This is topic Slight Bucking while cruising Help in forum Tech Talk at Northern California Ford Owners  .


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Posted by FivePTSlow (Member # 7682) on :
 
I have a 1993 Mustang 5.0. Motor mods: are Paxton SN 2000, k&n filter, upr boostmaster 4" inlet piping, MSD 6al box, MSD Blaster Coil, MSD Wires, 76mm C&L MAF 42# calibrated(green tube), 70mm bbk throttle body and spacer, bbk shorty headers, electric fan, off road h pipe a9p computer, FMS 42lb injectors

I've noticed recently a very slight bucking while cruising(driving at a steady RPM). If you didn't drive this car daily you probably wouldn't notice the bucking while cruising because it's very slight, but no hesitation under WOT.

Stuff done to try to fix the problem: cap, rotor, wires, plugs(autolite copper #24 one step colder)gapped at .038, new Fuel Pressure Regulator, new fuel filter. K&N cleaned and oiled recently, cleaned MAF sensor, T/B, and Air Idle Bypass. New EGR Valve, New EGR Position Sensor, New EGR Vacuum Solenoid, New Barometric Pressure Sensor(MAP), New Bosch o2 Sensors, New 255lph walbro in tank fuel pump, New fuel pump relay, New rubber vacuum hoses(every hose has been replaced including the ones under the upper intake plenum), tested all hard lines to 25in vacuum as well as zip tying all connection points, so I know there aren't any vacuum/boost leaks. Throttle position sensor set at .96 volts(proper base idle reset procedure was followed), timing set at 8* advance while running 91 octane from shell. I have 3 MAF Sensors it does the same thing with all of them.

Spray test with brake cleaner around all vacuum lines and intake manifold. Checked vacuum line diagram and all lines are run correctly. I have ran the suggested amount of Lucas fuel system cleaner in my past few tanks of gas.

Occasional check engine(typically only under acceleration) no codes come up in KOER, or KOEO

Tested my Ignition Control Module with my multi meter and it passed all test ranges no problem.

Tested the EGR Valve by putting 5in vacuum on it at idle and the car stumbles really bad. The EGR Valve holds that amount of vacuum as long as I leave it connected.

Tested the TPS Module with my Digital Voltage Meter. It appears to go through voltage smooth & steady, but then again since it's digital it could be reading so fast it's impossible to notice a dead spot.

My guess is either the PIP module inside the distributor, TFI, or TPS? Pretty much anything else I can think of that might cause this problem is brand new.

What are your thoughts?

[ November 01, 2011, 08:46 AM: Message edited by: FivePTSlow ]
 
Posted by FivePTSlow (Member # 7682) on :
 
No one with any similar experiences?
 
Posted by 707notchback jaejae (Member # 7958) on :
 
hmmmmm..plug gap?..o2's maybe
 
Posted by FivePTSlow (Member # 7682) on :
 
I have checked the plug gap and they all remain at .035" and with my MSD 6AL box that should be fine.
o2's have been replaced with brand new ones

[ September 30, 2011, 09:40 AM: Message edited by: FivePTSlow ]
 
Posted by 707notchback jaejae (Member # 7958) on :
 
hmmm you could try cleaning the maf
 
Posted by FivePTSlow (Member # 7682) on :
 
I just cleaned the MAF late last month, so it should be fine, but I'll clean it again just to be sure
 
Posted by JohnB (Member # 969) on :
 
Fuel pump is on it's way out.
 
Posted by FivePTSlow (Member # 7682) on :
 
Ya know I thought about that too. I remember my old 91 GT kind of doing the same thing then the fuel pump went out completely.
 
Posted by JohnB (Member # 969) on :
 
Having to key-on, key-off a few times to get it to start is a sign the check valve in the pump is failing. This is a typical sign of a pump failing.
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by JohnB:
Having to key-on, key-off a few times to get it to start is a sign the check valve in the pump is failing. This is a typical sign of a pump failing.
Sweet. Thanks for the info I appreciate it. More than likely I would have replaced all of the other stuff first like PIP, o2's, ICM etc
If I don't turn the key on and off a few times before I start up my car it turns over for a lot longer than normal before starting up
 
Posted by JohnB (Member # 969) on :
 
Ya, dropping the tank isn't fun, but normally the sh!tty jobs are the ones that fix things. And I know the feeling, the tank is out of my 03 Cobra for the second time in two weeks. lol
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by JohnB:
Ya, dropping the tank isn't fun, but normally the sh!tty jobs are the ones that fix things. And I know the feeling, the tank is out of my 03 Cobra for the second time in two weeks. lol
I've had several Fox's including: 1987 GT T-Top, 1988 GT Convertible, 1989 LX Coupe, 1991 GT, Two 1992 LX Coupe's, and my current LX Coupe which is a 1993. The more I work on these cars the more I realize how easy they are to work on compared to most other cars. This plus the fact that I have lifetime warranty on so many parts now is one of the many reasons I gravitate back to the 87-93 5.0. There is nothing on these cars that is out of the scope of mostly anyone with a decent set of tools and some willingness to learn.
 
