Help Another Surging Mustang

z3beemer · 08-22-2002, 06:13 PM

Ok, out of ideas and need some help from all you experts out there. 95gt 5.0 pretty much stock other than air intake, pulleys and Xpipe. Been running fine and no new mods. Car starts surging and running rough at idle once the thermostat open and even get worse when the fan kicks on. Stalls sometimes when coming to a stop and even surges at times at cruising speeds. So far we code scaned all OK on hard codes and engine run codes; get a 211 and 213 as stored codes. Have changed tfi module, coolant temp module, cap and rotor. Still same problem. Checked for ground and vacuum leaks, none found. One other symptom. when disconnecting the SPOUT and attembting to check base timing the timing light only seems to light once couple revelutions but lights consistently with the SPOUT connected. Could this be a fuel pump; filter; regulator or injector problem?
I originally rule this out because the problem doesn't show up until the thermostat opens. I'm out of ideas.

Thanks in advance for the help!
Paul

Mustang_289 · 08-22-2002, 10:24 PM

if your car has speed density on it then that is your problem. i had same problem on my car with speed density. it would diel real rough and at times it would not idle when i came to a stop. and then some times it ran great. i suggest (if you have speed denstiy ) to go and get a stock filter put it in and then save some money and get mass air. and then go crazy modding it. once i put a stock filter on and took off my k&n it ran fine.

94cobra2 · 08-22-2002, 10:43 PM

he does not have a speed density. its maf. Its your computer, 94-95 computers have problems with idle surge once you make some modifications. Their was a artical in MM&FF about the idle problem they had after installing edelbrock heads,cam,intake on a 94 GT. Their solution was to swap out the computer for a 93 computer and no more idle surge. I'll dig up the artical tonight and post more info tomarrow. I have not had a problem with idle with my car. It does bonce a little bit but nothing like you mentioned. Scott BTW. The timming gun should light when the #1 spark plug wire fires with or with out the spout connected.

jbakes · 08-23-2002, 09:12 PM

I finally just got mine to stop today. Rotate the mass air counter clock wise, that is all it took for me.

Hozer 88GTConv · 08-23-2002, 11:34 PM

One thing I noticed you said was "once the thermostat opened" it idled rough.
That's when you O2 sensors start talking to your computer. They are open looped until then.
Have you checked/replaced them? Are they OEM? Just an idea...Good luck.

z3beemer · 08-29-2002, 10:09 PM

Thanks to all for your input. Unfortunately (I hate to admit defeat) I decided to break down and take it to the shop. I have a guy who is pretty good and doesn't rip you off so I surrendered! At the rate it was going I was just guessing and changing parts so it was getting expensive. Turns out the problem was bad / broken pickup coil in the distributor and it was hitting the reluctor. The new pickup coil was only $65 but with the analysis and labor the total bill was $185. Not too bad.

I though I'd pass the info on in case someone has a similar problem in the future.

Thanks again to all.

Paul

08-22-2002, 10:24 PM	#2
Mustang_289 Registered Member Join Date: Sep 2001 Posts: 512	surging problems if your car has speed density on it then that is your problem. i had same problem on my car with speed density. it would diel real rough and at times it would not idle when i came to a stop. and then some times it ran great. i suggest (if you have speed denstiy ) to go and get a stock filter put it in and then save some money and get mass air. and then go crazy modding it. once i put a stock filter on and took off my k&n it ran fine.

08-22-2002, 10:43 PM	#3
94cobra2 Registered Member Join Date: May 2001 Location: St. Joseph, MI Posts: 33	he does not have a speed density. its maf. Its your computer, 94-95 computers have problems with idle surge once you make some modifications. Their was a artical in MM&FF about the idle problem they had after installing edelbrock heads,cam,intake on a 94 GT. Their solution was to swap out the computer for a 93 computer and no more idle surge. I'll dig up the artical tonight and post more info tomarrow. I have not had a problem with idle with my car. It does bonce a little bit but nothing like you mentioned. Scott BTW. The timming gun should light when the #1 spark plug wire fires with or with out the spout connected. __________________ 1994 mustang gt Zex 75-125 shot, BBK equel lentgh headers, off road x-pipe, flowmaster 2 chamber. bbk underdrives, FMS 3:73, MSD 6al ignition, BBK cold air induction, 70mm throttle body, C&L mass air, K&N cone. Pro 5.0. 96 corba rear buber, 1998 cobra wheels 17/8, BFG Comp TA ZR 275/40 rear,245/45 front Best ET 13.24@105.5

08-23-2002, 11:34 PM	#5
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	hmmmm... One thing I noticed you said was "once the thermostat opened" it idled rough. That's when you O2 sensors start talking to your computer. They are open looped until then. Have you checked/replaced them? Are they OEM? Just an idea...Good luck. __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy

08-29-2002, 10:09 PM	#6
z3beemer Registered Member Join Date: Apr 2001 Location: Valparaiso, IN USA Posts: 56	Problem Found Thanks to all for your input. Unfortunately (I hate to admit defeat) I decided to break down and take it to the shop. I have a guy who is pretty good and doesn't rip you off so I surrendered! At the rate it was going I was just guessing and changing parts so it was getting expensive. Turns out the problem was bad / broken pickup coil in the distributor and it was hitting the reluctor. The new pickup coil was only $65 but with the analysis and labor the total bill was $185. Not too bad. I though I'd pass the info on in case someone has a similar problem in the future. Thanks again to all. Paul

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08-22-2002, 06:13 PM	#1
z3beemer Registered Member Join Date: Apr 2001 Location: Valparaiso, IN USA Posts: 56	Help Another Surging Mustang Ok, out of ideas and need some help from all you experts out there. 95gt 5.0 pretty much stock other than air intake, pulleys and Xpipe. Been running fine and no new mods. Car starts surging and running rough at idle once the thermostat open and even get worse when the fan kicks on. Stalls sometimes when coming to a stop and even surges at times at cruising speeds. So far we code scaned all OK on hard codes and engine run codes; get a 211 and 213 as stored codes. Have changed tfi module, coolant temp module, cap and rotor. Still same problem. Checked for ground and vacuum leaks, none found. One other symptom. when disconnecting the SPOUT and attembting to check base timing the timing light only seems to light once couple revelutions but lights consistently with the SPOUT connected. Could this be a fuel pump; filter; regulator or injector problem? I originally rule this out because the problem doesn't show up until the thermostat opens. I'm out of ideas. Thanks in advance for the help! Paul

08-23-2002, 09:12 PM	#4
jbakes Registered Member Join Date: Jun 2002 Location: Zeeland Mi Posts: 2	I finally just got mine to stop today. Rotate the mass air counter clock wise, that is all it took for me.