CEL won't blink codes anymore
03-08-2012, 10:02 PM
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CEL won't blink codes anymore
After swapping another 22re into my 85, I think I blew my old ECU by forgetting the intake manifold ground. After a lot of troubleshooting, I swapped the ECU for a spare out of an 86. I thought that fixed the problem since I was now able to get the diagnostic codes to flash, and it flashed a code, #11, I THINK. It was very late and I was very tired, but I think I counted 11 quick blinks then a brief pause, then starting over again. I could have seen 10, but 11 is my recollection. Here's what I saw with the old ECU vs the newer one:
Original ECU
86 ECU (before problem)
Then I took it for a drive. I got a CEL pretty much right after my driveway, but it seemed to run better than before. I got back and now I have a solid CEL regardless of engine being on/off or T-E1 closed/open. CEL goes off when ignition's off, of course.
Some of the things I've checked:
I have concentrated so far on verifying grounds and the diagnostic mode requirements from the FSM:
Initial conditions
(a) Battery voltage above 11 volts.
(b) Throttle valve fully closed (throttle position sensor IDL
points closed).
(c) Transmission in neutral postion.
(d) Accessory switches OFF.
(e) Engine at normal operating temperature.
I still can't get any codes to display, though it looks like I should be. I know there are other problems, but this ECU/Diags thing is keeping me from pinpointing them. Am I wrong in thinking the TPS is the only thing that determines that the engine's at idle and therefore won't blink codes. If someone with a working ECU could check the voltage between T and E1 at the diagnostic port, that would be helpful, too. I have no idea if low voltage there is normal.
If anyone has any input, I'd love to hear it. I have about 4 hours each night that I can work on this thing, so I've had to be selective about what I check.
I just triple-checked timing. Shorting T-E1 definitely doesn't change the timing. Timing advances either with or without. Also no change in idle speed.
Went through the ECU testing steps more thoroughly and I saw low voltage (.1v) between both IGt (igniter) and E1 as well as IGt and body ground. This is supposed to be checked when idling, which I did. I have another igniter I could try out.
Original ECU
- Ignition on, engine not running: CEL solid on
- Ignition on, T-E1 closed, engine not running: CEL solid off
- No change in timing with T-E1 closed
- Never got a CEL when engine was running, though I knew something was wrong
86 ECU (before problem)
- Ignition on, engine not running: CEL solid on
- Ignition on, T1-E1 closed, engine not running: CEL blinked code 11... I think
- Engine running, T-E1 open: No CEL
- Timing: checked it at idle, T-E1 shorted, at 5deg BTDC at idle, advances with RPMs.
Then I took it for a drive. I got a CEL pretty much right after my driveway, but it seemed to run better than before. I got back and now I have a solid CEL regardless of engine being on/off or T-E1 closed/open. CEL goes off when ignition's off, of course.
Some of the things I've checked:
- TPS: Adjusted to specs (per fsm) and showing proper operation, even at idle.
- AFM: Haven't touched it yet
- O2: Replaced it anyway. I thought the old one had been through enough with the bad HG, and the glowing exhaust manifold. I only bring this up to say the wire isn't shorting anywhere.
- ECU: Checked that it's seeing proper voltages at the ECU according to FSM procedure. Spot check only though, +B1, +B, Batt, AFM, TPS, etc. Also checked TPS resistance there.
- Thermo sensor: Showed correct warm engine resistance
- T-E1: Voltage? I get 9-12v between T and E1. I don't know if this indicates anything, but it's not 12v...
I have concentrated so far on verifying grounds and the diagnostic mode requirements from the FSM:
Initial conditions
(a) Battery voltage above 11 volts.
(b) Throttle valve fully closed (throttle position sensor IDL
points closed).
(c) Transmission in neutral postion.
(d) Accessory switches OFF.
(e) Engine at normal operating temperature.
I still can't get any codes to display, though it looks like I should be. I know there are other problems, but this ECU/Diags thing is keeping me from pinpointing them. Am I wrong in thinking the TPS is the only thing that determines that the engine's at idle and therefore won't blink codes. If someone with a working ECU could check the voltage between T and E1 at the diagnostic port, that would be helpful, too. I have no idea if low voltage there is normal.
If anyone has any input, I'd love to hear it. I have about 4 hours each night that I can work on this thing, so I've had to be selective about what I check.
I just triple-checked timing. Shorting T-E1 definitely doesn't change the timing. Timing advances either with or without. Also no change in idle speed.
Went through the ECU testing steps more thoroughly and I saw low voltage (.1v) between both IGt (igniter) and E1 as well as IGt and body ground. This is supposed to be checked when idling, which I did. I have another igniter I could try out.
Last edited by GasGuzzlingZ71; 03-08-2012 at 10:10 PM.
