Surging/surges/bucks ..

[SNK-BIT]

whenever the engine (in any gear) is around 1500rpm and foot is off the gas. This is sooooo irritating. Whenever I'm just cruising I feel like such a noob. It's like I'm just learning to drive a stick all over again. It's only this rpm area and any "slight" throttle pressure and it smoothes right out.

Specs..
180 degree thermostat
13 degrees timing
BBK cold air intake
Stock 70mm mass air
Stock 65 mm throttle body
Stock 24lb (blue top) injectors
Walbro 225 lph fuel pump
BBK FPR set at (no vacuum) 39psi
Stock cobra lower and upper intake
AFR 165's
Scorpion 1.7RR
Comp XE270HR-14 cam (4 degrees advanced) 218/224 and 544/544
FRPP shorty headers
Bassani x-pipe - no cats - flowmaster 40's - 2.5inch from headers back
Stock X3Z (?) computer - no chips etc

I recently installed the heads,cam,pump,and regulator. Pretty much all upgrades came from your inputs and car (as long as it's above 1500) runs like stink. I'm pretty sure this surge was there before but is aggravated? by my new additions. The question is, have I approached the limits of my computer/injectors (wishful thinking). Could the BBK fenderwell cold air kit cause this as I don't really remember if the surge was there before this. It also irks me as to why FORD did not add the protocols to read DCL data as manually checking every sensor hot/cold is a pain. Would/could/should I use an A9L computer and if so could I read the DCL data on this? Am I just to the point of taking it for a dyno tune? Any ideas/suggestions? Thanks.

 

[BADBOYSPACK]

Time for a dyno tune.

 

[SNK-BIT]

Thanks .. but not sure it's what I wanted to hear. I thought it might be something I could fix. I guess I should be happy that your telling me I'm at the level were someone else needs to take over? If I could locate an A9L or similiar would this be feasible to look at inputs before a tune? If not then what should I expect to pay/receive for a dyno tune? Thanks.

 

[bat-stang]

At about 1700 rpm my car does this 'buckin' thing--it's my cam. This is notorious (according to my tuner) for the cam and heads on the car.

 

[SVT Lurch]

^ Exactly. Every fox I've ridden in/driven with a cam bucked like that without a tune.

 

[bad93svt]

mine does the same thing

I have the same problem, mine bucks really bad unless your over 2300rpm. so I am constantly revving it more.
afr 165 heads
comp cam 224-230 544 544
edelbrock rpm II
A9L w/pmas 75maf
70mm t-b & spacer
nitrousworks 125 kit
bbk longtubes
etc etc etc.
I have been running consistent 1180 @120
I drive the car to the track & bring it home & park it. The bucking is so bad that I don't even care to drive it.
Let me know if it gets better when you dynotune it..
but the computer switch alone want take care of your problem.

 

[Red Turtle]

I don't have my 93's anymore, but I had the same issue (twice).

Once was when I installed an e-303 cam/75mm maf with the cobra ecu (fixed by installing a9l), and second time it happed my MAF sensor needed to be replaced.

 

[SNK-BIT]

First off thanks for the input.

bat-stang..bucking @1700..what cam?
SVT Lurch..do you remember cam size? Does your name have anything to do with the cars you've rode in?
bad93svt..XE276HR cam? It looks like the bigger the cam the higher up in the rpm range the bucking is? Did you have the A9L in before or after the bucking? (side note..are those times with the n20 and whose 70mm tb?)
Red Turtle..Are you saying "no" dyno tune and the A9L fixed the problem?

It would seem that this is quite the issue with a bigger/hotter "cam" then anything else. I am assuming everyone has done the "normal" stuff (tps voltage,cleaned IAC,reset computer,cleaned salt n peppers, etc, etc, etc) to correct this problem? Am I wrong in assuming this is also connected to an idle problem as mine got much worse after the new parts addition. Is everyone of the same consensus that the "dyno tune" will take care of the problem we have? I'm not against the dyno tune for more power but I really want it to "fix" my problem. Thoughts?

