Hello all,
Some of you may remember my last major issue: https://www.ford-trucks.com/forums/4...the-block.html
Well this is kind of a continuation of that. The short story goes like this:
First emissions inspection, I had a blown head gasket.
Spent several months mostly rebuilding the engine.
Got it all back together to go for test #2.
Failed visual inspection, so I fixed that.
Got it all back together to go for test #3.
Failed for EGR valve not working/sticking, and no signal from ECU to open EGR.
Replaced EGR valve & picked up a spare ECU.

Some details:
The mechanic said the EGR valve was sticking, but could be "popped" open and it ran fine (it now has a new valve). He says he tested the solenoid and it was good, but that it was not receiving a signal from the ECU. He tested the wires between the ECU and solenoid and they checked out. He also said the ECU was so hot he couldn't hold it without gloves. He also claimed there were "no codes" coming from the ECU. So we suspected a bad ECU (I got another from a junkyard). IDK if he has tested the spare ECU, but it sounded like they are giving up on it.

Any ideas or questions are welcome. I am considering taking it to a local dealer to find this mysterious problem so I can finally pass emissions and get back on the road.

 

If you get it home, try pulling the codes from the ECU. I'd also compare the markings on the two ECUs to determine if they have the same calibration, at least the same basic part #.
I'd also disconnect individual components from the ECUs power load. Unplug EGR solenoid, O2 sensor, injectors, fuel pump, ECT, ACT,etc until the ECU is doing nothing, and then re-connect one at a time, to determine the one causing the overheating.. if it is not the ECM that is the problem.
Start simple, and add back one thing at a time.
tom

 

Thanks, I know the ECU part #s are the same. But I don't know if they even tried the spare ECU.

EDIT - I just talked to them, and he said the spare computer wouldn't activate the EGR either.

When you say unplug these items, do you mean with the engine running? I wouldn't think so since it would probably die, or is this something that is "key on, engine off"? I know the mechanic said the ECU got hot after running, but you think it would do the same thing while not running?

I did call a local dealer to see if they thought they could track it down. The service writer didn't seem to think it would be to hard for them to figure out. I am not too sure how much time I will be able to spend on this, since my "non-automotive inclined", "non-understanding" (when it comes to this truck) wife has voiced her distaste for working on the truck. I know this is some thing stupid, like a short, or a loose wire, or something that is just holding me back. So frustrating from both ends.

 

the boss has spoken. She who will be obeyed...

If you are able to wriggle a few minutes, check that the ECM will do a Key ON engine OFF self test, using a jumper wire and a VOM... If not, the dealer will be looking at fishing time... fishing around to find your problem on your dime, with no guarantee of how long it will take.
I'd be looking at the wiring under the hood by the starter solenoid... where the EGR solenoids are... check again to see that the wires are back where they belong.
Again, try to get a trouble shooting manual for vacuum and electric. It is worth it.
tom

 

tomw - IDK about that "obey" part. It just means more B___ing is soon to come. Are you talking about manually pulling codes? I have never done it yet, so I don't know where the "jumper wire" goes, or what a "VOM" is.

This is a compelation of acouple posts I have in another forum:

Update 8/20 - I went to get it last night, and the guy hadn't put the ECU back, it was just sitting on the floor plugged in. Ok, no big deal it has to get worked on anyway, so I try to start it and the starter stays running! EVEN WHEN I PULLED THE KEYS OUT! WTH did he do to the thing? I could't get the starter to disengage until I pulled the neg cable off the battery. Needless to say it is still sitting up there.


Update 8/21 - Well I got it just an hour ago. It seems the bone head has created more issues than he fixed. Good thing I didn't pay them anything.

The starting problem is a bad solenoid (it was good when I dropped it off). It stuck open so the starter was engaged all the time.

Mechanic "oh, you have a bad solenoid you will need to replace this" as the starter kicks in every time you touch the neg cable to the terminal.
Me "ok I will, but let me show you how to fix a Ford" I took the wrench out of his hand and hit the solenoid 3 times. Hooked the neg cable back up and turned the key. Vrrrooom. Haaaahhaahahah So I looked at him as he laughed and said "now you know how to fix a Ford".

The other problem he created was a VERY high idle. He said when he swapped the ECUs it started to idle really high. I don't have a tach, but it is at least 1500-2000rpm. Now what did he do?!

The other 2 things that really concern me (in my limited thought process) from what the mechanic told me:

1) ECU getting super hot, (sounds like a grounding problem).
2) EGR solenoid working, but not receiving a signal from the ECU.

So what tells the ECU it's time to open the EGR, or does the ECU make that choice internal?

Update 8/22 - All the #s on the ECU match the spare one. The original was put back in the truck before it left the (dis)service station.

I will have to check for the codes when I get the chance. I just spent a few min eliminating one of the issues that came up. I picked up a new starter solenoid and replaced it when I got home. It seems to start fine with no sticking so crossfingers on that one.

