My car all but died and won't wake back up!?!

DRASTiK · 05-15-2002, 01:33 AM

My car has been running very well for the past few months and all of a sudden today something happened. On the way to work, it was fine. On the way home for lunch, it was fine. I was driving back to work after lunch when I noticed the exhaust popping a little more than usual, and then when I got to work and pulled into a parking spot, I noticed it idling at about 500 RPM instead of the usual 800. It was so quiet that I could barely hear it running.

When I got back into the car to leave work, I started it up and it was popping and missing and had no power in the lower RPM's, and was just all around running crappy. The weird thing is that once I got up to around 3000 RPM, everything seemed fine until I let off the gas and it started backfiring all over the place through the exhaust. My first thought was that maybe a plug wire had popped off or a vaccum line had become disconnected. Of course it can't be that easy. I didn't have time to really try and diagnose it because I was trying to get to school (I go straight from work to school). I popped the hood and had a look around and didn't find anything obvious out of place.

It starts right up every time, and never stalls, but something is definately wrong. I know I should scan the codes before really trying to diagnose it, but I figured I'd post this in case someone has experienced this before. Between school and work (military), I don't really have much time during the week or on Saturday to do much, so I need all the ideas I can get ahead of time to try and squeeze them all in on Sunday when I'll try and fix it. Any ideas?? See sig for mods.

Dave

Mach 1 · 05-15-2002, 01:47 AM

My initial thoughts were MAF meter, but you might not have one being an 88'. Is your car speed density or mass air flow?

DRASTiK · 05-15-2002, 01:55 AM

My car has been converted to Mass air. I use a 73mm C&L with the 24lb sample tube. I thought about that as well, but hoped that wasn't the problem. The code scan should throw a flag for that when I do it. I'll be driving my wife's caravan until I get this resolved which is our only other vehicle, so hopefully this won't take too long.

It's kinda funny actually because just last week I was telling my wife "The car's been running great for a while, so knowing my luck, it's about time for something to go wrong with it." I think I jinksed (sp?) myself.

PKRWUD · 05-15-2002, 04:04 AM

I'd look into the MAF too. Popping in the exhaust, especially when letting off the throttle, is typical of a lean condition, and having it go away at higher rpm's had me thinking vacuum leak, but a vacuum leak will cause a stall during a hard stop, and you said it doesn't stall, so I'd look into the MAF.

Of course, I'd pull codes first.

Take care,
-Chris

KiltedBanshees93GT · 05-15-2002, 07:28 AM

My car burns oil in 2 cylinders, and will foul a plug now and then, and when it does it sounds very similar to what is happening to you. It will come on over the course of a day, with the car running just a bit rougher, and then next time I crank it, stumbling, popping, etc all over the place. My first instinct would be to check the plugs.

Just my $.02,
Jorge

DRASTiK · 05-19-2002, 11:18 PM

Well, I came back into town tonight and scanned the EEC for codes, but nothing out of the ordinary came about on the KOEO test. 81, 82, and 85 were there, but they always are because I have no emissions equipment. There was a continuous code of 51 (ECT), but I have no idea how old that is so I disconnected the battery to reset the EEC, and I'll scan it again tomorrow night.

The weird thing is that I tried a KOER test a few times, and it just beeped 5 times, and that was it. 5 is not a recognizable code, so I don't have a clue what that was all about.

I had to keep restarting it and keep my foot in it to keep it running until it warmed up and then it idled really low (about 500rpm) just like it was when I made this post.

If the 51 dissappears, then what should I look for?

I know the MAF was definately a suspect, but wouldn't that code have come up? The plugs all look fine and only have around 500 miles on them.

any help is greatly appreciated. I really would like to have this fixed by this weekend so I can attend a good friend of 5 years' graduation. I promised him a ride in the stang when he graduates over a year ago, and I don't want to let him down.
Thanks in advance,
Dave

Kamaro Killer · 05-20-2002, 01:58 AM

This probably doesn't help you much but, I had to pay someone to "look the other way" when passing my smog, and in doing so, they screwed my timing up really badly. I think they adjusted the timing somehow to pass me, and never put it back to the original setting of 10*.

