caffeine

iTrader: (2)

I'm just finishing up my swap and I have everything wired in. But I can't figure out how to program the computer and I can't get the engine to turn over with the key. When I turn the key to on, the fuel pump will turn on. I know I need to disable VATS in the PCM but when I try to read data from the PCM (with the key at the on position), it just says invalid signal (Tunercats). Any ideas? Also, why wouldn't turning the key all the way fire the starter? Firing the starter manually will start the engine for about two seconds before it dies, leading me to believe that if the VATS was disabled in the PCM it would keep running. I have power to all of the interior and the gauges.

cprmn14

iTrader: (3)

maybe you should just send it off for a tune instead.

like www.lt1pcmtuning.com

heard good things about them

caffeine

iTrader: (2)

Ok I figured out how to get the engine to start. I disabled what I believe to be the VATS relay (one large green wire, one small green wire, one large yellow wire, one small yellow wire, car is an '89 firebird) by splicing a ground into where the small green wire goes. This allowed me to turn the key to start the car, AND allowed me to read and flash my PCM through the OBD1 port.

However now I'm not really sure where to go from here, as I'm not a mechanic and not too knowledgeable about troubleshooting engines. With the MAF enabled in the computer, I can now idle the car and it seems to struggle, but stay idling. If I give it gas, it either really struggles to stay running or just dies. All of the header primaries get hot EXCEPT the #1 cylinder primary, so I think it's misfiring. I also tried running the car in speed density mode (MAF not used), and I can sometimes get the engine to rev up, but it won't even stay idling. My friend suggested that my spark plugs might not be gapped properly. I bought brand new NGK TR-55s IIRC and I wasn't aware that they would need to be gapped even though they are brand new. Also, sometimes there is a little un-burnt gasoline coming out the passenger's side header. My plug wires are also brand new.

Anyone have any ideas as to what is going wrong?
In case it's relevant, I haven't hooked up my factory dual fans yet, the engine coolant temp sensors aren't connected, and my crank balancer seems to wobble a little. I think that could have to do with the way I installed the hub, but could that also be affecting the way the engine is running? Oh and the gas that's in the car is at least 7 months old. I'm not sure if that's a significant issue or not.

ANY help would be greatly appreciated.

Firebat

iTrader: (7)

Don't assume that just because something is new that it is in good condition. My brother is a GM mechanic and says he sees bad spark plug wires very often that are new aftermarket especially the omnispark wires from O'reilly's. The only wires he recommends are AC Delco plugwires but I don't always listen to him and have MSD wires myself.

Get the temp sensors connected, the PCM makes adjustments based on those readings and it might be throwing stuff off.

Check fuel pressure and make sure its 41-47 psi

Check the MAP connector. Sometimes the plasitc tab breaks off the connector causing a bad electrical connection which causes bad MAP readings and that causes the engine to run bad. Check out all your other connectors as well.

Could do a leaky injector test also. Unbolt the fuel rail from the intake, leave the injectors wired up and leave fuel lines hooked up. Prime the pump, don't start the car, and see if any gas falls out of the injectors. Or could just see if the fuel pressure drops rapidly after fuel pump is primed.

caffeine

iTrader: (2)

I just tested for spark on one of the misfiring cylinders, and the plug wire is definitely sparking. I will probably check fuel injectors soon. The cylinders misfiring are #1, #3, #4, and #6. As for the temp sensors, I connected the gauge sender today but I don't have the pigtail for the computer's temp sensor on the water pump. I will get one as soon as I can.

caffeine

iTrader: (2)

Leaky injector test revealed no leaking injectors

caffeine

iTrader: (2)

Running datamaster revealed the following engine codes:
43: ESC fail
48: MAF System Fail

There were some other codes related to transmission stuff and it also threw a code to say that the coolant temp was too low.

Firebat

iTrader: (7)

Code 43 is the knock sensor circuit.

Look at the link below and click on the links for each trouble code. It will bring up a pic of the code and useful information about the code:

http://www.mifbody.com/vbulletin/sho...C-Codes-Sticky

Kind of silly but might be a good idea to double check if the plugwires are hooked up correctly:
http://shbox.com/1/opti.jpg

caffeine

iTrader: (2)

Apparently when code 43 goes off it retards timing by 6 degrees. Do you guys think this could be causing the cylinders to misfire.

kenlamb3

hey caffeine, was owndering if you might be able to help me out, im also doing an lt1 swap in a 91 camaro and im having issues with what wire to hook up to what so was womdering were do you get your info for how to hook up the wires and such?

thanks in advance
ken

Firebat

iTrader: (7)

It shouldn't cause what you are describing and especially shouldn't cause the engine to die. It will cause the car to feel normal but fell like it has less horsepower when you hit the throttle. I don't know the history of the car but if it has something like a 96-97 LT1 running off of a 95 PCM, then the Knock Sensor needs to be from a '95.

caffeine

iTrader: (2)

It's a 94 b-body engine that has two knock sensors. However I only have one plugged in. Do I need to have both of them plugged in?

