Heavily modified '89 LX idling badly, stumbling on cruise control

All -

It's been a while since I posted to this group, my ISP dumped Usenet
and I have avoided using Google Groups like the plague. But here I
am.

I have a 5.0 '89 LX. I've basically replaced the entire drive train.
I installed a Ford Racing 5.0 crate motor (M-6007-XEFM) with a M-6250-
E303 cam, .498" lift intake and exhaust, duration at .050" is 220
degrees intake and exhaust. It has Ford Racing aluminum GT-40
cylinder heads M-6049-X303 with 1.94" intake valves and 1.54" exhaust
valves.

For fuel/air delivery I added 24# injectors, a C&L 70mm throttle body,
EGR spacer, C&L 76mm mass air kit calibrated for 24# injectors, K&N
open element filter and Typhoon intake.

It has 1 & 5/8" shorty headers, BBK h-pipe and high flow cats, and
2.5" pipes.

It also has a new AOD transmission and 3.73 posi gears in the rear.

It runs OK when under throttle, but it doesn't idle worth a crap, and
at highway speeds on cruise control it seems like it is surging/
bucking. Sometimes it doesn't want to start, either - I have to crank
it and crank it before it will finally fire up.

We've checked and rechecked for vacuum leaks and we're very confident
there are none. My mechanic has tested every sensor he can think of,
replaced several, everything indicates all is well. It just won't
idle or run at a constant speed well. He did say that the plugs were
pretty white when he checked them, indicating we're running a little
lean. C&L said this is expected since it's running an open air filter
- their intake gear is really designed to run with the stock airbox.
Another odd thing which has happened a couple of times is that when I
accelerate hard I hear a light backfire - almost more of a loud "poof"
than a bang, if that makes any sense, then it blasts off.

My mechanic also bumped the high pressure fuel regulator up from the
recommended 38 to more like 43 on the recommendation of a peer of his
who does a lot of work on Mustangs.

The last thing we're going to try is to get a programmable chip and
have the ECU programmed by a shop here in Austin which has a
programmer and a dyno.

Does anyone have any suggestions as to anything else I should look
at? I am very hopeful that a reprogram will get this thing to run
more civilly. If a new ECU chip still doesn't do it I am considering
maybe going to 30# injectors, as Ford Racing said that's what they'd
recommend to get the full 340HP from this crate motor.

Honestly, I am much more interested in this thing driving civilly than
quarter mile times. It's my daily driver and I'm pushing 40. Good
manners are more important to me these days. :-)

Thanks for reading this,
Thomas

Thomas Cameron wrote:
> All -
>
> It's been a while since I posted to this group,
> my ISP dumped Usenet
> and I have avoided using Google Groups like the
> plague. But here I
> am.
>
> I have a 5.0 '89 LX. I've basically replaced
> the entire drive train.
> I installed a Ford Racing 5.0 crate motor
> (M-6007-XEFM) with a M-6250-
> E303 cam, .498" lift intake and exhaust,
> duration at .050" is 220
> degrees intake and exhaust. It has Ford Racing
> aluminum GT-40
> cylinder heads M-6049-X303 with 1.94" intake
> valves and 1.54" exhaust
> valves.
>
> For fuel/air delivery I added 24# injectors, a
> C&L 70mm throttle body,
> EGR spacer, C&L 76mm mass air kit calibrated for
> 24# injectors, K&N
> open element filter and Typhoon intake.

What fuel pump do you have? Is it keeping the
pressure and flow up to specs under a load?

--------
..boB
2006 FXDI hot rod
2008 Mustang Coupe
2007 Ram 2500 CTD/Auto/4x4
1965 FFR Cobra - 427W EFI, Damn Fast.