DRASTiK · 05-20-2002, 07:26 AM

I would absolutely love it if that were the case. Unfortunately it isn't this time. My timing is at 14 and I haven't changed anything as far as the state of the tune of the car in about three months. I didn't put a timing light to it to ensure it hasn't jumped timing, but because it fires right up every time with no problems, I don't think the timing has moved. I didn't check it last night however.

DRASTiK · 05-21-2002, 09:44 AM

Can anyone tell me what voltages I should have at the MAF from the four wires connecting it to the EEC? Is there any other way to test it?

jimberg · 05-21-2002, 10:11 AM

I had the same exact symptoms one day and it was caused by the ACT. Since the ECT is similar, I would just go ahead and replace it. You may want to check the ACT as well. Start small and worry about bigger stuff later.

DRASTiK · 05-21-2002, 11:01 AM

Thanks Jim,

I'll replace them both and see what happens.

DRASTiK · 05-24-2002, 01:02 PM

well I replaced the ECT and the ACT sensors and then fired the car up. It still ran like crap at first but didn't stall like it usually does when it's cold. The idle would drop until it started to stall, then it would rev up to about 2500 real fast as if I pressed the accelerator, and then drop down to around 600 or so.

After about a minute of that, it started idling normal. I was extatic!! I took it for a test drive and it ran great for about 2 miles, and then it started the same old crap again. It's in the same condition it was before I replaced the sensors.

I scanned for codes again and got 81, 82 and 85 like I usually do, but had a continuous code of 15. I think I misinterpreted it the first time as being 51. I had disconnected the battery and cut the headlight switch on and left it for 30 minutes while installing the new sensors.

I'm lost again. I hope my EEC isn't fried because I just bought it less than a year ago. I've read that a code 15 (KAM) could be from a short in the wiring, a bad EEC, or from disconnecting the battery. That doesn't really narrow it down too much since I disconnected the battery to reset the EEC. I'm gonna pin out the EEC with a DMM to check the voltage with the KOEO, and that should hopefully tell me if it's an EEC problem or an wiring problem. Any other suggestions?

PKRWUD · 05-24-2002, 01:27 PM

That's a real easy test, but in case you aren't sure, I'll tell you what to do.

1) Disconnect the 60 pin connector from the ECM.
2) Test for KOEO voltage between pins 1 and 40 or 60 at the 60 pin connector. If you get 10.5 vdc or more, the ECM is bad. If you don't get 10.5 vdc, start tracing the wires and find the open circuit.

Take care,
-Chris

jimberg · 05-24-2002, 01:39 PM

I think you get the code 15 if you don't disconnect the battery long enough for the KAM to be completely cleared.

How long did you let the car idle after it started idling properly? How did the sensors you removed look?

DRASTiK · 05-24-2002, 01:50 PM

The sensors looked fine when I removed them. The ECT was only a few months old and neither one had any apparent corrosion or crud on them. The contacts all were very clean for the most part.

I started the car after reconnecting the battery and let it idle for about 1.5 minutes and I noticed it was running better, so I took it for an easy test drive for about 2 miles. During the drive it started running like crap again so I disconnected the IAB, and it shut off, which I assume means it's working, then I fired it back up and checked the TPS and it was fine, and the timing is still at 14.

DRASTiK · 05-24-2002, 01:51 PM

The sensors looked fine when I removed them. The ECT was only a few months old and neither one had any apparent corrosion or crud on them. The contacts all were very clean for the most part.

I started the car after reconnecting the battery and let it idle for about 1.5 minutes and I noticed it was running better, so I took it for an easy test drive for about 2 miles. During the drive it started running like crap again so I disconnected the IAB, and it shut off, which I assume means it's working, then I fired it back up and checked the TPS and it was right at 1 with no throttle, so I adjusted it down a little, and the timing is still at 14. Basically I was just shooting in the dark at that point.

jimberg · 05-24-2002, 02:20 PM

Try giving it some time to relearn the idle. Once it starts idling, let it idle for 10 minutes without intervention. Then shut it down for 5 minutes. Start it back up and turn on all accessories if you have any and let it idle for another 10 minutes.

Do all of this after resetting the computer. See how that works for you.

Mach 1 · 05-24-2002, 04:31 PM

Did you ever check the MAF meter voltage? You might want to set your timing back to 10 degrees until you get it worked out.

