[94MI9C1]

I posted this in the engine problems side and no response so I figured I would post this up here, thanks in advance.
Hey guys I think that I have it nailed down to the problem but I am really not sure. I am working on a buddies car for some other stuff and it is running God awful rich. When he brought it over I could barely get it to start, found the TPS and idle adjustment screw not right, set them correctly and it would fire on the first bump. Still running rich though and it would never go into closed loop, at all. ECT sensor is working correctly as it is rising like it should. It tried to go to closed loop for about 2 seconds today and bounced right back out to openloop.


There has got to be something missing. Here is a ist of things that the scan revealed as well as the the tune that is in it.

- Tune: Seems to be correct for a mail order LT-4 hotcam tune, but my buddy changed the rockers to 1.6 ratio units, shouldn't matter as I think that he just had the 1.5's on for first start up. He had a shop put in the rockers for him though, so really not sure if they are adjusted right. Also the cylinder volume number is wrong as it is set right now, too low, for being a 355, would this matter much?
- CEL's: this is a T56 car and the tune is for an automatic car with all the diag codes that are set to show up for an auto trans. Right now it has 3>2 solenoid code 84, but there is no AT in it so that explains it. I will flash those codes out of the PCD, but would that make it stay in OL? I wouldn't think so but something to mention.
- As far as running, it really runs rough, motor vibrating quite a bit for just an aluminum headed LT4 hot cam motor, I would think that it would run like that. Not sure though. But you rev it and it revs fine, besides the fact that it is running so rich.

O2's seem to be swinging like they should but maybe not often enough to enable CL, I am not sure, oh another thing to mention BLM's are locked at 128 in cell 16, I revved the car for a minute came back to look at the computer and it was in CL and I was like damn finally, then it bounced out of CL back to OL, went to cell 18 for a brief second and BLMS were split, left 134, right 118 or so.

IT could be the O2's I guess but figured I would post up here and see what your guys thoughts are.

 

[94MI9C1]

Also some notes on above, I know that one of the O2 sensors isn't swinging like it should hence no closed loop operation. But this thing is running damn rough, almost like firing order is off or the rockers are adjusted wrong or something.

Also note I changed the tune to reflect what changes I felt need to be made with it, i.e. cylinder volume and such.

This is what I changed

- bumped cylinder volume from factory setting to 726.22 for being a 355
-subtracted .31 off the injector flow rate to a value of 31.69 for Ford 30 lb SVO's
- changed Min Coolant Temp for CAT protect to max value since there aren't any CAT's on the car
- bumped min coolant temp to enable air pump to max as there isn't an air pump on the car.
- Bumped CAT overtemp Threshold low, mid and high baro to max, since there are no CAT's on the car
- on the switch table, I deselected "TCC EnableDisable" "TCC release at low TPS" " TCC Release with rapid TPS decrease" " Downshift turns TCC Off" "MAF System Diagnostic, error 48" "TCC control feedback diag error 83" "3>2 downshift feedback error 84" and " shift light diagnostic, error 91"
Selected Fan 2 Diagnostic Error 78.

Loaded the program and it wouldn't start, blew smoke out of the intake or the air filter, WTF nothing that I changed in my eyes would have that big of an affect on something like that, reloaded the original flash and it fired up, though there was extend cranking due to being pig rich.

One thing to note it has a BBK 58MM throttle body as well. Just trying to do a friend a favor and I am lost as to why it would be running like this, and really idling at 1K it runs rough, like shaking the whole car rough, I could shoot a vid of it I guess. I doublechecked the firing order and connections to the opti on the drivers side and they are good, have to do teh passenger side yet, but that is what I am left with.

I guess I can try to reload the original tune that I modified back into it and see what happens. I don't know any thoughts on what else to check.

Oh on another note and not sure why this is, but I can go out there right now and it will fire right up, if I turn it off and try and fire it again you have to give it a bit of gas and then it stumbles to life.

Help !! thanks.

 

[Rocko350]

Has the idle port on the throttle body been modified to only allow flow to the IAC passage. These throttle bodies were designed for TPI cars as well. This is most likely the reason for the split blms. On the running rich, have the voltage offset tables and low pulsewidth tables been modified for the svo's? I have a 42lb injector equipped car that Iv'e been working with that would hard start and idle poorly until both of those table were properly adjusted. Scott Knight posted a thread on here about dialing in a set of 83 lb/hr Siemens injectors that had some conversion math and use of a cool program , Scilab, to generate a corrected table based on data from the Ford worksheets.

You might need to reduce the startup VE and lower the closed throttle timing at the 0 and 400 rpm points


Chris

 

[94MI9C1]

Yeah I will have to dig that up and see if I can find his post,

Not sure on the TB, maybe maybe not. When he brought the car over for me to do other stuff, I pulled it into the shop and it would choke you it was running so rich. Figured I would check the TPS and all that, I adjusted them within spec, tightened down some intake tubing and it fired right up, so I thought that was it. But obviously it wasn't,

Looking at the tables Inector offset vs. voltage all teh usec values as compared to my cars tune and another tune that I have have been adjusted 183 usec higher than normal, the only values that weren't changed was 3.2, 4.8, 5.2, 5.6 voltages

No difference between my factory injectors on my car tune and his in the "Low Pulse width Injector Offest Adder" table.

I did notice that the crank spark advance vs. coolant table has been changed from factory or from the tune that I have in my car. Pretty drastically as far as much as 6 degrees @ 20 4.0 degrees @ 32,44,and 56 and so on, this is more advance that has been added. looking at a hotcam tune that I got online, there is a huge different there as well. I was thinking that this table could be a factor as usually smoke out the intake would intake to far advanced or retarded, right?

As far as closed throttle timing at 400 and 800 rpm it is 8 degrees higher than a hotcam tune I am looking at. it is set at 27 degrees which I think is really damn high.

I don't know there maybe something up with my tuning laptop as I think that it would erronously change some values for the worse. I am going to try and load the file from the desktop of my laptop and see what happens, I Am going to take your advice and change the tables that we had talked about , as see what it does, VE is probably ok, I think that it is just dumping fuel at start and it is firing weird, don't know what the hell is going on, thanks man

 

[94MI9C1]

I also looked at the datamaster log that I took of it idling for a bit last night after I reloaded the tune in it and noticed at idle it is pulling 75-90 kpa on the MAP @ 50 degrees C and looking at the open loop table vs cool vs map it is trying to hold and pretty rich 11.3 afr , just something else that I noticed

 

[94MI9C1]

Ok changed the tune and it fired immediately, working over the closed TPS timing stuff, but it is still just dumping fuel at it. but the idle hunts alot now, I don't know. I did ntice that the opti vent line was off going to the intake so I plugged that in, maybe it has something to do with the idle fluctuating ? I dont' know.

 

[94MI9C1]

I did notice from the datalog that I ran on the car that the INJ DC is exactly twice as much as my car without a 355 lt1 of course as well as BPW mS at the same RPM, would that little variance in cam and bore cause that? The MAP value seems really high for idle as well. 70-90 KPA where as mine is 33 at the same RPM.

Any guidance would be great, thanks.

 

[Rocko350]

I've had to raise the commanded idle speed on hotcams to 800. I've also had them idle down to 40 kpa with some work.

You have a PM

Chris