On Jan 31, 6:33*pm, ".boB" > wrote:
> Thomas Cameron wrote:
> > All -
>
> > It's been a while since I posted to this group,
> > my ISP dumped Usenet
> > and I have avoided using Google Groups like the
> > plague. *But here I
> > am.
>
> > I have a 5.0 '89 LX. *I've basically replaced
> > the entire drive train.
> > I installed a Ford Racing 5.0 crate motor
> > (M-6007-XEFM) with a M-6250-
> > E303 cam, .498" lift intake and exhaust,
> > duration at .050" is 220
> > degrees intake and exhaust. *It has Ford Racing
> > aluminum GT-40
> > cylinder heads M-6049-X303 with 1.94" intake
> > valves and 1.54" exhaust
> > valves.
>
> > For fuel/air delivery I added 24# injectors, a
> > C&L 70mm throttle body,
> > EGR spacer, C&L 76mm mass air kit calibrated for
> > 24# injectors, K&N
> > open element filter and Typhoon intake.
>
> What fuel pump do you have? *Is it keeping the
> pressure and flow up to specs under a load?

Hrm - good point. I have not replaced the fuel pump so I imagine it
is still the stock one.

TC

On Jan 31, 6:33*pm, ".boB" > wrote:
> Thomas Cameron wrote:
> > All -
>
> > It's been a while since I posted to this group,
> > my ISP dumped Usenet
> > and I have avoided using Google Groups like the
> > plague. *But here I
> > am.
>
> > I have a 5.0 '89 LX. *I've basically replaced
> > the entire drive train.
> > I installed a Ford Racing 5.0 crate motor
> > (M-6007-XEFM) with a M-6250-
> > E303 cam, .498" lift intake and exhaust,
> > duration at .050" is 220
> > degrees intake and exhaust. *It has Ford Racing
> > aluminum GT-40
> > cylinder heads M-6049-X303 with 1.94" intake
> > valves and 1.54" exhaust
> > valves.
>
> > For fuel/air delivery I added 24# injectors, a
> > C&L 70mm throttle body,
> > EGR spacer, C&L 76mm mass air kit calibrated for
> > 24# injectors, K&N
> > open element filter and Typhoon intake.
>
> What fuel pump do you have? *Is it keeping the
> pressure and flow up to specs under a load?

In thinking of it, wouldn't it be OK since he was able to set the fuel
pressure regulator to 42-43? If the fule pump weren't doing the job
wouldn't that have been indicated when he set it? Forgive me, I am
not a mechanic, I'm a computer geek.

Thomas Cameron wrote:
> All -
>
> It's been a while since I posted to this group, my ISP dumped Usenet
> and I have avoided using Google Groups like the plague. But here I
> am.
>
> Thanks for reading this,
> Thomas

Hi Thomas, a few other of us also lost usenet from our ISPs and went to
Motzarella.org for a free account.

Just sign up and your back up using your usenet client!

Thomas Cameron wrote:
>.
>>
>> What fuel pump do you have? Is it keeping the
>> pressure and flow up to specs under a load?
>
> In thinking of it, wouldn't it be OK since he
> was able to set the fuel
> pressure regulator to 42-43? If the fule pump
> weren't doing the job
> wouldn't that have been indicated when he set
> it? Forgive me, I am
> not a mechanic, I'm a computer geek.


A bad pump would be fine at idle. But under a
load it wouldn't be able to keep up. That's a
tough thing to measure, though. Unless you have
a dyno.

Since you're upgrading everything else, I would
replace the stock pump anyway. They're pretty
inexpensive, and it's not a big job to replace
them. Go with a Walbro 255 L/Hr.

--------
..boB
2006 FXDI hot rod
2008 Mustang Coupe
2007 Ram 2500 CTD/Auto/4x4
1965 FFR Cobra - 427W EFI, Damn Fast.

On Jan 31, 7:32*pm, GILL > wrote:
> Thomas Cameron wrote:
> > All -
>
> > It's been a while since I posted to this group, my ISP dumped Usenet
> > and I have avoided using Google Groups like the plague. *But here I
> > am.
>
> > Thanks for reading this,
> > Thomas
>
> Hi Thomas, a few other of us also lost usenet from our ISPs and went to
> Motzarella.org for a free account.
>
> Just sign up and your back up using your usenet client!