DRASTiK · 05-25-2002, 01:32 AM

No, I haven't checked the voltage on the MAF yet because I'm not sure what it should be. Which of the four wires should I test and what should the voltage be?

Mach 1 · 05-25-2002, 08:44 AM

Theres 4 wires, labeled A,B,C and D. They should be labled on the plastic piece. If not, let me know.

Wire D is the MAF SIG, or Signal to EEC-IV module.

Wire C is the MAF return or Signal return.

Wire B is is the vehicle power ground.

Wire A is the VPWR, or vehicle power.

1) Test VPWR and Ground:

With key off, disconnect MAF connector
- Connect DVOM (digital volt ohm meter) between VPWR and GND at harness connector
- turn key on, leave engine off

You should have 10.5 volts or greater.

If not, theres a fault in VPWR ciruit or in GND circuit to battery.

2) MAF circuit short to ground:

Key off
Connect DVOM between MAF SIG and MAF RTN, and MAF SIG and GRD at harness connector

Results- 10,000 ohms or greater

if not, fault in wiring to control unit or faulty control unit. (EEC-IV)

3) MAF sensor voltage

MAF sensor connected
- backprobe MAF sensor connector between MAF and battery negative(-) terminal
Engine running

0.2 to 1.5 volts dc

If not, MAF sensor may be faulty

05-15-2002, 01:33 AM	#1
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	My car all but died and won't wake back up!?! My car has been running very well for the past few months and all of a sudden today something happened. On the way to work, it was fine. On the way home for lunch, it was fine. I was driving back to work after lunch when I noticed the exhaust popping a little more than usual, and then when I got to work and pulled into a parking spot, I noticed it idling at about 500 RPM instead of the usual 800. It was so quiet that I could barely hear it running. When I got back into the car to leave work, I started it up and it was popping and missing and had no power in the lower RPM's, and was just all around running crappy. The weird thing is that once I got up to around 3000 RPM, everything seemed fine until I let off the gas and it started backfiring all over the place through the exhaust. My first thought was that maybe a plug wire had popped off or a vaccum line had become disconnected. Of course it can't be that easy. I didn't have time to really try and diagnose it because I was trying to get to school (I go straight from work to school). I popped the hood and had a look around and didn't find anything obvious out of place. It starts right up every time, and never stalls, but something is definately wrong. I know I should scan the codes before really trying to diagnose it, but I figured I'd post this in case someone has experienced this before. Between school and work (military), I don't really have much time during the week or on Saturday to do much, so I need all the ideas I can get ahead of time to try and squeeze them all in on Sunday when I'll try and fix it. Any ideas?? See sig for mods. Dave __________________ Dave 88 GT - 13.4@106 on street tires (2.2 60ft) My Stang RHC member #75 My stang is FOR SALE!!

05-15-2002, 01:47 AM	#2
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	My initial thoughts were MAF meter, but you might not have one being an 88'. Is your car speed density or mass air flow? __________________ 2002 GT 1993 GT (SOLD) '93 Mustang GT RHC member #142

05-15-2002, 04:04 AM	#4
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	I'd look into the MAF too. Popping in the exhaust, especially when letting off the throttle, is typical of a lean condition, and having it go away at higher rpm's had me thinking vacuum leak, but a vacuum leak will cause a stall during a hard stop, and you said it doesn't stall, so I'd look into the MAF. Of course, I'd pull codes first. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

05-19-2002, 11:18 PM	#6
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	UPDATE Well, I came back into town tonight and scanned the EEC for codes, but nothing out of the ordinary came about on the KOEO test. 81, 82, and 85 were there, but they always are because I have no emissions equipment. There was a continuous code of 51 (ECT), but I have no idea how old that is so I disconnected the battery to reset the EEC, and I'll scan it again tomorrow night. The weird thing is that I tried a KOER test a few times, and it just beeped 5 times, and that was it. 5 is not a recognizable code, so I don't have a clue what that was all about. I had to keep restarting it and keep my foot in it to keep it running until it warmed up and then it idled really low (about 500rpm) just like it was when I made this post. If the 51 dissappears, then what should I look for? I know the MAF was definately a suspect, but wouldn't that code have come up? The plugs all look fine and only have around 500 miles on them. any help is greatly appreciated. I really would like to have this fixed by this weekend so I can attend a good friend of 5 years' graduation. I promised him a ride in the stang when he graduates over a year ago, and I don't want to let him down. Thanks in advance, Dave __________________ Dave 88 GT - 13.4@106 on street tires (2.2 60ft) My Stang RHC member #75 My stang is FOR SALE!!