 

[SNK-BIT]

Red Turtle..you actually answered :bash: my question as the A9L fixed one problem and the MAF fixed the other. How did you know it was the MAF? Thanks.

 

[bat-stang]

My cam is the Mo'sport E cam. My car has been tuned, but I don't consider this a problem. With my 77mm bullet maf, (relatively new--over a C&L) this has always been a constant. I don't completely have a grasp of lift and duration, etc., but now that I know that it can be tuned out, I may approaching it from a different perspective. My car is a theft recovery so I don't know if it still has the original computer. It may already have the A9L. Good thread; now I have a NEW project on my project!

As far as idling, I put the bypass dohickey on the t-body (beneath the iac) and that was that. Ford sells it.

Bad93, sounds like all you need is a tune! Your car looks like it would be a fun daily driver!

 

[Red Turtle]

Red Turtle..you actually answered :bash: my question as the A9L fixed one problem and the MAF fixed the other. How did you know it was the MAF? Thanks.

Well I have been down that road before with two different cars. Glad I could help.

 

[Red Turtle]

Red Turtle..Are you saying "no" dyno tune and the A9L fixed the problem?

Back in 93-95 a "dyno tune" meant taking it out and listening for detonation and then coming back and making adjustments, or get yourself a msd 6btm and just turn the knob.

Again glad I can help.

 

[bad93svt]

bucking

Yes, the 1st mod I did was change to the a9l computer & 75 maf. The car ran perfect w/the stock heads/cam/intake etc. I had nothing done but fms shorty headers/off road pipe/catback. & the car went 1350 @ 100.

I installed the new cam/heads/intake at same time & have the bucking ever since. I have installed new 02 sensors (they are different from cobra/gt) I figured since I had a gt processor.. might as well change o2 to match) New idle air motor/new t-b came w/tps & I set it correctly. The car does not surge & runs fine.. its only when you lug it in 4th & 5th.

I am sure a tune would help.. but the guys @ panhandle (great tuners) tell me to get c&L meter & toss the 75, the want me to ground battery to block (battery is in trunk) & they say they can make it drive like factory..
But that is going to cost me around a grand..& before I do it, I would like to hear from someone who has similar combo & has had a custom tune.

 

[LEE93COBRA]

I never had a problem with my car bucking when I had just the AFR 165's and a 'B' cam. Nor did I have a problem with my first univer and the 42# injectors.

After installing a different univer and 60# injectors I have had a bucking problem. After several months of changing the MAF curve with my tweecer and wideband hooked up with no improvements I have come to the conclusion that my maf is the problem.

With that being said, make sure you have no vacuum leaks anywhere and then see if somebody can datalog your car or retune it. (Or you can maybe find somebody to swap out the MAF with just to test it out) It is probably the cam that is giving you the problems. That's a pretty healthy cam to be running on stock X3Z or A9L EEC

 

[SNK-BIT]

First question..any one else having problems as of late connecting to this site? When I do connect no ones avatar is showing up. Second question..what is proper in bringing an old thread back up or keeping it alive? I ask as I have a few old ones that were not closed but I feel could be in the near future. I don't want to add to it to get it back to the top but just want to close it properly. Thanks.

Now to the subject of bucking/surge/surging/hitches/etc..Is anyone/everyone running a cooler (180) thermostat. And is anyone running a stock (maybe with K&N) airbox setup?

bat-stang..when you had your tune did you ask for power and/or fix surging? On your first post you stated that your tuner said this was notorious for the cam and heads on your car. I think my cam has larger #'s than an e-cam but your bucking is @1700 and mine is 1300-1500 and bad93svt (largest cam of the 3) is @ 2300rpm. I would think you and I would be switched in the rpm (bucking) department according to cam size if the cams are indeed (or at least part of) the culprit. It TOTALLY goes away with the slightest application of throttle. Does yours? By the way, which heads are you using? Please let us know if you have this dyno tuned and how it turns out. I will do the same when I'm satisfied I can do no more. Could you find out if you really do have an A9L? Do you have access to a scan tool and if so can you get DCL data from it? As a side note by doing the proper IAC reset (it's also a new IAC) with no KOEO or KOER codes I can get my present configuration down to a solid 750-800 rpm. No problem there.