Thanks! I have been trying to figure out what service to use, I'll
try out Motzarella.org!

On Sat, 31 Jan 2009 16:25:24 -0800 (PST), Thomas Cameron
> wrote:

>All -
>
>It's been a while since I posted to this group, my ISP dumped Usenet
>and I have avoided using Google Groups like the plague. But here I
>am.
>
>I have a 5.0 '89 LX. I've basically replaced the entire drive train.
>I installed a Ford Racing 5.0 crate motor (M-6007-XEFM) with a M-6250-
>E303 cam, .498" lift intake and exhaust, duration at .050" is 220
>degrees intake and exhaust. It has Ford Racing aluminum GT-40
>cylinder heads M-6049-X303 with 1.94" intake valves and 1.54" exhaust
>valves.
>
>For fuel/air delivery I added 24# injectors, a C&L 70mm throttle body,
>EGR spacer, C&L 76mm mass air kit calibrated for 24# injectors, K&N
>open element filter and Typhoon intake.
>
>It has 1 & 5/8" shorty headers, BBK h-pipe and high flow cats, and
>2.5" pipes.
>
>It also has a new AOD transmission and 3.73 posi gears in the rear.
>
>It runs OK when under throttle, but it doesn't idle worth a crap, and
>at highway speeds on cruise control it seems like it is surging/
>bucking. Sometimes it doesn't want to start, either - I have to crank
>it and crank it before it will finally fire up.
>
>We've checked and rechecked for vacuum leaks and we're very confident
>there are none. My mechanic has tested every sensor he can think of,
>replaced several, everything indicates all is well. It just won't
>idle or run at a constant speed well. He did say that the plugs were
>pretty white when he checked them, indicating we're running a little
>lean. C&L said this is expected since it's running an open air filter
>- their intake gear is really designed to run with the stock airbox.
>Another odd thing which has happened a couple of times is that when I
>accelerate hard I hear a light backfire - almost more of a loud "poof"
>than a bang, if that makes any sense, then it blasts off.
>
>My mechanic also bumped the high pressure fuel regulator up from the
>recommended 38 to more like 43 on the recommendation of a peer of his
>who does a lot of work on Mustangs.
>
>The last thing we're going to try is to get a programmable chip and
>have the ECU programmed by a shop here in Austin which has a
>programmer and a dyno.
>
>Does anyone have any suggestions as to anything else I should look
>at? I am very hopeful that a reprogram will get this thing to run
>more civilly. If a new ECU chip still doesn't do it I am considering
>maybe going to 30# injectors, as Ford Racing said that's what they'd
>recommend to get the full 340HP from this crate motor.
>
>Honestly, I am much more interested in this thing driving civilly than
>quarter mile times. It's my daily driver and I'm pushing 40. Good
>manners are more important to me these days. :-)
>
>Thanks for reading this,
>Thomas

My thoughts... seems unlikely it's the injector size unless perhaps
they are too big. Since you are having the problems at idle and at
cruise it's not an issue of not getting enough gas, it's an issue of
not getting a uniform flow. As was suggested, it's possible your fuel
pump isn't putting out enough volume but here again since you have
said you have plenty of power when you get on it it seems unlikely
it's a fuel pump problem.

Does this engine still have the original Idle Air Bypass valve? They
are notorious for causing idle problem and cruise problems. When I
had an 88LX 5.0 some years back a new IAB valve cured both those
problems for me. Also, setting the IAB valve, either the existing one
or a new one, can be tricky. I had the best luck in setting them by
backing the base idle screw completely out and then turning it in only
one-quarter turn past where it just barely touched the stop. Also
with the IAB valve there might be a "plate" you can buy from Ford for
that model that allows additional adjustment, it goes between where
the IAB mounts and the IAB and provides additional bleed air or
something.