Posted by FivePTSlow (Member # 7682) on :
 
Well my car finally wouldn't start at all the other day, so I thought the fuel pump went out, but it wound up being that some water got into the fuel pump relay under the hood, so I replaced it and it fired right up. Kind of odd is that this made my hard starting go away comlpletely, so now I'm just left with the slight hesitation when at a steady MPH/Cruising.

Still think it's the fuel pump...?

[ May 22, 2011, 05:13 PM: Message edited by: FivePTSlow ]
 
Posted by FivePTSlow (Member # 7682) on :
 
I've also noticed that I only get 10-13mpg city driving. Any other ideas?
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by JohnB:
Fuel pump is on it's way out.
Well today I finally replaced my fuel pump with a walbro 255lph in tank pump. I found that the in tank filter was clogged as well as the base of the pump, so it was probably caused by that. I replaced the pump with the walbro and everything looks good so far. Hopefully I'll get better MPG as well. The car starts up so much faster too.

[ August 21, 2011, 03:30 PM: Message edited by: FivePTSlow ]
 
Posted by FivePTSlow (Member # 7682) on :
 
Time for a necropost... My car has had this slight bucking problem all of this time and it really bugs me. Today I replaced both o2 sensors and the slight bucking while cruising is still there. Very irritating. I've been through just about everything I could think of and the problem still remains.
I'm going to purchase one of the Mityvac tools, so that I can put vacuum into the system without the car actually having to be on which should make it much easier to test for vacuum leaks.
I have updated the OP to show what all I have covered.
 
Posted by BackwardSnake (Member # 10857) on :
 
What kind of MAF do you have?
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by BackwardSnake:
What kind of MAF do you have?
I have 3 separate MAF's and it does the same thing with all of them. I have a stock MAF Housing, A 70mm MAF Housing from a 94 T-Bird, and a 73mm C&L MAF Housing with proper calibration tube for 19# injectors. I also have two different MAF Sensors and it does the same with both of them. I have basically played musical MAF's with all of them... on a couple of occasions
 
Posted by FivePTSlow (Member # 7682) on :
 
Think it could be IAB, or TPS?
 
Posted by FivePTSlow (Member # 7682) on :
 
Yesterday I did the base idle reset procedure and it seemed to help the problem out a little bit, but it's still there. I noticed the problem becomes considerably more noticeable if I just change the idle with the set screw and not go through the idle reset process.

I also did a quick test on my TPS. I left my DVM hooked up to it and open/closed the throttle body. The voltage went up and down smooth. I also would open it up a little bit and hold it there and the voltage stayed steady, so the TPS appears to still be in good working order. I also removed the IAB. It wasn't that dirty(I already cleaned it about 1,000 miles ago) and replaced the gasket.
I checked the voltage at the orange wire on the TPS and it read a steady 4.97/4.98v.

I'm starting to wonder if this problem might be caused by non motorcraft products? I bought my EGR Valve and EGR Position Sensor from Kragen, and I have no idea which brand of TPS is in my car, but it surely doesn't look factory.
 
Posted by FivePTSlow (Member # 7682) on :
 
anyone else?
 
Posted by FivePTSlow (Member # 7682) on :
 
Today just for the heck of it I removed my MSD 6AL box from my car just to test if it may be related to the problem and it seems to have went away. I'm going to start a new thread relating specifically to the MSD box.

Thank all of you guys for helping me out
 
Posted by turbo50 (Member # 6700) on :
 
Lemme know if it comes back because a failing EGR will cause this too.

Dan
 
Posted by FivePTSlow (Member # 7682) on :
 
my EGR and EGR position sensor were brand new as of May of this year. Lifetime warranty from kragen/oreilly. My car still pops a CEL often for EGR position sensor out of range. Think I should go swap them out?
 
Posted by FivePTSlow (Member # 7682) on :
 
Ya know what I think it's being caused by my electric fan. I'm using one of the coil wires as the switched power source for the fan and I think the fan just might be messing with my ignition a little. What would be a better 12v switched source wire to use?

