SeanR

Need some help here. My car, ’88 auto. GTS intake, intake spacer, X-pipe etc.

Last weekend we installed Victors supercharger kit and I provided the PEMs and 36lb FMS 4 hole injectors (bosch), measured ohms showing 18.1, previous were 19lb 4 hose FMS with measured ohms at 14.8. So both are high impedance ones. The PEMS were ones I had here for the past year or so that had the basic S4 tune. Installed the PEMS and the car ran great on the way up to Wichita, actually saw better performance from them than I did the stock chips in the rebuilt brains the week before.

Supercharger install went smooth, initial start up was quick and easy and was repeatable each time in the convention center; now this is where it goes to ****. Mike V and I went for a drive to get some Sharktuning for the trip home. Go for about a 7 mile drive and we cruise tune and the car is running fantastic except we have a rear knock sensor fault. I pull over since I remember that one might still be unhooked. Pop hood and plug it in while the car is still running but of course the fault is still there so I turn off the car to clear the fault and try to restart.

Nothing.

We reloaded the ST2 with base maps, make changes to maps, nothing we try will allow the car to start. We thought that the PEMS just didn’t recognize the whatever. Jumpered all the relays, all fuses checked etc. The plugs were not fouled out. We tried a new set of brains and still no go. After an hour of messing around we called in the cavalry and Tony towed us to the hotel. By then we were hot and tired so we went to dinner. When we got back Doc and I pulled a plug and tested spark at night. Spark was great so we eliminated the ignition switch. When I got it home I put in a new ignition switch just to eliminate it.

Next day the car showed up at the house, on the back of a trailer and for giggles I tried to start it and it fired right up so I put it in the garage and started to try and tune. Car starts with the 19lb setting for the injectors….rough but it starts. I gradually move it up to the 30lb custom setting and set the injector opening time in the mid to high 2’s and its idling great, has quick throttle response in the shop. Take it out for a drive and it feels worse than it did before the SC install.

Mike had pulled back some ignition timing on the first run/tune just to be on the safe side and do not have any base maps to replace it with. My cams are also set way flipping retarded at -4-6 because I was experimenting after doing a bunch of cam retimes and wanted to see how far we could go.

*note: there is NO WBO2 installed, I was assured that it would not be immediately necessary for initial install and quick tune. I will have one once Jim C sends me the set up he has when he gets home. Got the sensor, just no innovative.*

Now comes the fun part. Once I get the car started and shut it down, it will not restart. Sometimes when I switch back to the 19 (stock) setting the car will fire right back up but run like crap, other times there is no injector pulse. I’ve had a noid light connected on each restart to see what the pulse looks like and most of the time the light is very dim. When the pulse is bright it starts. So I went through the wiring harness for the injectors from the LH/EZK/Diagnostic port/Sensors and everything in between and can find no short in the harness. Half the time there is no or slight injector pulse. I’ve tried a stock set of brains (JDS rebuilt) with no better results and am at a huge loss of ideas. Both the brains I’ve been using are JDS rebuilds so an LH problem is small.

I’m a noob at Sting so this is most likely my own fault and not the cars. I need help.

Sean

SQLGuy

Not that I can see any good reason for it, but are you sure you have good 12V to the injectors after the shutdown and no restart? Just wondering whether the lack of injector pulse might be due to lack of supply rather than lack of ground pulse from the LH....

SeanR

Supply voltage is good on all 8 when the LH relay is jumpered and the W13 connection is powered at that point. I initially thought it was an LH issue but a replacement brain (2x) has sort of eliminated that. I thought I had an issue with signals between the brains so I went ahead and pulled all the connectors and ran continuity traces on all of it and even while moving the harness, there was no break in signal. I am losing power at those and can't seem to find out if it is a ground signal loss or a power issue. Each time I test it it seems to change and that is why I started to check the harness. With everything disconnected, the harness seems to check out good.

Tom. M

Probably not the issue...but one should always try to go back to what you did before the issues started. If I'm reading this right, you had a knock sensor fault, stopped, plugged in the rear sensor, and then started having issues.?

Did you try just unplugging the knock sensor to see if anything changes?

JWise

You set the latency times to "the mid to high 2's", as in 2.xx? IIRC, most latency times were less than 1, I think mine were best at .75 although manufacturers spec was like .55

SeanR

Yup, that was the exact thing I tried first while on the side of the road.

Right now, I have the ST hooked up, same maps loaded as I had when the car started and ran a couple of hours ago, but see nothing on the noid light. Typically I'd think relay.....so I swap in a few good ones. No change.

I'm dang near about to pull these injectors and the SC and put to back the way it was last week.

SeanR

Very odd, just went to try and start, and nothing. Plugged in a stock '88 EZK and nothing, but I put in my old LH with stock '88 chips and it started.

Hmmmm. Ran like **** but had something this time.

GregBBRD

Sean:

My first guess would be an injector wire, right at the boot, touching the other wire (power touching ground right by the injector.) I've had this happen several times. Several times. That would explain your "weak" injector pulse and intermittent problem.

My guess would be that you "bumped" the wires into touching, when you plugged in the knock sensor.

Pull "back" the boots and check for bare wires.

SeanR

If I said I'd never thought of this I'd be lying. All of the boots are in good shape and it's been on my mind for the past couple of years to change the connectors and boots........because the rest of them on the car have been changed. I suppose it is one of those things where you don't want to spend the $100.00 in connectors and time on your own car but have no issues saying to a customer that they need it done.



I suppose I might as well break down and do it on this one so I know that is not the issue.

It is very odd though that the car is now starting very fine on my stock (rebuilt) LH.....damnit. Why can't this be easy. If I'd just pass it off to you Greg I could pick it up and not worry.

cfc928gt

Sean, have you checked the MAF? I had mine running great, shut it off and the wire burned up during the burnoff cycle. When I tried to restart it would hardly run. Since you're not fully tuned it could be that you're so far off on your air/fuel that it can't run with the larger injectors and boost.

SeanR

MAF is only a year old, I did run the element test today and it came out ok.

I think I'll know more tomorrow. So far the car has started flawlessly with the old (rebuilt) LH and EZK. so it has to be a PEM problem or an LH problem with the new brain. I love having spare parts around for this stuff. Its getting too late to run the car up to temp to see if that has any effect. The neighbors are all car guys and my immediate neighbor is a huge boost dude so he understands. The rest wouldn't.

Dean_Fuller

Puss

killav

Sean,

You do have base maps if you want to load an EZK one. Just go to the File "NEW" and it will pull up a screen that will allow you to load a base LH or EZK map for various cars.....

I only removed about 3 or 4 degrees from the WOT map and on the cruise map from about 3k RPM's on up that is the only change I made just to give us some knock cushion while we were initially tuning...

Did you get that LH file from Victor yet?

SeanR

Thanks.

Yes, I did get those maps from him this morning and loaded them up. Same issues. Car started great on the 19lb maps, idled better as I changed the settings and then drove, stopped, turned off then nothing.

I'll load up the original EZK (new) and see how it is. Right now it starts continually on the stock computers. This is way too much fun.............

928er

wasn't there a bad batch of pems a while back?