Need diagnosis help

[S4Vince]

My Sy was running good after installing the following: plugs, wires, dist. cap and rotor, new K&N cone filter, K&N breather, oil change, aluminum turbo to IC hose, MSD coil, both PCV valves, adjustable fuel pressure regulator, new walbro 255 fuel pump, battery, 160 deg. thermostat. Truck runs quite well I might add after all this. I drove it for a good 20-30 miles without problem. Then I buy a 10-1 chip and install it. Truck immediately idles badly. It's ok for the first 10-15 seconds and then it kicks down and stubbles almost stalling. I then put the stock chip back in and it still idles like crap. Now I didn't make any chances since the orig. chip is back in which was smooth just 10 minutes before. I grab a new ECM and try again. Same thing, no change. I take it out for a drive and notice a longer turbo lag than normal and do not notice any substancial difference between the various settings on the chip, although the valet and disable mode works and the idle is better (for like 10 seconds) in the T116?? (the mode above stock +, sorry forgot the exact display).

What could be going on here? All is good, change a chip and runs bad. Put in original chip again and still bad :-?

I need some help here, what can I check?

Thanks all!

 

[ed hess]

just wondering here but before you plugged ANY of the chips back in did you disconnect the battery?

I beleive you should but i dont know if this could have damaged something electrical.

perhaps someone else can verify this.

but anyway did you disconnect the battery before unplugging and plugging in?

ed

 

[S4Vince]

I did not however I did pull the two ECM fuses (A & B)

 

[ty1548]

I once had a similar problem with my Ty, and it turned out to be that my base timing was off by 6 degrees retarded. It did the exact same thing until I corrected this. I had checked for vacuum leaks, IAC operation, O2 sensor replaced, plugs/wires. Nothing helped until I reset the timing.

Also, you do not need to disconnect the battery to install the chip.

 

[ed hess]

dont know if you ever checked your timing before on this truck but one more thought.

makes sure all the conectors are totally plugged to the ecm.

check that no wires are pulled out of the ecm

makes sure your chip is totally seated

There was a tech bulletin once about wire chafing on the ecm

so inspect the harness as far as you can see.

ed

 

[InvisiBill]

What's your fuel pressure set at? The Ultimate (not sure if that's the one you go) requires a higher FP than stock.

If it's an Ultimate, you also need a 3-bar MAP sensor. The stock chip requires a 2-bar. If you didn't use the appropriate sensor for each chip, the ECM wouldn't be seeing the correct boost levels.

 

[Flyin Ryan]

I did not however I did pull the two ECM fuses (A & B)

Pulling the fuses is fine but isn't there a learning portion to installing a new chip...isn't it something like run the truck with every one then with it off etc...??

Also I have this same problem changing chips... Then I notticed that I had three degrees of timing advance so I corrected that and now the truck idles like a pig... I replaced the iac, all vac lines with silicone ones, map sensor, plugs, wires, cap/roter, and other stuff I can't remember what but nothing helped so Im dealing with it right now but check your connectiions at the ecm.. make sure there good.

Good luck

Oh and I tried diff fuel pressure settings but couldn't find any that helped any. So keep me updated if you find your gremlin..

 

[ty1548]

dont know if you ever checked your timing before on this truck but one more thought.

makes sure all the conectors are totally plugged to the ecm.

check that no wires are pulled out of the ecm

makes sure your chip is totally seated

There was a tech bulletin once about wire chafing on the ecm

so inspect the harness as far as you can see.

ed

That's a good point. This too happened to me from yanking the ECM down too many times. I eventually pulled a ground wire and the IAC control wire out of the ECM connector. This was years ago and quite a headache to diagnose.

 

[S4Vince]

I have a (new) adjustable fuel pressure regulator and have played with the settings and they make no change to the way the Sy runs.

I did a brief vaccum test yesterday and all seems good.

Plugs, wires, dist cap, rotor, coil, PCV's etc all brand spankin new

My biggest issue is that it ran great prior to changing the chip. Now it runs like crap with the stock chip so maybe the last post has some merit. I will look at the wires going into the ECM carefully. Again, I tried two ECMs and they run the same way?????

I'll look this weekend!

Thanks all, I'll keep you posted.

 

[S4Vince]

Could a clogged fuel filter cause this? Just wondering as I have yet to change this. The guy I bought it from said he did it about 150 miles ago so I thought it to be OK. I must say he lied about a few other things so I may as well try.

 

[Mad Mike]

I know it was posted earlier but you have not responded. Are you putting a 3 bar map in with the ultimate?

 

[S4Vince]

I have a chip made by Todd A. (seems to be a great guy and product) with a small rectangular box with LED. This is the 10-1 which is different from the Ultimate, right? So therefore I shouldn't need the 3 bar map.

I seriously think it has something to do with the wiring since the stock chip idles poorly now as well and both chips run the same in both ECMS. I must have disconnected something.

Sometimes I miss my Firehawk, it was so reliable :-?

 

[ed hess]

vince

let me tell you something....

I am the original owner of my sy.

If proper maintenance is done this can be very reliable vehicle.

mine has been very reliable.

Only times it was ever one a flatbed.

broke transmission same day as the 9-11 ny thing

other than that i was never on a flatbed cuz it couldnt be driven.

once you get EVERYTHING sorted out yours can be also.

ed

 

[S4Vince]

Ed,

I agree, but my experience with Sys (had 2 now) is that they tend to be very tempermental. I have never had a car be so sensitive to even varying weather conditions. I've had a lot of cars, european and domestic, muscle cars and turbo cars and the Sy needs the most love. Granted, it is still the most fun!

The previous owner of my Sy wasn't the nicest caretaker either and I'm trying to get things straightened out

 

[ed hess]

On the other hand, ive never been cheap with this either.

At 75 k i rebuilt the front end just because i wanted it to be like new.

I guess a lot of it comes down to attention to detail.

ed

 

[S4Vince]

I agree with you, I do not spare a cent when it comes to the Sy, or any car for that matter. Hell, I spent $125 on wires for the Sy just recently. I invested (gotta be careful with that word) close to $10K in my vette last year and you can't see a bit of it sitting there.....my wife loved that one

 

[ty1548]

Vince purchased a 10-1, which uses the stock 2 bar sensor.

 

[fizzler]

How do you know for sure if it is an Ultimate or something else??
I have what I think is an Ultimate in my Sy but it only has one toggle button rather than two! To be honest,,,, I really don't know what I have
It looks like an Ultimate but how do you know if it is a model that requires a 3 bar or a 2 bar MAP sensor? One button, hmmm! No one can tell me!

James

 

[S4Vince]

I got the Sy running pretty good by palying with the fuel pressure. In fact, I have never heard it idle more smoothly. I'm pretty happy and put the ECM (with 10-1 chip) back up under the dash and put all the plastic back up. I start the truck and everything is still good. I put the thing in reverse and the "Check Engine" light comes on. WHAT THE HELL!!!!!! What is going on here??? I discount the neg. battery cable and try again, same thing.

HELP

 

[S4Vince]

Sorry for my spelling, that was suppose to say "disconnect" my neg. battery cable.

Typing too fast, that's all!