I know ECU's "nearly" never go bad, BUT...

[BLHTAZ]

To answer the question...no, I did not have it on a scanner. I did replace the TPS, but it made no difference so I put the old one back on and figured I can sell the new one I bought to recover some of that money.

 

 

On to some good news...

 

I had an epiphany...!!!

 

I went out as planned and started tracing wires, checking the c101, checking grounds with all of my diagrams printed and in tow. I got around to the passenger side of the truck and BOOM...it hit me as I looked at the new battery wiring harnes that I had put on a few months back.

 

The battery ground goes to a stud sticking out of the right side of the block that also holds the dipstick tube. That is also where the 4 primary block & wiring harness ground wires connect. Well...when I changed the battery harness, I could not get the nut off of that stud, so I just cut the old battery ground cable and then found an unused threaded hole below the oil filter to put a bolt in and attached the battery ground to that. I guess this was the wrong thing to do as all the problems I have been having seem to have been ever since I did that and now that I have taken the time today to get the nut off of that stud, removed the ole battery cable end and have now mounted the new battery cable end where it is supposed to be...THE FREAKIN' JEEP RUNS BETTER THAN IT HAS IN MONTHS. It starts faster, quicker throttle response, accelerates better etc, etc... :D

 

The EGR valve is still not working and the solenoid is still failing the tests per the FSM so I guess I need to replace that.

 

I am quite relieved, but still feeling like quite the idiot at the same time... :oops:

 

The great part is...it only took about 3.5 hours so now I can watch football & drink beer all day

[chicofuentes0224]

:cheers:

[Akula69]

 

:cheers:

[jeepdoggydogB]

To answer the question...no, I did not have it on a scanner. I did replace the TPS, but it made no difference so I put the old one back on and figured I can sell the new one I bought to recover some of that money.

 

 

On to some good news...

 

I had an epiphany...!!!

 

I went out as planned and started tracing wires, checking the c101, checking grounds with all of my diagrams printed and in tow. I got around to the passenger side of the truck and BOOM...it hit me as I looked at the new battery wiring harnes that I had put on a few months back.

 

The battery ground goes to a stud sticking out of the right side of the block that also holds the dipstick tube. That is also where the 4 primary block & wiring harness ground wires connect. Well...when I changed the battery harness, I could not get the nut off of that stud, so I just cut the old battery ground cable and then found an unused threaded hole below the oil filter to put a bolt in and attached the battery ground to that. I guess this was the wrong thing to do as all the problems I have been having seem to have been ever since I did that and now that I have taken the time today to get the nut off of that stud, removed the ole battery cable end and have now mounted the new battery cable end where it is supposed to be...THE FREAKIN' JEEP RUNS BETTER THAN IT HAS IN MONTHS. It starts faster, quicker throttle response, accelerates better etc, etc... :D

 

The EGR valve is still not working and the solenoid is still failing the tests per the FSM so I guess I need to replace that.

 

I am quite relieved, but still feeling like quite the idiot at the same time... :oops:

 

The great part is...it only took about 3.5 hours so now I can watch football & drink beer all day

Great news! Faulty grounds always are a pain to diagnose. Good work Brent!

[chicofuentes0224]

I also want to add for anyone reading this in the future to go and buy the negative battery cable that bolts to the engine AND has the second wire running to the fender to add an additional ground. This little wire fixed a lot of driveability problems my Comanche had. One of these days I'll get around to snapping a pic.

[HOrnbrod]

I went out as planned and started tracing wires, checking the c101, checking grounds with all of my diagrams printed and in tow. I got around to the passenger side of the truck and BOOM...it hit me as I looked at the new battery wiring harnes that I had put on a few months back.

 

The battery ground goes to a stud sticking out of the right side of the block that also holds the dipstick tube. That is also where the 4 primary block & wiring harness ground wires connect. Well...when I changed the battery harness, I could not get the nut off of that stud, so I just cut the old battery ground cable and then found an unused threaded hole below the oil filter to put a bolt in and attached the battery ground to that. I guess this was the wrong thing to do as all the problems I have been having seem to have been ever since I did that and now that I have taken the time today to get the nut off of that stud, removed the ole battery cable end and have now mounted the new battery cable end where it is supposed to be...THE FREAKIN' JEEP RUNS BETTER THAN IT HAS IN MONTHS. It starts faster, quicker throttle response, accelerates better etc, etc... :D

 

Hmmm, that's interesting. The primary negative mains cable engine ground on mine attaches to one of the bell housing bolts. Also attached to this bolt is the A/T dip stick tube bracket. The body ground attaches from the negative battery post to the right inner fender well. If your negative mains cable was attached securely to a bolt threaded into the block w. no corrosion, that's a great place for the engine ground; you should have been golden. Do you also have the engine ground and body ground tied together? There should be a mains cable the same size as the engine ground cable going from a stud on the left rear cylinder head to the firewall. The OEM "cable" was a braided mesh POS that ofter rotted in half. This 3-mains cable configuration provides a continuous loop that provides the same ground potential to the battery, body, and engine.