03-09-2012, 08:30 AM
#2
Code 11 would be: 1 blink, 1.5 second pause, 1 blink, 4.5 second pause, repeat.
Code 10 would be: 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, 4.5 second pause, repeat.
Are you wrong in thinking the TPS is the only thing that determines that the engine's at idle and therefore won't blink codes?
Yes, on many levels. First, no the TPS isn't the only thing that determines that the engine's at idle(and technically it doesn't even do that, rather it determines if the throttle is closed at idle). Second, if you really did have a code 11 it could have been because the IDL contacts weren't closed at the time. Meaning, it will blink codes if there's something wrong with the TPS(like when the IDL contacts aren't closed when checking for DTCs). But, it will also blink codes if there isn't anything wrong with it(except TPS codes obviously). The engine being at idle doesn't really have anything to do with checking for codes though, since the engine doesn't even have to be running to check for them. You're just way off base with the whole hypothesis frankly. Moving on...
I do however pity you. So you'll find some of the answers to you're questions, and other useful info for developing a better plan of attack, here http://autoshop101.com/forms/h27.pdf
You could probably learn a lot from that site, so here's the link to the rest of it http://autoshop101.com/
Code 10 would be: 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, .5 second pause, 1 blink, 4.5 second pause, repeat.
Are you wrong in thinking the TPS is the only thing that determines that the engine's at idle and therefore won't blink codes?
Yes, on many levels. First, no the TPS isn't the only thing that determines that the engine's at idle(and technically it doesn't even do that, rather it determines if the throttle is closed at idle). Second, if you really did have a code 11 it could have been because the IDL contacts weren't closed at the time. Meaning, it will blink codes if there's something wrong with the TPS(like when the IDL contacts aren't closed when checking for DTCs). But, it will also blink codes if there isn't anything wrong with it(except TPS codes obviously). The engine being at idle doesn't really have anything to do with checking for codes though, since the engine doesn't even have to be running to check for them. You're just way off base with the whole hypothesis frankly. Moving on...
I do however pity you. So you'll find some of the answers to you're questions, and other useful info for developing a better plan of attack, here http://autoshop101.com/forms/h27.pdf
You could probably learn a lot from that site, so here's the link to the rest of it http://autoshop101.com/
Last edited by MudHippy; 03-09-2012 at 09:53 AM.
03-09-2012, 09:21 AM
#3
- http://www.4crawler.com/4x4/CheapTri....shtml#Reading
So 10 is 10 flashes, 11 is 11 flashes, 12 is 12 flashes, etc.
03-09-2012, 10:27 AM
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Are you wrong in thinking the TPS is the only thing that determines that the engine's at idle and therefore won't blink codes?
Yes, on many levels. First, no the TPS isn't the only thing that determines that the engine's at idle(and technically it doesn't even do that, rather it determines if the throttle is closed at idle). Second, if you really did have a code 11 it could have been because the IDL contacts weren't closed at the time. Meaning, it will blink codes if there's something wrong with the TPS(like when the IDL contacts aren't closed when checking for DTCs). But, it will also blink codes if there isn't anything wrong with it(except TPS codes obviously). The engine being at idle doesn't really have anything to do with checking for codes though, since the engine doesn't even have to be running to check for them. You're just way off base with the whole hypothesis frankly. Moving on...
Yes, on many levels. First, no the TPS isn't the only thing that determines that the engine's at idle(and technically it doesn't even do that, rather it determines if the throttle is closed at idle). Second, if you really did have a code 11 it could have been because the IDL contacts weren't closed at the time. Meaning, it will blink codes if there's something wrong with the TPS(like when the IDL contacts aren't closed when checking for DTCs). But, it will also blink codes if there isn't anything wrong with it(except TPS codes obviously). The engine being at idle doesn't really have anything to do with checking for codes though, since the engine doesn't even have to be running to check for them. You're just way off base with the whole hypothesis frankly. Moving on...
Code:
|Clearance between lever and stop screw |Between terminals |Resistance (ohms) | |o mm (0 in.) | VTA - E2 | 0.2 - 0.8 k | |0.57 mm (0.0224 in.) | IDL - E2 | Less than 2.3 k | |0.85 mm (0.0335 in.) | IDL - E2 | Infinity | |Throttle valve fully opened position | VTA - E2 | 3.3 - 10 k | |N/A | Vcc - E2 | 3 -7 k |
When I say "at idle" I am using the FSM wording. The engine is off when I try to pull the codes. I have also verified operating temperature at the thermo sensor (next to the BVSB at the bottom-front of the intake manifold). Just trying to meet the conditions required to get this to flash codes. It did once...
