Jump to content

Fast Idle At Start And Running


Recommended Posts

First, I bought my 88 Pioneer 3 months ago. Spent dozens of hours reading through this tech forum. I've learned so much. THANKS!!! to everyone.

 

Now my question, My Manche is 4.0/Auto/4WD. all original. I don't have a tach but I believe it's currently idling too fast. It seems to take too many cranks to start and it races for a moment at start before settle back to fast idle. It seems to run great, plenty of power.

 

It was running rough when I bought it. Here's what I've done so far (that I can remember).

 

* Cleaned the C101

* cleaned as many connectors as I could find
* Replaced IAC

* Replaced TPS (voltage is 5v incoming and .8 at idle)

* Replaced the vacuum harness.

* Some of the Vacuum lines were connected wrong. Specifically to the EGR. I believe I've got them all correct now

* Searched and searched for vacuum leaks, Sprayed an entire can of Carb cleaner

* I've used a unlit propane torch to look for intake leaks

* cleaned the TB

* cleaned the CCV system.

 

The fast idling didn't start until I correctly routed the vacuum lines. After that I replaced the IAC and TPS on advice that they were the most likely culprits.

 

today I tried to check the CTS today but not sure if my multi meter is the right kind and not sure if I'm looking at it right.

 

Based on this info I have a couple of questions:

 

What's the most likely culprit for the racing at start and fast idle?
Is there an easy way for me to read the RPMS since my truck doesn't have a tachometer?

 

Thanks, D

 

PS - I'm working on wiring an LED array into my stock bed light assembly so I get both brake lights and bright bed light. I'll post a how too once I get it done.

Link to comment
Share on other sites

Check the throttle linkages and lube them up, The spring on my throttle body was not fully closing after letting off the gas and causing me to stick at a higher than normal idle, I was able to pull it closed from under the hood ad throttle body and my idle would return to normal... so I attached a generic return spring from slot on the arm of the throttle body to a spot on the fuel rail and its been working great. The linkage on these renix seems pretty sketchy with the little plastic socket and what not mine seems to sit on there pretty loose, but hey whatever works!

Link to comment
Share on other sites

Cruiser54: I'm honored to get your advise. I completed #1 today and then started 5. I'm getting about 5 ohms from the B connector on the TPS to the negative battery terminal. When I wiggled the C101 it fluttered around 12 and when pushing up hard on the C101 I got 100 ohms for a little bit. I opened the C101 and cleaned it with 1/1 a can of brake cleaner. After putting it together and wiggling the highest Ohms I got was 12.

 

Q: What the highest resistance reading is ok?

 

Thanks, D 

Link to comment
Share on other sites

Cruiser54: I'm honored to get your advise. I completed #1 today and then started 5. I'm getting about 5 ohms from the B connector on the TPS to the negative battery terminal. When I wiggled the C101 it fluttered around 12 and when pushing up hard on the C101 I got 100 ohms for a little bit. I opened the C101 and cleaned it with 1/1 a can of brake cleaner. After putting it together and wiggling the highest Ohms I got was 12.

 

Q: What the highest resistance reading is ok?

 

Thanks, D 

Less than 2. 

 

Read post 27 and see if you're comfortable doing that. I've seen incredible improvements doing that. One is an oxygen sensor I was monitoring with the factory scan tool and was gonna condemn for it being lazy. Something inside said to wait until the C101 elimination was done. Guess what? O2 sensor was reading like new..Hmmmmm. 

Link to comment
Share on other sites

Cruiser54: I have thought a lot about doing #27 and I am up to it. I have resisted the idea because I have a kind of fanatical desire to keep the truck as close to original as possible. I need to finish the rest of your last suggestion (1, 5, and 8) and I was thinking I'd do #6. I also didn't use a pick to adjust the female connectors. Thought I'd struggle through that as well. I know I can trust your advice, do you think doing #27 trumps my "original" fanaticism?

 

Also, I have found several things wrong that were clearly caused by the PO (I think his name was Uncle Bob). Jeeper's suggestion got me thinking maybe the PO had set the idle using the stop. I took off the air cleaner and saw that the butterfly in the TB was open a bit. I did #14 and the idle dropped down to normal sounding. I'm going to get a tach so I can tell you what the RPM's are.

 

Currently when I start up the RPMs flairs for what seems like too long then settles into the right idle. I'm wondering how long is a normal flair?

 

Again, thanks a ton. Really appreciate your help.

Link to comment
Share on other sites

I was hoping to keep the c101 in place. Here's my idea. Get a second c101.  pull all connectors, Drill holes where all the connectors were. Follow 27 but instead of using shrink tube I fish the wires through the holes in the second c101 and solder in the middle, leaving them exposed for now. Once all the solders are done, seal and secure them with epoxy to the firewall side of the c101 body. Bolt the c101 back together. Attach to firewall. Done.

 

I'm leaning toward this but not convinced my desire to retain original parts warrants the extra effort. Anyone, thoughts? 

