Cam suggestion and Tune Question

[Alexia]

Sidewaysstarion,

I really try to avoid being confrontational on public forums. However, you keep making vague references and claims over the years that you have the knowledge to do flashing without putting up the proof or helping further the community as a whole by helping out. If you do not actually have the knowledge to do it then do not mouth off at the people who are here to assist the Jeep performance community. It is small enough as is currently and only a handful of people are working at improving the current scope of user friendly PCM/performance modifications. Being rude to people will only help to drive them away from the community.

Now, can we all get this thread back on track?

To thepdk: Tuning the OEM JTEC PCM is the best, perhaps easiest, way to get factory driveability. However, the PCM is also very good at adjusting automatically to run properly even if it will not produce optimal power from the camshaft swap. So it really comes down to if you wish to sink around $600 into a handheld like the SCT and tuning labor costs or go all out in the $1,100 range to do a custom DIY EFI setup such as Megasquirt.

 

[FlyinRyan]

Source: http://thespeedfreaks.net/showthread.php?10039-DCX-JTEC-NGC-PCM-tuning

You made that post 2013 and then you said you've been tuning for over a year, that means you started tuning in 2012. so you have ~3 years under your belt playing with SCT and now you're some hot shot tuner. SCT gives you some of the tools you need to bang out a semi-decent tune, but tuning with the SCT tuning suite is like, how did you put it, only playing with half a deck? Have you figured out how to get a big cam magnum motor to idle without modifying the idle air circuit?

P.S. If you don't own the SCT tuning suite, did you steal it?

Sideways 'Calling it as he sees it' Starion

3 years and change with SCT, and by my best guess, about 350-400 trucks. I had some exposure with Diablo CMR prior to that, and before that, I did some carb tuning on bikes etc. Considering that the majority of the trucks I do are already tuned by someone else and THEN come to me to re-tune due to drivability problems or lack of power, I would like to think that counts for something.

Big Cam Magnums? Yes, I do them regularly?

No, I didn't steal the SCT suite I use. Come on now. :banghead:

 

[hexdmy]

Because anything else is like playing with half a deck! eace:

I will just make once comment to this, and it's not a criticism . If you are Jeep owner who needs tuning work, and the above statement helps persuade you to use, increases your confidence and/or comfort level with FlyinRyan, you would probably be better off with Ryan rather than me. I find that if you think you are the smartest man in the room, you tend to limit your opportunity to learn, so I try to approach things with a level of humility, even though I've been tuning Mopar EFI for over ten years.

 

[John(XJ)Jeep]

That's why I pick and choose from here and throw the rest away, because the rest ain't worth my time.

 

[thepdk]

Most cam packages are spec'd for up to 1997 model year, mine being a 98. Would this be a problem? any differences that would affect the cam?

Thanks!

 

[Russ Pottenger]

The early engines use a spring/dowel method to control the cam thrust.
The later engines utilize a cam plate which has a difference snout. Although cam blanks are available for both, most of us use the early style cam.

 

[thepdk]

The early engines use a spring/dowel method to control the cam thrust.
The later engines utilize a cam plate which has a difference snout. Although cam blanks are available for both, most of us use the early style cam.

were both used in 98? im getting conflicting information, some say 97+ uses the thrust plate, while others say 99-01 uses the plate

 

[cal]

I have seen 97's and 98's with the plate.

I have never seen one with a spring loaded dowel.

Doesn't mean they aren't out there I suppose.

 

[thepdk]

who makes a compatible cam, or is retrofitting the old style spring and cover the preferred way

 

[Russ Pottenger]

who makes a compatible cam, or is retrofitting the old style spring and cover the preferred way

Just returned your PM.

Thanks

 

[nosigma]

On topic but a little different question...

I have a 95 OBDI 4.7 stroker motor with a reworked head in my 66 Rambler American Convertible.

(see http://www.jeepstrokers.com/forum/viewtopic.php?f=5&t=226 for flow data).

The cam is a Comp Cams 69-232-4 206/212 deg at 0.050 with roller rockers for the higher rpms. Last motor was a bigger cam on a bored 258 with 3 45DCOE's. Ran great but I wanted better drivability.

