I have a 94 EB with a 5.8. It has the all to common pinging, missing, and rough idle with the spout connector in. Pull the spout out and it runs smooth with none of the above symptoms. I have the BLACK CCD TFI. I've replaced the EEC-IV, TPS, PIP, ant TFI (used one, but advertised at good), EVR, plugs, wires, dizzy, coil, and fuel filter. I've seafoamed 3 times, cleaned the IAB, and dressed up all my grounds. All wires from the EEC-IV to the TFI, and PIP have checked good. The timing is set at 10* BTDC. I have checked the balancer timing marks against piston 1 TDC to verify that it hasn't slipped. I have routed and re-routed all my plug wires to eliminate crossfire. I know my way around electrical troubleshooting, but this is really humbling me. I have a really nice OBDI/II scanner that you plug into a laptop and watch all the sensor readings while idling or driving and record them. I have taken some recordings and have some screenshots of the data, if you'd like to check them out. Someone, please help I'm pretty sure i'm developing an ulcer due to this truck. Thanks.

 

You won't get an EEC-IV scanner like that. What codes are you getting? Your 94 requires a jumper wire between two terminals of the test connector near the firewall to get codes from the "check engine light". Obviously replacing all of that stuff wasn't the problem. If you want to get to the bottom of it pull codes. I would almost bet on HEGO sensor circuit failure or bad signal and/or EVP sensor failure/dirty, stuck EGR valve.

Removing the SPOUT connector bypasses the entire spark timing adjustment made by the ECM. That's why it works with the SPOUT removed. It's ONLY running base timing as set by the distributor and at 10* BTDC you are on the money.

 

Did you check the spark plug wires? I had a loose one and one that stopped letting current thru it (shorted) replaced those two and it was smooth after that.

 

greystreak, I dunno if it's what he's talking about but there is a scanner that plugs into the computer that reads all sensor data, records it with a time stamp with values. I'm definitely getting one myself in the future.. All I know of is a $600 device that they don't make anymore, I've been sorta on the lookout for something similer.. what scanner is it? because I want one..

Sorry I can't help, sorta trying to figure out a similer issue myself.. Base timing is above 20degrees for me with spout plugged in. I'm suspecting EGR personally, other than for RPM changes I don't know of anything else in the system that increases timing other than EGR and HEGO (my HEGO is brand spanking new). EGR is finicky at best, you can tell from the number of posts here, everyone seems to throw EVP/EGR codes when they're not throwing anything else.

 

Errors,

With SPOUT connected you will NEVER see "base" timing. It would be like trying to read timing on an old vacuum advanced engine with the vacuum advance connected to the distributor. SPOUT MUST be removed to take a base timing reading.

I wasn't aware there was such a device for EEC-IV diagnostics. It would require piggy-backing onto the ECM connector to actually get that kind of information though. You couldn't just use the EEC-IV test connector.

 

I know you can't time, but on any vacuum advance I've seen I wouldn't get much advance, if any at idle.

 

Oh, and the one I saw went between the ecu and connector. I wish I could remember what it was called.

 

Sorry about the multiple posts but you can't edit from your phone. Go ahead and post the shots of the readouts, I would love to see it.

 

Vacuum advance engines typically idle a couple hundred RPM slower than an EFI-equipped engine so naturally, you are dealing with less needed advance. Mid 600's-700's is not out of line for a fully warmed 351 or bigger with a carb and vacuum advance. Heck, my Cadi 472 had a curb idle of 660 RPM and in-gear idle of 550 RPM.

 

as unbelievable as it sounds, there IS actually a scanner that works exactly like that. It plugs directly into your STI connector under your hood... it gives you live data of every sensor and what it's putting out. Reason i say this is because i picked one up the other day from EASE diagnostics. It's actually a really neat tool... yet, it still hasn't helped me figure out my problem. The auction on ebay is listed below... I got mine for $100 shipped.

OBD1 OBDI Ford Pro Scan Tool Diagnostic EEC-IV FSI | eBay

 

I took apart my EGR valve today... it works just fine. I tested my PFE sensor on top of the EGR valve... it KINDA functions like its supposed to. I read ohms and they decreased smoothly as i moved the plunger up and down, however there seemed to be a spot where the ohms reading was finnicky.


Photos from Full Size Broncos | Facebook

 

Not at the STI sorry, it cannot be done. The sensors deliver an analogue signal to the ECM. You need a conductor for every signal being sent to (and leaving) the computer and the EEC-IV test connector has a TOTAL of six (6) pins. There are more than six sensors/control devices in the system and the ECM produces NO external digital signal to carry all of that information over a single pair of conductors. That's why the interface is needed to convert the analogue information coming into it into digital information that your PC can understand.

Take a close look at the connectors in that photograph. You aren't plugging that into an EEC-IV STI connector. Note that it stipulates that it works with "1996-2000 Ford trucks" which would be OBDII and NOT EEC-IV as stated in the ad.

The sensor on top of the EGR valve is an EVP sensor in our trucks. The PFE sensor was used in the same capacity but does not function the same way nor was it used on the engines in the F-series trucks of this vintage. A "dead spot" in a potentiometer is the most common point of failure. The irony is that dead spots tend to occur in the location that the potentiometer sits at most of the time. Why? It wears away the contact area because it ALWAYS sits at this point.

 

Pardon me. I meant sti AND STO connector. I posted a link to a screenshot that i posted on the FSB facebook group. check it out.

 

Eh, excuse my inexperience.. though you couldn't be facing high reading at idle like with the EVPs ? I wouldn't be happy with erratic readings at any part of the range on any sensor. .
Im gonna try to find your link before my battery dies, excited to see these readouts. This reader sounds great.

 

ok, well then it's a magical box that plugs into my connector thats under my hood. and this magical box takes magic from those 6 wires and magically converts it into a serial connection. the serial connection on the other side of the box which COULD be magical too, then plugs into my laptop. Then the magic gets even crazier... i see live data from EACH sensor. I see HEGO, EVP, TPS, ENGINE RPM, VEHICLE SPEED, and many many more. Since you're so sure that i'm lying--it must just be friggin magic. my truck is a 94 which is OBDI.