Hello all,
This was 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 from the sounds of the message they left me, they are giving up on it .

Any ideas or questions are welcome. Keep in mind I am an electrical novice. I don't know much about wiring, but maybe someone has an idea why the ECU was getting so hot. 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.

 

I quickly scanned your other long thread. What I am trying to figure out first is;

Is it running ok but the guy doing the inspections is saying the egr will not pass for some reason? Or is he saying the engine is not running correctly, and it's the egr's fault?

If he cannot get any codes from the computer, how does he know the egr is faulty? I was reading the other post and someone correctly mentioned you should at least get a code 11. Do you get a code 11?

Give us a run down on the model year again too. I think I read it's a 2.3 4 cyl engine.

 

Sorry for the confusion.
1988 Ranger XLT, Super-cab, 2.3L, 5sp, 4x2, 120k+

The truck is back running after tinkering with it for months refreshing the engine with everything except rings & bearings. IE the crank, rods, and pistons stayed in, but everything else was replaced with mostly Motorcraft parts.

It failed on #s for high NOx (I don't have the sheets with me), so I had the inspector pass it off to one of the mechanics to run a few tests. According to the mechanic there were "no codes". I asked if there was a code 11 but he said they plug a tester into the port and they get different results than what I would see????? I admit, I didn't try pulling any codes since it was running fine with no CELs (come to think of it I have never tried to pull codes on this truck, I am not even sure how to for this truck). He said the EGR was not opening, but he could pop it open with a screwdriver and the engine would smooth out a bit. I thought it sounded like it idled fine to me. I got a replacement EGR from Advance since Ford doesn't make it anymore. I put it on last weekend in the lot of the station & I dropped off the spare ECU. According to the station manager the mechanic supposedly re-tested it with the 2 new parts and it still does the same thing. I know they said it is still failing on NOx @ 15mph, and just sliding by on NOx @ 25mph.

Now confession time, I did 2 bad things that were somewhere in my "mega" thread. IDK if it helps anyone or not but here it is: At one point in my exhausted efforts I tried to jump the battery and accidentally hooked the the wrong terminals up. D'oh! Well the battery kind of smoked, so a new Motorcraft battery was going to be put in (the old one was mostly dead anyway). The second "ooops" was before I put the new battery in I hooked both the + & - to the starter motor. When the key got turned there was a descent amount of smoke that came from the now burnt connections on the cables.....D'OH!!!! I am not perfect, but these were my only 2 screw ups in putting the whole engine back in, so I think I did ok. Battery was replaced, + starter, pos cable and neg cable.

Sorry for the long posts, but I feel full details are better than 1/2 details.

BTW - Where is Staunton, VA?

 

I want to know also.....I've spent the last hour+ reading your teardown thread--I was totally engrossed. I want to know what you find out. Wow--am I glad I'm outta texas and don't have to deal with that inspection thing too much here in N.C.

 

npccpartsman - lol, yea, that is one hell of a saga, and I know some of the guys were getting a good laugh out of it. It was up to ~16-17 pages at one point and I think one of the mods cut out like 2-3 pages of junk. Anyway, it was like a redneck soap opera. I don't think anyone would have believed a head could be that stuck. I am glad I had to go through all of that so I could have a nice looking/running engine. Too bad I can't find this one issue that is keeping me from passing the "sniffer". I don't mind being 100% emissions legal, but there should be an easier way to track these things down.

I hope to have a ride to go get it tomorrow or the next day.

 

Here's a little bit of what I could find on your egr system.
http://www.autozone.com/servlet/UiBr...3d800f8d37.jsp

Basically you are putting exhaust gas into the intake manifold. That is what the EGR does. You have to have the valve, because you can't put exhaust gas into the intake when the engine is idling, or it will stall and run rough. So you have all these controls to tell the egr when to open, and how much.

The first thing I would do is when the engine is idling, see if you can open the egr manually like the mechanic was doing. When you do this at idle, the engine should run rough and or stall out. If it doesn't that is a sign the passageways are clogged with carbon. Unclog them, and then see if it will pass.

If the passageways are not clogged, then the next thing I would do is warm the engine up, and then unplug the vacuum line to the egr valve. Rev the engine, and you should feel some vacuum on the egr valve hose. If you don't, follow the hose back and you should find a valve that cuts the vacuum on and off. Unplug the line on the other side of the valve. It should have vacuum on it. If it does, then I would start suspecting something wrong with the egr vacuum valve.

 

Thanks for the link. Some of that looks like it might be helpful.