Regarding the autoshop links, I have been using those as well as my 85 FSM. I practically have page 10 and 11 of the h27.pdf memorized. I don't get 12 volts at the T circuit like it says I should. I get between 9 and 10.5 volts. That's why I was hoping someone else could tell me what voltage they are seeing between T and E1. I really think it's a wiring issue, but I was wanting to see if anyone had any other ideas before I go tearing apart my wiring harness.
Thanks.
Edit: 4Crawler, I forgot to thank you for the information on your site. It has proven to be an invaluable resource for me. This truck is so much different than my '83, and your site really helps me out a lot. I like your diagnostic panel, too. I may have to copy that.
Last edited by GasGuzzlingZ71; 03-09-2012 at 10:31 AM.
03-10-2012, 09:52 AM
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So either the TPS I swapped in or the igniter and coil I swapped in is bad. Maybe both I should have known better than to replace both at the same time, but oh well. The engine died on me and I had a heck of a time getting it started. The odd thing was that I heard what I thought was an injector clicking away (engine off) when I looked under the hood.
Really scratching my head now...
Really scratching my head now...
03-15-2012, 07:20 PM
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Are you wrong in thinking the TPS is the only thing that determines that the engine's at idle and therefore won't blink codes?
Yes, on many levels. First, no the TPS isn't the only thing that determines that the engine's at idle(and technically it doesn't even do that, rather it determines if the throttle is closed at idle). Second, if you really did have a code 11 it could have been because the IDL contacts weren't closed at the time. Meaning, it will blink codes if there's something wrong with the TPS(like when the IDL contacts aren't closed when checking for DTCs). But, it will also blink codes if there isn't anything wrong with it(except TPS codes obviously). The engine being at idle doesn't really have anything to do with checking for codes though, since the engine doesn't even have to be running to check for them. You're just way off base with the whole hypothesis frankly. Moving on...
I do however pity you. So you'll find some of the answers to you're questions, and other useful info for developing a better plan of attack, here http://autoshop101.com/forms/h27.pdf
You could probably learn a lot from that site, so here's the link to the rest of it http://autoshop101.com/
Yes, on many levels. First, no the TPS isn't the only thing that determines that the engine's at idle(and technically it doesn't even do that, rather it determines if the throttle is closed at idle). Second, if you really did have a code 11 it could have been because the IDL contacts weren't closed at the time. Meaning, it will blink codes if there's something wrong with the TPS(like when the IDL contacts aren't closed when checking for DTCs). But, it will also blink codes if there isn't anything wrong with it(except TPS codes obviously). The engine being at idle doesn't really have anything to do with checking for codes though, since the engine doesn't even have to be running to check for them. You're just way off base with the whole hypothesis frankly. Moving on...
I do however pity you. So you'll find some of the answers to you're questions, and other useful info for developing a better plan of attack, here http://autoshop101.com/forms/h27.pdf
You could probably learn a lot from that site, so here's the link to the rest of it http://autoshop101.com/
Mudhippy,
- I don't need your pity.
- I don't need your condescension.
- I don't need rtfm-like responses. I quoted the freaking FSM for my year/model for crying out loud.
- Instead of jumping to conclusions about something I said that doesn't make sense (an "at idle" condition on an engine that's not even running), you could instead ask for clarification.
Updates to come in my next post... with pics
Last edited by GasGuzzlingZ71; 03-15-2012 at 07:58 PM.
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03-15-2012, 07:56 PM
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Original 1985 ECU:
No conclusive visible signs of damage. Some components did see some heat, but the board and solder joints are visibly OK. If the ECU is damaged, I think it's a component (or more than one) that's internally damaged. This is according to my father, who checked it out for me. He's an engineer for a company that manufactures/assembles boards for other companies, so this is 2nd hand info based on his inspection.
Wait for it.....
Replacement ECU (1986? Can't read the label #'s anymore):
So, the truck was actually running with the ECU in the above picture. It was running poorly, but it was running. It wouldn't rev above 4k if revved quickly, had terrible power, sucked down gas like it was going out of style, etc. The timing actually did advance with RPM, which surprised me. Like I said in my original post, this ECU actually gave me some diagnostic codes at first. I guess it just took it a few minutes to blow.
No conclusive visible signs of damage. Some components did see some heat, but the board and solder joints are visibly OK. If the ECU is damaged, I think it's a component (or more than one) that's internally damaged. This is according to my father, who checked it out for me. He's an engineer for a company that manufactures/assembles boards for other companies, so this is 2nd hand info based on his inspection.
Wait for it.....
Replacement ECU (1986? Can't read the label #'s anymore):
So, the truck was actually running with the ECU in the above picture. It was running poorly, but it was running. It wouldn't rev above 4k if revved quickly, had terrible power, sucked down gas like it was going out of style, etc. The timing actually did advance with RPM, which surprised me. Like I said in my original post, this ECU actually gave me some diagnostic codes at first. I guess it just took it a few minutes to blow.
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