99 Jimmy Idle problem. - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 10-05-2005, 06:25 AM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
99 Jimmy Idle problem.

1999 GMC Jimmy 4.3 (W) 4L60E 3.42 geared 4WD.

Problem: Engine starts normally, idles normally, then begins a slight stumble varying the idle rpm's, but seemingly not out of the ordinary, if transmission is shifted into gear (any) it has NO power and stumbles with a very noticable roughness and acts like there is a backfire condition. This is "slightly" eliminated by rapidly feathering the throttle.

Temporary Solution: I start the engine, and raise the engine to around 1500 or 2000 for roughly 30 seconds, then let the engine idle and shift into gear and drive normally.

The wife has told of a power loss around 45 mph, but I have driven the Jimmy more than her and I have not experienced it as of yet.

I have no real test equipment to speak of and am more than prepared to use the multimeter to check the IAC, TPS, O2 sensor, and the likes, I just have little information in the Haynes manual to go on to check these.

I have heard there is a major problem with the fuel injection lines possibly splitting and the poppet balls sticking, but the symptoms do not seem to point to these.

The PCM shows no codes with a OBD II reading Actron scanner.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 10-05-2005, 07:33 AM
1931 steve's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild an engine Last photo:
Join Date: Nov 2004
Location: Michigan
Age: 42
Posts: 1,207
Wiki Edits: 4

Thanks: 0
Thanked 0 Times in 0 Posts
Like you said the fuel injection set up on this engine is known for problems. usually it causes a hard misfire. Have you checked fuel pressure, fuel pumps go bad quite often in these also. Fuel pressure should be at 60-66 psi with key on engine off. How long does these symptoms stay or do they never go away?

Quote:
Temporary Solution: I start the engine, and raise the engine to around 1500 or 2000 for roughly 30 seconds, then let the engine idle and shift into gear and drive normally.
This sounds like maybe you have some injector poppet's that are stuck open and you are just clearing out the unspent fuel. Sometimes they (poppet valves) will start to work after the engine warms up.

Do you live in California by chance or does the truck have Cali emission system on it? if it does they (GM) has a recall on the injection set up.
Hope this helps, I will try to help as much as I can.

Steve
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 10-06-2005, 06:08 AM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
Quote:
Originally Posted by 1931 steve
This sounds like maybe you have some injector poppet's that are stuck open and you are just clearing out the unspent fuel. Sometimes they (poppet valves) will start to work after the engine warms up.

Do you live in California by chance or does the truck have Cali emission system on it? if it does they (GM) has a recall on the injection set up.
Hope this helps, I will try to help as much as I can.

Steve
I don't live in CA, Pennsylvania, but the Jimmy has the RPO code NC1 indicating: EMISSION SYSTEM, CALIFORNIA, LEV .

I'll have to check with the local GM dealer on this before spending any $$$.

I have tried to check initially the IAC valve operation or lack thereof by disconnecting it.
With the engine warm, disconnecting the IAC connector & starting the engine it actually seemed to run better, I have waited for it to cool down to check it again cold, I will go out right now to check it and type the results. . . . .
I didn't allow it to cool to a fresh start situation, but disconnected the IAC wiring, and drove it 1 mile and stopped, the engine acted as before (normal because it was still warm), when I stopped and shifted into park the engine went to a high idle.

I opened the hood to reconnect the wiring to the valve and drove it back home, it had a slight stumble when taking off from the dead stop, but acted normally as before.

I will let it fully cool and try again later as the problem only presents itsself then.