It was still doing the high idle thing so that needs to get straight before I can do any other diag. I smacked the IACV a few times to see if that was sticking & the idle did drop a little on the next start. So I pulled the hose while it was running and plugged the TB inlet with my thumb. The engine rev'ed up for a split sec until I got my thumb over the hole and the idle dropped down a bit. It wasn't up to temp so I don't know if this "idiot check" would tell me if the IACV is truely bad. When I shut it off, I pulled the wire to it just to see if I would get a CEL. Nothing! I am convinced this thing won't give a CEL for any reason. . Maybe the light is burnt out.

As far as the emission goes......the other thing I realized is I may not have the timing set correctly according to the manual and the sticker on the rad support. ooooops. It runs ok, but lacks a little power, so I think the timing is retarded. Could this cause the high NO ppm readings? I don't think it would have anything to do with the EGR issues. I must of mentioned to the mechanic 10x that the timing could be off, but something tells me he didn't touch it. I didn't post the reaings before but here goes:

15 mph
...................limit.........reading
HC ppm.........179.........89
CO%.............1.52.......0.18
NO ppm.........1227......1176

25 mph
...................limit.........reading
HC ppm.........174.........73
CO%.............1.96.......0.15
NO ppm.........1121......1300

 

FWIW, 'she who must be obeyed' is a local radio jocks comment ... I just copied him.

I don't think the EGR kicks in below 25-30 mph. generally speaking. It could cause "trailer-hitching" easily. So, it is probably not causing the hi NOx at 15mph. NOx is formed because of hi combustion temps, and EGR lowers the peak by adding an unburnable (already burnt) gas to dilute the mix, and lower peak temp.
The CO and HC numbers look decent.
I would 1)check the timing and 2)make sure the ECM is functional enough to send out error codes or the '11 I'm OK' code. Also check the CEL bulb is not burned out or removed. I don't have one on my old truck (85).
The 'tarded timing could cause high temps, thus the NOx peak.
Maybe the EGR was not operated because it was not supposed to, given the circumstances of temp and MPH. You might be chasing a non-existant problem. Might.
tom

 

Yes those are my next 2 orders of business (timing & codes). However, I don't think I am supposed to try setting the timing if it won't idle down where it is supposed to. Do you think the IACV is messed up based on what I did?

I haven't been able to find my timing light in forever. So I may have originally set it with the calibrated ear......... So I may be going to find another light. I will also check for the CEL bulb. On these Rangers, is the CEL supposed to come on for a sec when you first trun the key and then click off? That is what my other cars do. If so, then I know I have never seen it.

 

By now, I've forgotten the year... MAF/MAP issues: If you have an air leak, the idle will go up. The MAF will not 'know' about the extra air, so may run cruddy (lean). The MAP knows, because the manifold vacuum is not as 'vacuumy' as it should be, so the engine 'must' be under some sort of load (throttle open, essentially), so the MAP adds fuel..
The IAC on mine is over by the fender on top of the air cleaner box. I'd take it out and see if it needs to be cleaned, and clean it if so. The mechs may have fiddled with the distributor, and thus changed the timing and consequently the idle.
Borrow a timing light, maybe from Advance/Autozone, etc whoever 'loan' tools. You can buy one for cheap nowadays. Back when, I used a neon in-line light that needed darkness to be visible. When you do set the timing, make sure to unplug the SPOUT connector down near the lower intake manifold. Hanging in the bundle of wires from the engine to the drivers side inner fender. 10dBTDC is the usual.
As I said, my CEL does not have a bulb. Never did. Don't think there are wires on the printed circuit in that area. The manual even talks about an 'upshift now' light ... which I don't have either.
A VOM is a Volt Ohm Meter. Used to measure volts - AC/DC and Ohms of resistance. You'd set it on the 20V dc scale, plug it into the connector, and put a jumper in there somewhere and it will pulse 0v- 12v 12v -0v 0v 0v.. 12v 12v with pauses inbetween pulses. Eash 'pulse' is a '1'. each pause is a '0'. You get a 'feel' for timing the pulses, and there are long pulses to tell you where you are in the series. If you get the shop manual or (cheaper) get the code reader for Ford vehicles($35?) you can read how to do the test. I *think* there are instructions on this site also.
tom

 

"Some" testing done.

On the way home I picked up a code reader to help see if anything was showing up I had about 20 min to spare, so I did the basic KOEO (key on engine off) test. The tester puts out 2 "sections" of tests. I think it is stored codes then hard codes. Anyway, there WERE codes in there (thanks bone head)...

1) 23 - TPS
2) 31 - EVP
3) 67 - NPS?? I don't think this one is important
---------
4) 11 - System ok

I still have to check the timing, see if the CEL light is out, re-run KOEO test, run KOER test and of course fix the problems.

 

Picked up a timing light, engine tester w/ tach, TPS, and the EVP I had.

