I think my Gen6 dfi is not working anymore

[ChrisChow]

Looks like my gen 6 DFI has given up the ghost. At least I think that's the case.

Here are my issues:
1) The throttle follower seems to reset to the wrong position causing the car to stall (this is intermittent).

2) I think one or more of the injector drivers are not working because I checked the #2 spark plug and it looks like it hardly ever fires. The engine has good compression and I checked for the possibility of a flat cam. Also, I changed coil packs and the ignition module I'm using seems to be in working order. I noticed that at a certain amount of load causes the engine to missfire. I checked for electrical shorts from the harness to the injector and couldn't find anything wrong.

3) I installed the DFI into my other GN just to see if it's the computer and it runs like crap on that car.

4) I also switched to a new injector harness and that didn't seem to help the situation either.

5) On most cold mornings, while warming up, the car definately missfires until I drive a few miles and then it clears up. But, now I get a missfire under partial load to WOT.

6) At WOT, the boost needle fluctuates rapidly (13 to 15 psi). The only time I've seen this before was due to a blown head gasket. But my compression is OK. I will schedule a leakdown (I have a 10 month old baby girl), but I want to eliminate all probable causes.

I will probably go back to the stock computer and see if it's something else in the wiring.

The mods on this car are: TE54, 72lb injectors, mild cam, ported iron heads, walbro 340, 489 rwhp at 19psi of boost.

 

[norbs]

Is this a sequential box or batch? If its batch its impossible for just 1 cyl to not be working.

 

[ChrisChow]

It's a batch fire.

 

[norbs]

Tell me if the coolant temp, tps and intake air temp sensors are wacked out also?

 

[ChrisChow]

Maybe I have to check all the wiring to the coil module as well as all the injector wires.

Usually, when there's a spark problem the plug is fouled and still wet with fuel and carbon deposits all over. The # 2 spark plug comes out looking like it barely fired. It's bone dry and hardly any carbon on the insulator.

I'm pretty sure it's not a blown headgasket as far as I know because I don't get hot spikes on my coolant temp and I never have low coolant situation in the reservoir.

 

[ChrisChow]

Tell me if the coolant temp, tps and intake air temp sensors are wacked out also?

As read on my laptop, the coolant temps match the gauge temp.

I'll check into TPS sensor. I'll check it's full range of operation through the DFI and with a digital volt meter and see if there's something odd.

I'll check into the IAT sensor. (These were out of whack until I bought a new sensor and relocated the air intake tract, but I haven't checked lately).

 

[norbs]

1 injector could have started to plug up and is just sputering fuel in. You would have to swap the injector to another cyl and see if theres any changes.

 

[norbs]

Check if you have 5 volts at the tps incoming, and check the voltages on the dfi view screen, the sensor could be ok at that end, but usually if you have other than close to volt outs there for refernence theres a problem with the box

 

[ChrisChow]

1 injector could have started to plug up and is just sputering fuel in. You would have to swap the injector to another cyl and see if theres any changes.

Good idea. I did pull that injector to see if the screen was clogged, but it looks like this injector didn't come with a screen. I observed what looks like a screw where the screen is usually located.

I'll swap it to #6 or #5, cuz those plugs look like the typical used and abused situations.

Also note that there's a definate missfire situation when using the Gen6 on my 10.60 Grand National that normally runs on the FAST.

 

[ChrisChow]

Just and intereting tidbit is that this Gen6 was purchased from Duttweiler back in 1990. I've never had a problem until several months ago. I've been tuning with a wide band (Innovative Motorsports) and got a really sweet map for her. But this recent issue has been hard to nail down.

I appreciate your feedback! Please keep 'em coming.

 

[norbs]

Well you won't need the fast once you get the lm-1 connected to the gen 6 in narrow band emulation Set the wot correction to 100% and the gen 6 will try and maintain the a/r ratio set in the lm-1. Instead of 14.7 you can set the 500mv set point to 11.5 or anything you want.


I am presently building a plug n play module that will connect the lm to switch between the two analog outputs. So under boost it corrects to analog 1 settings and under cruise analog 2 settiings.


I will put you on the list for testing.......

 

[ChrisChow]

I was thinking about doing this and I believe you posted about this before. But my LM-1 took a crap and I just sent it back to Innovative Motorsports.

I expect my LM-1 to be back any day now. I'd like to try your PNP module anytime

Well you won't need the fast once you get the lm-1 connected to the gen 6 in narrow band emulation Set the wot correction to 100% and the gen 6 will try and maintain the a/r ratio set in the lm-1. Instead of 14.7 you can set the 500mv set point to 11.5 or anything you want.


I am presently building a plug n play module that will connect the lm to switch between the two analog outputs. So under boost it corrects to analog 1 settings and under cruise analog 2 settiings.


I will put you on the list for testing.......

 

[Joe Lubrant]

Just and intereting tidbit is that this Gen6 was purchased from Duttweiler back in 1990. I've never had a problem until several months ago. I've been tuning with a wide band (Innovative Motorsports) and got a really sweet map for her. But this recent issue has been hard to nail down.

I appreciate your feedback! Please keep 'em coming.

Gee Chris "Got your $$$ worth out of that Old ECU".... You think

BTW....you can switch the Injector....but I would never run any injectors without the fine filter screens. If thats the only one with out one, its probably the cause of your problem?

 

[John Wilde]

Gee Chris "Got your $$$ worth out of that Old ECU".... You think

Chris can make a $1 out of 15 cents.

 

[norbs]

I will gladly take it off Chris's hands, time for him to step out of 1985!

 

[EightSecV6]

The boost fluctuation raises a concern. I would look for a broken valve spring or something along those lines.

 

[John Wilde]

The boost fluctuation raises a concern. I would look for a broken valve spring or something along those lines.

Could it be a flattened lobe?

 

[EightSecV6]

Could it be a flattened lobe?

fo sho

 

[ChrisChow]

The boost fluctuation raises a concern. I would look for a broken valve spring or something along those lines.

I'll check. It's a new cam with only 3K miles. When I checked 3 months ago, all the pushrods were rotatating and I didn't see any lame rocker movement. So, it can't be flat cam but I didn't check the valve springs. I'll have to take the rocker covers off again.

Also, I'm going to remove the injectors... I think that's the problema. I installed the FAST system on this car and it fires but won't run. And it seems the Gen6 works on the Idaho Grand National that I have.

It's nice to have more than one turbo Regal for just such cases :smile:

 

[John Wilde]

I'll check. It's a new cam with only 3K miles. When I checked 3 months ago, all the pushrods were rotatating and I didn't see any lame rocker movement. So, it can't be flat cam but I didn't check the valve springs. I'll have to take the rocker covers off again.

Also, I'm going to remove the injectors... I think that's the problema. I installed the FAST system on this car and it fires but won't run. And it seems the Gen6 works on the Idaho Grand National that I have.

It's nice to have more than one turbo Regal for just such cases :smile:

It must be nice to have extra ECU laying around.
Especially mine!
I hope it is not the cam!