SVT Lurch..do you remember cam size? Does your name have anything to do with the cars you've rode in? A tune fixed those cars you rode in?

bad93svt..which throttle body? .. I was thinking of getting a 70mm BBK..comes with TPS. Your tuner says that for 1K they can make it drive like "factory". I hope this is not the norm for a dynotune! Can you read the DCL data from the A9L you have now?

LEE93COBRA..Advice taken..so it looks like your the first in this thread to have a hotter cam, bigger MAF, bigger injectors, better heads and had no bucking. What size was the MAF with 42lbs and then with 60lbs Injectors?

General observations..I have cold and hot checked resistance values on every sensor and they all checked good. I started replacing them anyway. 2 new Bosch o2 sensors, smoother..still surges. IAT sensor..still surges. ECT sensor..still surges. MAP sensor..still surges. TPS sensor .set @.96v..still surges. Vacuum @ idle 16inhg. Tried raising fuel rail pressure and bucking seems to lessen when doing this. Have gone as far as 50psi. What is the computer looking at between closed throttle at 1500rpm and "slightly" open throttle @ 1500rpm? Some where in there is the answer. Have new MAF coming tomorrow..will see..might even try the stock airbox myself..I'll be back.
Thanks again to everyone.

 

[93Cobra#2771]

First question..any one else having problems as of late connecting to this site? When I do connect no ones avatar is showing up. Second question..what is proper in bringing an old thread back up or keeping it alive? I ask as I have a few old ones that were not closed but I feel could be in the near future. I don't want to add to it to get it back to the top but just want to close it properly. Thanks.

Now to the subject of bucking/surge/surging/hitches/etc..Is anyone/everyone running a cooler (180) thermostat. And is anyone running a stock (maybe with K&N) airbox setup?

bat-stang..when you had your tune did you ask for power and/or fix surging? On your first post you stated that your tuner said this was notorious for the cam and heads on your car. I think my cam has larger #'s than an e-cam but your bucking is @1700 and mine is 1300-1500 and bad93svt (largest cam of the 3) is @ 2300rpm. I would think you and I would be switched in the rpm (bucking) department according to cam size if the cams are indeed (or at least part of) the culprit. It TOTALLY goes away with the slightest application of throttle. Does yours? By the way, which heads are you using? Please let us know if you have this dyno tuned and how it turns out. I will do the same when I'm satisfied I can do no more. Could you find out if you really do have an A9L? Do you have access to a scan tool and if so can you get DCL data from it? As a side note by doing the proper IAC reset (it's also a new IAC) with no KOEO or KOER codes I can get my present configuration down to a solid 750-800 rpm. No problem there.

SVT Lurch..do you remember cam size? Does your name have anything to do with the cars you've rode in? A tune fixed those cars you rode in?

bad93svt..which throttle body? .. I was thinking of getting a 70mm BBK..comes with TPS. Your tuner says that for 1K they can make it drive like "factory". I hope this is not the norm for a dynotune! Can you read the DCL data from the A9L you have now?

LEE93COBRA..Advice taken..so it looks like your the first in this thread to have a hotter cam, bigger MAF, bigger injectors, better heads and had no bucking. What size was the MAF with 42lbs and then with 60lbs Injectors?

