Pokageek's Pain thread. 351 stroker (414c.i.) swap PROBLEMS.

[Pokageek]

Thanks BV. I just am hoping my issues can help someone else avoid trouble when they build theirs. That's the goal for me and why I post mainly.

 

[Pokageek]

Ok. Took it too a muffler shop and they basically rebuilt my H-Pipe to fit the Cobra R headers. They seal real nice now! Now that the car is quieter..I can tell I have to adjust the rockers better..Acouple of them sound like a vw beetle, lol.

Next Issue:
When she warms up and on the beltway for a bit, it begins to run rough and really buck below 2k rpm..like it is on 7 cylinders and the check engine lights up. But when I got off the b-way, check engine light turned off again but still runs ruff When I start it up though, for the first few minutes it runs smooth..Any ideas experts?

 

[Zero_chance]

Poka sorry to hear about your troubles. Hope you get that all sorted out. I have a question though. Im starting to accumulate parts for a mild 351 setup that Ill be swapping into my 95 down the road. One of the several things Im still not sure on is can you still use the stock PCM to control the 5.8? Ive heard people on both sides of the fence and I figured Id rather ask someone that has one up and running.. even if it is running a little rough.

 

[1slow95]

Poka sorry to hear about your troubles. Hope you get that all sorted out. I have a question though. Im starting to accumulate parts for a mild 351 setup that Ill be swapping into my 95 down the road. One of the several things Im still not sure on is can you still use the stock PCM to control the 5.8? Ive heard people on both sides of the fence and I figured Id rather ask someone that has one up and running.. even if it is running a little rough.

You can use the stock computer, but a custom tune is highly recommended. If you choose the right parts, it will run fine on the stock tune. It might be a little rough, but it will run.

My car runs pretty good on the stock tune. It even idles just fine. I drove it for a year like that because I couldn't afford to have it dyno tuned. (My engine went slightly over budget )

The important things you need for it run right are:
MAF calibrated to injector size
GOOD (working) O2 sensors
A milder cam setup, in the 114LSA or higher range. A custom cam is the best way to go.

 

[Black95GTS]

Next Issue:
When she warms up and on the beltway for a bit, it begins to run rough and really buck below 2k rpm..like it is on 7 cylinders and the check engine lights up. But when I got off the b-way, check engine light turned off again but still runs ruff When I start it up though, for the first few minutes it runs smooth..Any ideas experts?

This sounds like you are having troubles when you go from open loop to closed loop in your tune. Your car's pcm runs open loop when you start the car, go wide open throttle, hard acceleration, or the engine is cold.

Oxygen sensors are not in operation.

After the car is warmed up, the O2 sensors come into play affecting the A/F mixture. So I would think your problem is:

1 - Tune related or 2 - Your O2 sensors are malfunctioning.

Adam

 

[Pokageek]

Yes, yo can run on the stock pcm..at least I am and I know Low 5.0 is. But a tune is highly recommended if you do..

Thanks for the input Black95GTS. Kinda sucks cuz my sensors are about a year or so old. I will try the tune first..

[EDIT] (as usual) I forgot to mention that new huge sway bar? WOW!!! Real stiff front end and NO LEAN in turns AND GREAT handling!!! Wow what a difference!! And not that expensive a mod!

 

[BlackVert]

+1 on the tune and computer thing. i have a stock pcm too. for me, it'll be a while before i can say my tune is done, because i want it to idle and cruise like a stocker, but go like a raped ape when i drop the hammer

hey man, post a link to that swaybar, ok?

 

[1slow95]

Next Issue:
When she warms up and on the beltway for a bit, it begins to run rough and really buck below 2k rpm..like it is on 7 cylinders and the check engine lights up. But when I got off the b-way, check engine light turned off again but still runs ruff When I start it up though, for the first few minutes it runs smooth..Any ideas experts?

I agree on the O2 sensors. I would check the codes first tho.

 

[Pokageek]

I ot it from mustangs unlimit. Looks like they don't sell that size anymore. It is a 1 3/8 front swaybar. The largest it looks like is 1 1/4.

 

[final5-0]

Poka sorry to hear about your troubles. Hope you get that all sorted out. I have a question though. Im starting to accumulate parts for a mild 351 setup that Ill be swapping into my 95 down the road. One of the several things Im still not sure on is can you still use the stock PCM to control the 5.8? Ive heard people on both sides of the fence and I figured Id rather ask someone that has one up and running.. even if it is running a little rough.

The pcm family for 94-95 Stangs consists of 5 different versions of software

One of them is the ZA0 which was used in the Cobra R powered by a 351

As a matter of fact

You could use a Tweecer to upload the ZAO calibration file to your existing
pcm you now are using

Grady

 

[nmcgrawj]

The pcm family for 94-95 Stangs consists of 5 different versions of software

One of them is the ZA0 which was used in the Cobra R powered by a 351

As a matter of fact

You could use a Tweecer to upload the ZAO calibration file to your existing
pcm you now are using

Grady

x2


And for another who has done it, i put a 351 with ported twisted wedge heads, TFS-R intake, and a Ed C. cam in my car and tuned it with a PMS just fine.....

Which means i used the stock GT setup and just modified it...no use of an actual 5.8 program....

I think its so easy with the PMS because our cars are load based (right grady? ) so a 5.8 will just have more load compared to a 302 using the exact same computer.

Anywho, just my experience....