[ September 13, 2011, 11:00 AM: Message edited by: FivePTSlow ]
 
Posted by FivePTSlow (Member # 7682) on :
 
Well I switched the fan to a different 12v switched source and the problem still remains
 
Posted by FivePTSlow (Member # 7682) on :
 
I have also noticed that the problem is more noticeable with my MSD 6AL box hooked up. Without the box it's still there, but not as noticeable. It's driving me crazy!
 
Posted by FivePTSlow (Member # 7682) on :
 
Problem still there. What I find odd is that ir doesn't occur while I'm cruising down the freeway
 
Posted by MACK.GT (Member # 10461) on :
 
try running it without the air filter, maybe clogged.
 
Posted by Q8_Hatch (Member # 11265) on :
 
Looks like you've changed almost everything in the ignition system, but did you change the coil? Do you have a good grounding point to your engine? Any codes from the ecu?
 
Posted by 707cOkEwHiTe707 (Member # 10763) on :
 
Stock alternator?
 
Posted by dvuspny (Member # 10949) on :
 
Check Grounds...Check start and charge system thoroughly. And coil may not be getting enough saturation time; In other words weak.
How about the metal baffle in the fuel tank? Have you taken the tank down and looked inside? Has the car ever been in a rear accident or show signs that it may have been with past owners?

[ September 27, 2011, 10:46 AM: Message edited by: dvuspny ]
 
Posted by BTLD GT (Member # 5229) on :
 
from my experience it sounds like your egr might be opening to much. unplug the vacuum hose going to the egr and plug it.

lmk if this helps.

Daniel
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by MACK.GT:
try running it without the air filter, maybe clogged.
air filter has been cleaned and oiled properly it's a k&n
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by Q8_Hatch:
Looks like you've changed almost everything in the ignition system, but did you change the coil? Do you have a good grounding point to your engine? Any codes from the ecu?
I haven't changed the coil yet and I have thought about this being the problem, but from my experience it seems like coils either work, or they don't, so I haven't replaced it yet.

The only code I get is sometimes it reads that the EGR Position Sensor is out of range, but I replaced the sensor and EGR valve with brand new units May of last year, so I dunno what the deal is with that.

quote:
Originally posted by dvuspny:
Check Grounds...Check start and charge system thoroughly. And coil may not be getting enough saturation time; In other words weak.
How about the metal baffle in the fuel tank? Have you taken the tank down and looked inside? Has the car ever been in a rear accident or show signs that it may have been with past owners?
From my previous experience I always check grounds and connections when I first get a car. I go through and make sure they're all in tact and remove all grease etc and then sand the area to bare metal and put dielectric grease between the connection, so the grounds should be good

quote:
Originally posted by 707cOkEwHiTe707:
Stock alternator?
No it's a 3g alternator

quote:
Originally posted by BTLD GT:
from my experience it sounds like your egr might be opening to much. unplug the vacuum hose going to the egr and plug it.

lmk if this helps.

Daniel
I'm going to go try this right now
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by BTLD GT:
from my experience it sounds like your egr might be opening to much. unplug the vacuum hose going to the egr and plug it.

lmk if this helps.

Daniel
Ok, so I unplugged the EGR vacuum hose and it didn't hesitate at all in the few miles I just went and drove. I have lifetime warranty on the EGR Valve and the EGR Sensor, but I haven't replaced the Vacuum Solenoid for the EGR Valve yet. Should I change the solenoid, or exchange the egr and sensor?
 
Posted by BTLD GT (Member # 5229) on :
 
quote:
Originally posted by FivePTSlow:
quote:
Originally posted by BTLD GT:
from my experience it sounds like your egr might be opening to much. unplug the vacuum hose going to the egr and plug it.

lmk if this helps.

Daniel
Ok, so I unplugged the EGR vacuum hose and it didn't hesitate at all in the few miles I just went and drove. I have lifetime warranty on the EGR Valve and the EGR Sensor, but I haven't replaced the Vacuum Solenoid for the EGR Valve yet. Should I change the solenoid, or exchange the egr and sensor?
the best thing to do is leave it unplugged. unless your car is custom tuned then your tuner can go in to your file and adjust your egr multiplier to reduce the amount of flow. everything is working properly its just the egr is recycling to much and causing a lean miss fire. so there is no need to replace parts either leave it unplugged or have it retuned.

