[RESOLVED] Help!!! I think my ECU is bad!!!

[94dsmgsx]

I have a 1994 GSX. I bought it just recently with some problems. Upon working on the car, I have discovered that it's only running on two cylinder's. The cylinder's that aren't running are #1 and #2. I checked all wiring to and from the coil packs(which are new by the way) to the power transistor. I pulled all the plugs and grounded them to the valve cover and I'm getting spark on all four.

So my next step was pulling off the fuel rail to check for fuel. When I had it pulled off, I had my friend crank over the motor and injector's #1 and #2 are NOT spraying out any fuel. I switched the injector's from cylinder's #1 and 2 to cylinder's #3 and 4, and same story, the injector's for cylinder's #1 and 2 are still not spraying fuel. So I now know it's not the injectors. WTF is going on.

I really am starting to think it's the ECU not firing the injector's. I don't have a multimeter until Sunday. Tomorrow once I get it, I will check the resistance for the injector's wiring. So my question is what do you guy's think about all of this? By the way, I checked the compression and I posted the numbers below. I checked each cylinder approximately three times with the throttle all the way down. I'm pretty sure the valves are fine. Also I checked the mechanical timing and it's all lined up. I also checked the ignition timing and what I found is the motor, at idle, is 10 degrees BTDC. I'm really confused.

I also want to know if any of you know if the ECU'S on these cars have two injector drivers or four injector driver's in the ECU. If it's a batch fire injection system(I.E. two injector driver's) this would make sense. Anyway's if you guy's have any help for me, please let me know.

CYL#1 CYL#2 CYL#3 CYL#4

136 142 145 145

 

[scooter24]

I dont know if it will help you out or not but I am pretty sure these ecu's are commom for blowing capacitors so you can check that by pulling your ecu apart and look. i dont know friend i wish the best of luch in your venture.

 

[luv2rallye]

You either have a bad CAS (gives injector and spark timing pulses to ECU) or bad ECU. Open ECU first and see if it has a rotten egg smell or capacitors are visually leaking or foil paths blown. http://www.dsmtuners.com/forums/art...585-troubleshooting-fried-ecu-components.html

 

[1SickAuto]

also make sure u have the right firing order, my buddies 91 was doing this and he couldnt figure it out for 2 years until i helped him work on it

 

[94dsmgsx]

The firing order was the very first thing I checked. But yesterday I pulled the ecu out, just eliminate that as a problem and the pictures below show you what I found. It's not pretty. I ordered a new E-PROM ecu from Motoguy's Garage and should have it on Wednesday. So we will see.

 

[steve]

Yep, caps leaked. Other than the leakage it doesn't look too bad. Shame to see a EPROM in that shape but it still looks better than a lot that show up here to be repaired.

 

[94dsmgsx]

OK well I ordered a Socketed EPROM ECU from Motoguy's Garage. I received it today, put it in and to no surprise still not the problem. So I removed the CAS, turned the ignition on and i hear the #3 and 4 injectors firing, but not #'s 1 and 2. So I ordered a new CAS. Please wish me luck as a lot of money has been put into this now. Thanks for all your guy's help.

 

[steve]

I received it today, put it in and to no surprise still not the problem.

Well it wasn't the root problem but there's no question that your ECU was bad.

 

[94dsmgsx]

Well it wasn't the root problem but there's no question that your ECU was bad.

Oh yeah, without a doubt it was bad. At the very least I know my ECU is good now and the new one is Socketed, so that will help. As soon as I get the CAS, I will post what happens. I wanna give a huge thanks to the Wisemen and Members of this forum for all your help!!!

 

[94dsmgsx]

Ok well same ol' story. I replaced the CAS and still only have cylinder's #3 and 4 running. Now for the very weird part, when I remove the CAS and do the manual test on it, all four injector's are clicking/firing and I'm getting spark.

I checked the injector's and their not clogged. Also, the fuel rail is getting fuel to the injector's. I have checked all grounds and fuses. I just replaced the battery. It has new coil packs, plugs, Taylor wires and fuel filter. I also replaced the seals on the injector's.

I'm really at a stump here. Especially since that injectors are clicking/firing. With the old CAS, The injectors on cylinder's #1 and 2 were not clicking/firing. My timing, at idle, is 5 degrees BTDC. The only thing I have a question about is when installing the CAS, the thing that engages with the camshaft, does it matter which way it's turned when installing it? I haven't yet tried to switch it around.

Also, I have not checked the power transistor. I didn't think I needed to, since I am getting a strong spark on all four cylinder's. Please help me as I have searched high and low for a possible answer or explanation and cannot find one. I really don't want to take it to a mechanic.

Thanks,
Ryan

 

[steve]

The only thing I have a question about is when installing the CAS, the thing that engages with the camshaft, does it matter which way it's turned when installing it? I haven't yet tried to switch it around.

http://www.dsmtuners.com/forums/problem-diagnosis/200476-tips-cas-replacement-indexing.html

 

[94dsmgsx]

http://www.dsmtuners.com/forums/problem-diagnosis/200476-tips-cas-replacement-indexing.html

Sorry Steve, I guess I didn't search hard enough. I will re-install it today and post what happens. Thanks for your help.

 

[Black92GST]

hey 94dsmgsx, I hope you're having better luck with your problem than me.

quick question, which part number did you use when ordering the eprom ecu off motoguy's garage?

 

[94dsmgsx]

hey 94dsmgsx, I hope you're having better luck with your problem than me.

quick question, which part number did you use when ordering the eprom ecu off motoguy's garage?

I used #MD193295. I had to cause my car is CA emission's.

 

[94dsmgsx]

Okay so, I put the motor at TDC, took off the CAS, lined up the notch and reinstalled it. When I started the engine, it's starts and idle's a whole lot better, but I still only have cylinder's # 3 and 4 running. Please somebody give me something else to check. I feel as though I have checked everything.

 

[94dsmgsx]

Okay so I found out what is wrong. There is a plug with a metal cover on it, it's mounted on the firewall to the left of the cruise control box. There is four wires coming out of it and two of the wires were apparently chewed by a squirrel or something. Anyway, I soldered them back together and I got my two cylinders back.

Thank you to everybody for all your suggestions.

Thanks,
Ryan

 

[steve]

Okay so I found out what is wrong. There is a plug with a metal cover on it, it's mounted on the firewall to the left of the cruise control box. There is four wires coming out of it and two of the wires were apparently chewed by a squirrel or something. Anyway, I soldered them back together and I got my two cylinders back.

Thank you to everybody for all your suggestions.

Thanks,
Ryan

Four wires? How about five, from the location I'm guessing your talking about the injector resistor pack.