Ran KOEO tests before replacing any parts just to varify, & I still get:
1) 23 - TPS
2) 31 - EVP
3) 67 - NPS?? I don't think this one is important
---------
4) 11 - System ok

So if I unplug the TPS and plug the new one in (not mounted) and re-test, it comes up good. After mounting it on the TB it throws the same 23 code again. Now it does get turned just a little when you mount it. Is this what's causing it to throw a code?

I swapped out the EVP, & I still get the same code 31 with the new one. On the other hand, I found the cause of the high rev'ing idle....... Apparently it's a bad thing if you misalign the EGR gasket. D'oh! But bone head (aka mechanic) didn't catch that either.

Now I checked the timing with the new timing light. I "THINK" I unplugged the right connector near the coil to check base timing. Anyone have a pic of the correct one. The pic in the Haynes is for a 90+ (not the same) Well,......... I think 20deg BTDC is a little off. Unfortunately, the light stopped working before I could get it set. So I will have to get another one to try again. Is it safe to assume that the timing is the cause of the high NOx?

 

The older TPS needed to be adjusted, so if it has a slotted mounting, it will need to be adjusted. Measure the volts at closed throttle. Someone may also have adjusted the hard throttle stop screw so the TPS does not close all the way, causing a code because the ECM expects Xvolts at close throttle, and will get X.x because the TPS is a little higher than idle position.
I *think* EVP is evaporative control and charcoal canister stuff. If so, I'd check the hose routing and leakage as I believe the ECM tests for pressure/vacuum control and sets codes if it can't keep vacuum, etc. If you have leaky hoses, it will erroneously report an EVP problem, well not erroneous, but not the EVP itself.
Whatza NPS?
tom

 

IT PASSED!!!!!!!!!

I was "forced" into taking it to a local dealer to have them check it out. At first they wanted to do a full diagnostic ($135+) just to CHECK IT OUT! I said I know you are going to have to set the timing & test the emissions, can't we just do that? They reluctantly agreed. Service manager called 2hrs later to say the timing was out of spec and once it was set it passed! This whole ordeal has been going on for ~1yr so maybe I can finally put it to rest.

tomw - Yea, someone else in another forum mentioned that screw too. I know what you mean about the slots on the mount for the TPS. I might be able to rotate it to have the correct reading. 2 yrs ago when I bought the truck it was turned way up and the idle was too high, so I backed it out until it was down in a more normal range. Lately since the whole thing has been apart, I did have to turn it a little. If you think that is the reason for the code I will check it out. Remember when I plugged the new TPS in (not mounted on the TB) it tested fine. Only once it was screwed in place did it show bad again. Also FYI, I tried the same thing with the old TPS and I got a different code (still TPS related) so it was bad for sure.

One listing has:
31 Canister or EGR valve control system or EVP circuit below minimum voltage
Another: reference mentioned the EGR solenoid or EGR valve not in correct position.

67 Neutral Drive Switch fault, switch circuit open / Air conditioner on during self-test

This one kind of makes sense. On this truck Ford used 2 neutral switches. One was in the trans. Well I had to replace the trans with a newer unit last year so that sensor is not plugged in. I believe it is the one throwing this code.

 

Remember to keep the shiny side up now that it moves on its own...
tom

 

I assume you mean, "keep it on all 4s, or at least 2". Esspecially since the only shiny thing on the whole truck is the new lug-nuts.

Anyway, thanks. I am also going to assume it still has the same codes when I get it back. I wasn't going to pay the dealership rates to fix minor issues like this. It was so close to passing anyway, so I was ~80% sure the correct timing would lower the readings.

For resolving the #23, the advice is to try adjust the position of the TPS on the TB to get it reading in the correct range?

For resolving the #31, ????? I guess it isn't the EVP, so is it the EGR solenoid? The old one looks like crap, but so does the rest of the truck so IDK.

For resolving the #67, I don't care. This shouldn't affect anything so unless I am going to put the old trans back in (not going to happen) then this code will stay. The switch on the clutch pedal is the 2nd sensor, so that's all I need.

 

#23 is adjust the TPS as you say. Close throttle. Use VOM to check volts, and adjust TPS to get specified voltage with throttle closed. This is assuming the hard stop is in the right place.
If you have an EGR with the position sensor, it can set a code if the EGR does not move to the right position on command.
If on the other hand, the volts are off as stated, check the volts at the sensors. One may just have a loose connection. Ford (and others) use a 'base' voltage to all sensors, and a bias + or - from the base to get their readings. I.E, the TPS is supposed to be .5 volts closed... (NOT THE SPEC), and you adjust the slots to get it to show that, and lock it down. WOT on the other hand could be 5.0 volts... My brain can't hold em all. The O2 has a ground, power, and sense. And a heater power in some (most, anymore) cases. The 'sense' is measured relative to the power, to take the varying resistance and poor grounds out of the picture as much as they can.
So your problems may just be bad grounds or loose/corroded connections.
tom