I want to assume opening the valve by hand is no problem since the mechanic said he could do that with the old one, and now there is a new one on there. As far as the passage ways goes.... when I had the engine out I had the exhaust and intake manifold dipped and cleaned. They were both spotless. That tube that runs down the back of the engine I had to clean that by hand with some engine cleaning brushes, brake clean & water. I ran brake clean & water through it until it was clear water coming out (started as dark black sludge). So that should be clear.

I also remember him telling me about the vacuum & regulator and those tested good.

There are 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?

 

I do not know how hot the ECU can get, but it seems to me if there was a major problem with the ECU,the truck would not run.

I would double check the vacuum feeding the egr solenoid, and make sure the engine is warmed up and the rpm's are above idle and see if you can hear it clicking.

The ECU has a check for the EGR valve, and it will throw a code if it sees it's not working. There is a couple of ways they did this, and I think your system may have the pressure method. What they do is monitor the exhaust backpressure that builds up in the metal tube you cleaned out. There should be a tee in the line or a passageway somewhere along the way that leads to a pressure sensor. When the ECU opens the egr, it looks for a pressure drop from the sensor. A pressure drop after it opens the valve verifies the valve really did open. If it doesn't see a pressure drop, it will send a code saying there is something wrong with the egr valve.

Sometimes people will modify the exhaust system and cut out the cats or get the exhaust flowing so freely, there is not enough backpressure in the system to push the gases up the metal tube and into the egr. So then there is not enough pressure to make the sensor work, and the ECU gives egr codes, even though the system is in working order, but has reduced flow.

So in other words, I do not understand why you do not have any codes in the computer.

 

Update - 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.

Franklin2 - I'm with you, I don't understand either. I know he told me that even when the old EGR was in there "sticking" it wasn't throwing a code. I don't know if this means the EVP on the back of the EGR is bad??? If it isn't telling the ECU what position the EGR is in I would have thought it would give a code.

As for that "tee" connection you mentioned: There is nothing in between the EGR and the manifold (stock). It is just a formed tube. The only other connections to the EGR is the 1 vacuum, 1 exhaust tube, 1 electrical connection to the EVP which would be the only thing directly telling the ECU if it is working.

Wait a min (currently scratching my head).......... I am not sure since I am only going off memory, but isn't the EGR solenoid (somewhere over on the passenger's side) supposed to supply vacuum to the EGR valve? And there must be some supply of vacuum provided to the the solenoid......... I don't think the vacuum line from the solenoid is connected to the EGR???? There is only 1 vacuum connection on the EGR right? I think I have a hose routing problem. If I do then that is the way one of the previous owners had it hooked up, because I connected all the vacuum lines back where they came from. I am not 100% sure of that but I guess we shall see. I have been thinking this is electrical since signals are not being passed like they should, now I am totally confused.

 

Ok, you must have the other system with the position sensor on top the valve. Once you get it starting and running correctly again, I would pursue your vacuum line theory. One line in the wrong spot could ruin the whole operation.

 

Yes, it is EFI 2.3L so it is like the system in the link posted above. It has a EVP mounted on one end and the exhaust inlet tube on the other with a vacuum line at the middle.

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".

I looked at the vacuum lines real quick while he was talking and it looks like they are fine. There is a red line and a green line. I will have to look at it more when I have some time. He tried to say that the EGR solenoid is now bad, but he also said it was good last week. Can the Solenoid be bad without throwing any codes?

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?!

 

Make sure the numbers are correct on the ECU. You may want to go to a site like www.partsamerica.com, and plug in your truck. Pretend you are going to buy the engine computer and sometimes they have the ECU numbers listed with the price screen.

If the egr solenoid is bad, it will throw a code. When the computer tells the solenoid to open, it then looks at the feedback from the egr sensor. If the egr sensor doesn't move, then the computer recognizes this and gives an error code. When the solenoid opens and applies vacuum to the egr valve, the sensor should move with the valve.

 

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

 

Definitely try to set the timing. That could be part of the idle problem, and a host of others we never may know about. Always fix the obvious first. Do you know how to set it? You have to unplug the spout connector to release timing control from the computer. If you don't do this, when you try to move the timing, the computer will just electronically move it back.

 

Know how? Yes (with a Haynes manual + sticker), but not off the top of my head. Did it correctly? No. Can't find my timing light so I may have originally set it with the calibrated ear......... But that is why I said to "bone head" it is probably not set right.

I didn't think I could get it set correctly now that it is idling way too high, or can I? Do you think the IACV is messed up based on what I did?

I will also check for the CEL bulb to see if it's burnt. 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.