Daniel


Advanced Auto
925-831-9338
 
Posted by CobraCoupe (Member # 7233) on :
 
quote:
Originally posted by BTLD GT:
quote:
Originally posted by FivePTSlow:
quote:
Originally posted by BTLD GT:
from my experience it sounds like your egr might be opening to much. unplug the vacuum hose going to the egr and plug it.

lmk if this helps.

Daniel
Ok, so I unplugged the EGR vacuum hose and it didn't hesitate at all in the few miles I just went and drove. I have lifetime warranty on the EGR Valve and the EGR Sensor, but I haven't replaced the Vacuum Solenoid for the EGR Valve yet. Should I change the solenoid, or exchange the egr and sensor?
the best thing to do is leave it unplugged. unless your car is custom tuned then your tuner can go in to your file and adjust your egr multiplier to reduce the amount of flow. everything is working properly its just the egr is recycling to much and causing a lean miss fire. so there is no need to replace parts either leave it unplugged or have it retuned.

Daniel


Advanced Auto
925-831-9338
+1000 had the same problem with the egr position sensor and was opening up when its not supposed to choppy accel and sputtered too, delete it!
 
Posted by turbo50 (Member # 6700) on :
 
quote:
Originally posted by turbo50:
Lemme know if it comes back because a failing EGR will cause this too.

Dan
Man I already told you what the issue was..........
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by turbo50:
quote:
Originally posted by turbo50:
Lemme know if it comes back because a failing EGR will cause this too.

Dan
Man I already told you what the issue was..........
My EGR and Sensor seriously have less than 2,000 miles on them and they were bought brand new from O'Reilly. I would like to keep the EGR system in tact for many reasons. Most importantly so that I don't get sent to the referee and second so that I don't have to change a million things once it's smog time. I have been sent to the referee before and it's not fun.
I have an engine that I'm building as we speak and have made sure that everything is CARB Certified for the very same reasons.

Keeping all of this in mind should I go and swap out the EGR & Sensor, or replace the EGR Vacuum Control Solenoid? The Solenoid is the only part of the EGR System that has not been replaced and I think they're only $20-30
 
Posted by turbo50 (Member # 6700) on :
 
quote:
Originally posted by FivePTSlow:
quote:
Originally posted by turbo50:
quote:
Originally posted by turbo50:
Lemme know if it comes back because a failing EGR will cause this too.

Dan
Man I already told you what the issue was..........
My EGR and Sensor seriously have less than 2,000 miles on them and they were bought brand new from O'Reilly. I would like to keep the EGR system in tact for many reasons. Most importantly so that I don't get sent to the referee and second so that I don't have to change a million things once it's smog time. I have been sent to the referee before and it's not fun.
I have an engine that I'm building as we speak and have made sure that everything is CARB Certified for the very same reasons.

Keeping all of this in mind should I go and swap out the EGR & Sensor, or replace the EGR Vacuum Control Solenoid? The Solenoid is the only part of the EGR System that has not been replaced and I think they're only $20-30
Run a vacuum test on the egr valve watch the diaphragm.


Replace evap solenoid anyway for 20 bux ya know?
 
Posted by FivePTSlow (Member # 7682) on :
 
[/qb][/QUOTE]Run a vacuum test on the egr valve watch the diaphragm.


Replace evap solenoid anyway for 20 bux ya know? [/QB][/QUOTE]

I have done the vacuum test on the EGR valve at idle with my mityvac vacuum tester. My car stumbles really hard when I put 5" of vacuum directly on the EGR Valve at idle. I'm sure the car would die eventually, but I didn't leave the EGR Valve under vacuum for extended periods of time. Maybe 30 seconds or so just to make sure it held the vacuum.

Is this the test you're talking about?
 
Posted by turbo50 (Member # 6700) on :
 
quote:
Originally posted by FivePTSlow:
Run a vacuum test on the egr valve watch the diaphragm.


Replace evap solenoid anyway for 20 bux ya know? [/QB][/QUOTE]

I have done the vacuum test on the EGR valve at idle with my mityvac vacuum tester. My car stumbles really hard when I put 5" of vacuum directly on the EGR Valve at idle. I'm sure the car would die eventually, but I didn't leave the EGR Valve under vacuum for extended periods of time. Maybe 30 seconds or so just to make sure it held the vacuum.

Is this the test you're talking about? [/QB][/QUOTE]


yep makin sure its not blown which you did.
 
Posted by BTLD GT (Member # 5229) on :
 
im not saying to remove the egr system simply plug the vacuum hose with a bb or something of that nature. that way it looks like its hooked up and u wont have a smog ref problem.
 