I will also check on the CA emissions recall too. does anyone have the recall campaign number?
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 10-06-2005, 08:31 AM
1931 steve's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild an engine Last photo:
Join Date: Nov 2004
Location: Michigan
Age: 42
Posts: 1,207
Wiki Edits: 4

Thanks: 0
Thanked 0 Times in 0 Posts
Recall # 99066F

I read the campaign wrong, from what I get from the campaign is the vehicle needs to be registered in California. Sorry

It does list a injector cleaner GM part #12345104 It is stated that this is the ONLY cleaner that has any effect on the poppet valve deposits.
If you would like I can fax you these TSB. Sorry AllData will not let me copy
and paste there info, too much to retype. Send me a PM with your fax #

Steve
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 10-06-2005, 05:08 PM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
Only one problem with a fax right now, I just put a new printer/fax/copier/card reader in service here, and that is one of the things I still have yet to take the time to figure out.

I'll work on it and drop the PM to you.

Does anyplace else post TSB's for free?

I did a cold start with the IAC disconnected, and there was little change? EXCEPT for the fact I seemed to have a little more power? along with the high idle.

I was only able to set one trouble code, and that was unintentional as I knew I did it when it happened.

I was unable to check the injector harness with the limited noid light set I have, but I do not believe there is a problem with any of the injectors NOT working.

I have to make two service appointments for a two vehicles here and they are at two different dealers, and will make sure to ask if there is anything they can do for me as to what I should look for on the Jimmy. I will make sure to hit up the salesman to get any freebie work done that I can, he owes me one already anyway.

Also, should it start & run that easily with the TPS connector disconnected too?
__________________________________________________ ________________

I am researching the TSB's on the NHSTA website.

Last edited by M&M CUSTOM; 10-06-2005 at 05:29 PM.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 10-06-2005, 05:55 PM
1931 steve's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild an engine Last photo:
Join Date: Nov 2004
Location: Michigan
Age: 42
Posts: 1,207
Wiki Edits: 4

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Does anyplace else post TSB's for free?
Not sure if anyone does.

Quote:
Also, should it start & run that easily with the TPS connector disconnected too?
Yes, it should make no difference at start up with the TPS unplugged. It will set a light on.

Do you have a fuel pressure tester. If so leave it hooked up for the cold start, and see if by just turning the key to the run position if the fuel pressure holds steady or if it drops off, if it drops off you have a sticking poppet injector.

I hope we are on the right track by assuming that it is a fuel related problem.

Steve
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 01-22-2006, 09:02 AM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
I have not completely found this problem's cause OR the solution.

BUT, I have only put a few hundred miles on the Jimmy since then, I had to R&R the heater core because of the wonderful effects of GM's Dex-Cool clogging up the cooling system and specifically the heater core.

Backflushing the entire cooling system and in particular different portions of it did nothing more than remove the immediate loose stuff. I went up to a full chemical flush, which did little because of the vague directions on the bottle, and eventually repeated for the recommended PROLONGED timeframe, which broke a bunch more crud loose.

I ended up saving myself $1200 at the dealer and removed the entire dash to get the heater core out of the vehicle to chemically clean it and to make sure it wasn't going to leak because this was going to cost me $140 if it did.

I sent several gallons of water under pressure in both directions through the core, and treated it to several different chemicals, fully flushing the core in between treatments. I was finally satisfied with the results and re-installed it in the vehicle.

I found an agricultural chemical sprayer screen type filter that would accept fittings large enough to be installed into the heater hoses, and routed the hoses through the filter, but not through the cleaned heater core, and then a full dose of cooling system CLEANER for a whole week (which is still within the recommended timeframe. I pulled the screen out of the filter after each drive and cool-down cycle and was surprised at the amount of junk I removed from it. I removed what resembled small rust FLAKES and chunks of sediment that couldn't be good for anything at all.

When the filter stopped collecting this crud, I finally went through the task of flushing the cooling system, then I backflushed, and I flushed individual portions of the entire system until I found nothing coming out but water.

I removed as much water as I could, replaced all hoses and plugs, and included the filter as a full-time part of the system then with the information that the system held a total of 12 quarts I added 6.75 quarts for a slightly more than 50% solution for the conditions it would be up against here in the area where I live, and then added water to make up the difference.

The main difference in the system now is that I got rid of every trace of the problematic orange Dex-Cool coolant, and added a properly mixed solution of green ethylene-glycol coolant.