Link to comment
Share on other sites

Yesterday,Based on your lack of enthusiasm for retaining the c101 I decided to do 27 as written. I picked up some shrink tubes and got started. While disassembling the c101 In preparation I got a new idea. I completed each wire one at a time exactly as instructed, except I pushed the connectors out of the firewall half of the c101 and threaded the wire back through the hole left by the missing connector. Once all the wires were soldered I took the two connector blocks that make up the non firewall side of the c101. I removed the connectors then used soldering iron to hollow out the interior of each, I then used a sharp blade to cut a slot lengthwise down the side of each so I could wrap them around the wires to reinstall. I have it all back together and save for the two impossible to notice seams it looks and works great. The whole thing took me less than 2 hours.

 

My resistance from TPS to negative battery terminal is now 0.2 ohms

 

I then tried to adjust the TPS. I got 4.92v as my reference. So I calculated .836v should be my output at idle. The best I can seem to adjust it too is about .75. Is that closed enough? Should I try something else?

Link to comment
Share on other sites

Interesting twist on the C101 elimination. 

 

One thing I am concerned about is that the crimps in the ground circuit are still there. Post 6 helps you narrow this down.

 

How does it idle with the TPS set at .84? Are you shooting for .75 for some reason? 

Link to comment
Share on other sites

Sorry, forgot to mention I did the #6 update as well. I went out this morning and got the TPS adjusted to .85v. Seems to be idling fine. Still waiting on my brother for a tachometer.

 

I have now completed 1, 5, and 8 as per your recommendation above. Below I've listed 1- 27 noting what I've completed and what I'm planning. I also thinking I'm in a good place to do the tests listed on http://www.lunghd.com/Tech_Articles/Engine/Basic_Sensors_Diagnostics.htm

 

Would love for you to review and offer a recommendation for next steps or change of plans.

 

1 - Done, but, didn't replace the braided wire. Not urgent in my mind, but, thinking I will upgrade grounds and battery cables as per www.kellyswip.com at some point in the future.

2 - Done - now moot since I did 27

3 - A while ago I did a less than perfect attempt and skipped the lights). Now that I'm more aware of the sensors etc I'm planning on doing #3 more meticulously.  

4 - Wondering if I should do even though I'm not having starting issues.

5 - After doing 27 and 6 now getting .2 ohms

6 - Done

7 - pending - not urgent

8 - Done

9 - pending - not urgent

10 - pending - not urgent

11 - done. replaced IAC

12 - pending - not urgent

13 - not planning on this

14 - Done -

15 - had the rear main seal, pan gasket, and valve cover gasket replaced by a shop when I bought it.

16 - Don't have a vacuum gauge and had the cat and muffler replaced. Don't think I have problem here.

17 - I want to keep my Renix a Renix

18 - pending

19 - pending - Wondering where I get a supplemental headlight harness?

20 - N/A

21 - Done

22 - replaced 715-1365, 715-1367 was still good.

23 - not planning and wonder why I would want to do it

24 - Engine is original

25 - Pending - going to do this soon.

26 - Pending

27 - Done!!!

 

As always I really appreciate the advice!!!
D

Link to comment
Share on other sites

4,10,18 done. I'm Waiting for 19 to arrive.

 

I checked the rotor and distributor cap.  Two of the contacts have grooves cut into them. Po said he'd done a tune up. The distributor looks new to me and doesn't seem sloppy, but, I'm not experienced. Thinking I'll start with new cap and rotor.

Link to comment
Share on other sites

4,10,18 done. I'm Waiting for 19 to arrive.

 

I checked the rotor and distributor cap.  Two of the contacts have grooves cut into them. Po said he'd done a tune up. The distributor looks new to me and doesn't seem sloppy, but, I'm not experienced. Thinking I'll start with new cap and rotor.

Maybe poor quality cap?

 

With the engine running, does the distributor wobble at all?

 

Use only cap and rotor with brass contacts.

Link to comment
Share on other sites

didn't see or feel wobble and contacts aren't brass. replaced with quality stuff today. will check again after a few miles.

 

Another question, I'm getting a knocking sound. I ran some seafoam and changed the oil today. Might be louder. Took it up to a neighbor who has 3 jeeps with 4.0 of various vintage. Told me to ask cruiser if the rockers are adjustable.  

 

Btw with everything I've completed and especially your help it's running great. Seems to be shifting perfect. Thanks

Link to comment
Share on other sites

didn't see or feel wobble and contacts aren't brass. replaced with quality stuff today. will check again after a few miles.

 

Another question, I'm getting a knocking sound. I ran some seafoam and changed the oil today. Might be louder. Took it up to a neighbor who has 3 jeeps with 4.0 of various vintage. Told me to ask cruiser if the rockers are adjustable.  

 

Btw with everything I've completed and especially your help it's running great. Seems to be shifting perfect. Thanks

Glad to hear it's running better. Rockers are not adjustable however. Shine a light into the oi lfiller hole and see what kind of sludge build-up there is on the rockers etc.

 

Seafoam in oil or through the intake? 

 

Auto trans? 

Link to comment
Share on other sites

Fram. When I was at tims yesterday his buddy was there, he was an experienced mechanic. Both said they though I was getting excessive noise from the valve train. I have a stethoscope. It all just sound like ticking to me. I checked out the how to and watched the video. I'm thinking quite likely I have that problem too. I'm going fix the flex plate. Worst case I get that area clean. D

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...