Firebat

iTrader: (7)

I'm not familiar with the 2 knock sensor set up and don't know if it absolutely needs both. If it's easy to plug in then it would be a good idea to try it.

caffeine

iTrader: (2)

Oh and I also hooked up the ECT (engine coolant temp) sensor and there was no change. Maybe some bad injectors?

caffeine

iTrader: (2)

I believe the wire for the second knock sensor would just need to be spliced into the first. Because of that I wouldn't expect there to be a significant difference with just one plugged in.

caffeine

iTrader: (2)

Oh and I was able to drive the car to a muffler shop about 10kms away. I might try driving it to a shop after the exhaust is built to help get the engine running properly. One thing I haven't tried yet is a compression test.

Firebat

iTrader: (7)

One more simple thing to check would be the connectors to the injectors. Each connector will have a number on it and that number matches up with the cylinder number that the injector is going into. Other than that, kind of stumped. Map sensor, injectors, fuel pressure regulator, optispark, vacuum leak, ignition coil, something internals are a few guesses.

caffeine

iTrader: (2)

I already double checked the injector plugs and tried switching the misfiring ones on the drivers side (1 and 3). There was no difference. Since the computer was throwing a MAF code I could try seeing if I could borrow someone's MAF and see if that makes a difference. Other than that I'm out of ideas as well.

caffeine

iTrader: (2)

I recently talked to a guy at a local tuning shop and he thinks that the injectors could easily be clogged because the motor was sitting for a few years before I bought it. He suggested soaking them in gasoline overnight to clean them. Is there a way to test if they are clogged or not? I'm sure it would be a good idea to clean them anyways but I'd like to know for sure if I'm solving a problem or not.

92rs85berlintta

iTrader: (1)

first off without your maf working your computer has no idea how to control fuel mixture... your headers are glowing because its way to lean. fix the maf is step one. next pull your injectors and soak them in injector cleaner over night. you can hear them click if you quikly add 12v to them... do not hold it to them or you will ruin them. if they dont click they are clogged.. mine were clogged all of them but one after sitting. they wouldnt even fire. i soaked them and now they work great again. once you do those two things you should be ok. you can tell what injector is not firing by simply holding your hand near the headers.. the one with cold header primary obvioulsy aren't firing.

caffeine

iTrader: (2)

Well according to my research, if the MAF isn't working, the computer uses speed density (MAP sensor) to control the fuel mixture, so it should actually be possible for the computer to compensate. I do believe that the MAF is at least partially working though because if the MAF is unplugged while the engine is running, it stalls. I already know which cylinders aren't firing because after driving to a muffler shop I could still touch my hand to the #1, #3, #4, and #6 primaries.

To test if injectors aren't firing, could I just remove the fuel rail and turn over the engine? If the injectors are working properly, they should all spray a similar amount of fuel, am I right? Any that aren't spraying or aren't spraying much could be causing misfiring.

caffeine

iTrader: (2)

I should also probably grab a fuel gauge as well because I'm still using the stock (L98) fuel pump. It is supposed to be able to supply an LT1 properly as far as I know though.

caffeine

iTrader: (2)

Ok so I checked the injectors by doing the click test mentioned above. Sure enough, injectors 1, 3, 4, and 6 didn't click. So I think that is my main problem. I also realized that I got the vacuum/intake lines backwards on the vented optispark, so there was probably a vacuum leak there. I'm hoping that was the issue with my maf. Right now the injectors are soaking in gasoline and I will check them tonight and tomorrow morning. If they still don't click should I just replace them?

92rs85berlintta

iTrader: (1)

I would use injector cleaner instead of gas. replace the o rings or at a bare minimum remove them before soaking, they will swell if you dont. take your air compressor and put about 30lbs to them and have a friend apply the power to the injectors just like you did with the click test. The air will help free up the junk in them. you can get them working good again once you get the debris out. It wont take you long.

caffeine

iTrader: (2)

Ok I tried injector cleaner and also the air compressor thing, still nothing. I just dropped them off at a shop to get them fixed so hopefully that will solve the problem (it better at $30 each).

chevyowner02

iTrader: (3)

Wished I would seen this, I have a good set of stock one's I would have gave you.

caffeine

iTrader: (2)

So it turns out my injectors were beyond cleaning. The guy at the shop showed me the filters and also said that a chunk of one of the injectors had actually rusted away. So in any case I had to get new ones. I know I could have gotten them cheap on-line but I kinda needed them right away because the only 1/4 mile event of the year around here is tomorrow and I've really been looking forward to going.

In any case I installed the new injectors and the engine fired up great right away. It still needs some fine tuning but it's better than I could have imagined. I'm really excited to be driving the car for the first time!

Anyways thanks everyone for the help and advice!