I don't know what it is about these 5.0s but a friend of mine is
having exactly the same problems you are on a stock setup and has
tried just able all the same stuff you have (and most of my ideas) and
he is still fighting it. He's looking into possible EGR issues now
and considering getting the "plate".

Check the TPS sensor. It may be worn out. Mine did the same thing and
I unpluged the TPS while it was running and the idle went from crap to
perfect. I went and bought a new one and everything has been good
since.




On Sat, 31 Jan 2009 16:25:24 -0800 (PST), Thomas Cameron
> wrote:

>All -
>
>It's been a while since I posted to this group, my ISP dumped Usenet
>and I have avoided using Google Groups like the plague. But here I
>am.
>
>I have a 5.0 '89 LX. I've basically replaced the entire drive train.
>I installed a Ford Racing 5.0 crate motor (M-6007-XEFM) with a M-6250-
>E303 cam, .498" lift intake and exhaust, duration at .050" is 220
>degrees intake and exhaust. It has Ford Racing aluminum GT-40
>cylinder heads M-6049-X303 with 1.94" intake valves and 1.54" exhaust
>valves.
>
>For fuel/air delivery I added 24# injectors, a C&L 70mm throttle body,
>EGR spacer, C&L 76mm mass air kit calibrated for 24# injectors, K&N
>open element filter and Typhoon intake.
>
>It has 1 & 5/8" shorty headers, BBK h-pipe and high flow cats, and
>2.5" pipes.
>
>It also has a new AOD transmission and 3.73 posi gears in the rear.
>
>It runs OK when under throttle, but it doesn't idle worth a crap, and
>at highway speeds on cruise control it seems like it is surging/
>bucking. Sometimes it doesn't want to start, either - I have to crank
>it and crank it before it will finally fire up.
>
>We've checked and rechecked for vacuum leaks and we're very confident
>there are none. My mechanic has tested every sensor he can think of,
>replaced several, everything indicates all is well. It just won't
>idle or run at a constant speed well. He did say that the plugs were
>pretty white when he checked them, indicating we're running a little
>lean. C&L said this is expected since it's running an open air filter
>- their intake gear is really designed to run with the stock airbox.
>Another odd thing which has happened a couple of times is that when I
>accelerate hard I hear a light backfire - almost more of a loud "poof"
>than a bang, if that makes any sense, then it blasts off.
>
>My mechanic also bumped the high pressure fuel regulator up from the
>recommended 38 to more like 43 on the recommendation of a peer of his
>who does a lot of work on Mustangs.
>
>The last thing we're going to try is to get a programmable chip and
>have the ECU programmed by a shop here in Austin which has a
>programmer and a dyno.
>
>Does anyone have any suggestions as to anything else I should look
>at? I am very hopeful that a reprogram will get this thing to run
>more civilly. If a new ECU chip still doesn't do it I am considering
>maybe going to 30# injectors, as Ford Racing said that's what they'd
>recommend to get the full 340HP from this crate motor.
>
>Honestly, I am much more interested in this thing driving civilly than
>quarter mile times. It's my daily driver and I'm pushing 40. Good
>manners are more important to me these days. :-)
>
>Thanks for reading this,
>Thomas