General observations..I have cold and hot checked resistance values on every sensor and they all checked good. I started replacing them anyway. 2 new Bosch o2 sensors, smoother..still surges. IAT sensor..still surges. ECT sensor..still surges. MAP sensor..still surges. TPS sensor .set @.96v..still surges. Vacuum @ idle 16inhg. Tried raising fuel rail pressure and bucking seems to lessen when doing this. Have gone as far as 50psi. What is the computer looking at between closed throttle at 1500rpm and "slightly" open throttle @ 1500rpm? Some where in there is the answer. Have new MAF coming tomorrow..will see..might even try the stock airbox myself..I'll be back.
Thanks again to everyone.

MOST of the time, bucking is attributed to two things:

•Lean condition
•too much timing

Head design, and cam design both affect bucking. My old combo with TFS TW heads, had much less bucking than when I swapped to my GT40Y heads. Bucking got SIGNIFICANTLY worse.

The lean condition is often caused by the cam. At low rpms, you have enough overlap that unburnt fuel makes it into the exhaust. The O2's see this fuel, and lean the motor out thinking it is running rich. Reality is that it wasn't running rich, it just isn't as efficient at low rpms/low load. This is referred to by Ed Hohenburg as "cam dieseling".

Do me a favor before you replace any more parts.

•Unhook battery.
•Step and hold on brake pedal for 1 minute (clears KAM).
•Disconnect O2's and go for a drive and see what happens.

 

[LEE93COBRA]

First question..any one else having problems as of late connecting to this site? When I do connect no ones avatar is showing up. Second question..what is proper in bringing an old thread back up or keeping it alive? I ask as I have a few old ones that were not closed but I feel could be in the near future. I don't want to add to it to get it back to the top but just want to close it properly. Thanks.

Now to the subject of bucking/surge/surging/hitches/etc..Is anyone/everyone running a cooler (180) thermostat. And is anyone running a stock (maybe with K&N) airbox setup?

bat-stang..when you had your tune did you ask for power and/or fix surging? On your first post you stated that your tuner said this was notorious for the cam and heads on your car. I think my cam has larger #'s than an e-cam but your bucking is @1700 and mine is 1300-1500 and bad93svt (largest cam of the 3) is @ 2300rpm. I would think you and I would be switched in the rpm (bucking) department according to cam size if the cams are indeed (or at least part of) the culprit. It TOTALLY goes away with the slightest application of throttle. Does yours? By the way, which heads are you using? Please let us know if you have this dyno tuned and how it turns out. I will do the same when I'm satisfied I can do no more. Could you find out if you really do have an A9L? Do you have access to a scan tool and if so can you get DCL data from it? As a side note by doing the proper IAC reset (it's also a new IAC) with no KOEO or KOER codes I can get my present configuration down to a solid 750-800 rpm. No problem there.

SVT Lurch..do you remember cam size? Does your name have anything to do with the cars you've rode in? A tune fixed those cars you rode in?

bad93svt..which throttle body? .. I was thinking of getting a 70mm BBK..comes with TPS. Your tuner says that for 1K they can make it drive like "factory". I hope this is not the norm for a dynotune! Can you read the DCL data from the A9L you have now?

LEE93COBRA..Advice taken..so it looks like your the first in this thread to have a hotter cam, bigger MAF, bigger injectors, better heads and had no bucking. What size was the MAF with 42lbs and then with 60lbs Injectors?

General observations..I have cold and hot checked resistance values on every sensor and they all checked good. I started replacing them anyway. 2 new Bosch o2 sensors, smoother..still surges. IAT sensor..still surges. ECT sensor..still surges. MAP sensor..still surges. TPS sensor .set @.96v..still surges. Vacuum @ idle 16inhg. Tried raising fuel rail pressure and bucking seems to lessen when doing this. Have gone as far as 50psi. What is the computer looking at between closed throttle at 1500rpm and "slightly" open throttle @ 1500rpm? Some where in there is the answer. Have new MAF coming tomorrow..will see..might even try the stock airbox myself..I'll be back.
Thanks again to everyone.

