Idle Probs (have done research)

[FoxBod93]

Okay first off I have done plenty of searches on corral, and some here.

I have a 91lx. I have just recently had some mods done to it. Now the car idle surges, and wants to dies on me. It does not do this all the time, but enough. I thought it may be the IAC, so I bought a new one. It didn't help. I swapped out the MAF with one from my old car (57k miles on it) it didn't help either.

Is there anything else I can do. The TPS needs to be checked, but I don't think only that would cause the car to act so funny. It drives fine. Only while I'm sitting at a light or in neutral does it surge/die.

Only thing I can think of is sensors (o2 maybe). I didn't use an EGR due to the cobra intake. I was told I wouldn't need one. The car has no Smog pump either.
Anyone with any experience with this problem please give me advice.

Thanks.

 

[FoxBod93]

Bump.

 

[jrichker]

Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 88 or earlier stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

 

[GoldenEye]

I'm having some of the same problems as foxbod93 although my car is completly stock. Question: are there codes even if the check engine light is not on?

 

[jrichker]

I'm having some of the same problems as foxbod93 although my car is completly stock. Question: are there codes even if the check engine light is not on?

YES. The computer stores codes picked up on the fly as the engine operates.

 

[Icepick]

Is there anything else I can do. The TPS needs to be checked, but I don't think only that would cause the car to act so funny. It drives fine. Only while I'm sitting at a light or in neutral does it surge/die.

I just went through this, it was my TPS, it's voltage was almost 4, I replaced it with a new one from the dealer and all is fine.

 

[88_GT_5_oh]

i had this same problem, and i read on this site that the two "salt and pepper shaker" connectors on the back of upper intake sometimes loose contact and make it idle funny. I unclipped them and cleaned the pins and it actually fixed this problem for me.

heres that article
http://www.fordmuscle.com/archives/2002/01/tenpin/index.shtml

 

[FoxBod93]

Thanks for the info guys. First thing I'll do is set the TPS, I'm for sure it's off. Then I'll check the codes.

Thanks again.

 

[FoxBod93]

Well I went and had autozone check the codes. Just out of curiousity...here is what it said.

16). 1 9L & 2 5L - Throttle stop set too high - IDLE or Idle Set Procedures
66). Vane Air Flow (VAF) or Mass Air Flow (MAF) signal low - VAF MAF
71). 1 9L TBI, 2 3L TBI, 2 5L TBI - ITS signal was grounded when throttle should have been opening ITS-ISC ISC motor problem or Idle Tracking Switch (ITS) signal wire shorted to ground - ISC
76). Vane Air Flow (VAF) did not respond to "goose" test - VAF

Any Suggestions?

 

[jrichker]

Well I went and had autozone check the codes. Just out of curiousity...here is what it said.

16). 1 9L & 2 5L - Throttle stop set too high - IDLE or Idle Set Procedures
66). Vane Air Flow (VAF) or Mass Air Flow (MAF) signal low - VAF MAF
71). 1 9L TBI, 2 3L TBI, 2 5L TBI - ITS signal was grounded when throttle should have been opening ITS-ISC ISC motor problem or Idle Tracking Switch (ITS) signal wire shorted to ground - ISC
76). Vane Air Flow (VAF) did not respond to "goose" test - VAF

Any Suggestions?

The codes do not match the engine you have in your sig. Th AutoZone guy must have set the scanner for a 4 cylinder car, because from the descriptions, those are all 4 cylinder codes. The only useful code is the 66, which is a MAF problem.

Code 66 MAF below minimum test voltage.
Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF (usually pins A & B).

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element casing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer.

At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF and ground.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

 

[FoxBod93]

The codes do not match the engine you have in your sig. Th AutoZone guy must have set the scanner for a 4 cylinder car, because from the descriptions, those are all 4 cylinder codes. The only useful code is the 66, which is a MAF problem.

thats what I thought also...all well I couldn't really expect a whol lot of help from 'em


Thanks for the info though

 

[topdri]

There was allot of good information in this thread. I have an 89 LX 5.0 and have been experiencing this idle surge problem too. I just replaced the IAC last night and it actually seemed worse this morning. It surged up as high as 2500 RPMs and stuck there. Very dangerous!