[Cabz]

glad to hear ya got it going better brent , but get that heep on a scanner and get the TPS set right :D you'll be glad you did .

[BLHTAZ]

glad to hear ya got it going better brent , but get that heep on a scanner and get the TPS set right :D you'll be glad you did .

Yeah...I was thinking that it is not likely to be right since I have had it off. I'll get that set ASAP. :cheers:

[BLHTAZ]

Hmmm, that's interesting. The primary negative mains cable engine ground on mine attaches to one of the bell housing bolts. Also attached to this bolt is the A/T dip stick tube bracket. The body ground attaches from the negative battery post to the right inner fender well. If your negative mains cable was attached securely to a bolt threaded into the block w. no corrosion, that's a great place for the engine ground; you should have been golden. Do you also have the engine ground and body ground tied together? There should be a mains cable the same size as the engine ground cable going from a stud on the left rear cylinder head to the firewall. The OEM "cable" was a braided mesh POS that ofter rotted in half. This 3-mains cable configuration provides a continuous loop that provides the same ground potential to the battery, body, and engine.

The braided "cable" is still there on the left rear of the head to the firewall and is in good solid condition as I looked it over good and grabbed it and pulled hard on both ends to be sure it was still attached firmly. I thought my way of grounding should have been good too, but obviously it wasn't ;) .

 

I did the TPS adjustment tonight. The input voltage was good at 4.9v, but the output was a bit too high at .92v so I got that adjusted down to .76v. It gave me a scare when I started it and it went flying right up to 3000 RPM, but I quickly shut it down and disconnected the battery ground for a couple minutes. When I hooked it back up and fired it up...everything was good again :D

 

Thank ya'll for helping a real electrical dummy get through this :cheers:

[FxRacing282]

It gave me a scare when I started it and it went flying right up to 3000 RPM, but I quickly shut it down and disconnected the battery ground for a couple minutes. When I hooked it back up and fired it up...everything was good again :D

 

Thank ya'll for helping a real electrical dummy get through this :cheers:

 

man i hate that feeling

[Cabz]

no problem brent , just keep in mind thour .76 is still a bit high,

the rande is .60-.70 . Mine is set a .65 just to be safe :D

[BLHTAZ]

no problem brent , just keep in mind thour .76 is still a bit high,

the rande is .60-.70 . Mine is set a .65 just to be safe :D

The FSM says that it should be .8 ...it doesn't give a range. It says the input should be 5v and output should be .8v :???:

 

Here is a snip from the FSM...

 

THROTTLE POSITION SENSOR (TPS)

 

1) Turn ignition on. Check throttle position sensor input

voltage. Connect voltmeter negative lead to terminal "B" (M/T), or

terminal "D" (A/T) of sensor connector. Connect voltmeter positive

lead to terminal "A" (M/T and A/T) of sensor connector.

 

NOTE:

• On (A/T) models, connector terminals are identified by
  letters molded into back of connector. On all models, do not
  disconnect TPS harness connector. Insert voltmeter test
  leads through back of wire harness connector. On some
  models, it may be necessary to remove throttle body from
  intake manifold to gain access to sensor wire harness.

 

2) Move and close throttle plate completely (M/T and A/T).

Ensure throttle linkage contacts stop. Note voltmeter reading. Input

voltage at terminals "B" and "A" (M/T), or terminals "A" and "D"

(A/T) should be 5 volts.

 

3) Return throttle plate to closed throttle position (M/T

and A/T). Check sensor output voltage. To do so, disconnect voltmeter

positive lead from terminal "A" and connect it to terminal "C" (M/T),

or terminal "B" (A/T).

 

4) Maintain throttle plate in closed position (M/T and A/T).

Ensure throttle linkage contacts stop. Note voltmeter reading. Output

voltage should be .8 volt (M/T), or 4.2 volts (A/T).

 

5) If output voltage is incorrect, loosen bottom sensor

retaining screw and pivot sensor in adjustment slot for a coarse

adjustment. Loosen top sensor retaining screw for fine adjustments.

Tighten screws after adjustment.

[Cabz]

True the FSM list those as the readings you want. I am going of the scanner specs , I have set them both ways and the scaner spec seems to be better of for the jeep . Mine is set at .65 and I'm getting round 22MPG

 

If your commin up for jeeptoberfest bring the ole MJ and I'll scan her for ya :D

[BLHTAZ]

I wish I could bring it to Jeeptoberfest, but we will be bringing the YJ as I believe we are putting her up for sale and figured it would be good exposeure to have it there. We were going to bring the MJ until we decided to sell the YJ.

[mjdoa]

Amazing how critical grounds are,huh?

Glad you got it going,I'll remember this thread.

[Cabz]

I wish I could bring it to Jeeptoberfest, but we will be bringing the YJ as I believe we are putting her up for sale and figured it would be good exposeure to have it there. We were going to bring the MJ until we decided to sell the YJ.

 

well if ya ever have the MJ up in these parts, gimme a ring :D