05-20-2002, 01:58 AM	#7
Kamaro Killer Mustang Enthusiast Join Date: Mar 2002 Posts: 528	this happened to me too.. This probably doesn't help you much but, I had to pay someone to "look the other way" when passing my smog, and in doing so, they screwed my timing up really badly. I think they adjusted the timing somehow to pass me, and never put it back to the original setting of 10*. __________________ 1993 GT 5.0-My Stang Rice Hater's Club Member 22

05-15-2002, 01:55 AM	#3
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	My car has been converted to Mass air. I use a 73mm C&L with the 24lb sample tube. I thought about that as well, but hoped that wasn't the problem. The code scan should throw a flag for that when I do it. I'll be driving my wife's caravan until I get this resolved which is our only other vehicle, so hopefully this won't take too long. It's kinda funny actually because just last week I was telling my wife "The car's been running great for a while, so knowing my luck, it's about time for something to go wrong with it." I think I jinksed (sp?) myself.

05-15-2002, 07:28 AM	#5
KiltedBanshees93GT Registered Member Join Date: Jun 2000 Location: Pigeon Forge Tn Posts: 611	My car burns oil in 2 cylinders, and will foul a plug now and then, and when it does it sounds very similar to what is happening to you. It will come on over the course of a day, with the car running just a bit rougher, and then next time I crank it, stumbling, popping, etc all over the place. My first instinct would be to check the plugs. Just my $.02, Jorge

05-20-2002, 07:26 AM	#8
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	I would absolutely love it if that were the case. Unfortunately it isn't this time. My timing is at 14 and I haven't changed anything as far as the state of the tune of the car in about three months. I didn't put a timing light to it to ensure it hasn't jumped timing, but because it fires right up every time with no problems, I don't think the timing has moved. I didn't check it last night however. __________________ Dave 88 GT - 13.4@106 on street tires (2.2 60ft) My Stang RHC member #75 My stang is FOR SALE!!

05-21-2002, 09:44 AM	#9
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	Can anyone tell me what voltages I should have at the MAF from the four wires connecting it to the EEC? Is there any other way to test it?

05-21-2002, 10:11 AM	#10
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	I had the same exact symptoms one day and it was caused by the ACT. Since the ECT is similar, I would just go ahead and replace it. You may want to check the ACT as well. Start small and worry about bigger stuff later. __________________ 351W 89 Mustang GT Convertible

05-21-2002, 11:01 AM	#11
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	Thanks Jim, I'll replace them both and see what happens.

05-24-2002, 01:02 PM	#12
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	another update well I replaced the ECT and the ACT sensors and then fired the car up. It still ran like crap at first but didn't stall like it usually does when it's cold. The idle would drop until it started to stall, then it would rev up to about 2500 real fast as if I pressed the accelerator, and then drop down to around 600 or so. After about a minute of that, it started idling normal. I was extatic!! I took it for a test drive and it ran great for about 2 miles, and then it started the same old crap again. It's in the same condition it was before I replaced the sensors. I scanned for codes again and got 81, 82 and 85 like I usually do, but had a continuous code of 15. I think I misinterpreted it the first time as being 51. I had disconnected the battery and cut the headlight switch on and left it for 30 minutes while installing the new sensors. I'm lost again. I hope my EEC isn't fried because I just bought it less than a year ago. I've read that a code 15 (KAM) could be from a short in the wiring, a bad EEC, or from disconnecting the battery. That doesn't really narrow it down too much since I disconnected the battery to reset the EEC. I'm gonna pin out the EEC with a DMM to check the voltage with the KOEO, and that should hopefully tell me if it's an EEC problem or an wiring problem. Any other suggestions? __________________ Dave 88 GT - 13.4@106 on street tires (2.2 60ft) My Stang RHC member #75 My stang is FOR SALE!!