 

[final5-0]

x2


And for another who has done it, i put a 351 with ported twisted wedge heads, TFS-R intake, and a Ed C. cam in my car and tuned it with a PMS just fine.....

Which means i used the stock GT setup and just modified it...no use of an actual 5.8 program....

I think its so easy with the PMS because our cars are load based (right grady? ) so a 5.8 will just have more load compared to a 302 using the exact same computer.

Anywho, just my experience....

You bet

Hey ... this is a great time to point out a basic but important fact

Stock 94-95 Stangs with 302 or 351 .........
They all use the same pcm as far as hardware is concerned
Its only the info in those pcms that is different

So no matter if you use

SCT Pro Racer
Tweecer
PMS
as a self tuning interface
or even
You have a Pro burn you a chip

The same basic objective is sought with each method :Word:

You gotta get the pcm updated
with info that matches the needs of your current combo

Grady

 

[Pokageek]

Next Issue: As you know I did the fox TB conversion but I couldn't justify paying $94 for a new throttle cable. So I bought a used one,..but every time I hit the gas...Sqqqqqueeeeeek! Anybody run into this? I wd40'd it too.

 

[nmcgrawj]

Next Issue: As you know I did the fox TB conversion but I couldn't justify paying $94 for a new throttle cable. So I bought a used one,..but every time I hit the gas...Sqqqqqueeeeeek! Anybody run into this? I wd40'd it too.

I got a used throttle cable for my fox swap too....the throttle cable itself is squeeking? Thats really weird. I assume you're finding the squeek by pushing the gas with the car off? Maybe soak the whole cable in something...i dunno maybe some soap? Maybe it'll coat it enough if u cant spray into the cable housing.

Or maybe its just dirty inside so a good underwater wash in a lot of soap might help

 

[Pokageek]

Maybe it is the "ball " end. I will re-oil it. Yes, with the car off too.

Ok,I reoiled that and it seems that the throttle cable is no longer squeaking...I tightened up all the vacuum lines and throttlebody. SO now I am thinking it is POSSIBLY my belt? It SOUNDS like a metal squeak BUT it might be a belt that is slightly loose deceiving me...

 

[Pokageek]

Still chasing down the squeak. The car drove fine today for a short run though b/c my belt keeps coming off as it is 1/2 inch too long at 85..if I go to 84, I cant even get it to go on.. Plus it APPEARS that my tensioner pulley is a little off or something...weird.

Solve: I (think) best way around this is to put the dummy pulleys back on (a/c elimintae and smog delete...that I sold lol. That may correct the issue..

The 36# tune seems ok, and new 02's and plugs but on start up, I still need to floor it sometimes to crank over - not sure why. I will need more driving and testing b4 I feel it is 100%.

Anyone elses's header wrap smoke alot BTW?

 

[final5-0]

The 36# tune seems ok, and new 02's and plugs but on start up, I still need to floor it sometimes to crank over - not sure why.

If you are still using an unmodified pcm
or
Unless your start up fuel table has been optimized

It thinks you got 19lb inj's
but
In reality you are suppling almost twice the fuel when you crank it

Grady

 

[Pokageek]

If you are still using an unmodified pcm
or
Unless your start up fuel table has been optimized

It thinks you got 19lb inj's
but
In reality you are suppling almost twice the fuel when you crank it

Grady

Ahh, ok, so there is a "startup" table too?? Thanks x10 for the info Grady! I think the startup table is either programmed for 24# or 19# . Kauffman's just programmed the 36# tune thru te mail for me to get it running well enough to drive it up to them in the next few weeks..I bet they did not tune that particular table.

Also I FOUND THE SQUEEK! It is coming DIRECTLY out of the air filter! .. so I wonder if I put the vacuum tube back into the intake tube then maybe it will go away! But I will have to close of the OTHER valve cover's breather if Hisson was right.

It was kind of funny...I drove into the garage and the car pooped the belt out on the driveway... it is like the idler pully is the one that's off..although I did get a new alternator with a slightly larger pulley..Maybe changing back to the old pulleys will work..frustrating..

 

[final5-0]

Ahh, ok, so there is a "startup" table too?? Thanks x10 for the info Grady! I think the startup table is either programmed for 24# or 19# . Kauffman's just programmed the 36# tune thru te mail for me to get it running well enough to drive it up to them in the next few weeks..I bet they did not tune that particular table.

I'm sure they can take care of that issue for you
but
Don't forget to tell them about it

In the meantime ... as you talked about ......
you can crank it with the skinny pedal on the floor
and
that will kill the fuel during the cranking period

It just takes a while to get things all sorted out

Grady

 

[Pokageek]

Once again Grady is the MAN! Ok, latest solves to issues:

#1 I would also like to mention that I changed my "pcv system" over to a closed system again and will check it in the morn. This means I capped the one valve cover and basically went back to the 94/95 setup with a tube going from one breather to the intake tract just behind the MAF. I will report back on results. Hopefully this gets rid of the SKREEEEK!! coming from the cone air filter.

#2 I figured out that my was of "rigging" the tensioner pulley was kinda dumb.. I was putting a washer behind it that did NOT allow it to center properly on the spindle that the bearing wraps around.. So to correct that yet still move the tensioner out a hair (it seems to stop spitting the belt out when I do that) , I fabricated a nylon washer to fit AROUND the spindle so that the pulley can still center AND mobe properly. I will report back tomorrow..

Once again, thanks to everyone here for listening and I hope my build helps someone else one day.