The only difference between me and the rest of the posts is that when I turn the car off and back on, the idle surging stops completely or so it appears. Given this - would I fall in the same category as the information in this thread? The only new mods over the past week or so have been a BBK Cold Air Induction System and 373s. That is it!

I am going to Myrtle Beach on Thursday morning for Stang Week and do not have much time to deal with this problem. Thanks for your help!

 

[FoxBod93]

Yea, I still need to set the TPS. I'm probably going to change the MAF, and put a new fuel pump in it. This is probably overkill, but good maintenance anyhow.

 

[jrichker]

There was allot of good information in this thread. I have an 89 LX 5.0 and have been experiencing this idle surge problem too. I just replaced the IAC last night and it actually seemed worse this morning. It surged up as high as 2500 RPMs and stuck there. Very dangerous!

The only difference between me and the rest of the posts is that when I turn the car off and back on, the idle surging stops completely or so it appears. Given this - would I fall in the same category as the information in this thread? The only new mods over the past week or so have been a BBK Cold Air Induction System and 373s. That is it!

I am going to Myrtle Beach on Thursday morning for Stang Week and do not have much time to deal with this problem. Thanks for your help!

See http://www.members.tripod.com/spark...igh and sticks until you shut off the engine.

 

[FoxBod93]

Well I had My TPS set...it was at 85.
Come to find out the source of all my problems was simple. Go figure.
Looks like the butterfly on my T/B was sticking, causing the car to die. Simple fix. Car runs fine now...or so it seems

 

[GoldenEye]

I had decided I wouldn't tell anybody what I did this last weekend but it's too stupid to let pass. I set my TPS up, got it to around .94 and wouldn't go anymore. Decided I would also clean the throttle body so I went and bought some of that Pyrol stuff. I take the bellows off and put the little spray tip on the can and start to spray in the TB. So I open the TB to WOT and start spraying. Suddenly the f'ing tip come off and shoots straight into my intake. Man I just stood there for about 2 minutes thinking about how I'm going to have to take off the entire intake because of this. I'm just besides myself at this point so I start to think of ways to fish this thing out which I can't see, feel, and have no idea how far in or how deep this thing could have landed. First I tried to take a coat hanger and put tape on the end to stick this thing, problem was the tape got oily and slid off the end of the hanger inside the intake (at this point I was about ready to throw my cigarette in there as well and end the entire thing). So I go get a the shop vac and try to suck the treasures out but the hose won't fit. So I find some heater hose and tape it to the end of the vacuum hose and shove it in there and after about 5 minutes of looking like a fool while all my neighbors watch me vacuum my engine i shut off the vacuum and take it apart and see that I was successful. I got the spray tip and the tape out of the intake. So, there's my idiotic episode of the month. I get ahead of myself sometimes.

 

[D347643]

haha it happens man

 

[90whitepony]

My car seems to be doing the same thing but the weird part is it all started at the track last weekend.I made one run parked it in the staging lanes I get back in to go for anouther run look at my voltage gauge reads 9 volts so low and behold my alternater went crapped on me.So I go to the parts store get anouther one put it on now the thing will not idle at all.It ran great before even witht he thing at 9 volts.It pretty much killed the battery sitting in line till I could get out.I have an air/fuel gauge and it seems to be leaning itself way out so bad that only the last led is barely lit.I pulled a few codes out of it 33,85,44,94,21 the only one that bothers me is the egr code.Also I just out a clutch in the night before is it possible I screwd one of the o2 sensors up.But it is like I said it ran fine before the alternater went.

 

[topdri]

Ok - after spending hundreds of dollars in parts in order to find my idle issues, it ended up being the cars brain that was bad. On a last ditch effort, I spent $200 on a replacement brain for the car and so far everything is working. The idle goes right back to 750 and does not stick. I will feel better if the idle still works after a week. I will be in touch. I decided to do this because my mechanic has a friend that swapped out brains between two mustangs and the idle problem moved to the other car. This guy also spent hundreds of dollars before doing this.