Posted by FivePTSlow (Member # 7682) on :
 
-EGR vacuum solenoid works with the on-board computer to provide a calibrated vacuum source for the EGR valve

-When not replaced, vehicle may experience excessive flow or non-functioning EGR valve, engine dies at idle, failed emission test, high NOx emissions, surging at highway speeds and/or hesitation

Here's what one sight says about the EGR Vacuum Solenoid. Why did I not read this before? lol

[ September 29, 2011, 12:51 PM: Message edited by: FivePTSlow ]
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by FivePTSlow:
-EGR vacuum solenoid works with the on-board computer to provide a calibrated vacuum source for the EGR valve

-When not replaced, vehicle may experience excessive flow or non-functioning EGR valve, engine dies at idle, failed emission test, high NOx emissions, surging at highway speeds and/or hesitation

Here's what one sight says about the EGR Vacuum Solenoid. Why did I not read this before? lol
Ok, so I replaced the EGR Vacuum Solenoid yesterday. It definitely decreased the amount of times the Check Engine Light comes on(almost none now), but the problem is still there. I am starting to think that I am just insane and there is no problem lol
 
Posted by turbo50 (Member # 6700) on :
 
HOLD THE MAIL!!!


Did your issue start AFTER relocating the evap canister to the location as depicted in the photo about half way down this post????


http://www.californiafords.com/ubb/ultimatebb.php?ubb=get_topic;f=6;t=025321
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by turbo50:
HOLD THE MAIL!!!


Did your issue start AFTER relocating the evap canister to the location as depicted in the photo about half way down this post????


http://www.californiafords.com/ubb/ultimatebb.php?ubb=get_topic;f=6;t=025321
No, unfortunately not. This problem has been going on for quite awhile including when the evap can was in it's stock location. I only had it there because it didn't look like it wouldn't fit in it's stock location after the supercharger install, but yesterday I put it back on the factory mount and it fits just fine.

[ September 30, 2011, 09:29 AM: Message edited by: FivePTSlow ]
 
Posted by FivePTSlow (Member # 7682) on :
 
When I bought my car it didn't have the smog pump setup and the crossover tube was capped.Do you think this problem could be caused by the heads passages being clogged up with carbon? I pulled the crossover tube off and it was clear.
 
Posted by FivePTSlow (Member # 7682) on :
 
OP updated problem still remains. I unplugged the vacuum line to my EGR Valva and capped it and drove around for several days. The problem was still there. I keep getting a CEL under acceleration, but when I plug in my OBD Reader no codes come up during KOEO, or KOER

[ October 28, 2011, 09:34 PM: Message edited by: FivePTSlow ]
 
Posted by MACK.GT (Member # 10461) on :
 
Take out some timing , make sure you have a full battery. Maybe load test it. Could be an intake vacuum leak in a remote spot. If the needle moves even half an inch , could be that. Have you power balance tested yet? Are all cylinders contributing the same?
 
Posted by racsirx (Member # 1710) on :
 
Distributor?
 
Posted by Venomousnotch (Member # 8695) on :
 
quote:
Originally posted by racsirx:
Distributor?
+1 I agree with lee... [patriot]
 
Posted by FivePTSlow (Member # 7682) on :
 
quote:
Originally posted by MACK.GT:
Take out some timing , make sure you have a full battery. Maybe load test it. Could be an intake vacuum leak in a remote spot. If the needle moves even half an inch , could be that. Have you power balance tested yet? Are all cylinders contributing the same?
I've had my timing all over the place from 4*-14* it still does the exact same thing. Battery is perfectly fine. There are no vacuum leaks anymore I spent several hours going through every single line and testing them all individually one by one, and replaced all rubber vacuum line in addition to zip tying all ends on all vacuum lines. I have not done any sort of leak down, or compression testing.

quote:
Originally posted by racsirx:
Distributor?
I have had this idea all along just like it says in the OP I tested the tfi module and it passed all ranges, but the pip module remains un tested, so it very well might be. As you can see I've replaced quite a bit of stuff it could be already and I'm still working on finding the problem.
 
Posted by racsirx (Member # 1710) on :
 
I have seen three Mustangs this year with drivability problems this year with cutting in and out, and it turned out to be the distributor. Once the distributors were pulled out the shafts had way too much play in them.
 
Posted by FivePTSlow (Member # 7682) on :
 
Well today I bought a new TPS from O'Reilly and so far it really smoothed out a lot of things like idle, cruising, and acceleration. I hope this is the fix I have been searching for for all of this time.
 




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