I have since handed the keys over to the wife and she has put several hundred Miles on it and has no complaints about the heating capabilities inside the vehicle.

I still haven't completely found the problem with the stumble off idle yet. . .
Attached Thumbnails
Click image for larger version

Name:	Dex-CoolResidue.jpg
Views:	95
Size:	64.2 KB
ID:	9472  

Last edited by M&M CUSTOM; 01-23-2006 at 07:00 PM. Reason: Adding picture.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 01-22-2006, 09:44 AM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
I have since then, installed a fuel pressure gauge, and found that the key-on-engine-off reading was at the lower end of the recommended pressure range.

The engine running at idle reading was low, and the rev-throttle low end reading was below the low end of the recommended range.

I am also replacing the original factory installed 78,000+ miles ago, cap/ rotor/ wires/ & plugs, and as long as I'm at it fuel pressure regulator, removing and cleaning the throttle body as it's VERY dirty inside and out.

I have seen what to look for when I remove the throttle body, to determine if anything with pressurized fuel is leaking under the upper intake manifold, and have the gasket set to make those determinations and repairs if necessary, the only things I will have not replaced by the end of today are the fuel pump and the 6 injectors.

I have also gotten the recommendation to pull the linear EGR valve and chech to make sure it isn't plugged, I have been told that it will be more than obvious if it is working because there will be signs of the valve's movement.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 01-23-2006, 06:39 PM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
Cap, rotor, plugs, and wires are changed. The plugs were the only things that weren't factory original. I have never seen build-up on the cap and rotor posts like these had.

The whole thing took over 4 hours, with the plug on cylinder three being over 1 hour in itsself because of what was in it's way.

The throttle body cleaned up quickly with a little paint thinner to loosen the crud and a wire brush on my dremel.

There is a difference but there is still the fuel pressure regulator to work on changing.

While I had the thottle body off the upper manifold, I noticed there looked to be some fuel washed areas in the lower manifold, so while I have the manifold halves apart to change the regulator, I will also try and check the injectors for sticking poppet valves. This may have to wait until this weekend.

I have gotten OBD II codes P0171 (bank 1 lean condition) and P0172 (bank 2 lean condition) twice now, the second time just hours before the ingition tune-up. This thing was using gas at a rate of 11-12 miles per gallon while I was doing the majority of the cooling system cleaning, and isn't much better now. I also had a P0300 (random/ multiple cylinder misfire detected) but I had wires 3 and 5 crossed, I know, something I should have checked more accurately before starting it.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 02-05-2006, 08:01 PM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
I changed the left and right bank oxygen sensors this afternoon as well as the fuel filter.

The recommended mileage for the sensors is 60,000, and it has 78,000 on the clock.

The filter will be cut apart tomorrow to look inside, it still flowed freely but a change for $9 couldn't hurt anything.

I will change the after catalytic converter oxygen sensor when I get that one, they had to order it from another store.

Next will be the fuel pressure regulator, snow with a 12 MPH wind and 26 degrees said no today, the wind and rain yesterday said the same thing.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 02-06-2006, 06:50 AM
1931 steve's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild an engine Last photo:
Join Date: Nov 2004
Location: Michigan
Age: 42
Posts: 1,207
Wiki Edits: 4

Thanks: 0
Thanked 0 Times in 0 Posts
If you are at the low end of the fuel pressure readings, just replace the fuel pump assembly, They are pricey at about $300.00 + give or take. I would suggest that you buy a Delphi or Delco if you can, I just replaced the pump assembly last week in my wifes Jimmy. My cost at a discount was $275.00 for the Delphi unit. Did I miss the reason why you are replacing the FP regulator?

Steve
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 02-07-2006, 09:40 AM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
The regulator is a must if there is a fuel washed area around it, which is only evident after the upper manifold is removed, which I haven't done yet.

And since I have the upper off to check, I already have the regulator.