The FI stroker is horrible

The motor leans out something awful at 2400 rpm under moderate acceleration, 25:1 (innovate motor sports wide band).

Injectors are 27lb EV1 blue tops
Adjustable MAP sensor voltage (doesnt fix it)
Adjustable Fuel Pressure (set to 40lbs now, had it up to 50) doesnt help
The throttle body is stock (it could use a lot more)
The exhaust manifold is stock (it could use a header)

I assume that the lean out is due to the fuel map and not the headers or throttle body. It runs moderately rich most of the time, 13:1.

The car is basically undrivable unless I just want to cruise around at low RPM and never accelerate.

I would love to find some help on getting this thing tuned up but its OBD I and as far as I know there is little to nothing I can do about it other than build a custom FI system and build a map for it. Suggestions welcome

John

 

[Dr. Dyno]

John, your engine shouldn't be leaning out like that.
I'm running a stock OBD1 PCM, stock FPR, Ford Racing 24lb injectors, and a MAP adjuster set at 5.30v on the 4.6L stroker (stock '92 cam, ported head) in my '92 XJ. My engine runs great and has no such issues.
I wonder if you either have a problem with your PCM or your MAP adjuster isn't wired up correctly.

 

[Talyn]

How old is the O2 sensor?

 

[nosigma]

Dr. Dyno:

Borrowed a Snap-On OBD I diagnostics kit. I can record data. I will run it later this afternoon and have an excellent read out on what the FI system is doing.

Talyn
The O2 sensor is new when I built the motor two years ago (very little drive time).

Dr. Dyno
The fpr is set at 40lbs right now.
I did some stationary runs idle to 2500 rpm last night with the Snap On test rig. MAP sensor seems to behave properly. I will have data before and during the lean out later tonight to report.

What would I look for in the PCM for a problem? I will have plenty of info to diagnose in a few hours. The injector pulse width (4.3 micro sec at idle) will probably tell a lot.

John

 

[nosigma]

Found a problem, not sure if its THE problem but its a problem......

When I first ran this motor about 2 years ago I had the lean out problem when I went to go do the ring break in. I drove it maybe a total of two miles trying to sort it out but then tun my attention to a clutch problem. It took a long time to figure that out and its a long story that I wont go into but it ended up involving a transmission rebuild and making a custom throw out bearing so the T-5 would be happy behind the 4.0 block using the AMC multipattern bell......During all the driving I did I never noticed a fuel pressure problem. I have a fuel pressure gauge mounted so I can see it.

When I got running again a few days ago the fuel filter clogged with the fuel pressure dropping at an idle. Put in a new one and it clogged again. Dropped the tank dumped the fuel (dark brown and NASTY) and sloshed new fuel till it came out clean. Put in a couple gallons, drove it gently to the gas station and put in 4 more gallons. It would still lean out on heavy throttle but I never noticed the fuel pressure dropping, though I must say my eyes were glued to the lamda sensor to make sure I didnt burn a piston. Did some more idling with good fuel pressure.

Today when I took it out to run it I got one good run and it pulled really well through 3000 rpm with no problem!!!!!!! Whats that all about??? Car fixes itself sitting still, its magic!!!

Set up the data logger and tried to do it again logging data and it died with fuel pressure dropping from 40 to 20 lbs. Let is sit, tried it again, good idle but when I got on it I lost fuel pressure.


Before I waste more of your time: Ordering up a new fuel tank and going to build an internal pump set up instead of using an inline pump. When thats done and fuel delivery is fixed I will post up again, back on the original topic of Cam and tuning.

John

 

[Dr. Dyno]

It seems clear that you have a fuel delivery problem so that rules out the PCM. Have you checked the fuel lines to see if any are kinked?

 

[nosigma]

The fuel lines are all 5/16ths hard lines except for short runs of high pressure hose which are straight I am sure the tank is full of gunk and the filter clogged up again, both inside and outside the tank. The fuel coming out of the injector rail is light tan. Dropping the tank and going to renew everything from there forward as needed. I need to get clean fuel at a stable pressure delivered before I do anything else.

John