came to me in a dream -- yeah, it bothers me that much.

The scanning tool on KOER goes through the "set-up" process ie get up to temp, turn off engine, leave off 10 seconds, turn back on, etc and then displays the following message that it is hung up on and does not go through with the KOER test.

"Cannot detect Cylinder #"

This is after a new ECM install and oil change and I'm 100% confident the oil didn't do it.

Ideas?
 

Sparky83

Virginia Chapter member
5,564
217
Norlina NC
i sent a pm to someone that use to frequent the forums in hopes maybe theyll pop in to offer suggestions.
 
The current L6/V6? I don't understand this?
Although the E40D is a much better and stronger transmission, the AOD is great under the right set-up. When the AOD was installed was the mechanical "kick-down" linkage installed?
This linkage is not for passing gear as most people think(including some mechanic's) this linkage preset's the line pressure needed for correct shifting.
 

Kaajot

Micro Machine Manager
The current L6/V6? I don't understand this?
Although the E40D is a much better and stronger transmission, the AOD is great under the right set-up. When the AOD was installed was the mechanical "kick-down" linkage installed?
This linkage is not for passing gear as most people think(including some mechanic's) this linkage preset's the line pressure needed for correct shifting.

I don't think so. That would have required thinking very hard. When we pulled the engine 21ish days later because it was running like crap the flex plate was cracked in a perfect circle and the bell housing was broken at the top mounting location.

The mechanic was not very observant of what he was working with and how he was doing it. As far as I know, I never saw a kick-down linkage to the AOD. I know the old Electronic plug from the engine or harness (wherever it comes from) was zip tied or taped on the top side of the transmission because there was obviously no connection point coming from the AOD transmission.

What's the kick-down linkage look like?

Neither here nor there, except if I take the guy to court over it, as it won't change anything that an E40D is now installed and running well.
 

Kaajot

Micro Machine Manager
i sent a pm to someone that use to frequent the forums in hopes maybe theyll pop in to offer suggestions.

Thanks Sparky -- any help is appreciated about the Cylinder # detection problem.


ALSO:

Anyone know if the tube coming off the Cat converter to the EGR Tube is able to be purchased separate for a 4.9L straight 6 300?
 

blacksnapon

Moderator
Staff member
stalling

the coolant temp reading -40 means that the coolant temp sensor is disconnected (or the pcm "thinks"it is)with that reading the pcm will make adjustments in timing, injector duty cycle in an attempt to "warm it up". Theres where your fuel is going. if you create a massive vacuum leak, you'll get stalling just like you have. looking at a scanner, look at lft (long fuel trim) that's the adjustment that the pcm makes to compensate for a vacuum leak. ideally you want that reading around 0
 

Kaajot

Micro Machine Manager
the coolant temp reading -40 means that the coolant temp sensor is disconnected (or the pcm "thinks"it is)with that reading the pcm will make adjustments in timing, injector duty cycle in an attempt to "warm it up". Theres where your fuel is going. if you create a massive vacuum leak, you'll get stalling just like you have. looking at a scanner, look at lft (long fuel trim) that's the adjustment that the pcm makes to compensate for a vacuum leak. ideally you want that reading around 0

Thanks blacksnapon!

Yeah, we had a -40 when they pulled it and didn't reconnect it. Reconnected and it ran fine. PCM (ECM/EEC-IV?) (Primary Computer Module?) is working if that's all the same thing. I know ECM/EEC-IV are used interchangeably on this generation.

It's showing the correct temps now. I'll check for the LFT (didn't see it with the tool we were using, but we're using the mechanic next door's computer to pull codes next and will monitor for a 0 reading, else we'll know we still have problems causing a loss of gas).

Good news on that front - after oil change, no smell of gas mixing in the oil so far after 200 miles of driving. Hoping the next 800 is just as clean.
 

blacksnapon

Moderator
Staff member
Thanks blacksnapon!

Yeah, we had a -40 when they pulled it and didn't reconnect it. Reconnected and it ran fine. PCM (ECM/EEC-IV?) (Primary Computer Module?) is working if that's all the same thing. I know ECM/EEC-IV are used interchangeably on this generation.

It's showing the correct temps now. I'll check for the LFT (didn't see it with the tool we were using, but we're using the mechanic next door's computer to pull codes next and will monitor for a 0 reading, else we'll know we still have problems causing a loss of gas).

Good news on that front - after oil change, no smell of gas mixing in the oil so far after 200 miles of driving. Hoping the next 800 is just as clean.

pcm is powertrain control module
 

blacksnapon

Moderator
Staff member
as far as the cannot detect cylinder#, look at the crankshaft position sensor on the front pulley. it will Read off of the "star" wheel that is attached to it. perhaps it isn't plugged in or a broken wire or damaged lower pulley.
 

Kaajot

Micro Machine Manager
as far as the cannot detect cylinder#, look at the crankshaft position sensor on the front pulley. it will Read off of the "star" wheel that is attached to it. perhaps it isn't plugged in or a broken wire or damaged lower pulley.

Thanks, BlackSnapOn! I'll run this by my mechanic!
 

dustybumpers

don't play well w others
Did you ever fix the problem?

If not, read your first post, where you state you have a "slight vacuum leak, due to the mechanic using 2 gaskets to try and smooth out the problem"

Everything you discribe through the whole thread screams major vacuum leak.

Take the intake off, and put (1) gasket back on. I think you will be pleased with the result
 
Last edited:

Kaajot

Micro Machine Manager
Did you ever fix the problem?

If not, read your first post, where you state you have a "slight vacuum leak, due to the mechanic using 2 gaskets to try and smooth out the problem"

Everything you discribe through the whole thread screams major vacuum leak.

Take the intake off, and put (1) gasket back on. I think you will be pleased with the result

Thanks, Dusty!

We're doing that this month. I've been repairing other systems -- tow kit assembly, after-market fog light wiring repair, and recently a windshield wiper repair that "worked" but now is not. I think the windshield wiper motor (new) may have become slightly loose since I've already replaced the circuit breaker relay in driver side fuse panel. Those cbs aren't cheap, but think I'm going to keep the new one and once the problem is solved sell it on ebay since it appears to be "good" (will put on a multimeter to verify with some power from a 9v battery) on the cheap $10 vs rockauto's $26 for the same, that being the cheapest location online and going up to the $35-$45 range after that at most autoparts stores.

I'm excited to get the exhaust repaired. We painted all of the covers from the original assembly (which were on the original motor that came out in 2015 and swapped the intake/manifolds/covers in order to paint the "nicer" set). So it's all painted red white and blue and going to get a custom RED IX logo where the original Ford sticker went on the plate cover, but everything else is 100% ready to be swapped.

Still have an engine light and a non-detection cylinder # error code when attempting to run the codes (will not actually get past attempting an engine-rev or reading the codes upon hitting start). We've got one more machine to hook her up to and try to extract a better code read out.

Incidentally, if anyone wants a stripped 4.9L 300 short-block ready for rebuild, I've got it on craiglist and ebay in the upstate Watertown, NY area. 132K actual miles (maybe less, but definitely no more than 132K) when she came out of my truck. Has a lot of the seals, etc brand new to come with the engine. It's already in pieces and ready for a hot dip to clean her off and be rebuilt.
 

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