I don't like the price of the stock fuel pump, and the warranty period is the same as the others. A Master E3992M at the local parts place is $264.44, but I have only checked 1 of the 5 parts places in town.

I used a Master pump when the Caravan needed a new one after our local refinery put out some bad gas, they offered to pay for repairs, but my luck- I had already changed mine and their offer was not grandfathered to repairs already done without receipts from a garage they had authorized. I ran it for 2 years without problem (from the fuel system- anyway).
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 02-07-2006, 09:23 PM
1931 steve's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild an engine Last photo:
Join Date: Nov 2004
Location: Michigan
Age: 42
Posts: 1,207
Wiki Edits: 4

Thanks: 0
Thanked 0 Times in 0 Posts
[QUOTE=M&M CUSTOM]The regulator is a must if there is a fuel washed area around it, which is only evident after the upper manifold is removed, which I haven't done yet.

I must have missed what you said about the fuel wash. if that is the case yes replace the FP regulator. When you order the pump assembly, make sure you tell them it a 2 door or 4 door model, it does make a difference.

Steve
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 02-08-2006, 06:03 AM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
[QUOTE=1931 steve]
Quote:
Originally Posted by M&M CUSTOM
I must have missed what you said about the fuel wash. if that is the case yes replace the FP regulator. When you order the pump assembly, make sure you tell them it a 2 door or 4 door model, it does make a difference.

Steve
The only ways to check the lower manifold for fuel wash are small snake flashlight and a dental mirror, or remove the upper manifold from what I can see, I couldn't see much at all when I had the throttle body off to clean it.

I seen that there was a difference between the pumps for the 2 & 4 door models BUT there is also a notation to replace some section of wiring harness as *highly recommended* from more than one source. What section of harness is this referring to?

I haven't yet gone to get the third oxygen sensor yet, the Jimmy runs better with a slightly noticable gain in mileage- but the off idle engine cold stumble is there at much less of a strength.

I also noticed that when coming to a stop, the idle does not go down as low as it should (1200 rpm's).

This is really stumping me as I don't have a multi-meter to check anything with at the moment.

Absolutely NO SES codes as of yet either.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 02-12-2006, 08:57 AM
M&M CUSTOM's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Transmission identification
Last journal entry: 1988 Suburban, the project continues.
Last photo:
Join Date: Mar 2003
Location: Northwest Pennsylvania.
Age: 42
Posts: 2,230
Wiki Edits: 9

Thanks: 0
Thanked 1 Time in 1 Post
As of yesterday:

Third oxygen sensor changed, with a little more mileage back to where it should be.

Fuel pressure regulator changed, took 3 hours, and there was a section of the rear portion of the lower manifold that was fuel washed, as long as it was out I cleaned the upper manifold, and removed built up gunk from the ends of the injector nozzles.

I used just a quarter tank of gas through it last night, and am at the point in miles where it was down around the halfway mark so the mileage has increased dramatically.

I still have that pesky stumble at/ and off idle, and I noticed that when I removed the throttle body that the IAC valve didn't look like it had been seating, If I could test this (still haven't found a good enough multimeter to replace my old one) I could replace or rule this out. It DOES however go through the motions of resetting itsself, I disconnected it and drove a mile, connected it and drove it again and it brought the idle back down to where it should be.

Next step for this is either buy the software and cables for reading OBD II, or take it somewhere and have tham charge me too much.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Help! Jeep Idle Air Control 68NovaSS Engine 1 09-16-2005 04:17 AM
Performance cam with a 2 corner idle Holley DP 650 Mad Maggot Engine 15 08-02-2005 06:04 AM
Pontiac 250 idle problem youngbw Engine 1 07-07-2005 07:30 PM
Stumble off idle in park, carb or ignition problem Dubz Engine 3 05-18-2004 10:29 PM
Q jet won't idle! Trav Engine 6 11-13-2003 06:44 PM


All times are GMT -6. The time now is 09:13 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.