F355 RH Cylinders Not Firing - Any Easy Solutions?

Really, this car has more gremlins than the damn movie some days. So my car was running "fine" and has been for quite some time (> 1 year), now the right hand cylinder bank is not running. No smell of gas leads me to suspect that it is either a relay or fuse to the injector bank... Or that damn ECU is possessed again.

Looking for suggestions... Some days this car drives me nuts.

#1 on my list is battery drain possibly.
#2 Relays
#3 Fuses (didn't see any blown)

I wish these relays had a little LED on top (patent pending, lol) to show when they were actually engaged.

M

 

As a matter of fact, I swapped ignition modules and problem remains on the right side. I was rather hoping it was, as that would be an easy issue.

With regard to the Slow Down ECU/Limp Home it may be in such a state, but I am unsure as to why. The slowdown lights are not illuminated and the Aerospace logic is correctly outputting temps to the display and does not appear to be faulty... which is how I isolated it to the right hand side of the car, before I even touched the headers.

I can see how the limp home could be a result of a cam sensor fault, that would really suck ass, but I do have an O-scope to troubleshoot.

This is a 1997 F355, so being that it is a 1997, there are some differences between this (a 5.2 car) and the 2.7 cars. Number one being that there are not two fuel pumps, fuel ECU's, and associated relays for all those separate things on the 2.7 ECU cars.

I agree that the SRI gold connector kit is a good upgrade and an important consideration for the future, but right now we are talking about a car that was previously running well (and reliably for a significant period of time) and appears to have suddenly stopped injecting on 4 cylinders. Gold connector kit or not, this would have likely still need troubleshooting.

M

 

So the SDL is not the problem, the motronic is pulsing the injectors on the bank that is not running, so either I have no spark being output (doubtful since I am not smelling excess fuel) or I have no fuel flowing through that rail (which I suspect may be the problem).

http://www.aerospacelogic.com/index.php?dispatch=products.view&product_id=220 <- this is what I am using to replace the Slow Down ECU's, the output is 2.0v to the Motronic when below the warning and overtemp temps set in the ECU, (over 1600F) the Aerospace logic output 3.83v (warning) and 4.096v (overtemp) to cause the SD lights to come on properly.

 

Don't have a spare ECU. I wish I did, but I am thinking that it's a fuel flow/pressure problem now.

 

Interestingly, someone mentioned the MAF, which may be a culprit. I disconnected the MAF with no difference in running, but potentially due to the low amount of airflow at idle having nothing to do with the MAF, or that the ECU has a minimum amount of fueling that it is willing to throw at the motor.

I'm a little stumped, time for a beer and some thinking. I also spent $35 on a spare MAF, just to have one around... I don't think it's bad, but for $35, I'll keep a spare around.

M

 

That's next on the list to check... I had my timing light hooked up, was able to see it flash on one bank (obviously the one running), but not on the other.... made me very suspect about it. Fuel looks like it is fine and flowing through the rail, near as I can tell.

Mark

 

Nope, 12v at the coil... Strange, very strange.

 

So let's start over and also list the things that I have ruled out.

This is a 1997 5.2 car
Battery at 12.5 volts, turns over easily.
This means only 1 fuel pump, fuel pump relay, 1 ECU, 1 MAF
Fuel tank gauge reads 1/4 full tank

Ruled out: No blown fuses, all fuel/ECU relays (ECU, ignition circuits, injector power, and fuel pump power relays/fuses).

Things that can shut down the right bank of cylinders?

1. Slow Down ECU failure or output above 4v -

Not an SD ECU problem. Checked, not activated (2.0v output provided by Aerospace Logic EGT gauge). Disconnect the Aerospace logic unit and SD light flashes appropriately.

2. Bad Coil Pack - Not a bad coil pack

Coils swapped, problem remained on RH bank. 12v present at the #2 plug of coil connector w/ ignition on. Did not see evidence of RH bank firing ignition, but could see LH side with old timing light that I don't 100% trust.

3. ECU -

Not yet checked. Could potentially be the problem, no evidence of RH bank ignition firing.

4. Fuel Rail blockage - Uncertain.

Scope used on RH fuel injector suggests that the injector is firing. Do not smell excess fuel. Spraying starting fluid does not clean up the problem. Opened RH rail return, rewarded with minor amount of fuel leakage, probably fine.

5. MAF - ???, no troubleshooting information available.

Could this throw the whole car into limp home mode on the LH bank only?

What else can throw the car into running on only one bank???

 

I have not seen the OBD-II connector... LOL... I looked before and must have missed it. I assume it's by the steering wheel somewhere. I will pull codes in a bit.

 

Found connector, recieved "F... you. Unable to establish a link with the vehicle". Thanks OBD-II scanner... Running to get my backup scanner now... perhaps that one speaks Italian.