Maf's with 42's and 60's were/are 3.5" Pro-M univers. My cam with both setups is a AFM B-31 grind which is .544 lift intake/exhaust and fast ramp up. Can't remember the lobe center and duration on this cam.

My combo with the 42# injectors was AFR 165's, .030 over shortblock, B-31 cam, Procharger D-1R and the first pro-m univer, stock t/b, stock intakes. Never had a problem with bucking.

Since I upgraded to the Sieman Deka 60's and changed my univer out for another univer (no other changes) I have had a bucking problem when at steady cruise (1800-2500 rpm) Actually you can feel it a little bit, when coasting in gear at hwy speeds with my foot off the throttle. If you try to maintain a steady speed it will buck and as soon as you tip the the throttle a little it goes away.
I am pulling my engine to teardown very soon to inspect some things and then I am going to send the univer off for a recal/test. When i get everything back together I am going to get back started EEC tuning again

 

[SNK-BIT]

93Cobra#2771..I did as you suggested. I then drove it for approx 20mi and it seems the same to me or "maybe" a little less violent. It really doesn't matter which gear I'm in either and acts EXACTLY like LEE93COBRA's post above. In my previous post I made the remark that upping fuel pressure helped and this is about equivalent to that. I assume this is making the EEC go into limp mode to "fatten" up the fuel flow? So per your request if it's not fuel then should I reconnect 02's and pull some timing out or leave them disconnected and also pull timing out?

LEE93COBRA I feel for ya brother/sister as this is about as annoying as all hell. Doesn't it seem odd that you "had" for lack of better words "bigger" mods than me which worked fine. Then all you do is change 2 parts and it goes to hell in a handbasket? I'm suprised you could not "fix" it with the ability to retune. I know it can be a biotch to do as my son is using a standalone system for his Escort Gt with turbo now added and getting it right borders on genius. Have you tried putting those 2 parts back on to eliminate the problem? Best of luck in your rebuild.

P.S. I ordered a 70mm BBK throttle body and someone screwed up and dropped a 75mm in the box. Would this be good for my combo or should I send it back and get the 70? Thanks.

 

[93Cobra#2771]

93Cobra#2771..I did as you suggested. I then drove it for approx 20mi and it seems the same to me or "maybe" a little less violent. It really doesn't matter which gear I'm in either and acts EXACTLY like LEE93COBRA's post above. In my previous post I made the remark that upping fuel pressure helped and this is about equivalent to that. I assume this is making the EEC go into limp mode to "fatten" up the fuel flow? So per your request if it's not fuel then should I reconnect 02's and pull some timing out or leave them disconnected and also pull timing out?

Actually, I wanted to see if the adaptive process was interfering and causing the problem. It is not, evidently. EEC will richen the mixture some with the O2's being gone. Unfortunately, upping the FP won't last, as adaptive will eventually trim out those changes, unless you disable adaptive or leave the O2's unplugged.

I've got a super mild combo, and the only thing that made my severe bucking better was tweaking the maf transfer curve. I've got most of my bucking tuned out, but still have a little bit left that I haven't messed with in over a year.

If feel for you, as it is about the most annoying thing in the world...

 

[LEE93COBRA]

93Cobra#2771
LEE93COBRA I feel for ya brother/sister as this is about as annoying as all hell. Doesn't it seem odd that you "had" for lack of better words "bigger" mods than me which worked fine. Then all you do is change 2 parts and it goes to hell in a handbasket? I'm suprised you could not "fix" it with the ability to retune. I know it can be a biotch to do as my son is using a standalone system for his Escort Gt with turbo now added and getting it right borders on genius. Have you tried putting those 2 parts back on to eliminate the problem? Best of luck in your rebuild.

.

yeah it sucks. As far as fixing it with the tune, that's why I am sending the MAF back for a recal and inspection. I have adjusted my MAF curve to where it was better than OEM for this MAF curve and I still have the problem, so that's got to be it.
We'll find out after I put some better cylinder rings in and get the MAF checked out.

-Lee