SeanR

Might have a set of those, I remember a few asking me about that last year.

Bill Ball

Normally a FI harness short kills the signal to the injectors, not just "weakens" it. It seems you may have evidence it's not the harness, but it's real unclear. You have it running on your rebuilt brain.

killav

I have four PEMS here that are Roger's. I can send two with Laura in the morning if you would like.

SeanR

If you would that would be fantastic. I can head over in morning on my stock computers to pick them up.

killav

Ok done.

SeanR

Thanks Mike, as always, you might just save the day.

RKD in OKC

When i first started ST ing I had problems with the car and the battery going dead. Didn't check for spark or injector pulse because ST also stopped talking to PEMs. And would always fix it to install stock chips. Re-installing PEMs and would not start. Putting in new PEMs from Jim and it would work for a while then same issues. Finally replaced LH and everything is working great with PEMs and ST.

Did have on issue with new LH and PEMS, got impatient and cancelled file update and the LH locked up (no start, no talk to ST). Disconnecting car ground to reboot everything fixed it and no issues since.

jcorenman

Sean, there were a few bad PEM's last year but the symptom was entirely different: They would not load into ST, or run. That is not the problem that you have.

OK, car starts cold, and then won't restart hot, then starts the next day... is that about right? Sounds flooded to me. I know you checked for wet plugs, just sayin...

What is the cranking PW in ST? The default setting is 3.9 IIRC for 19# injectors. You swapped those for 36#, almost 2x. If you don't reduce the cranking PW accordingly then you are injecting almost twice too much fuel when cranking... instant flood. You can get away with that cold, but not hot.

With 36# injectors, ST's injector-size setting needs to be within rock-throwing distance of 36#. You can fudge it a bit for fine-tuning, but but if you set it to 19# then again you are injecting almost 2x more fuel than the LH thinks it is squirting.

The opening-time setting is important especially at idle and light-load where the pulse-width is short (2-point-something ms). This is not "opening time" strictly, but rather "latency" or whatever you want to call the difference from the electronic pulse-width and the actual fluid injection-time. Spec's are hard to come by (other than FMS) but the numbers I've seen are in the 0.7-1.2 ms range. If you an send the injector part# I will try to get the correct spec.

Are you sure that the injectors that you installed are what you think they are? It might be worth double-checking.

And you can't do this without a WBO2. I'll put together a "plug 'n play" kit when I get home (late tomorrow), but you need something. If you can beg/borrow/steal an LM-1 or LM-2 then that is perfect for temporary use (and for tuning other people's cars), but you need something.

Cheers, Jim

Lizard928

Sean,

I concur with Jim on this.

Dont forget though that the pulsewidth will be significantly shorter with 36# injectors so that may show up as "weak".

As to the injector opening time, you really need to get us a part #, or track down a spec sheet for those. If it is at 2.0ms, this also will explain the weak signal.
My 60# siemens injectors run a 1.14ms @13.1V. I couldnt see yours being much more than that if even that.

I also concur on the WB, just spend the money and buy an innovate digital MTX they are $199 on their site, and worth every penny for tuning. If you dont have that, you shouldnt even be driving the car!

If you want to call me tomorrow and I will help walk you through some of this.

hacker-pschorr

+1
Who ever suggested otherwise should have their head examined. That's like saying you should go test the brakes on a car before installing pads.

Please don't go any further until you have a WBO2 - the potential for catastrophic damage is too great. You cannot rely on the narrow band to pull you within range with larger injectors unless you know for a fact the injector size in the ST is already optimal. Based on Jim's post, that is a big "what-if" right now.

On my car for the initial fire up with the 42's and LH 2.2 I set the injector size as big as it would go and with my modified MAF, simply kept adjusting injector size with the engine warm at idle until it was happy. That was enough to give me a safe enough tune for some really tame driving around town - before the supercharger was re-installed.

What does the voltage read in the ST? Long time ago we had a car doing some really erratic things, then "discovered" the ST was reporting high 12's for voltage. Found the two smaller power lines on the battery loose (which power the brains) - that fixed it.

Bill Ball

Sean reported it intially started and ran pretty well for 7 miles. So, although I certainly agree you can't tune w/o a WBO2 (I hope no one was suggesting that and I'm not sure what Sean was doing on the "tuning" ride), there appears to be something else going on now other than bad tuning. The weak noid light and the fact it will start on a 19 lb setting (and run like crap as you would expect) but won't start with PEMs needs to be reconciled. It should start and run on Victor's supplied files (he did supply some Sharktuned files, didn't he?) and just need fine tuning from there....with a WBO2 sensor installed.

In the meantime, I would probably temporarily remove a boot from the supercharger intake (or some other simple maneuver to return the car to NA), reinstall the 19 lb injectors and try to run it with a stock set of LH and EZK files in both the stock brains and the PEM-loaded brains, just to eliminate a whole bunch of confounding variables for now.

John Speake

When you "resize" the injector settings with the ST2, you alter most of the fuelling in step with the size setting EXCEPT the cranking pulse width. So you need to edit that down in length (Parameters screen). I need to edit the User Manual to emphasise that point.

Like Jim said....

I remember Tony had hot start issue when S/C with 42# and found that adjusting the cranking pulse length fixed the issue.

Also note there is a "cranking fuel map" available in the fuel map drop down menu. Once you have adjusted the main cranking pulse length on the parameters screen, you can then make the cranking pulse variable with engine water temperature, as required. The map only allows you to richen at lower temps, relative to the value set at normal temp in the Parameters screen.

I must say I was puzzled about "tuning " the car with no WBO2 - was that just for ignition ?

docmirror

I've never STed a car, but I did sit in on Jim's most excellent primer at OCIC. I think Sean has changed the pulse width but if not, that could certainly cause grief. I'm going up there in a bit, and maybe get in his way, and kibbitz on the process.

victor25

Just to confirm what I said.... was that the car should run fine on the files we loaded for the PEMs at install without installing a wideband, and that he should get one later to fine tune everything, esp WOT. Everything happened just a few days before the event, so Sean did not have time to put a wideband in his car. And yes I said we would not need one to do the install and get it a basic tune done.
Also... Yes I can tune without a wideband, and get everything but WOT pretty much spot on. Anyone who is good with a sharktuner knows that if you watch the O2 sensor adjustment you can do some pretty good tuning. Obviously if the O2 adjustment is floating around +20 then you need to add fuel in that target cell area (or adjust your opening time if you talking about idle). and vise/versa if it is -20.
After all the LH doesn't use the wideband, and neither do 99% of the cars on the road.

victor25

+ + to Jim and John though. I think you need to go back to the original tune, get the injector opening time correct and then get the crank pulse time lowered back down, way down. You were going the wrong way with your crank pulse time, you need to go down, not up.
Also find out exactly what LB those injectors are that you supplied. They were a different color than what I am use to seeing.