On Jan 31, 10:07*pm, Ashton Crusher > wrote:
> On Sat, 31 Jan 2009 16:25:24 -0800 (PST), Thomas Cameron
>
>
>
> > wrote:
> >All -
>
> >It's been a while since I posted to this group, my ISP dumped Usenet
> >and I have avoided using Google Groups like the plague. *But here I
> >am.
>
> >I have a 5.0 '89 LX. *I've basically replaced the entire drive train.
> >I installed a Ford Racing 5.0 crate motor (M-6007-XEFM) with a M-6250-
> >E303 cam, .498" lift intake and exhaust, duration at .050" is 220
> >degrees intake and exhaust. *It has Ford Racing aluminum GT-40
> >cylinder heads M-6049-X303 with 1.94" intake valves and 1.54" exhaust
> >valves.
>
> >For fuel/air delivery I added 24# injectors, a C&L 70mm throttle body,
> >EGR spacer, C&L 76mm mass air kit calibrated for 24# injectors, K&N
> >open element filter and Typhoon intake.
>
> >It has 1 & 5/8" shorty headers, BBK h-pipe and high flow cats, and
> >2.5" pipes.
>
> >It also has a new AOD transmission and 3.73 posi gears in the rear.
>
> >It runs OK when under throttle, but it doesn't idle worth a crap, and
> >at highway speeds on cruise control it seems like it is surging/
> >bucking. *Sometimes it doesn't want to start, either - I have to crank
> >it and crank it before it will finally fire up.
>
> >We've checked and rechecked for vacuum leaks and we're very confident
> >there are none. *My mechanic has tested every sensor he can think of,
> >replaced several, everything indicates all is well. *It just won't
> >idle or run at a constant speed well. *He did say that the plugs were
> >pretty white when he checked them, indicating we're running a little
> >lean. *C&L said this is expected since it's running an open air filter
> >- their intake gear is really designed to run with the stock airbox.
> >Another odd thing which has happened a couple of times is that when I
> >accelerate hard I hear a light backfire - almost more of a loud "poof"
> >than a bang, if that makes any sense, then it blasts off.
>
> >My mechanic also bumped the high pressure fuel regulator up from the
> >recommended 38 to more like 43 on the recommendation of a peer of his
> >who does a lot of work on Mustangs.
>
> >The last thing we're going to try is to get a programmable chip and
> >have the ECU programmed by a shop here in Austin which has a
> >programmer and a dyno.
>
> >Does anyone have any suggestions as to anything else I should look
> >at? *I am very hopeful that a reprogram will get this thing to run
> >more civilly. *If a new ECU chip still doesn't do it I am considering
> >maybe going to 30# injectors, as Ford Racing said that's what they'd
> >recommend to get the full 340HP from this crate motor.
>
> >Honestly, I am much more interested in this thing driving civilly than
> >quarter mile times. *It's my daily driver and I'm pushing 40. *Good
> >manners are *more important to me these days. *:-)
>
> >Thanks for reading this,
> >Thomas
>
> My thoughts... *seems unlikely it's the injector size unless perhaps
> they are too big. *Since you are having the problems at idle and at
> cruise it's not an issue of not getting enough gas, it's an issue of
> not getting a uniform flow. *As was suggested, it's possible your fuel
> pump isn't putting out enough volume but here again since you have
> said you have plenty of power when you get on it it seems unlikely
> it's a fuel pump problem.

Well, I *think* it is giving enough power but I also am a little
surprised at how hard it is to break the rear tires loose. I would
think that with 3.73 gears even with posi I should be able to do a
nice burnout, and I just can't. I think a new fuel pump is in my
future.

> Does this engine still have the original Idle Air Bypass valve? *They
> are notorious for causing idle problem and cruise problems. *When I
> had an 88LX 5.0 some years back a new IAB valve cured both those
> problems for me. *Also, setting the IAB valve, either the existing one
> or a new one, can be tricky. *I had the best luck in setting them by
> backing the base idle screw completely out and then turning it in only
> one-quarter turn past where it just barely touched the stop. *Also
> with the IAB valve there might be a "plate" you can buy from Ford for
> that model that allows additional adjustment, it goes between where
> the IAB mounts and the IAB and provides additional bleed air or
> something.

As far as I know it is the stock IAB. I'll look at that as well.

> I don't know what it is about these 5.0s but a friend of mine is
> having exactly the same problems you are on a stock setup and has
> tried just able all the same stuff you have (and most of my ideas) and
> he is still fighting it. *He's looking into possible EGR issues now
> and considering getting the "plate".

Thanks for the suggestions, I'll chase them down.

TC