05-24-2002, 01:27 PM	#13
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	That's a real easy test, but in case you aren't sure, I'll tell you what to do. 1) Disconnect the 60 pin connector from the ECM. 2) Test for KOEO voltage between pins 1 and 40 or 60 at the 60 pin connector. If you get 10.5 vdc or more, the ECM is bad. If you don't get 10.5 vdc, start tracing the wires and find the open circuit. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

05-24-2002, 01:39 PM	#14
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	I think you get the code 15 if you don't disconnect the battery long enough for the KAM to be completely cleared. How long did you let the car idle after it started idling properly? How did the sensors you removed look? __________________ 351W 89 Mustang GT Convertible

05-24-2002, 01:50 PM	#15
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	The sensors looked fine when I removed them. The ECT was only a few months old and neither one had any apparent corrosion or crud on them. The contacts all were very clean for the most part. I started the car after reconnecting the battery and let it idle for about 1.5 minutes and I noticed it was running better, so I took it for an easy test drive for about 2 miles. During the drive it started running like crap again so I disconnected the IAB, and it shut off, which I assume means it's working, then I fired it back up and checked the TPS and it was fine, and the timing is still at 14. __________________ Dave 88 GT - 13.4@106 on street tires (2.2 60ft) My Stang RHC member #75 My stang is FOR SALE!!

05-24-2002, 01:51 PM	#16
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	The sensors looked fine when I removed them. The ECT was only a few months old and neither one had any apparent corrosion or crud on them. The contacts all were very clean for the most part. I started the car after reconnecting the battery and let it idle for about 1.5 minutes and I noticed it was running better, so I took it for an easy test drive for about 2 miles. During the drive it started running like crap again so I disconnected the IAB, and it shut off, which I assume means it's working, then I fired it back up and checked the TPS and it was right at 1 with no throttle, so I adjusted it down a little, and the timing is still at 14. Basically I was just shooting in the dark at that point. __________________ Dave 88 GT - 13.4@106 on street tires (2.2 60ft) My Stang RHC member #75 My stang is FOR SALE!!

05-24-2002, 02:20 PM	#17
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Try giving it some time to relearn the idle. Once it starts idling, let it idle for 10 minutes without intervention. Then shut it down for 5 minutes. Start it back up and turn on all accessories if you have any and let it idle for another 10 minutes. Do all of this after resetting the computer. See how that works for you. __________________ 351W 89 Mustang GT Convertible

05-24-2002, 04:31 PM	#18
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	Did you ever check the MAF meter voltage? You might want to set your timing back to 10 degrees until you get it worked out. __________________ 2002 GT 1993 GT (SOLD) '93 Mustang GT RHC member #142

05-25-2002, 01:32 AM	#19
DRASTiK Registered Member Join Date: May 2001 Location: Yuma, AZ Posts: 536	No, I haven't checked the voltage on the MAF yet because I'm not sure what it should be. Which of the four wires should I test and what should the voltage be?

05-25-2002, 08:44 AM	#20
Mach 1 Registered Member Join Date: May 1999 Location: Georgia Posts: 3,866	Theres 4 wires, labeled A,B,C and D. They should be labled on the plastic piece. If not, let me know. Wire D is the MAF SIG, or Signal to EEC-IV module. Wire C is the MAF return or Signal return. Wire B is is the vehicle power ground. Wire A is the VPWR, or vehicle power. 1) Test VPWR and Ground: With key off, disconnect MAF connector - Connect DVOM (digital volt ohm meter) between VPWR and GND at harness connector - turn key on, leave engine off You should have 10.5 volts or greater. If not, theres a fault in VPWR ciruit or in GND circuit to battery. 2) MAF circuit short to ground: Key off Connect DVOM between MAF SIG and MAF RTN, and MAF SIG and GRD at harness connector Results- 10,000 ohms or greater if not, fault in wiring to control unit or faulty control unit. (EEC-IV) 3) MAF sensor voltage MAF sensor connected - backprobe MAF sensor connector between MAF and battery negative(-) terminal Engine running 0.2 to 1.5 volts dc If not, MAF sensor may be faulty __________________ 2002 GT 1993 GT (SOLD) '93 Mustang GT RHC member #142